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MiceDNA Viral Infections
Non-envelopedAdenovirus DDX:
Mouse Adenovirus-1 Murine adenovirus A Polyomavirus, cytomegalovirus
Mouse Adenovirus-2 Murine adenovirus B Enterotropic runting Intestinal epithelial are unique to Madv-2
EnvelopedHerpesvirusBetaherpes
Mouse Cytomegalovirus Murid Herpesviris -1 salivary glands
Mouse Thymic Virus (MTLV) Murid Herpesvirus -3 INIB Thymus Thymic necrosis, granuloma DDX: Coronavirus or stressPolyomaviridae
Murine Polyomavirus INIB Multifocal necrosis and inflammation
K-Virus liver, lung, brain, spleen
Parvoviridae
Mice Minute Virus (MVM) Kidney, intestine, lymphoid tissue, liver
Mouse Parvovirus 1
Poxviridae
Ectromelia Ectromelia virus (ECTV)
MousePox
RNA Virus
Arenavirus zoonotic
Arterivirus
Coronavirus Murine Hepatitis Virus (MHV)
Paramyxoviridae
Murine pneumovirus (MPV)
Sendai Virus Sendai Virus (SeV)
Picornaviridae
Replicate in nucelus; INIB
Macrophage, endothelial cells, adrenal cortex, renal tubule, thymus
Hemorrhagic encephalitis in susceptible mice; Hemorrhagic enteritis, fatty liver,
wasting disease
thymic involution, necrosis of liver and spleen
Replicate in nucleus and cause cytomegalic
inclusions with INIB and ICIB
Does not cross the placenta, may cause fetal death and resorption, delayed birth,
runts
Eosinophilic INIB, ICIB, in salivary
glands, ;lymphoplasmacytic infiltration of the interstitium,
focal necrosis
DDX for sialoadenitis w/ Inclusions: Polyomavirus, (no inclusions=Reovirus 3, Mouse thymic virus, Mammary
tumor virus)
Salivary gland tumors, kidneys, 40 other cell types
Tumors of mammary gland, salivary gland, thymus, skin
tumors, renal sarcoma, osteosarcoma,
hemangiosarcoma, fibrosarcoma
DDX: Mouse hepatitis, Pneumocystis, Sendai, Pneumonia virus of mice, adneovirus, cytomegalovirus
Murine pneumotropic virus (MPtV
INIB in vascular endothelium
replicates in intestinal capillary endothelium
pulmonary vascular edema and hemorrhage
DDX: Polyoma virus of mouse, adenovirus, cytomegalovirus
INIB in spleen mononuclear cells
hemorrhage, hematopoietic involution, renal papillary infarction
more pathogenic for hemopoietic tissue than MPV; Targets outer granular layer of
cerebellum
similar to MVM, but infects mice of all ages
related- vaccinia, variola, monkeypox, cowpox
ICIB, basophilic to eosinophilic especially
hepatocytes
Direct contact through cutaneous trauma; readily infects placenta and
fetus
spleen, liver, kidney, lung, intestine; amputating lesions, intestinal
hemorrhage, necrosis
necrosis of spleen, liver, lymph node, peyer's patches,
thymus
DDX: Hepatitis, MHV, Tyzzers, Salmonella, bite wounds, alopecia, hypersensitivity, gangrene
Lymphocytic Choriomeningitis Virus
runts, wasting, vasculitis,
glomerulonephritis, lymphocytic infiltration in brain , liver, adrenal,
kidney, lung
necrotizing hepatitis, lymphocytic meningitis
DDX: Lymphoproliferative disorders, amyloidosis, glomerulonephritis, Chronic renal disease
Lactate Dehydrogenase-Elevating Virus Infection
(LDV)
Necrosis of T cell in lymhpoid tissue,
generalized splenomegaly,
lymphadenomegaly
Scattered neuronolysis with apoptosis and perivasculitis, non-suppurative leptomeningitis, myelitis, radiculitis
DDX: Mouse encephalomyelitis virus (MEV), MHV, or retrovirus
hepatic nodular hyperplasia with
parenchymal collapse and fibrosis, splenic
necrosis, Neurologic, vestibular, paresis in immunodeficient mice
necrosis and syncytia of parenchyma and endothelial cells- liver spleen, red
and white pulp, GALT, thymys and bone marrow
enterotropic MHV- depends on age- neonates have villous attenuation,
syncytia, and mucosal necrosis
Residual brain lesions- perivascular cuffing of
lymphocytes and vacuolation/ granulomatous serositis in IFN
deficient mice
DDX: adults- Salmonella, Tyzzers, Mousepox; Neonates- Reovirus, Cytomegalovirus, adenovirus; Enteritis- epizootic
diarrhea, salmonella, Tyzzers, Reovirus; Demyelinating- Mouse encephalomyelitis virus, LDV, Polyoma virus in
immunodeficient mice
Pneumonia virus of mice (PVM)
Mild necrotizing rhinitis, necrotizing
bronchiolitis, non-suppurative interstitial
pneumonia with neutrophils,
lymphocytes and macrophages
Alveolar septae are thickened with edema and macrophages and
leukocytes, and alveolar spaces are collapsed and filled with fibrin, blood and
macrophages and large polygonal mononuclear cells (detached Type II
pneumocytes)
DDX: Pulmonary disease and wasting- Sendai and Pneumocystis murinus (immunodeficient) PVM tends not
to induce bronchiolar hypertrophy like Sendai virus
Infects respiratory epithelium and Type II
pneumocytes
CD-8 Triggered apoptosis of infected cells
Segmental necrotizing airways with inflammation as well as foci of interstitial
pneumonia
neutrophils, macrophages, lymphocytes, fibrin in alveoli,
atelectasis; Bronchiolar epithelium may be
hyppertrophic and hyperplastic prior to apoptosis
DDX: Mycoplasma, Corynebacterium kutscheri. Mild lesions can look like PVM or MHV. Immunodeficient mice
can look like PVM or Pneumocystis murina
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Reoviridae
mouse reovirus neonatal disease
Rotavirus-A (RV-A)
Caliciviridae
Norovirus Murine norovirus (MNV-1)
Retroviridae
general info
MMTV- tropism for mammary tissue
MuSV-sarcomavirus
MuLV Exogenous and endogenous
MMTV
Bacterial Infections
Enteric Infections
Citrobacter rodentium
Escherichia coli Coliform typhlocolitis perineal fecal staining DDX: C rodentium, Helicobacter, Enterotropic MHV
Clostridium piliforme Tyzzer's Disease
Helicobacter hepaticus DDX: Salmonella, Proteus, Tyzzers, MHV, ectromelia
Salmonella Typhimuriumintracellular, in macrophages histiocytic granuloma
Enteritidis
Mouse encephalomyelitis virusMEV or Theilovirus (ThV);
Mouse poliovirus or Theiler's virus
Viral encephalitis and demyelination
attacks neurons and glia; neuronolysis, neuronophagia, microgliosis, non-
suppurative meningitis and perivasculitis
SCID mice have marked vacuolation and enlargement of affected neurons, in the brain stem and ventral horn of a spinal
cord.
DDX: neurological disease- trauma, neoplasia, otitis, MHV, LDV; In immunodeficient mice polyoma virus
Mammalian orhtoreovirus (MRV)
enters through Peyer's patches
Runted, jaundiced, steatorrhea, dorsal alopecia
Diffuse encephalitis with vascular distribution;
Necrotizing myocarditis, necrosis of lymphoid tissue, necrotizing hepatitis, portal
hepatitis, acinar pancreatitis, and sialodacryoadenitis
DDX: Neonatal disease with steatorrhea- mouse hepatitis virus, EDIM virus, Salmonella
Epizootic Diarrhea of Infant Mice (EDIM)
Infects terminally differentiated
enterocytes of villi of small and large
intestine
Loose mustard colored feces staining the perineum
Hydropic change and vacuolation of enterocytes at the tips of villi
DDX: Enterotropic MHV, MAdV, reovirus, Salmonellosis, Tyzzer's disease
Non-pathogenic, tropism for
macrophages and dendritic cells, replicate
in lung liver, and lymphoid organs in
macrophages
Alveolitis, pulmonary edema, coagulation necrosis in liver, minimal inflammation, necrotizing splenitis,
endothelial hypertrophy in STAT1 null mice
Multiofcal mononuclear hepatitis, interstitial pneumonia, pleuritis,
peritonitis
retroelements make up 37% of the mouse genome, most considered genetic parasites. These require transcription
from RNA to DNA- gag, pro, pol, env genes flanked by LTR's
MuLV and MMTV's encode their own
reverse transcriptase and are incorporated
into the genome (provirus)
Most are methylated and transcriptionally silent due to mutation
Other autonomous retroelement flanked by LTR's are: Intracisternal A particles
(IAP's), MusD elements, VL30 elements, glutathione tRNA primer binding sites
(GLN's), and murine endogenous retroelements (MuERV's- include
MuERVC, MuRRS, MuRVY's) These are mi
LINE's are long interspersed nucleotide sequences and
make up 20% of the genome- these lack LTR's
Non-autonomous retroelements must borrow reverse transriptase- they encode no proteins but are flanked by
LTR's (early transposons (Etns), Short interspersed nuclear elements (SINES); Also there are numerous LTR's
with no internal reading frame
Exogenous retroviruses are transmitted horizontally as conventional viruses
Endogenous retroelements are mostly defective, they do represent mobile DNA that can re-integrate in other regions of the genome during cell division withour virion assembly and re-
infectionLTR's encode superantigen gene (sag)
LTR's include enhancers, promotors, which dictate transcriptional acitivty and tissue specificity
incorporate a host cell proto-oncogene that directly alters
cell division
Once in the viral genome they are called
viral oncogenes and may be mutated to
increase their pathogenicity, but also
may be defective
Acute transforming retroviruses have such v-onc genes and are capable of transforming a cell quickly instead of
relying on random insertional mutagenesis
transmitted through milk, semen, saliva, etc
Re-integration into the somatic genome results in random insertional
mutagenesis and neoplasia follows integration near host proto-oncogenes
Mouse lymphoma - B cell and arise in spleen.
