Infectioue Bursal Disease in Poultry
Infectioue Bursal Disease in Poultry
Infectioue Bursal Disease in Poultry
Sreenivas
Gowda
Former VC- KVAFSU, Bidar .
Why it is Economically
Important?
Economic impact of
IBD
The economic impact of an Infectious Bursal
Disease Virus (IBDV) infection is two fold:
1.Direct mortality that can reach levels in
excess of 40% to 100%
2.Secondary infections, due to a suboptimal
immune system, having a negative impact on
production efficiency.
At least
sixantigenicsubtypes of
IBDV serotype 1 have been
identified byin vitrocrossneutralization assay.
Viruses belonging to one of
these antigenic subtypes
are commonly known as
variants, which were
reported to break through
high levels of maternal
antibodies in commercial
flocks, causing up to 60 to
100 percent mortality rates
vvIBD in chickens.
Transmission
In recent years, very virulent strains
Transmission..cont
This virus is highly contagious and persistent in the environment of
poultry houses.
Affected birds excrete the virus in faeces for 10-14 days.
Virus survives upto 120 days in poultry sheds.
Water, feed, droppings from infected birds are viable for 52 days in the
poultry houses.
Hardy nature of this virus survives heat, cleaning and disinfectant
procedures.
Survives in the environment between outbreaks.
Meal worm, Aedes vexan (Mosquito) and litter mites appear to act as
carriers and remains infective for up to 8 weeks.
Egg trays, vehicles used in the transport of birds, eggs and personal
handling of birds in sheds and elsewhere are very important source of
carriers of infection.
Role of mechanical vectors (Human, wild birds, insects).
No vertical transmission and carriers. (Disease is not transmitted
through eggs).
Older birds (due to Bursal regression) are more resistant to infection.
Clinical signs
Disease may appear
SUBCLINICAL IBD
Characterised by bursal
atrophy, immunosuppression
and resultant increased
susceptibility to secondary
infections (such asE. coli).
No peak mortality as
evidenced with clinical IBD.
Secondary infections in
broilers, mainlyE. coli, result
in a continuous above
standard daily mortality and
poorer feed conversions.
Due to immunosuppression
there can be a poor response
to subsequent vaccinations.
infection of chickens..
Young chicks up to 0-6 weeks are more
susceptible.
Incubation period is short and clinical signs
observed in 2-3 days following infection.
Morbidity is 100% and mortality is 80-90%.
Clinical signs
Self vent pecking.
Anorexia
Depression and trembling
Watery and whitish
diarrhoea
Soiled vents
Ruffled feathers
Reluctant to move
Closed eyes and death.
Gross lesions
Dehydration of carcass.
Petechial / paint brush haemorrhages on
Enlarged Bursa
Enlarged and
hemorrhgic BF
Enlarged BF &
congested kidney
Kidney Lesions
SWOLLEN CORRUGATED
KIDNEY
Diagnosis
Flock History
A sudden onset of mortality in chickens between 2 and 8 weeks of
age could indicate an IBDV infection. The presence of distinctive
lesions in the bursa of Fabricus and accompanying blood spots in the
musculature of the breast and thigh of affected chickens are strong
indications.
Serology
Molecular diagnostic assays are most often used to identify IBDV in
diagnostic samples.
They use reverse-transcriptase PCR to identify the viral genome in
bursa tissue.
analysis of the VP2 coding region has been used to further
characterize the viruses.
Viral Isolation
IBDV may be isolated in 8- to 11-day-old, antibody-free chicken
embryos with inocula from birds in the early stages of disease.
weeks of age.
Booster vaccination with intermediate strain (live) after 3
weeks of age.
Recommended vaccination schedule for layer
chicks:
Age in Days
Name of the
Vaccine
Route
12-14
IBD-live
(primary)
I/O
22-24
IBD live
(Booster)
I/O
Vaccination of Breeders
Vaccination of breeder stock and seromonitoring by
Treatment
Since it is a viral disease better to have good
Mosquitos