Leishmaniosis in dogs Simple Steps for In Clinic Diagnosis 18 March 2020– Dr. Inbal Peled, Biogal
Leishmaniosis in dogsSimple Steps for In Clinic Diagnosis
18 March 2020– Dr. Inbal Peled, Biogal
✓ Leishmaniasis is endemic in 88 countries on five continents—Africa, Asia, Europe, North America and South America.
✓ 12 million people are affected by leishmaniasis✓ 50 000 to 90 000 new cases of VL occur worldwide
annually✓ An estimated 600 000 to 1 million new cases of CL
occur worldwide annually.
HUMAN LEISHMANIASIS
Human Leishmaniasis - cont
• Mostly affects poor people
• Associated with:
- malnutrition,
- population displacement,
- poor housing,
- weak immune system
- environmental changes:
deforestationbuilding of dams
irrigation schemes urbanization
Human Leishmaniasis – clinical signs
MucocutaneousCutaneous (most common)
Visceral (most serious form)
partial or total destruction of mucous membranes of the nose, mouth and throat
• irregular bouts of fever• weight loss• Enlarged spleen and liver• Anemia
skin lesions, mainly ulcers, on exposed parts of the body, leaving life-long scars
Canine LeishmaniosisL. Infantum
Leishmaniosis in dogs,Simple steps for in clinic Diagnosis
✓ General aspects of the disease
✓Clinical signs
✓Diagnostics options
✓ In-clinic diagnostics
✓ Disease staging and prognosis
Topics
Leishmania Infantum Canine infection -General aspects
Canine Leishmaniosis
Cutaneous LeishmaniosisVisceral Leishmaniosis
Leishmania braziliensis*
Leishmania amazonensis
Leishmania infantum
Because the internal
organs and skin of
the dog are affected,
the canine disease
is termed
viscerocutaneous
WORLD CANINE LEISHMANIA DISTRIBUTION
http://www.cvbd.org/en/occurrence-maps/world-map/
The CVBD World
Forum is supported
by Bayer Animal
Health, a specialist in
the field of parasite
prevention.
Canine leishmaniosis is extremely common in the Mediterranean area and South America; -also found in Africa, Asia, Central America
Prevalance of L.infantum (2014)
• Spain, France, Italy and Portugal – 2.5 million
• Spreading to North Europe – Alps, Pyrenees, and north western Spain.
• South America – estimation ~ Millions • Highest in Brazil (90% of cases) and Venezuela
• Highly endemic countries• canine infection rates 70-90% • Balearic islands of Spain, Greece, Marseille area France, Naples area in Italy.
Canine leishmaniosis is extremely common in the Mediterranean area and South America;
Transmission modesSand fly transmission
Sand fly bite Dermis
Macrophages penetration and
replicationBlood
Lymph nodes, Spleen, bone
marrow, whole body
promastigotes
amastigotes
Non sand fly transmission
✓Blood products from carriers
✓Vertical
✓Venereal
Suspected yet unproven
✓ direct dog-to-dog transmission through bites or wounds
✓ other blood feeding arthropods (ticks and fleas)
Transmission modes - cont
Canine Leishmaniosis – L. Infantum
Incubation period:
3 months – 7 years
Higher Incidence
• Age at least 2 years
• Prolonged exposure to the outdoors
• Lack of topical insecticide use
• Short haircoat
• Breeds - Rottweilers, GSD and Boxers
Chronic subclinical infection40-80%
Self limited disease
Fatal disease
L.infantum infection outcome
The dog as a reservoir of L.Infantum
Long pre-patent period of infection
High concentration of protozoan amastigotes in the skin
Complete eliminationof the parasite is uncertain
Factors influencing infection outcome
OthersHost relatedParasite related
Stress
Immunosuppressive treatment
Immune status
Genetics
Susceptible breeds
Nutritional state
Co-infections
Other non-infectious debilitating diseases
Strain
VirulenceParasitic load
Proliferation in macrophages, lymphocytes, plasma cells
Lymphadenomegaly
Splenomegaly
Hyperglobulinemia
Granulomatous lesions in the skin
Over antibody production
Immune-complexes deposits in the
kidneys, joints, eye and blood vessel
walls.