Mammary gland neoplasia, lymphocytotropic
insertional mutagenesis transforms
lymphocytes
can be endogenous or exogenous and transmitted in milk
Transmissible murine colonic hyperplasia (TMCH)
hyperplastic, catarrhal colitis; Induce
dissolution of brush border, actin filament
rearrangement, pedestal formation
similar to attaching and effacing E coli (EPEC
and EHEC)
non-flagellated, species specific, requires direct contact, colonizes cecum
and colon, attachment mediated by bacterial intimin and Type III proteins including translocated intimin receptor
(Tir)
bacterial colonization elicits intense mucosal epithelial hyperplasia/ cryptal
cysts that fill with mucin; rectal prolapse; contracted thickended colon, erosion,
multifocal hepatitis and splenitis
Acquired immune response is necessary for clearance but is also a major factor in disease
severity
DDX: hyperplastic colitis, E coli, Helicobacter, enterotropic MHV
Large intestinal hyperplastic lesions,
thickended colon mucosa, mucosal
hyperplasia
red mucosa, inflammation, necrosis
in mucosa and muscularis
multifocal liver necrosis with neutrophils, myocyte degneration, myocarditis,
intracellular bacteria
DDX: MHV, mousepox, salmonellosis, pseudomoniasis, corynebacterium, Helicobacter spp, clostridial enteropathy
Hyperplastic typhlocolitis and hepatitis
4mm white foci in liver, hypertrophy and
hyperplasia of ito cells and oval cells
bile duct hyperplasia, fibrosis, helical microorganisms
mucosal crypt hyperplasia, organisms in crypt lumen
Hepatocellular tumors, typhlocolitis (IBD)
via fibriae to M cells--> phagocytosis by enterocytes--> replication--> to
diarrhea, conjunctivitis, splenomegaly, pale liver foci, fibrinous peritonitis,
venous thrombosis,
DDX: Tyzzer's, coronaviral hepatitis, mousepox, Helicobacter, pseudomoniasis
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Chlamydiae obligate intracellular
Klebsiella
Leptospira
interrogans ser copenhageni focal hepatic necrosis, interstitial nephritis and tubular damage
Mycoplasma M pulmonis Mitogenic for B cells
M neurolyitcum Rolling disease exotoxin conjunctivitis
M Coccoides severe anemia and death
M hemomuris typically infects rats
Lawsonia intracellularis
Pasteurella pneumotropica
Proteus mirabilis Suppurative pyelonephritis Fibrinous peritonitis septic thrombi in vessels
Pseudomonas aeruginosa DDX: Corynebacterium kutscheri, Enterobacter cloacae
Burkholderia gladioli
Coxiella burnetti
Streptobacillus monoliformis Cervical lymphadenitis Rat Bite Fever- potentially fatal zoonotic
Clostridium perfringens large or small intestine necrotizing and hyperplastic changes
Clostridium difficile C diff toxin A and B
Corynebacterium kutscheri hematogenous DDX: Staph, Strep, Mycoplasma (arthritis)
Corynebacterium bovis Hyperkeratosis DDX: Low humidity, some other bacterial dermaitis
Corynebacterium spp Conjunctivitis
Staphylococci Staphylococci Conjunctivitis
pulmonary perivascular and peribronchiolar
lymphocyte infiltration and non-suppurative interstitial pneumonia
organisms grow within bronchiolar epithelium, type 1 alveolar cells,
macrophages,, intracytoplasmic vesicles containing inclusions
Cilia-Associated Respiratory Bacillus
Chronic suppurative cranioventral
bronchopneumonia with marked
peribronchiolar infiltration with
lymphocytes and plasma cells
Warthin starry shows long filamentous bacteria along cilia
associated with viruses like Sendai and PVM
K oxytoca- suppurative female repro tract lesions
old mice with suppurative
endometritis, cystic endometrial
hyperplasia, salpingitis, perioophoritis/
peritonitis (abscesses and adhesions)
interrogans ser icterohemorrhagiae
pulmonary fibrinoid vasculitis, thrombosis, hemorrhage
renal tubular necrosis and interstitial nephritis
Lethal disease, discohesion of hepatic cords, hyperplasia
of Kupffer cells and macrophages,
respiratory and genital tract disease ans sometimes
arthritis
colonizes the apical cell membranes or
respiratory epithelium, exacerbated by viral
infections and Pasteurella
mucopurulent exudate, vestibular signs, bronchiolectasiss, abscessation,
suppurative rhinitis, hyperplasia of mucosal glands
flat epithelium, syncytia, peribronchiolar and
perivascular lymphocytes, metaplasia of respiratory
epithelium
DDX: CAR bacillus, Sendai, Streptobacillus and Corynebacterium (Pneumonia and arthritis)
transmitted by Polyplax serrata- louse
attahced to erythrocytes and free in
plamsa
Proloferative enteritis, typhlitis or colitis
rats hamsters, guinea pigs and rabits
Respiratory, enteric and genital tracts
Conjunctivitis, panophthalmitis, dacryoadenitis,
periorbital abscressation, rhinitis,
otitis, cervical lymphadenitis
Necrotizing dermatitis, mastitis, metritis, UTI, abortions
ddx: fighting injuries, M pulmonis, pneumocystis, Sendai virus
splenomegaly, multifocal hepatic
lesions in SCID mice
Conjunctivitis, nasal discharge
subcutaenous edema and sudden death
ulcerative lymphangitis, vasculitis, thrombosis, necrosis, hemorrhage
Mice that received bovine xenografts
necrotizing hepatitis, with Kupffer cell and Ito
cell hyperplasia, and basophilic cytoplasmic
inclusions
Commensal of respiratory tract
Suppurative embolic nephritis, polyarthritis, osteomyelitis
DDX: pseudomoniasis, corynebacterial, staphylococcal, streptococcal infections, (mycoplasma and
corynebacterium for arthritis)
Non-Type A, type B and Type D
generalized lymphoid apoptosis and renal tubular vacuolation
DDX: Tyzzer's disease, (and hyperplasia- citrobacter, Helicobacter, E coli)
Pneumonia, caseous necrosis
liver, kidney, lungs, lymph nodes
conjunctivitis, thrombosis, gram positive bacilli
lipophilic and grows in keratin
Marked epidermal hyperplasia, orthokeratotic hyperkeratosis ans mononuclear and PMN cells in the
dermis
DDX: Ectromelia virus, Pasteurella pneumotropica, Staphylococcus, Foreign bodies, genetic factors (entropion
etc
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Necrotizing dermatitis
Lymphadenitis
Streptococci Streptococcus Lancefield groups A, B, C, G
Strep agalactiae Group B
Strep equisimilis Group C
Group G
Enterotoccus Lancefield group D enterococcus durans and faecalis
Mycobacteria
M. avium intracellulare
Mycotic Infections
Dermatophytosis
Trichophyton mentagrophytes
Microsporum canis
Systemic and Pulmonary Cryptococcus neoformans B6.129S6-Cybb mice Chronic granulomatous disease
Candida tropicalis B6-p47 Null mice Trichosporon beigelii
ActinomycesGastric
Candida pintolopesii
Canida albicans normal inhabitant
Pneumocytsis murina
Parasitic diseaseEctoparasites
Acariasis fur mites
Myobia musculi hypersensitivity
Follicle Mites Demodex musculiPsorergates rare
Ornithonyssus bacoti tropical rat mite blood sucking intense pruritis
Pediculosis Louse
Polyplax serrata
Eimeria
Cryptosporidium muris
hemolysins, nucleases, proteases, lipases,
hyaluronidase, collagenase
exfoliative exotoxins, leukocidin, Enterotoxins and Toxic shock syndrome
toxin-1
superficial colonization with underlying burn like lesions
B6 mice prone to trichotillomania causing
ulcerative dermatitis followed by colonization with staph and
then necrotizing dermatitis
DDX: other bacterial abscesses, Streptococcal necrotizing dermatitis, amputation of the tail (mousepox)
Gram pos bacteria surrounded by
splendore hoeppli material
(botryomycosis)
Chronic disease can cause multisystemic amyloidosis and
splenomegaly
Group A- bacteremia, cervical lymphadenitis
Group B- Meningoencephalitis, ependymitits, periventriculitis, (from nose), pyelonephritis, septicemia
DBA/2 mice with pyelonephritis and
subsequent bacteriemia with
disseminated lesions to the heart, kidneys,
spleen, liver, uterus, thorax
subcutaneous, hepatic, and abdominal
abscesses
Necrotizing dermatitis with vasculitis and
thrombosis
with Pseudomonas can cause bacteremia in
SCID mice
asymptomatic with subpleural granulomas
DDX: M pulmonis, Corynebacterium kutscheri, Freunds adjuvant lesions
Cuplike crusts on head ears, face, tail, extremities
epithelial debris, exudate, mycelia,
masses of arthrospores, with
underlying dermatitis
Defective NADPH oxidase
Paecilomyces, Aspergillus, Rhizopus, Candida
Defective NADPH oxidase
yeast of the surface mucosa of the glandular stomach
Pseudomemrane formation with epithelial
hyperplasia and hyperkeratosis and
leukocytes
Pseudohyphae in the kersatinized layer
Non-filamentous yeast-like trophic forms
adhere to type 1 pneumocytes
Asci (cysts) are also present and contain 8
ascospores
carriers are asymptomatic and disease presents in immunosuppressed mice
causing pneumonia
Interstitial pneumonia with proteinaceous exudate in the alveolar lumina,
thickening of alveolar septa
3-5 um cysts, irregularly flattened
DDX: viral pneumonia, Sendai virus, PVM, Congestive heart failure
Myobia, Radfordia, Mycoptes, Tichoecius
epidermal hyperplasia and hyperkeratosis
DDX: Pediculosis, trauma, bacterial dermatitis, dermatophytosis, hair chewing, muzzle alopecia
(mechanical)
do not feed on blood but secretions; cause pruritis and self trauma leading to
hair loss and secondary infections
heavy infestations can result in anemia
Protozoal endoparasites
vermiformis, falciformis, papillata, ferrisi
gastric mucosa, relatively non-pathogenic
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Cryptosporidium parvum
Giardia muris lumen of duodenum
Spironucleus muris (formerly hexamita)
Toxoplasma gondii rare in lab mice cats definitive hostsSarcocystis muris rare in lab mice cats definitive hostsKlossiella muris renal coccidiosis
Encephalitozoon cuniculi
Helminths
Oxyuriasis (pinworms)
Tapeworms Rodentolepis nana all use arthropods as intermediate hosts
Hymenolepis diminuta
Rodentolepis microstoma
adults live in cats
Amyloidosis 2 types AA inflammatory response spleen liver intestine and kidney
AapoAII produced by liver
nasal mucosa
Soft Tissue Calcification
BALB/c
C3H
DBA mice
DBA, C3H, BALB
AMP B6, 129
Hyalinosis part of the syndrome
Reye's like Syndrome
Male aggression DBA, Swiss, BALB/c
Stereotypy repetitive funtionless behavior
Barbering tritrichotillomania females> males B6 and A2G self or conspecific can initiate ulcerative dermatitis
small intestine, marginally pathogenic
enteritis secondary to viral infections
cholangiohepatitis with focal hepatic necrosis, peribiliary fibrosis
poor hair coat, distention
commensal inghabitant of intestine
crypts and intervillous spaces are distended, lymphocytes and plasma
cells
microsporidiosis (more like fungi)
granulomatous hepatitis, interstitial nephritis,
meningoencephalitis
spores are gram positive
rectal prolapse, intussusception, fecal impaction, diarrhea
nana also capable of superinfections via direct ife cycles
cysticerci in lamina propria and threadlike adults adults in
lumen
larger and intermediate forms do not appear in the mucosa
as large as diminuta and often exist in bile ducts or pancreatic ducts inciting
pancreatitis and cholangitis
Taenia taeniaformis (cysticercus fasciolaris)
mice ar intermediate host
larval form in stobilocercus (cysticercus fasciolaris)
scolex and segments within a cyst found in the liver (may resemble adult tapeworm)
Nutritional and Metabolic
serum precursor apoSAA
precursors are degraded by macrophages to AA fibrils
DDX: glomerular hyalinosis (agre related), glomerulonephritis, hydronephrosis, spontaneous cardiac
atrial thrombosis
Primary or Senile Amyloid
