Immunosuppressive Diseases in Poultry عة فى الدواجنلمنامراض المثبطة ل اBy Mohamed Hossany Negm Senior Technical Support Specialist and Marketing Master ’ s Degree, Poultry Science, very good TEL: 00201123223874 Faculty of Agriculture Zagazig University
46
Embed
Immunosupressive diseases poultry1 الامراض المثبطة للمناعة فى الدواجن
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Immunosuppressive Diseases
in Poultry
االمراض المثبطة للمناعة فى الدواجن
By
Mohamed Hossany Negm
Senior Technical Support Specialist
and Marketing
Master’s Degree, Poultry Science, very good
TEL:00201123223874
Faculty of Agriculture Zagazig University
Immunosuppressive Disease-General Indicators-
Increased incidence of complicated
respiratory disease
Increased E. coli problems
Increased condemnations-- airsacculitis and
Septicemia/Toxemia
Failure to resolve vaccine reactions
Failure to respond to medication
Immunosuppressive Disease-General Indicators-
Increased mortality and poor performance
Decreased serologic response to
vaccination
Increased incidence of secondary disease
Gangrenous dermatitis
Inclusion body hepatitis
Necrotic enteritis
Immunosuppressive Disease-Specific Indicators-
Early/permanent damage to bursa of Fabricius
<2 weeks of age
Early/permanent damage to thymus in young
chickens
General lymphoid cell depletion
Failure to respond immunologically to antigens
Vaccines
Experimental antigens- sheep red blood cells,
Brucella abortus
Immunosuppressive Disease-Specific Indicators-
Failure to respond to vaccination as
evidenced by lack of resistance to field
challenge following challenge
Failure to mount a cell-mediated immune
response (CMI)
Fowl Pox, ILT
Inability to clear bacteria from the
bloodstream following IV inoculation
Immunosuppression-Confusing Factors-
Introduction of new pathogen for which
current vaccines are not protective or
available.
Variant Infectious Bronchitis
Variant Infectious Bursal Disease
Very virulent Infectious Bursal Disease
Variant Mycoplasmas
Etc.
Immunosuppression-Confusing Factors-
Inappropriate or ineffective vaccination programs
Use of virulent vaccine
– ‘hot’ Gumboro vaccine
Maternal and/or vaccine titer to low at vaccination
Improper vaccination techniques
– Fine spray versus coarse spray
– Respiratory vaccines-IBV, NDV
– Gumboro vaccines
Misuse of vaccines that cause Immunosuppression or
interfere with immune response
Immunosuppression-Confusing Factors-
Development of resistance to commonly used antibiotics
Environmental factors
Sanitation
Biosecurity
Ventilation
Bird density
Down time between flocks
Breed differences
Avian Immune System
Bursa of Fabricius (B-lymphocytes)
Thymus (T-lymphocytes)
Liver
Spleen
Bone marrow
Lymphoid cell aggregates
Blood
LYMPHOID
PATCH
CECAL
TONSILS
HARDERIAN
GLAND
THYMUS
HEART
SPLEEN
BONE
MARROW
BURSA of
FABRICIUS
YOLK OR
YOLK
REMNANT
AVIAN IMMUNITY
Factors Affecting Function of
Immune System
Innate resistance
Age
Sex
Physiology
Genetics
Factors Affecting Function of
Immune System
Environment
Air quality
Temperature
Stress
Nutrition
Sanitation in hatchery and grow-out
Biosecurity
Infectious Diseases
Factors Affecting Function of
Immune System
Diet
Formulation
– Profound effect on function of immune system
Dietary toxins
– Mycotoxins
– Biogenic Ammines
– Rancid fat
Infectious Diseases that Affect the
Immune System
Infectious Bursal Disease
Chicken Anemia Virus
Marek’s Disease
Reovirus
Interactions
Infectious Bursal Disease
Clinical Form
Typically in birds 2.5-6 weeks of age
Classical and vvIBD virus strains- gelatinous
transudate on bursa of Fabricius, edema,
hemorrhage, followed by atrophy due to
lymphocyte destruction and depletion.
Mortality especially with vvIBD
Transitory immunosuppression
Infectious Bursal Disease
Subclinical Form
Occurs prior to 2 weeks of age
Characterized by atrophy of bursa without evidence of clinical disease
Most important form of disease in many parts of world, results in permanent and severe damage to bursa of Fabricius
The earlier the damage occurs to bursa of Fabricius, more severe the immunosuppression
Infectious Bursal Disease
Effects on immune responses to IBV, NDV
and ILT vaccines
NDV- decreased response to vaccination,
increased persistence of virus in trachea
IBV- reduced resistance to challenge,
increased virus persistence by several weeks
ILT- decreased response to vaccination, but
does not increase viral persistence
Effects of IBD Virus on Immune Response
Immune Response to NDV Vaccine following Infection with
IBDV at Different Ages
Treatment Mortality
IBDV
Challenge
NDV
Vaccine
NDV
Challenge
# dead/total
1 day 28 d 49 d 27/31
7 day 28 d 49 d 13/31
14 day 28 d 49 d 3/31
21 day 28 d 49 d 3/31
None 28 d 49 d 3/35
None ---- 49 d 33/33
Chicken Anemia Virus (CAV)
Loss of immature T-cells in thymus
Decreased erythropoiesis and increased
fat infiltration of bone marrow
Effects of CAV on Immune
Response
CAV infectious resulting from transovarian or
infection shortly after hatch can be
immunosuppressive
Responses to IBV, NDV, and ILT are affected
Increased susceptibility to bacterial infections
(gangrenous dermatitis)
Age associated resistance to CAV induced
immunosuppression in birds older than 2 weeks
Effects of IBDV on Susceptibility of
Chickens to CAV
IBDV alters age-associated susceptibility
to CAV and allows CAV to be
immunosuppressive in older birds
Decreased dose of CAV is necessary to
cause disease
Marek’s Disease Virus
Interactions with other infectious agents
CAV
Subgroup J virus (Myeloid Leukosis)
E. coli
Coccidiosis
Avian Reoviruses
IBD (Gumboro)
Respiratory disease viruses
Avian Reoviruses
Specific Reoviruses—Miss-B Reovirus
Isolated from bursa of SPF sentinels
Antigenically similar to S1133 Reovirus
High mortality and reduced body weights in
broilers infected at 1 day of age
Bursa and thymic atrophy
Liver necrosis, tenosynovitis
Virus widely disseminated in tissues for
several weeks post infection
Avian Reovirus
Avian Reovirus (Miss-B isolate) can suppress
immune responses to NDV and IBV
Susceptibility to CAV is increased by prior
Reovirus exposure
CAV, IBDV, and Reovirus interact to induce
more severe disease
Programs to Minimize Impact of
Immunosuppressive Diseases
Accurate diagnosis
Control pathogens that are known immunosuppressive agents IBDV
CAV
Marek’s Disease virus
Interactions
Manage environmental factors than can exacerbate immunosuppressive diseases
Consider and control influence of breed and nutrition on disease susceptibility