Immune mediated hemolytic anemia
Co -infections
Ehrlichiosis
Hepatozoonosis
L. Infantum Pathogenesis
Canine Leishmaniosis,L.infantumDiagnosis
•History
•Clinical Findings
• Laboratory Findings
Main purposes for the diagnosis of L. infantum infection
Disease confirmation
Imported dogs
Blood donors
Breeding dogs (vertical transmission / presence in semen…)
Clinical diagnosis challenges
• Almost 50% of the affected canine population does not exhibit clinical signs
• When ill – variable clinical signs and nonspecific • Any organ can be involved• Lab findings not disease specific
(thrombocytopenia, anemia, renal disease….)• more diagnostic methods – each one has some
limitations
Typical clinical findings and history
• Skin lesions (90%)
• Weight loss
• Exercise intolerance
• Decreased appetite
• Lethargy
• Lameness
• Vomiting, and Diarrhea
• Lymphadenomegaly
local or generalized
• Splenomegaly
• Polyuria and polydipsia
• Ocular lesions
• Epistaxis
• Onychogryphosis
Variable Cutaneous lesions
• Exfoliative dermatitis with/without alopecia
• Nodular, popular or pustular dermatitis
• Erosive ulcerative dermatitis
• Nasal hyperkeratosis
• Onychogryphosis (abnormal nail growth)
Mucocutaneous ulcerationExfoliative dermatitis
Skin ulceration on the ear Exfoliative dermatitis
Visceral LeishmaniosisMucocutaneous lesion
Cutaneous signs - basic facts
• Visceral involvement
• Rarely pruritic
• Generalized or localized
Occular signs
Uveitis
• Anterior Uveitis
• Keratonconjunctivitis
• Blepharitis
Conjunctivitis and blepharitis
• Muscular atrophy
• Skin Lesions
• Weight loss
Canine LeishmaniosisLaboratory Abnormalities
CBC
• Anemia (mild to moderate non regenerative)
• Thrombocytopenia
Serum Biochemistry
• Hyperproteinemia
• Hyperglobulinemia
• Hypoalbuminemia
• Renal azotemia
• Elevated liver enzymes
Urinalysis
• Proteinuria
• Isosthenuria (depending on renal
stage)
Laboratory Abnormalities
Canine Leishmaniosis – Specific Diagnostic methods
• Parasitological: cytology/histology(requires experience in slide examination)
✓ Skin lesions✓ Bone marrow ✓ Spleen ✓ Lymph Node✓ Liver ✓ Rare- WBC
• Serological
• Molecular: PCR
• IFAT: Indirect Fluorescent Antibody Test• Cross reactivity with other Trypanosoma spp
• ELISA• Higher specificity • Technically easier to perform
• Rapid lateral flow
.Qualitative
.Quick, simple, yes/no result
.point of care test
Serology
Canine Leishmaniosis diagnostics
• Negative serologic test results may reflect delayed seroconversion in some animals, which can take several months to occur
• Affected by vaccination• Performed in a referral Lab
SEROLOGIC TESTSLimitations
✓Goal: Detection of Antibodies in the blood
✓Antibodies indicate exposure to pathogen (past and present) but not necessarily disease
✓Antibodies develop within 3 weeks after infection (following establishment of disease)
✓Antibodies can persist for months to years post exposure without presence of disease
✓Antibodies can persist regardless of effective treatment
MOLECULAR TESTSPolymerase Chain Reaction (PCR)
✓ Traditionally restricted to high complexity laboratories with dedicated space and equipment.
✓ New technology is now available for use in regular clinical laboratory environments.
✓ Detects and amplifies a specific sequence of of the
pathogen’s DNA
✓ Allows for sensitive and specific diagnosis of infection
✓ Monitoring treatment efficacy
Biogal’s PCRundiagnostic devices
Molecular detection- PCR
✓First choice samples: bone marrow, lymph node, skin and conjunctival swabs.
✓ Less sensitive samples: blood, buffy coat and urine.
✓Most sensitive technique: real-time PCR.
✓Results are not affected by vaccinations (DNA not present in the vaccine)
✓ PCRun: in-clinic diagnosis
Source: LeishVet guidelines for the practical management of canine leishmaniosis
Clinical stages Serology PCR Clinical signs Laboratory findings Prognosis
Stage I Mild disease
Negative to low positive antibody
levels+
mild clinical Lymphadenomegaly/papular
dermatitis
Usually normalcreatinine < 1.4 mg/dl;
non-proteinuric: UPC < 0.5Good
Stage II Moderate
disease
Low to high positive antibody
levels+
stage I + Cutaneous lesions
anorexia, weight loss,
fever, epistaxis
• Mild non-regenerative anemia
• High Glob
• Low Alb
• serum hyperviscositysyndrome
Normal renal profileUPC < 0.5
Good to guardedCreatinine <1.4 mg/dl;
UPC = 0.5-1
Stage III Severe disease
Medium to high positive antibody
levels+
stages I and II, +immune-complex related
lesions: vasculitis, arthritis, uveitis
glomerulonephritis.
Creatinine < 1.4 mg/dl; UPC > 1 Guarded
to poorCKD stage II(Creatinine 1.4 -2 mg/dl)
Stage IV Very severe
disease
Medium to high positive antibody
levels+
stage III + Pulmonary thromboembolism,
nephrotic syndrome end stage renal disease
CKD stage III (creatinine 2-5 mg/dl)
PoorCKD stage IV (creatinine > 5
mg/dl)
Nephrotic syndrome: marked proteinuria UPC > 5
Leishmania infantum canine infection
Meglumine Antimoniate, Allopurinol, Miltefosine, Domperidone
Prevention:
• Vector control- Parasiticides with repellent activity
• Vaccines
Prognosis: Good to poor depending on disease stage
• Treatment is rarely, if ever, curative and dogs usually remain infected for life
• With no treatment - death within 2-3 years from onset of clinical signs due to renal failure.
Treatment
PARAMETERS
➢ Clinical history and physical examination
➢ CBC, Biochemistry
➢ Complete urinalyisis & UPC
➢ Quantitative serology*
➢ PCR
FREQUENCY
Sick treated dogsClinically healthy
Infected dogs
After the first month of treatment and then every 3-4 months during the first year.
Later on, every 6-12 month in dogs fully recovered clinically with treatment.
Every 3-6 months
Not before 6 months after initial treatment and every 6-12 months
Every 3-6 months
At the same time as serology Every 3-6 months
*Some dogs have a significant decrease in antibody levels (i.e. more than three two-fold dilution difference between monitoring samples) associated with clinical improvement within 6-12 months of therapy. A marked increase in antibody levels (i.e. more than three two-fold dilution difference between monitoring samples) should be interpreted as a marker of disease relapse, especially in dogs following the discontinuation of treatment.
Source: LeishVet guidelines for the practical management of canine leishmaniosis
Take home messages
• Serology alone DOES NOT provide a definitive diagnosis
• Full comprehensive diagnosis and monitoring:
✓ Physical examination
✓ CBC, Biochemistry, UA
✓ Serology & PCR
• First choice samples for PCR
• Bone marrow / Lymph nodes
• Skin
• Conjunctival swabs
• Buffy coat
• Peripheral blood
Thank you