Adrenals, intestine, heart, lungs, thyroid, parathyroid, ovaries, testes
some say it is not amyloid since it does not stain with Congo red and is trichrome
positive
Epicardial mineralization with fibrosis of the RV free wall
foci of degeneration and mineralization throughout LV
myocardium and IVS
Skeletal myofiber mineralization
epicardial and myocardial mineralization
dystophic mineralization in the aorta, testes, tongue,
muscle, cornea, kidney, stomach, small
intestine, ovary
in the tongue can form inflammatory polyps
Dystrophic mineralization of the superficial corneal stroma
Acidophilic Macrophage Pneumonia/ Epithelial
hyalinosis
focal to diffuse accumulation of acidophilic crystals within
macrophages, alveolar spaces, and airways
cytoplasm packed with needle to rhomboid shaped crystals
Any disease that impairs normal pulmonary clearance can predispose to
AMP
olfactory, nasal respiratory, middle ear, trachea, lung, stomach, gall bladder, bile duct and pancreatic duct
epithelium
In the cytoplasm of epithelial cells, with blebbing and filling of glands
hepatoencephalopathy and fatty degeneration of the
viscera
anticedent viral infections and aspirin therapy are
participating factors in humans
mitochondrial swelling with hepatocyte
dysfunction in the primary lesion
livers are swollen greasy and pale, kidneys are swollen
hepatic lipidosis, Alzheimers type II astrocytes, intestinal lesions associated
with MHV are variable
DDX: BALB/c hepatic fatty degeneration (lesser degree of change)
Behavioral Disorders
The presence of males will synchronize estrus (Witten
effect)
diffuse wounds or centered around the
tail and external genitalia
Bar-mouthing, jumping, circling, somersaulting,
routetracing
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Penis self mutilation B6
HusbandryMechanical muzzle alopecia
Ringtail low humidity
Cotton Sloughing
Spinal fracture cage lid closure
Dehydration check for hydrocephalus
Hypo-Hyperthermia
Frostbite gangrene nude mice proneEar gangrene and Notching Albino Swiss and C3H
Alopecia areata C3H mice
Alopecia of B6 mice behavioral disorder Myobia hypersensitivity
Clown Mouse syndrome weaning age mice runted and general alopecia associated with MHV
Siezures DBA/2, SJL, LP audiogenic siezures
Hypocallosity aplasia of corpus callosum
Hydrocephalus C57Bl
Vacuolation of White Matter fixation artifact
thalamus of old mice
Cochlear degeneration
Spontaneous corneal opacity
Blepharitis and Conjunctivitis suppurative conjunctivitis
C57BL females>males assymetric
Retinal degeneration Homozygous rd-1 allele
Malocclusion B6 hereditaryForeign Body periodonittis
Celft lip palate
Megaesophagus
Gastric mucosal hyperplasia etiology unknownIleus in lactating mice abdominal distention
Liver Problems- incidentalCytomegaly of hepatocytes
Fatty change BALB- normal
age related
Bile duct proliferation
Polyarteritis small to medium sized arteries usually incidental
Vestibular syndrome manifestation of polyarteritis Head tilt, circling
left side usually
Pulmonary histiocytosis lipid laden macrophages
annular constrictions of the tail and feet
necrosis and sloughing of digits due to cotton fibers
require large volumes of drinking water
Massive thymic apoptosis
mice are inefficiaently homeothermic
Massive thymic apoptosis
Aging Degenerative and Miscellaneous
irregular diffuse alopecia of the dorsal and ventral trunk
hairloss increases with age
dense anagen follicles with dystrophic hair follicles, melanin incontinence, interfollicular epidermal thickening,
perifollicular mononuclear leukocyte infiltrates
predispose to necrotizing dermatitis
hyperkeratosis and glabrous skin
neuronal necrosis of cortex, hippocampus, thalamus, generalized
gliosis
centrilobular coagulation necrosis of liverejaculation with retention of urethral
plugs resulting on obstructive uropathy
domes, runted and dehydrated
reduced neuronal proliferation, defects in ependyma, lamination
of cortex, microencephaly
Multilaminated mineralized concretions
acute to chronic inflammatory changes
vascularization, mineralization of corneal basement
membranes
abscessation of meibomian glands
corynebacterium, staph, pasteurella
pneumotropica
Microphthalmia and Anophthalmia
absence or degeneration of rods, outer nuclear layer,
outer plexiform layer,
smooth muscle I nthe abdominal segment
aplasia of the myenteric plexus with fibrosis
Eosinophilic cytoplasmic inclusions
intranucelar cytoplasmic invaginations
polyploidy, karyomegaly, anisokaryoiss, polykarya
Biliary epithelial hyalinosis and crystals
fibrinoid degeneration and necrosis of tunica media
neutrophilic or mononuclear
Atrial thrombosis and heart failure
thrombosis of the auricle leading to heart failure
precipitated by multisystemic amyloidosis
Perivascular lymphoid infiltrates
mild to severe in the adventitia of pulmonary vessels
antecedent to lymphoproliferative disorders
cholesterol or hemoglobin crystals
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Alveolar lipoproteinosis
Alveolar hemorrhage
Aspiration pneumonia
Murine Urologic Syndrome obstructive uropathy
Amyloidosis
LCMV and retroviruses
Hydronephrosis usually incidentsl
renal InfarctionPolycystic disesae BALB/c
Renal tubular hyaline bodies
Inclusion body nephritis
Chloroform Toxicity Renal tubular necrosis mineralization DBA and C3H mice
NSAID nephropathy
Mucometra/hydrometra BALB/c, B6, DBA abdominal distension
Cystic endometrial hyperplasia aged female mice
Adenomyosis oftne extends to serosa DDX- neoplasia
Mammary Hyperplasia virgin female FVB/N
Bulbourethral glands cysts Small pear shaped
sternebrae, vertebrae, femurs aged female B6C3F1 DDX- histiocytic sarcoma, osteosarcoma
NeoplasmsMammary Tumors C3H/HeTesticular Tumorsa 129/Sv
Multicentric lymphoma BALB/cThymic lymphoma AKR
Hepatocellular neoplasia DBA
Lymhphoid neoplasms B cell Precursor B cell
Mature B cell small cell
spleninc marginal zone multifocal in spleen
Follicular B cell
Diffuse large B cell Resemble follicular lymphomas spleen, LN, mediastimum can be histiocyte associated
Burkitt-lymphoma
progressive intraalveolar accumulation of granular pale
eosinophilic phospholipid (surfactant)
hypertrophy and vacuolation of Type II pneumocytes
may overlap with acidophilic
macrophage pneumonia
extravasation of blood into alveolar spaces is common
agonal finding
Freunds adjuvant pulmonary granulomata
cellulitis, paraphimosis, hydronephrosis
prostatitis, cystitis, urethritis,
balanoposthitis
DDX- agonal release of coagulum from accessory sex glands
Chronic Glomerulonephritis/ Glomerulopathy
Membranoproliferative glomerulonephritis
chronic progressive nephropathy (resembles the
disease in Rats)
non-specific basement membrane thickening (glomerular hyalinosis)
glomerular sclerosis, tubular degeneration, regeneration,
interstitial inflammation, dilated tubules with protein
rich fluid
DDX- renal papillary necrosis due to amyloidosis
Hyaline eosinophilic bodies in cytoplasm of tubules
association with histiocytic sarcomas
Homogenous intranuclear eosinophilic inclusions
adjacent interstitial infiltrates of lymphocytes
negative for Polyoma virus, K virus, adenovirus
Males > Females; castration eliminates
sensitivity
Tubular degeneration with mineralization
may progress to chronic nephropathy
Pale kidneys with irregular outlines,
tubular degeneration and atrophy in cortex
and medulla
one or both uterine horns dilated
some have congenital imperforate vagina
DDX- Pyometra, retained fetuses, neoplasia
may be associated with secondary bacterial
pyometras
glandular invasion of the myometrium
at the base of penis and embedded in skeletal muscle
secretions are part of copulatory plug
Cystic glands present as unilateral or bilateral swellings of the perineum
may be suppurative- Staph aureus, Pasteurella pneumotropica
Seminal Vesicular Dilatation and atrophy
Pseudocanalization and Megalokaryocytosis of male
reproductive epithelium
Fibro-osseus lesions in Aged mice
bone marrow replaced by fibroblast like cells
and osteoblasts embedded in an
eosinophilic matrix
can extend into the periosteum; Non malignant
Lymhpoid and NonLymphoid Hematopoeitic Neoplasia
multisystemic, lung , kidney, often with leukemic phase
arise in marginal zones and extend into both red and white pulp
spleens are enlarged; cells have abundant cytoplasm
Most common; spleen, Peyer's patches, Mesenteric lymph nodes
arise from follicles; typicallyu low grade and resemble germinal centers with
large cells
arise from centroblasts in the splenic white pulp, medium sized with scant cytoplasm
Page 8
Burkitt-like lymphoma
Plasma cell PlasmacytomaExtraosseus plasmacytomaanaplastic plasmacytoma
B natural killer cell
T cell Precursor T cell Cd4-/ Cd8-, CD3+ enlarged thymuses
Mature T cell Small cell
T-natural Killer cellLarge cell anaplastic
Non-Lymphoid neoplasms
With maturationWithout maturation
Erythroid leukemiasMegakaryocytic leukemia
Biphenotypic leukemiahematopoeitic sarcoma
Granulocytic
Histiocytic sarcoma
Mast cellMyeloid dysplasia
Myelodysplastic syndrome
Genetic myeloproliferationMyeloproliferative disease
Mammary tumorsGlandular composed of glands
Acinar
Cribriform
Papillary
Solid
Squamous
Fibroadenoma
Adenomyoepithelioma myoepithelium and glands
Adenosquamous
NOS
Pulmonary Tumors
Primary pulmonary Adenoma DDX- focal alveoalr epithelial cell hyperplasia (older mice)
columnar cells
PapillomaSquamous cell carcinoma
Adenosquamous carcinomaneuroendocrine carcinomaHepatocellular neoplasia
Aged males > females A and DBA strains Helicobacter spp
Lymphoblastic . Not Herpes virus associated
medium sized and uniform with scant cytoplasm
Splenomegaly, lymphadenomegaly, not Thymic associated
Myeloid (granulocytic) Leukemias
originates in the spleen, can go to BM,
liver, lung, adrenal. Kidneys
sparing of splenic follicles/ splenomegalylarge vesicular nuclei, round, indented or
ring shaped
Myeloproliferative disease-like myeloid leukemia
enlarged spleen, multifocal nodules in lungs, liver, ovaries, uterus, kidney, bone marrow, lymph nodes
large nuclei and multinucleated giant cells
erythrophagocytosis espiecially in the liver
Cytopenia with increased blasts
Non-reactive Myeloid proliferation
glandular structures with small lumina (MMTV)
MMTV's are either exogenous or endogenous (low grade)
multicentric and multinodular, well
circumscribed, pulmonary metastasis
is common
Sheets or nests forming lumina with round punched out
spaces
fingerlike projections of epithelium covering a central
vascular core
solid sheets of epithelium with little or no glandular
differentiation
Squamous cells with or without differentiation, no
glandular pattern
Myxoid and fibrous stroma and glands
glandular and squamous elements
Does not resemble any of the above
A strain is highly susceptible due to a mutated K-ras allele
enhanced with viral infections such as Sendai
originate from Type II pneumocytes or its
precursor common to Clara cells
closely packed cuboidal to lining remnants of alveolar septa with sparse
collagenous stroma
Cells are non ciliated and may have mucinous differentiation
Primary pulmonary adenocarcinoma
Sub-pleural masses +/- invasion and seeding of visceral and parietal pleura
Hepatocellular adenomas and carcinomas
Antecedent: cell alteration, clear cell foci, basophilic foci, eosinophilic cell foci
grey to tan nodules, trabecular and solid types,
well circumscribed, unencapsulated,
anisokaryosis, karyomegaly, cytomegaly
Page 9
Hepatoblastoma or forming rows and rosettes
CholangiomaCholangiocarcinoma
hemangiomahemangiosarcomaHistiocytic sarcomaIto cell tumors (rare)
Harderian gland tumors
Adenocarcinomas
Myoepitheliomas BALB/c and BALB/cBy Females > Males
Reproductive NeoplasmsFemale
Papillary cystadenomasovarian tubular adenomas
Dysgerminomas rarehemangiomas/sarcomas urterus
adenocarcinomasLeiomyosarcomas
Histiocytic sarcomasMale
Teratomas of the testisExtragonadla teratoma perigenital region
Rhabdomyosarcomas
Mesenchymal tumors
Soft tissue sarcomas Trp53Multicentric osteomas OF-1 mouse
Primary Osteosarcomas lumbosacral region present with posterior paralysis
Endocrine Neoplasms
Pituitary Gland Adenomas B6 and Swiss mice, FVB/N prolactin producing Females > Males
Adrenocortical adenomasPheochromocytomas
Pancreatic Islet tumors
organoid structures arranged around vascular channels
papillary cystadenomas or solid adenomas
slow growing, appear late in life
protrusion of the eye with porphyrin staining
lobulated resilient, light tan to white mass in
the retroorbital space
well differentiated epithelial cells with vacuolated cytoplasm
highly invasive with infiltration of bone and othe rstructures of
the head
Arise from submaxillary and parotid salivary
glands
may also be associated with mammary, preputial, and Harderian glands
Cystic chambers containing serous fluid (necrosis)/ large pleiomorphic spindle cells with epithelial and mesenchymal
features
metastasis to lungs, myeloid hyperplasia of bone marrow
and spleen
granulosa cell and thecal tumors
Uterine endometrial stromal tumors
Sebaceosquamous adenomas and carcinomas
pregutial glands of both males and females
Mesenchymal and Bone Neoplasms
arise from skeletal muscle in BALB/cj, and BALB/cByJ
can be induced by carcinogens and viruses
Moloney Murine Sarcoma Virus
from spinal vertebrae, sternebrae and long bones
metastasis to lung, liver, spleen, kidney
Solid, sinusoidal, cystic, compress overlying brain
Thyroid Follicular cell Adenomas
Page 10
RatsDNA Viral Infections
Non-envelopedAdenovirus DDX:
Mouse Adenovirus MAdV-2
EnvelopedHerpesvirus
Rat Cytomegalovirus
Polyomaviridae
Parvoviridae
Group 1 Kilhams rat virus (RV)
H-3X-14RV-Y
HER virusGroup 2 Toolan's H1
HT
Group 3 Rat Parvovirus (RPV)
Poxviridae
interstitial pneumonia may be cowpox virus
RNA Virus
Coronavirus
Bunyaviridae Hantavirus genus
no disease
HPS
Rat Respiratory Virus
Rats have a serologically related virus but do not have
disease
Intranuclear inclusions in enterocytes
antigenically distinct from CMV
Salivary and Lacrimal glands
cytomegaly with INIB and ICIB
Non-suppurative interstitial inflammation
Serologically distinct from polyoma and K
virus of mice
Pneumonia and sialoadenitis
INIB in ductal epithelium
euthymic rats did not develop disease
scrotal hemorrhage with peritesticular
fibrinous exudation, necrosis and infarction
due to thrombosis
Splenomegaly, liver necrosis,
encephalomalacia
INIB in hepatocytes, endothelial cells and bile duct epithelium
cerebrallar hyoplasia, hepatitis, and jaundice
in neonates
may have reproductive disorders
DDX- pseudomoniasis septicemia, Mycoplasma
pulmonis, trauma
Turkmenia rodent Poxvirus
related to cowpox, distinct from ectromelia
dermal pox and tail amputation
Sialodacryoadenitis Virus (SDAV)
also produce pulmonary disease in
young rats
excessive lacrimation with crusts
parotid and submandibular
salivary glands are swollen
coagulation necrosis of ductal structures
nonkeratinizing squamous metaplasia
of ducts
ddx: Mycoplasma, Sendai, Pneumonia virus of mice
(pneumonia), Pseudomonas (edema), stress events, ammonia
in environment
Parkers Rat Coronavirus
rhinitis, tracheitis, interstitial pneumonia
salivary and lacrimal gland lesions
Necrotixing tracheitis, flattening of
epithelium, loss of cilia
Athymic nude rats develop chronic
wasting
aerosol and contact spread
Hantaan virus (HFRS)
Humans- thrombocytopenia,
myalgia,
Humans- pulmonary capillary leakage
Perivascular lymphohistiocytic
interstitial alveolitis
some neutrophils and type II pneumocyte
hyperplasia
DDX: Sendai, and Pneumonia virus of Mice
Page 11
Paramyxoviridae
Pneumonia virus of Mice
Sendai Virus Parainfluenza 1 Mice, rat, hamster DDX: PVM, RRV, Rat corona,
Picornaviridae
Rat CardiovirusesMHG neurologicRCaV
Rotavirus
Eosinophilic ICIB DDX: E coli
Reovirus
Bacteria
GRAM (-) Enteric
Campylobacter
Lawsonia Intracellularis
Clostridium piliforme Tyzzer's disease
Helicobacter gastritis
Salmonella focal liver necrosis
GRAM (-) Respiratory
uncommon Suppurative Rhinitis
use Warthin Starry stain
Haemophilus
mice, rats, hamsters, guinea pigs, gerbils
Non-suppurative vasculitis and
interstitial alveolitis with necrosis
Perivascular infiltrates, hyperplasia of BALT,
perivasculitis
DDX: Sendai, Rat Respiratory virus, Rat coronavirus
respiratory epithelial necrosis
rhinitis, neutrophils, plasma cells, lymphocytes
hyperplastic to suppurative bronchitis and bronchiolitis with
perivascular and peribronchial cuffing
additive effect of Mycoplasma infections
Infectious Diarrhea of Infant Rats (IDIR)
villus attenuation, necrosis of
enterocytes, epithelial syncytia
Rats do not have disesae, but seroconvert
Young rats with diarrhea
filamentous weak gram negative, spore
forming obligate intracellular
Necrotizing and hemorrhagic ileitis
Enterocyte necrosis, hepatocyte necrosis , myocardial necrosis with neutrophils and mononuclear cells
Dilation of SI with flaccid dialatation
Proliferative and ulcerative typhlitis, colitis, and proctitis
enteritidis and typhimurium
Thickening of gut wall, crypt epithelial hyperplasia,
inflammation, focal ulceration
septicemia, bacterial emboli with fibrin and
exudate
Spleen- focal granulomas, fibrinous exudation and focal
necrosis
DDX- Pseudomoniasis, rotaviral enteritis, cryptosporidiosis,
management issues and Tyzzers
Bordatella bronchispetica
important in guinea pigs and Rabbits
Bronchopneumonia with peribronchial
lymphoid hyperplasia
Maybe concurrent infection with Rat
coronavirus, Mycoplasma
Cilia-Associated Respiratory Bacillus
filamentous argyrophilic bacillus
similar to primary mycoplasma
infections
Chronic suppurative bronchitis and bronchiolitis
Peribronchial cuffing with lymphocytes and
plasma cells
DDX- Mycoplasma , bacterial pneumonia, complications to
Sendai, PVM, RRV, Rat Coronavirus
Page 12
M pulmonis multifocal abscesses
Intestine
GRAM (+) Respiratory
Fibrinous pleuritis
Staphylococcus Ulcerative Dermatitis bacteria in crust
Botryomycosis heads
abdominal distention
Erysipelas
Klebsiella pneumonia Opportunistic
Leptospira
Lung spleen, kidneys
Rat Bite Fever
cystitis, proctatitis
Murine Respiratory Mycoplasmosis
Catarrhal and suppurative
bronchopneumonia
dark plum colored and tan
peribronchial cuffing with lymphocytes, metaplasia and hyperplasia of
respiratory epithelium
genital tract lesions and otitis media
DDX: Corynebacterium kutscheri, CAR bacillus, Pasteurella
pneumotropica metritis
Pasteurella pneumotropica
Rhinitis, sinusitis, conjunctivitis, otitis media, suppurative bronchopneumonia, chronic necrotizing mastitis, pyometra
Corynebacterium kutscheri
Multifocal suppurative /granulomatous
necrotizing pneumonia
(pseudotuberculosis)
Multifocal nephritis and hepatitis
coagulation and caseous necrosis, hematogenous,
interstitial pneumonia,
perivascular cuffing
rib cage, submandibular, neck, ears, head, with hair
loss
hyperplasia of epidermis,
Streptococcus pneumoniae
Fibrinopurulent polyserositis and
meningitis
Suppurative bronchopneumonia
DDX: Corynebacterium, Salmonella, Pseudomonas,
Pasteurellosis
Enterococcus faeciumdurans-2
Enteropathy in Infant Rats
gram postiive bacteria on villus tips of small
intestine
Fibrinopurulent polyarthritis, myocarditis, endocarditis
Mycoplasma haemomuris
formerly hemobartonella muris
transmitted by Polyplax spinulosa
Natural infections are inapparent
abscesses in cervical, inguinal, mesenteric
lymph nodes and kidney
subclinical with no lesions
Pseudomonas aeruginosa
Septicemia, pulmonary edema,
splenomegaly, visceral ecchymoses
Endocarditis, vasculitis with thrombosis
DDX: Corynebacterium kutscheri, Pasteurella pneumotropica, Salmonellosis, Mycoplasma
Streptobacillus moniliformis
Zoonotic, maculopapular rash,
fever, headache, polyarthritis
Bacterial Pyelonephritis/ Nephritis
E. coli, Klebsiella, Pseudomonas,
Corynebacterium, Streptococcus, Enterococcus,
Proteus
Page 13
Brown Norway Rats
Mycotic Infections
Dermatophytosis
Parasitic Diseases
Lice Polyplax spinulosa pruritis, anemia
Holopleura pacificaFleas Xenopsylla
LeptopsyllaNosopsyllus
Mites
Demodex spp
Notoedres muris disfigurment of the ear
Cryptosporidium
Tryanosomiasis Trypanosoma lewisi
Giardia muris small intestine
Spironucleus muris
Helminths
Syphacia obvelata cecum and colon
Syphacia muris
Aspiculuris tetraptera
Other nematodes
urinary tract
Tapeworms
Rodentolepis nana
Pulmonary Lesions of Unknown Etiology
Eosinophilic Granulomatous
Pneumonia
Multifocal pale tan to grey to red foci
Eosinophils, epithelioid macrophages, and
MNGC
Aspergillus fumigatus or niger
rhinitis with epithelial hyperplasia and
squamous metaplasia
fungus found on epithelial surfaces
Trichophyton mentagrophytes
lesions on the neck back and base of tail
Hyperkeratosis, epidermal hyperplasia, folliculitis, arthrospores
in hair shafts,
Pneumocystis carinii/ wakefieldii
alveoli contain foamy pink material with
honeycomb appearance
Numerous black trophozoites and
yeastlike cysts 3-5um in the alveoli
Type II pneumocyte proliferation and interstitial fibrosis
vector for Mycoplasma haemomuris
Radfordia ensifera (myobia ratti)
diarrhea and high mortality
Hyperplastic mucosa and blunted villi with
fusion
infected by ingestioin of fleas or flea feces
giemsa stained blood films
Catarrhal enteritis with weight loss
Pinworms (nematode): Oxyuris
eggs deposited in colon and perianal
area, embryonate and become infectious
rectal prolapse, impactions, diarrhea,
intussusceptions
Trichosomoides crassicauda
found in lumen and bladder mucosa and
renal pelvis
Rodentolepis and Hymenolepis
arthropod intermediate host
Page 14
R. Microstoma
Taenia taeniaformis
Males> females
Nephrocalcinosis various dietary factors
Hydronephrosis
S-D: highly heritable
Urinary Calculi
SPF SD rats M>F
Polyarteritis Aging rats M>F
Hymenolepis diminuta
Cysticercus fasciolaris is the
larval stage
eggs ingested--> migrate through
bowel--> encyst in liver of mice
(cysticercosis)
Cat eats mouse and becomes Taenia
taeniaformis
Sarcomas may develop around the
cysticerci
Aging and Degenerative
Disorders
Chronic Progressive Nephropathy/ Nephrosis
pitted and irregular with pallor
chronic glomerulopathy/
glomerulosclerosis/ interstitial fibrosis
proteinuria/casts/ PAS positive hyaline
droplets
secondary changes: Hyperparathyroidism,
mineralization
Nephrotic syndrome- hypercholesterolemia,
hypoproteinemia, BUN/CT
Brown Norway Rat- autosomal
polygenetic disorder
Gunn Rat_ autosomal dominant
may be due to urethral obstruction by sperma
DDX: pyrelonephritis, polycystic kidneys,
renal papillary necrosis
don’t confuse with agonal copulatory
plugs
Hematuria/ renal Papillary Hyperplasia
associated with hydronephrosis
renal papilla have focal proliferation with
necrosis and hemorrhage
Myocardial Degeneration and
Necrosis
ventricular hypertrophy and pale streaks
vacuolation of the cytoplasm.
Fragmentation of sarcoplasm, loss of
cross striations, mono-nuclear cell
inflammation
interstitial fibrosis with proliferation of fibrous
tissue
Mesenteric vessels, tortuous and thickened
microscopic lesions not in lung
fibrinoid degeneration and thickening of the
media of affected arteries with smudging
of the normal architecture
mononuclear cells with few neutrophils,
thrombosis
Alveolar histiocytosis/ Alveolar proteinosis
dull pale yellow foci, subpleural
Intra-alveolar macrophages with
needle shaped crystals and
vacuolated or homogenous
eosinophilic material
Degenerative nervous system changes
Wallerian degeneration in focal
areas of the spinal cord
Segmental demyelination of the peripheral nervous
sytem
Spontaneous radiculoneuropathy-
spinal root degeneration with
muslce atrophy of the lumbar region and hind
limbs
Page 15
Liver changes
Malocclusion spontaneous/genetic
Ringtail
Dehydration
Retinal Degeneration
Corneal lesions
Bedding
Chloral Hydrate Ileus
Auricular Chondritis SD/ Wistar Rats
Neopalsia
anemia and icterus
Lymphoma/ Leukemia
Polyploidy, megalokarya,
binuclear hepatocytes, intranuclear cytoplasmic
invaginations
Focal sinusoidal dilatation and peliosis, either spontaneous or
drug induced
Bile ductular proliferation, lined by atrophic epithelium,
surrounded by collagenous tissue
Miscellaneous Disorders
secondry to poor alignment of upper and lower incisor
teeth
cellultis and salivation are sequela
Annular constrictions of the skin of the tail
leading to dry gangrene
attributed to low environmental
humidity
genetic factors, low environmental temps, degree of hydration, and nutrition may be
involved
Epidermal hyperplasia with
orthokeratotic and parakeratotis
hyperkeratosis
Dilated and thrombosed vessels, necross,
hemorrhage
accompanied by porphyrin staining
around the eyes (sign of stress)
albino rats are predisposed due to unpigmented uveal
tracts
progressive reduction of photoreceptor
nuclei in the outer nuclear layer of the
central retina
Advanced disease has marked depletion and alteration of the retinal
layers with cataract formation
this muct be distinguished from peripheral retinal
degeneration (inherited disorder)
Conjunctivitis- Pasteurella,
environmental factors
Lacrimal gland dysfunction- following rat coronavirus- virus
damages the harderian gland (KCS)
dusty bedding predisposes to
aspiration pneumonia
Multinodular, granulomatous
inflammatory foci with chondrolysis and
invasion by mesenchymal cells
Large Granular Lymphocytic Leukemia
Splenomegaly with erythrophagocytosis
DDX- Lymphoma and histiocytic sarcoma
Splenomegaly, enlarged lymph
nodes, hepatomegaly
Cutaneous Lymphoma (mycosis fungoides)
circumscribed erythematous
plaques pregressing to ulceration
epitheliotropic/ medium to large size,
T cell lymphocytes and dissociated
adjacent epidermal cells
Page 16
Histiocytic Sarcoma SD/ Wistar Rats
Mammary Tumors
Fibroadenoma
Carcinoima rare variety of patterns
Pituitary gland tumors
Chromophobe adenoma pars distalis
Testicular Tumors
Interstitial cell tumor F344 older males lobulated light yellow`
Mesothelioma F344
Zymbals Gland Tumors
Other
Liver, LN, Lung, Spleen, Mediastinum,
Retropertoneum
Vesicular nuclei, ample cytoplasm, MNGC
morphology varies from sheets to pallisading and
streaming fusiform cells
SD females; recurrence is likely
retroviruses not involved
circumscribed moveable firm lobular
mass
interlobular and intralobular
connective tissue
may consist of primarily connective tissue, or
epithelial cells predominate
majority/ SD/ Wistar rats
IHC required for positive identification
Prolactin secreting tumors most common;
may contribute to mammary tumors
polyhedral to elongated cells with granular
vacuolated cytoplasm
also have smaller cells with
hyperchromatic nuclei and scant
cytoplasm
concurrent hypercalcemia
Tunica vaginalis of testis
Holocrine gland at the base of the ear
circumscribed and ulcerated
sheets of epithelial cells with abundant
vacuolated cytoplasm, with necrosis and
leukocytes
adenoma or adenoacarcinoma
Polyhedral cells and acinar structures
containing keratinized material and debris
Page 17
HamstersDNA Viral Infections
Non-envelopedAdenovirus
General Ileal enterocytes
EnvelopedHerpesvirus
Cytomegalovirus Acinar epithelium cytomegaly with INIB and ICIB
Parvoviridae
Missing incisor teeth
Polyomavirus
Transmissible Lymphoma Hamster Polyoma Virus can be papilloma like
Lymphoma liver, kidney, thymus
RNA Virus
Arenaviral infection
Paramyxovirus unknown significance
Sendai virus
Bacteria
Large amphophilic intranuclear inclusions,rarely
in crypts, asymptomatic
Salivary and Lacrimal glands
H-1: necrosis and inflammation of dental pulp with mononuclear leukocytic
infiltration of the dental lamina and osteoclasiss of
alveolar bone
New Strain: enamel hypoplasia,
periodontitis, suppuration and mineralization,
hemorrhage in dental pulp
Multifocal cerebellar and cerebral hemorrhage and thrombosis with
transmural hemorrhage
keratinizing skin tumors of hair follicle origin
Non glabrous skin- keratinizing follicular structures reminiscent of
trichoepitheliomas
Abdominal masses, large lymph nodes
usually lymphoid but erythroblastic, reticulosarcomatous, and myeloid types
have been described, sometimes plasmacytoid features
Lymphocytic Choriomeningitis (LCM)
chronic wasting, lymphocytic infiltration into the liver, lung, spleen, meninges, and brain
vasculitis and glomerulitis with Ag/Ab complexes in glomeruli
Zoonotic (mild influenza like to meningitis)
Pneumonia virus of Mice (PVM)
Interstitial pneumonia with consolidation
Segmental rhinitis --> necrotizing tracheitis and
bronchoalveolitis
antigen in respiratory epithelium
hyperplasia of epithelium follows infection plus peribronchiolar
lymphocytes
Page 18
GRAM (-) Enteric
Campylobacter jejuni Zoonotic
Lawsonia intracellularis soiling of perineum
Tyzzer's Clostridium Piliforme intracellular
E coil
Helicobacter
Salmonella Embolic glomerulonpehritis
Gram (+) Enteric
Clostridium difficile
Non-Antibiotic-associated Clostridium difficile high fat diet
Gram (+) Respiratory
Corynebacterium kutscheri oral cavity, lymph nodes
Streptococcus pseumoniaeS. agalactia
Gram (-)
co infection with Lawsonia
Runted and emaciated hamsters
Segmentally thickened ileum with prominent serosal nodules and fibrinous peritoneal
attachments
marked crypt and villus epithelial hyperplasia, villus elongation
varying necrosis and hemorrhage, crypt abscesses, granulomatous
inflammation
Hepatic necrosis, Ileum , cecum, colon
focal granulomatous myocarditis with conspicuous bulging nodules
DDX: Salmonella, Coliform enteritis, Antibiotic associated C difficile,
Campylobacter
yellow to dark red fluid, blunting and fusion of villi,
lined by cuboidal epithelium
neutrophilic inflammation
focal necrosis fo liver, with neutrophils
DDX: Clostridium, Lawsonia, Salmonella
Gastric antrum and pyloric duodenal
junction
Gastric mucosal hyperplasia to dysplasia
may progress to carcinoma
Proliferative and dysplastic typhlocolitis
mucosal thickening and sibmucosal edema,
hypertrophy of enterocytes
Cholangiofibrosis (H Cholecystis)
Liver: Pinpoint necrosis, with thrombosis
Lung: hemorrhage, interstitial pneumonia, and thrombophlebitis
Spleen: focal necrosis and splenitis
Antibiotic -associated Enterocolitis
Lincomycin, clindamycin, ampicillin, vancomycin,
erythromycin, cephalosporins, gentamicin,
penicillin
cecum is distended with gas and tan to red
fluid contents
mild pseudomembranous typhlitis. Effacement of epithelium, edema
of LP, mucosal hyperplasia
DDX: Salmonella, Enteropathogenic E Coli, Tyzzer's dz
Necrotizing to hemorrhagic typhlitis
Cecal mucosal hypertrophy of Unknown etiology
ceca ar congested contracted and opaque
increased mitotic activity and hyperplasia of enterocytes
lining the crypts
local granulomatous and suppurative lesions
Page 19
Francisella tularensis
Leptospira ballum
Yersinia pseudotuberculosis
Mycoplasma pulmonis
Mastitis
StrepP pneumotropica
E coli
Actinomyces bovisStaphylococcus aureus
StreptococcusPasteurella pneumotropica
Parasites
Ectopic Mites (Acariasis)
Demodex cricetiaurati
Notoedres notoedres
Notoedres cati
Myiasis
Wohlfahrtia vigilSarcophaga haemorrhoidalis
Musca domestica
Endoparasites
Spironucleus muris intestinal flagellate incidental findingCryptosporidium
Giardia misocricetus
Giardia muris mostly asymptomatic
Microscporidia
ruffled fur, lungs had mottled hemorrhage,
livers pale and seollen, spleens enlarged
Lymphoid necrosis and focal hemorrhages and bacteria
hemolysis, jaundice, nephritis, hepatitis
Chronic emaciation with intermittent diarrhea
Caseous nodules in intestine, mesenteric lymph nodes, liver, spleen, and lungs
Pasteurella pseumotropica and others
URI, Otitis, Bronchopneumonia
Cutaneous and cervical abscess
burrows in stratum corneum
Ornithonyssus bacoti and sylvarium
chronic lesions- thickening of SI cecum and colon
Encephalitozoon cuniculi
Page 20
NematodesPinworms Syphacia criceti
S mesocricetiS obvelata more common
S murisTrichosomoides nasalis
TapewormsCysticercus fasciolaris (Taenia taeniaformis) dogs and cats
Rodentolepis microstoma Lower small intestineNana Lower small intestine
Hymenolepis diminuta upper small intestine
Stillborn or weak Vitamin E related/ deficiency
Diabetes Mellitus
DDX: trauma and cannibalism
Malocclusion
Periodontal Disease
Pugilism Females are aggressive Chinese hamsters
Cannibalism
Hibernation and Estivation
Nutritional and Metabolic Disorders
Spontaneous Hemorrhagic Necrosis (SHN) of the CNS of
fetal hamsters
Prosencephalon: Symmetrical, subependymal, vascular degeneration, with
edema and hemorrhage
intraventricular hemorrhage
strain related variations to susceptibility
Recessive in Chinese hamsters
Weight loss, glucose intolerance, hyperglycemia,
polyuria, polydypsia, hypoinsulinemia, ketonuria
Environmental Genetic and
Other Disorders
Bedding-associated Dermatitis
Wood shavings- footpads
degeneration and atrophy of the digits, with granulomatous
inflammation
necrosis and ulceration with foreign
body dermatitis
Congenital/ Hereditary Hydrocephalus
No obvious changes in behavior
doming of the calvaria was absent
stenosis of cerebral aqueduct
Inconsistent and permissive
Low temps, short days, solitude, nesting material,
inadequate food stores
high temps, low water may stimulate
estivation
Age related disorders
Page 21
Amyloidosis (older animals) Females > Males
Atrial Thrombosis Left auricle and atrium
Alveolar Histiocytosis
Neoplasia
Lymphoma
epidermotropic
Adrenocortical adenomas
Hamster Glomerulopathy (arteriolar Nephrosclerosis)-
young animals
Gross: Pale granular with irregular cortical
depressions; radiating cortical scarring
Histo: Thickening of BM with eosinophilic material
may be concurrent amyloid in advanced
lesions
variable degeneration of tubules and minimal inflammatory
response, proteinaceous casts, fibrinoid change in vessels
Hamster female protein similar to Amyloid P
Gross: pale, irregular granular capsule, livers are swollen
Histo: Amyloid in glomeruli, tubular BM, portal triads, intestine
often associated with amyloidosis
bilateral ventricle hypertrophy is
common
focla to diffuse myocardial degeneration; medial
degeneration and calcification of coronary arteries
Polycystic Disease (polycystic Liver Disease)
Multiple Hepatic cysts in older hamsters
epididymis, seminal vesicles, pancreas, endometrium
Cysts are thin walled containing clear straw colored fluid lined by flattened to cuboidal
epothelium
pressure atrophy of hepatic cords, hemosiderin, proliferation of bile
ducts, periportal lymphocytic infiltration
Bile Ductular Hyperplasia/ Hepatic cirrhosis
spontaneous, uniform nodularity, periportal
fibrosis, bile duct proliferation
nodular hepatocellular degeneration, necrosis, and mixed leukocyte infiltration
Fibrinoid degeneration of arterioles
Polyoma virus or spontaneous
spontaneous tumors are Multicentric, thymus, lymph
nodes, spleen, liver
Cutaneous Lymphoma resmbling mycosis fungioides
Page 22
GerbilsVirus
Reovirus type 3
Bacterial Infections
Tyzzer's Disease Clostridium piliforme
Clostridium difficile
Citrobacter rodentium goblet cell hyperplasia
Salmonella typhimurium diarrhea, dehydration high mortality
Group D
Staphylococcal dermatitis Staph aureus
Nasal Dermatitis S Aureus and S xylosus dermatitis and alopecia may become ulcerative
Bordetella bronchiseptica
asymptomatic
Leptospirosis not natural infection
Helicobacter pylori
Parasitic DiseasesDemodexGiardia Upper small intestine
degenerative lesions in pancreas and focal
necrotic lesions in the CNS
Multifocal periportal necrosis in liver with neutrophils and macrophages/ Focal fibrosis
Ileum and cecum, necrosis and
sloughing, blunting, edema, neutrophils and macrophages,
focal Peyer's patch necrosis, lymph node mecrosis, myocardial necrosis with myofiber collapse,
and leukocyte infiltration
diffuse suppurative encephalitis
DDX: Cl. Difficile, salmonella
Antibiotic associated enterocolitis
following Amoxycillin and Metronidazole
bloody diarrhea, thickening of the colon and rectum
testicular enlargement, focal hepatitis, splenic necrosis,
suppurative orchitis, interstitial pneumonia
pyogranulomatous leptomeningitis
gross- moist dermatitis of face, nose, feet, legs, ventral
abdomen
Histo- suppurative dermatitis with acanthosis and hyperkeratosis
porphyrin containing lacrymal secretions
have been an important contributing
factor
older animals are resistant, younger animals can have severe mortality
Ciliary Associated Respiratory Bacillus
Acute didsease- hemolytic anemia,
icterus, centrilobular liver necrosis, necrosis
of renal tubules
Chronic- Renal interstitial fibrosis, inflammation, cysts,
chronic gastritis, gastric ulcers, gastrointestinal
metaplasia, gastric adenocarcinoma
Page 23
Pinworms no clinical problems
Tapeworms Rodentolepis nanaGenetic Disease
Epilepsy
MalocclusionBehavioral disease
Streptomycin Toxicity
Lead Toxicity
Amyloidosis filariid worm liver, spleen, lymph nodes
Obesity and diabetes
only bred animala
Age related disease
necrosis and fibrosis
Dentostomella translucida
no histopathologic lesions
twitching of vibrissae and pinnae, motor arrest,
myoclonic jerks, clonic-tonic siezures, vestibular
alterations
Periodontal disease and dental caries
Toxic and Metabolic Disorders
Direct neuromuscular blocking by inhibition of acetylcholine release
Chronic progressive nephropathy with acid
fast intrnuclear inclusions in renal proximal tubular
epithelium
Lipofuscin pigment granules in hepatocytes and Kupffer
cells
microcytic hypochromic anemia
with basophilic stippling
DDX: Age related glomerulonephropathy, and
erythrocytic basophilic stippling
reduced glucose tolerance, elevated
insulin, and hyperplastic or degenerative changes in the
endocrine pancreas
Hyperadrenocorticism/Cardiovascular disease
plaquesof intimal and medial ground substance with
mineralization of the aorta and mesenteric, renal, and
peripheral arteries
elevated serum triglycerides, enlarged pancreatic islets. Fatty
livers, thymic involution,
pheochromocytoma
focal myocardial necrosis and fibrosis
Focal myocardial degeneration
Page 24
Chronic glomerulopathy
Aural cholesteatoma
Cystic ovaries
Ocular proptosis
NeoplasmsMongolian gerbils Ovarian
Adrenocorticalcutaneous
Granulosa cell tumorsDysgerminoma
luteal cell tumorsleiomyomas
thecal cell carcinoma
males, ventral marking glands
Other species
thymoma
Hodgkin-like lymphoma
adrenocortical tumorsprimary ovarian tumors
Helicobacter pylori Gastric carcinoma
glomerular hypercellularity,
thickening of glomerular basement membranes, tubular degeneration
with dilatation and cast formation, mononuclear
cell interstitial inflammation
Keratinized epithelium arising from outer
tympanic membrane and external auditoryt
canal
displaces tympanum into moddle ear with compression and secondary inflammation resulting on destruction of
temporal bone and iner ear
head tilt and keratin plugs in external ear
canal
ovulation and corpus luteum formation
continue
protrusion of the nictitating membrane and conjunctiva with
bulbar proptosis
Marking gland adenocarcinoma
Squamous cell carcinoma
Uterine adenocarcinoma
Page 25
Guinea Pigs
Kurloff cells NK counterpart
normal
normal
Osseous metaplasia in lungs not significant
Thymus
DNA Viral InfectionsNon-enveloped
Adenovirus
Adenoviral Pneumonia
EnvelopedHerpesvirus
Cytomegalovirus CMV group
kidney cell cultures
Guniea Pig X virus (GPXV) isolated from leukocytes
RetrovirusCavian Leukemia Retrovirus Type C
RNA Viral Infections
finely granular cytoplasmic inclusions
found in spleen and bone marrow and
thymus
Pulmonary arterial medial thickening
Adventitial lymphocytes in pulmonary vesels
lamellar bone with varying degrees of calcification
degenerate thymocytes near Hassals corpuscles
Cardiac glycogenosis (Rhabdomyomatosis)
incidental degenerative condition and
congenital tissue malformation with
blastemoid features
pale pink poorly delineated foci or streaks mostly in left
ventricle
Low morbidity and mortality
consolidation of cranial lung lobes and hilus
necrotizing bronchitis and bronchiolitis with
desquamation of lingin epithelial cells and
leukocytic inflammation with fibrin
Intramuclear round basophilic 7-15 um
inclusions
DDX: Parainfluenza, cytomegalovirus,
bacteria (bordatella)
humans, primates, mice, rats, guinea pigs
Karyomegaly and intranuclear and intracytoplasmic
inclusions
Ductal epithelial cells, salivary glands, kidneys,
liver, lung
Guinea pig herpes-like virus (GPHLV)
focal hepatic necrosis and mortality
Page 26
Arenavirus
Coronavirus-like Infection
Parainfluenza-3 (PI-3)
Paramyxovirus
Sendai virus
Picornavirus
Murine Poliovirus LamenessBacterial Infections
Enteric Infection
Clostridial disease Clostridium difficile enterotoxin recovered
necrosis of epithelium
Clostridium piliformeC difficile
Tyzzer's Disease Clostridium piliforme organisms in enterocytes
Lawsonia intracellularis
Salmonella typhimurium
enteritidis
Pseudotuberculosis
Lymphocytic Choriomeningitis (LCM)
lymphocytic infiltrates in the meninges, choroid plexi,
ependyma, and liver, adrenals, lungs,
Typical lesions and disease
interstitial pneumonia and alveolitis with
pulmonary congestion and hemorrhage, relative sparing of
airways
Pneumonia virus of mice
Murine Encephalomyelitis Virus
strain GDVII
Antibiotic Associated Dysbacteriosis (antibiotic
toxicity)
cecum atonic and dilated with fluid and gas,
mucosa is hemorrhagic and edematous
hyperplasia of the mucosa with
mononuclear cell infiltration on the LP
Spontaneous Clostridial Enterotyphlitis
Clostridium perfringens Type A
necrotizing ileitis and typhlitis, frequently
transmural
Adenomatous Intestinal Hyperplasia
intracellular bacteria in enterocytes
multifocal pale foci in liver and spleen
necrotizing fibrinous enteritis, colitis
granulomatous hepatitis, splenitis, lymphadenitis
Yersinia pseudotuberculosis
acute form: miliary cream-colored nodules in the
intestine wall in ileum and cecum
subacute to chronic: miliary caseous
nodules in mesenteric lymph nodes and
spleen, liver and lung
Page 27
Respiratory Infection
Bordetella bronchiseptica
Citrobacter fruendii
Klebsiella
Pseudomonas aeruginosa sulfur granules
Streptobacillus moniliformis
Staphylococcus
Staphylococcus dermatitis
Streptococcus zooepidemicus group C suppurative lymphadenitis
S. pneumoniae
Bacterial SyndromesOtitis media S pneumonia
S zooepidemicusBordetella
PseudomonasBacterial Mastitis E coli
Klebsiella
mucopurulent or catarrhal exudate in
nares, nasal passages, and trachea
pleuritis, typanitis, chronic suppurative
bronchopneumonia, heterophilic, obliteration of
normal architecture
Guinea pig Inclusion Conjunctivitis
Chlamydophila caviae (formerly Chlamydia
psittaci)
red conjunctiva, purulent exudate, sloughed
epithelium, intracytoplasmic inclusioins and bacteria
pneumonia, pleuritis, enteritis
septicemia, necrotizing bronchopneumonia, pleuritis, pericarditis,
peritonitis, splenic hyperplasia
Pulmonary botryomycosis
cervical lymphadenitis, pyogranulomatous bronchopneumonia
Ulcerative pododermatitis (bumblefoot)
secondary to trauma, poor sanitation
plantar surface is swollen and painful
with necrosis
amyolid in the spleen, liver, adrenals and islets
in rare cases
erythema, hairloss, scabs, ventral abdomen
and extrematies
epidermal cleavage, parakeratosis
abrasions in oral mucosa
cervical lymph nodes, retrobulbar abscess, otitis
media, bronchopneumonia,
pericarditis
Diplococcal (pneumococcal) infection
no toxins, just resistant to phagocytosis
fibrinopurulent pleuritis, pericarditis,
peritonitis
bronchopneumonia with fibrin
ddx: Strep, Bordetella,
Page 28
Strep zooepidemicusBacterial Conjunctivitis Chlamydia
Strep zooepidemicusStaph aureus
Pasteurella multocidaMycotic infections
Dermatophytosis
Microsporum canisParasitic Diseases
Ectoparasites
Acariasis Trixacarus caviae Sarcoptic mange
Demodex caviae
Pediculosis (lice) Gliricola porcelli Large biting lice
Gyropus ovalisEndoparasite
Protozoa Cryptosporidium wrairi juveniles
Eimeria caviae
Klossiella cobayae renal coccidiosis
Trichophyton mentagrophytes
scaly pruritic, alopecia, hyperkeratosis, epidermal
hyperplasia, pustules, folliculitis, arthrospores
inner thighs, neck , shoulders, abdomen
ortho and parakeratosis, heterophils, eosinophils,
flaccid paralysis, epidermal hyperplasia,
stratum corneum contains mites and eggs
pruritis, rough hair coat, alopecia
thin, potbellied, fecal staining, jejunum,
ileum, cecum
hyperplasia of crypt epithelium, edema of
lamina propria, necrosis and sloughing of
enterocytes, villous atrophy
intestine contains fluid, mucosa is congested,
edematous, with petechia
colonic hyperplasia, sloughing of
enterocytes, PMNS and mononuclear cells
micro and macrogametocytes
ddx: Crypto, clostridium,
dysbacteriosis
schizogony in endothelium of
glomerular capillaries--> rupture -->
schgizogony repeated in tubular epithelium
Gametogeny occurs in epithelium of Loops of Henle--> sporulated
occysts are released in urine
oocysts are ingested and invade intestinal capillaries--> kidneys
Page 29
Toxoplasma asymptomatic
Helminth Baylisascaris procyonis
Paraspidodera uncinata asymptomatic
Scurvey Hypovitaminosis C
Encephalitozoon cuniculi
(microsporidiosis)
granulomatous encephalitis, interstitial nephritis
hepatitis, pneumonia, myocardial cysts, CNS
cysts
larval migrans- cerebral malacia, eosinophilic
granulomatous inflammation with nematode larvae
cecal worms up to 25 mm in length, also located in colonic
mucosa
Nutritional, Metabolic and others
deficient in L-gulonolactone oxidase (converts L-
gulonolacotne to L-ascorbic acid)
primates, guinea pigs, indian fruit bat, some birds, some fish, and
cetaceans
required for formation of hydroxyproline and
hydroxylysine in collagen molecules
deficient in interstitial and osteoid production
C is required for cholesterol to bile acid
formation
Lesions: Persistent primary spongiosa
(retained cartilage cores), and reduced osteoid production. Calcified
cartilgae is susceptible to microfractures
increased capillary fragility
enlargemnet of costochondral junction with hemorrhage;
proliferation of poorly differentiated fusiform mesencgymal cells in periosteal regions and
medullary cavity;; aggregates of eosinphilic mateiral
interspersed between the mesenchymal cells; dental anomalies- fibrosis of pulp
and derangement of odontoblasts
periarticular hemorrhage
widening of intercellular spaces between
endothelial cells, vacuolar degeneration and
depletion of subendothelial
collagenous tissue// Increased pro-thrombin
time
Page 30
Necrotizing myopathy
Nutritional muscular dystrophy Vit E/ Se deficiency
Metastatic Calcification > 1 year old
end of pregnancy
Diabetes Mellitus
Alopecia back and rump
Malocclusion molar and premolars genetics and fluorosis
Gastric dilatation and vovlulus
hemosiderin laden macrophages in lamina propria of
intestine
increased susceptibility to streptococcus
pneumoniae (impaired macrophage migration
and heterophil phagocytosis)
idiopathic necrosis with leukocyte infiltration,
loss of cross striations, and mononuclear cell
infiltrate
DDX: nutritonal muscular dystrophy, spontaneous
muscular mineralization with degeneration
pallor of affected muscles, coagulative necrosis and hyalinization of myofibers,
fragmentation of sarcoplasm, increased basophilia of
sarcoplasm, rowing of nuclei, and regeneration
multinucleated muscle fibers may be present
in regenerating myofibers,
mineralization is not an important feature
testicular degeneration is a later development
Myocardial and Skeletal Muscle Degeneration with
mineralization
may be incidental finding
soft tissues around the elbows and ribs
lung, trachea, heart, aorta, liver, kidney, stomach, uterus,
sclera
low magnesium and high phosphorus(high Ca and P diets interfere with Mg
absorption)
Pregnancy Toxemia (Hepatic lipidosis with ketosis)
Fasting or Metabolic Form
acidosis, ketosis, proteinuria, ketonuria, low urine pH
(acidosis)
lowblood glucose, ketosis, hyperlipidemia
Circulatory or Toxic form (preecclampsia)
uteroplacental ischemia due to
compression of the aorta
placental necrosis, hemorrhage, ketosis, and
death, periportal liver necrosis, leukocyte,
nephrosis,
infectious agent unidentified
vacuolation of and degranulation of islet Beta cells with fatty infiltration of
the exocrine cells
advanced pregnancy and lactation
ddx: barbering, pediculosis,
dermatophyte
Page 31
Cecal torsionIntestinal hemosiderosis lamina propriaFocal Hepatic necrosis Subcapsular considered terminal ddx: Tyzzer's
Liver contusions traumatic fractures
Behavior
Diseases of Aging
Segmental Nephrosclerosis interstitial lymhpocytes
Cystitis and urolithiasis
Ovarian cysts
Fatty infiltration of pancreas
Neoplasia'
Kurloff cells act as NK cellsHematopoietic
Cavian Leukemia
Chronic Idiopathic Cholangiofibrosis
Periportal fibrosis, hepatocyte
degeneration and interstitial fibrosis,
proliferation of cholangioles
Foreign body pneumonia (Pneumoconiosis)
aspirated food or bedding
granulomatous bronchiolitis, or pneumonia
Adjuvant associated pulmonary granulomas
Subcutaneous injections with Freunds
adjuvant
Lung: multifocal granulomatous inflammation
ddx: perivascular lymphoid nodules,
pneumoconiosis, focal pneumonia
ear chewing and hair pulling
irregular pitted granular cortices
pale linear streaks extend down into the cortex
interstitial fibrosis, tubular dilatation
Fecal contaminants such as E coli
thick bladder mucosa, congestion intraluminal
hemorrhage, mononuclear leukocytes, fibroblast
proliferation, urinary calculi
rete ovarii- large fluid filled cysts on the surface (cysts are
continous with follicles and mesovarium)
cystic endometrial hyperplasia, mucometra,
endometritis, fibroleiomyomas
large areas of adipose tissue between normal
panreatic acini
serum factor (Asparaginase) has anti tumor effects
gross- lymph node enlargement (cervical, axillary, mesenteric,
inguinal), Splenomegaly, Hepatomegaly,
Lymphoblastic cells in spleen. Liver, BM, interstitium of lung, thymus, alimentary tract, and lymphoid tissue, heart, eyes,
and adrenals
Page 32
Reproductive tractOvary Ovarian teratoma
Granulosa cell tumorsUterus (benign) Uterine leiomyoma
Uterine fibromaUterus (malignant) Uterine myxosarcoma
Mammary
AdenomaRespiratory tract
Benign Papillary Adenoma bronchogenic originNasal Adenocarcinoma
Tumors of the skinTrichoepithelioms
PapillomasSebaceous adenoma
Penile papillomasLipoma
FibrosarcomaFibroma
Carcinoma
adrenocrotical adenomaInsulinoma neurologic signs
Rhabdomyomatosis
Other tumorsbile duct tumors
undifferentiated carcinomaLipoma
fibrosarcomahistiocytic lymphosarcoma
Uterine leiomyosarcoma
adenocarcinoma, ductal origin
Malignant mixed mammary tumor
Endocrine and Cardiovascular
Benign mixed tumors (myxoma) of the
Cardiovascular system
well differentiated mesenchymal
components like bone cartilage and fat
congenital condition characterized by
vacuolation of myofibers and glycogen
deposition
Page 33
Rabbits
Order Lagomorpha induced ovulators
Appendix is the tip of the cecum
DNA Viral InfectionsNon-enveloped
Adenovirus
Adenoviral enteritis
EnvelopedPapillomavirus
2 rows of upper incisors, one right behind the other in the
upper jaw
Lab Rabbits descended from the
European Orytolagus cuniculus
Birthing is called Kindling
Cecotrophy- re ingestion of mucous coated "night feces"- high in protein and Vitamin B
complex
Erythrocytes 6.5-7.5 um, heterophils (9-15 um) with acidophilic
granules
Sacculus rotundus- spherical thickwalled enlargement at
the ileocecal junction
the adjacent cecum has around patch of
lymhpoid tissue called the cecal tonsil
(lymphocytes and macrophages in the lamina propria and
submucosa
the length of the duodenum has
Brunners glands
Urine contains Calcium carbonate crystals and triple
Phosphate crystals
Calcium is absorbed in proportion to diet and is
excreted in the urine rather than bile
Urine may be pigmented due to dietary porphyrins,
elevated urobilin (all non-pathologic)
Hematuria may be caused by
adenocarcinoma, uterine polyps,
episodic bleeding from endometrial venous
aneurysms, cystitis, or polyps
Hemoendothelial placentation, receiving antibodies through
placenta
duplex uterus with 2 hors and 2 cervixes
Bones are fragile, and light comared to muscle mass
Right chambers of heart are thin walled and may
contain post mortem clots with no contraction
associated with significant increases in
E coli
Virus was isolated form the intestinal wall and GI
contents, spleen, kidney, and lung
Page 34
Rabbit (Shope) Papillomatosis frequently on eyes and ears
Oral Papillomatosis
Poxvirus
Myxomatosis (Leporipox)
Rabbit Pox
Polyoma virus
Parvovirus
Lapine Parvovirus
Herpesvirus
Benign in cottontails (Sylvilagus), but causes
Papillomas with progression to Squamous cell Carcinoma in
Oryctolagus rabbits (but no infectious virus is
produced)
Rabbit oral papilloma virus
pedunculated masses on the ventral aspect of the tongue and regress spontaneously
Basophilic intranuclear inclusions
Leporipoxvirus (indistinguishable from
vaccinia)
Proliferation of large stellate mesenchymal cells (myxoma cells) interspersed within a
homogenous matrix of mucoid material
hypertrophy and proliferation of
endothelial cells , and epithelium becomes
hyperplastic or degenerative
intracytoplasmic inclusions in the affected epidermis only (not
mesenchyme) and conjunctiva; Insect transmitted
South american type and Californian type
that causes lethal disease of
myxomatosis in European rabbit
(Orytolagus)
Rabbit (Shope) fibromatosis (leporipox)
related to Myxomaytosis and Hare
and Squirrel Fibroma viruses
benign self limiting disease in wildlife
transmissibel to European Rabbits (Orytolagus) and
cottontails
Inclusions in the epidermis and mesenchyme
Papules on skin with necrosis and hemorrhage,
oropharynx, respiratory tract, spleen, liver
Pockless form, hepatic necrosis, pleuritis,
splenomegaly, lymphoid necrosis
Rabbit kidney vacuolating virus
intranuclear inclusions in the renal tubular
epithelium
Legs and feet- Visceral metastasis in young animals,
fibroblast proliferation with mononuclear and PMN
infiltration
transient depression and anorexia with no
mortality
Page 35
Epstein Barr virus analog
Herpes Simplex
Herpes-like viral infections
RNA Viral InfectionsCalicivirus
Rabbit Hemorrhagic Disease Fatal to Orytolagus, not Sylvilagus
Coronavirus
Coronaviral enteritis
Not a natural pathogen
Rotavirus
Rotaviral enteritis
Miscellaneous
Sendai virus
Rabies racoon variant rabiesBacterial Infections
Leporid Herpesvirus 1 (Herpes Sylvilagus)
Lymphoproliferative disease, lymphoid
hyperplasia to lymphosarcoma
Experimental model for herpes simplex
encephalitis
Non-suppurative meningoencephalitis with necrosis of neurons and
prominent intrnuclear inclusion bodies in neurons
and astroglial cells
Hemorrhage, hydropericardium
necrosis in spleen, dermis, lungs, adrenald, Intranculear eosinophilic to amphophilic
inclusions
DIC thought to play arole
bloody nasal discharge, pulmonary hemorrhage and
edema, hepatomegaly, splenomegaly, perirenal
hemorrhage, serosal ecchymoses
necrosis of hepatocytes with
hepatic dissociation, crypt necrosis,
pulmonary edema, hemorrhage, necrosis
of lymphocytes, erythrophagocytosis in
spleen
small and large intesitne, enterocyte
necrosis, villous blunting, mucosal
edema, inflammation
Pleural effusion disease and Cardiomyopathy
lymphoid depletion of spleninc follicles, focal
degenerative changes in the thymus, and lymph nodes,
proliferative changes in glomerular tufts and uveitis
myocardial degeneration and
necrosis
similar lesions to coronavirus
Upper respiratory tract following intestinal
innoculation
Page 36
Bordatella bronchiseptica
Asymptomatic usually lymphoid hyperplasia
Enteritis Complex5-12 week old rabbits Multi-factorial
RotavirusCoronavirus
Clostridium perfringens Type E Iota toxin
difficile
spiroforme most common
E coli
Respiratory Bacterial Infections
Pasteurella multocida Serotype A and sometimes D
Snuffles, atrophic rhinitis, otitis media,
conjunctivitis, bronchopneumonia, abscessation, genital infections, abortions,
chronic rhinitis- catarrhal to mucopurulent exudate,
turbinate atrophy
Suppurative otitis media, with squamous metaplasia of tympanic
bulla lining
Bronchopneumonia- cranioventral to acute necrotizing fibrinopurulent
bronchopneumonia; chronic bronchitis with peribronchial lymphocytic inflammation, alveolitis with heterophils
predominating, multinucleated giant cells, pleuritis
pyometra, salpingitis, perioophoritis,
necrotizing metritis// Acute septicemia,
meningoencephalitis
suppurative bronchopneumonia and interstitial pneumonia
peribronchial and perivascular cuffing
Cilia-Associated Respiratry Bacillus
typical findings for all: submucosal edema,
hemorrhage, ulceration and
fibrinous exudate- necrotizing typhlitis
disruption of normal gut flora predisposes
damage to enterocytes, profuse diarrhea, dehydration and death
Enteropathogenic strains (attaching and
effacing)
serosal ecchymoses, edema of the walls of the cecum and colon, edematous mesenteric
lymph nodes, prominent lymphoid tissues in Peyer's
patches and sacculus rotundus
Small and large intestine: Rods and
cocci lining the villi, villi often blunted, lamina propria is edematous
and infiltrated by heterophils
Page 37
o153, o145
Lawsonia
SalmonellaVibrio
Coccidia
DDX: listeriosis and staph (liver)
Klossiella pneumoniae hemorrhagic enterotyphlitis
Salmonella
Vibrio
Mucoid enteropathy
Other Bacteria
Listeriosis
Staphylococcus aureus
Acute septicemic form
Enterohemorrhagic Strains (EHEC)
cecal and colonic edema, serosal
hemorrhage
sloughing of enterocytes, vasculitis, edema, heterophils- Hemolytic uremic syndrome-
fibrinous vasculitis in interlobular blood vessels, swelling of
glomerular tufts with leukocytic infiltration, glomeruli had swelling and fibrin deposition in capillaries
Proloiferative enteritis/ histiocytic enteritis
Suppurative and erosive to proliferative with hyperplasia of enterocytes lining crypts and villi with mononuclear
infiltration
histiocytes with abundant granular
cytoplasm and MNGC. PAS positive granular
material (degrading bacteria)
Silver and PAS stains show apically located epithelial bacteria
Clostridium piliforme (Tyzzer's Disease)
serosa- fibrin on cecum and colon
thickened and edematous, multifocal necrosis in liver
and myocardium, transmural necrosis in cecum and colon
intracytoplasmic bacteria
rarely associated with disease, normal
inhabitant
S typhimurium and enteritidis
Synonyms: mucoid enteritis, bloat,
hypoamylasemia
teeth grinding, cecal impaction, gelatinous mucus
in colon
Stomach distended with fluid and gas.
acute fatal disease, focal hepatitis, ascites, enlarged mesenteric
lymph nodes
death typically is in advanced pregnancy
Newborns may develop systemic
listeriosis, stunting, meningoencephalitis
straw colored fluid in the abdominal cavity. Miliary pale foci
of suppurative hepatitis in liver. Placenta is thickened with friable
surface
Chronic suppurative lesions
skin, mammary gland, genital tract, conjunctiva, footpads, upper and lower respiratory
tract.
ddx: Pasteurella, Listeria, and Tyzzers
suckling kits, multifocal suppurative lesions in the skin, lung, kidney, spleen,
heart, liver
Page 38
Mastitis swollen, red
Respiratory
Pododermatitis sore hocks
Treponema paraluiscuniculi Venereal spirotrichosis
Helicobacter unknown significance
Yersinia pseudotuberculosis
Necrobacillosis Schmorls Disease
Streptococcal septicemia young rabbitsDiplococcal
Mycotic Infections
Dermatophytosis
Aspergillus
ddx: Staph, Pasteurella, Streptococci
mucopurulent rhinitis and localized bronchopneumonia
and abscesses
vulva, prepuce, anal, muzzle, periorbital
edema, erythema, papules at
mucocutaneous junctions
Syphilitic lesions progress to ulceration and crusting;
Microscopically- hyperplasia of epidermis, necrosis of epithelium,
erosions, ulcerations, plasma cells, macrophages, heterophils,
focal caseation necrosis of liver spleen, cecum, LN and reproductive
tract
dermatitis secondary to moist skin, in dewlaps, excessive
environmental moisture, malocclusion, panting
lesions are suppurative with
erosion and ulceration
Corynebacterium pyogenes cause
ulcerative skin lesions
Trichophyton metagrophytes
head and ears, paws, alopecia, crusting raised
hyperkeratosis, epidermal hyperplasia,
folliculitis, mononuclear and
polymorphonuclear cells
DDX: idiopathic molts during nest building, Barbering
pulmonary granulomas, well circumscribed, central coagulation
necrosis
Page 39
Pneumocystis carinii
Parasitic Diseases
Coccidia Intestinal
Heaptic Eimeria steidae
Encephalitozoon cuniculi
Cryptosporidium cuniculus usually asymptomatic occasional bluning of villi
Toxoplasma gondii clinical disease is rare
Pinworm Passalurus ambiguus adults in cecum
Pulmonary edema, congestion of alveolar
vessels, thickening and hypercellularity of
septaw, mononuclear and PMNS
Eimeria intestinalis, Eimeria flavescens,
Ingested sporulated oocysts release
sporozoites invade enterocytes and
multiply (Shizonts) --> Gametogeny -->
Oocysts
Sexual life cycle causes destruction of enterocytes and
cells of the lamina propria. Cecotrophy does not infect because the oocyst require sporulation at room temp
overnight
Sporozoites invade duodenal mucosa and spread systemically, migrate to liver via
mononuclear cells and invade bile duct
epitheliium where schizogony begins-->
gametogeny--> oocysts released in to
bile ducts
Liver: raised linear bosselated areas, yellow to grey
circumcsribed areas, gall bladder thickened and contains flocculent
material
Histo: Periportal fibrosis, dilation of bile ducts, mixed
inflammation, hyperplasia of bile
epithelium with papillary projections
lined by reactive epithelial cells
overlying collagenous tissue stroma
Obligate intracellular microsporidian parasite
"infectious motor paralysis" can infect mice, guinea pig, ssquirrel monkey, cat, dog
Usually subclinical in rabbits, and renal
lesions are incidental findings
Spores shed in urine, transplacental infection can occur, oral or respiratory transmission is
common. Spores travel via monocytes hematogenously, targets are lung, liver, kidney
Kidney: Focal irregular depressed areas- Granulomatous
nephritis
Lung, liver, CNS also granulomatous lesipons
1.5 x 2-5 um spores in epithelial cells,
macrophages, or free in the interstitium
In chronic renal lesions there is fibrosis and collapse of the
parenchyma
Phacoclastic uveitis and cataracts
may have multiple foci of necrosis and granulomatous
inflammation in lung, liver and spleen
Page 40
Bylisascaris procyonis cerebrospinal disease
NematodirusTrichostrongylus
Psoroptes cuniclui
Cheyletiella parasitovorax
Sarcoptes scabei
Notoedres catiListrophorus gibbus
Aging and Miscellaneous
Hair Chewing (Barbering)
Hatch Burn
Physical injury
Ulcerative Pododermatitis
torticoolis, ataxia, circling, opisthotonus
Gross- Raised white nodules in
subepicardial and subendocardial
locations and liver serosa
Histo: Pyogranulomas/ eosinophilic granulomas; In CNS lesions are in the grey and white matter. Mostly in the brain stem
and cerebellum. Malacia, astrogliosis, gitter cells
Nematode larvae have excretory
columns and lateral alae
Taenia pisiformis (Cysticercus)
Multiple or single white noduels, necrotic
centers with inflammation and
fibrosis
Obligate non burrowing mites
Proliferative and hyperkeratotic otitis externa with euxdation mostly oily
Dorsal trunk, scapula, ventral abdomen
Burrowing mites in the superficial epidermis
(Parakeratotic) hyperkeratosis, seborrhea
and hair loss, face, nose, lips, feet, abdomen, external
genitalia
pruritis and self mutilation is common
patchy alopecia on face and back, young group
housed rabbits
Boredom and low roughage diets have been implicated
Urine scalding of the perineum- hyperemic and excoriated with
serous exudate
Exfoliative Dermatosis and Sebaceous adenitis
non-pruritic scaling dermatitis with patchy coalescing alopecia
histo- Hyperkeratosis, interface dermatitis and
folliculitis, reduced sebaceous glands and
perifollicular fibrosis
One case was associated with a
thymoma
circumscribed ulcerative area covered by
granulation tissues
Poor sanitation, trauma, and wire cages are implicated
staphylococcus is most frequently
implicated
Prolapse of the deep gland of the third eyelid
may be due to laxity in the supporting
connective tissues
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Vertebral fracture
incidental findings
Gastic Pyloric Hypertrophy
Intestinal Plasmacytosis
Chronic Renal Failure
Renal Amyloidosis sparing of the gloeruli
Vitamin E deficiency
Hypervitaminosis D
Hypo or Hyper Vitaminosis A
Pregnancy toxemia
can lead to incontinence
Site is usually lumbosacral L7 with hemorrhage around the
psoas muscles
Tracheal injury following intubation
Erosive to ulcerative tracheitis
Gastric Trichobezoar (Hairball)
predisposing factors include excessive grooming and hair
chewing due to boredom
Insufficient dietary roughage, poor gastric motility, and sedentary
lifestyle are more important
Marked muscular hypertrophy with
interference with gastric emptying
Marked plasma cell infiltration in the intestinal tract
usually asymptomatic, frequently in animals used for
antibody production and cholesterol studies
Cardiomyopathy associated with Ketamine/Xylazine/
detomidine
Multifocal myocardial degeneration with interstitial fibrosis
Attributed to ischemia secondary to vasoconstriction with reduced coronary blood
flow
Metastatic mineralization of the
aorta
Nutritional muscular dystrophy
neonatal mortality and infertility
pale mineralized streaks in muscle
Calcium and Vitamin D deficiency
Osteomalacia, overgrowth
Medial degeneration and mineralization of
major arteries, glomerular tufts, tubular
BM
In long bones there is depostion of basophilic
material (osteoblasts) on the periosteal and endosteal
surfaces
Poor ceonception, congenital
abnormalities, fetal reabsorbtions
Microencephaly, hydrocephalus, cleft palate
Mobilization of fat deposits leads to
metabolic acidosis and ketosis with fatty liver
Obesity, hereditary, imparied blood flow, pituitary
dysfunction all predisposing factores
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Lead Toxicosis
Hereditary Disorders
Malocclusion
Neoplasms
Uterine Adenocarcinoma
Lymphosarcoma
Thymoma
Anemia, tremors, and posterior ataxia
Myocardial degeneration, hepatic necrosis, renal tubular degeneration,
hemoglobin casts
Congenital Glaucoma (Buphthalmia)
New Zealand White Rabbits
Enlargement of 1 or both eyes with corneal opacity
Autosomal recessive, Absence or
underdevelopment of the outflow channels
with incomplete cleavage of the
iridocorneal angles
Autosomal recessive, the mandible is long in relation to the maxilla
overgrowth of premolar and molar teeth also occur (seen in animals with diet deficient
in calcium and vitamin D)
Endometrial Venous Aneurysms
Persistent urogenital bleeding, clotted blood
in uterus
Blood filled endometrial varices consisting of dilated
thin walled veins
Most common spontaneous neoplasm
in Oryctolagus cuniculus
Nodular frequently multicentric enlargements of
one or both uterine horns
Cauliflower like surface and central
ulcerations
Serosal implantation and metastasis to the lung and liver
Leukemia only occasionally occurs
In cottontail has been associated with Herpesvirus
sylvilagus
Kidney and gastric mucosa most common sites, confined to renal
cortex
Liver is enlarged, pale, and swollen, spleen is large and lymph
nodes large
Stomach wall is thick with irregular plaques
and mucosal ulceration
Aside from thymic involvement there may be variable lymphocytic infiltrates in the other
organs like, lymph nodes, liver, heart, and
lungs
1 case of hypercalceima and exfoliative dermatitis
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Prolactin-producing Pituitary Adenomass with Associated
Mammary Dysplasia
Swelling of 1 or more mammary glands with
enlargement and discoloration of the teats, thinning of
haircoat
Dilated cystic ducts lined by flattened cuboidal epithelium
with papillary projections
Page 44
Common Mice StrainsCommon Diseases
C57BL/6 (B6) Hydrocephalus
Hippocampal neurodegeneration
Microphthalmia
Anophthalmia
cochlear degeneration- age related
malocclusion
Pulmonary proteinosis- aged
epithelial hyalinosis
amyloidosis- late onset
lymphoma
hemangiosarcoma
pituitary adenoma
BALB/ c or cBy Dystrophic epicardial mineralization
myocardial degeneration
auricular thrombosis
corneal opacities
conjunctivitis and blepharitis
periorbital abscesses
resistant to amyloidosis
normal hepatic lipidosis
lung adenomas
lymphoma
Harderian gland tumors
adrenal adenomas
C3H/ He corneal opacities
Hearing loss
myocardial degeneration
alopecia areata (HeJ)
Back ground strain, longevity
Melanism- coat color, heart valves, splenic capsule ,
meninges
barbering- with alopecia and Staph dermatitis
Albino,Pugilistic males
Hypocallosity (aplasia of corpus callosum)
Myoepitheliomas of salivary, preputial, and other exocrine glands
Agouti, Blind (rd1 mutation)
focal myocardial and skeletal muscle mineralization
Page 45
hepatocellular tumors
129 mice
Pulmonary proteinosis
epithelial hyalinosis
Megaesophagus
conjunctivitis and blepharitis
lung tumors
Harderian gland tumors
Ovarian tumors
hemangiosarcoma
FVB/ N Siezures
persistent mammary hyperplasia
lung tumors
pituitary adenoma
Harderian gland tumors
Liver tumors
lymphoma
pheochromocytoma
amyloidosis- late onset
retinal degeneration
lymphoma
Pulmonary adenoma
Liver tumors
pituitary adenoma
hemangiosarcoma
Murine Mammary tumor virus- induced mammary tumors
Embryonic stem cells; variation in coat color and
behavior
Hypocallosity (aplasia of corpus callosum)
Testicular teratomas (embryonal carcinomas)
Swiss Mice, blind (rd1)
adenoma of prolactin secreting cells of anterior pituitary
Outbred Swiss Mice