IBD

Synonym

Gumboro disease

Definition

It is the most important immunosupptessive disease in poultry. It has special affinity to pre b lymphocytes

Etiology and serotype

IBDVvirus, birna virus, birnaviridae

It has 2 serotype 1 and 2,serotype 1 pathogenic, only to chicken

Sero1 three antigenic subgroups

Classic or std 10-50 mortality

Variant-no mortality

Very virulent virus-50-100

Morphology

Non enveloped hexogonal, icosahedral

Genome

2 unrelated molecules of linear dsrna

Four atructural protein (vp1-4) and one non stop protein(rna polymerase) vp2 neutalizing antigen

Vp3:grp specific antigenic determinants

Transmission

Excrete in feces of infected

Thru oral route via contaminated water feed litter

Highly contagious

Very stable virus 120 days

No veryical transmission

3-6weeks of age highly susceptible

Diagnosis

Clinical materials bursa spleen

Vorus isolation(embryonated eggs)

6-8 day old by yolk sac route

9-11 day old by cam route

Dwrfing of embryo, subcut edema, liver spleen mottled show patchy congestion

Chickens

Thru conjuctival sac or intracloacolly

Virus kill chicken 72 -80 hrs, bursa yellowish or haemorrhagic tugid with prominent striations

Cell culture

Lymphoblastoid cells

Chicken embryo fibroblast

Ag detection

AGID, IFT, antigen capture elisa and rt pcr

Syrain differentiation

Cnt Or by sero tests using serotyoe specific monoclonal abs

Serologic test

Agid elisa vnt

Dd

Md ib

Prevention and control

Live attenuated, inactivated, recombinant vaccines are available

Low maternal ab atten vaccine before one to two wks of age

Live vaccine by serial passsagein emb eggs

Depend on degree of attenuation vaccine strain

Mild leukart

Intermediate Georgia India

Intermediate plus or hot

Broiler layer breeder

Broiler in ovo 18 day incor 13 day intermediate + de

Layer 14 to 28 day syd intermediate+dw and 21 inter +de

Breeder

Oral live vaccine 18 wks

Inact vaccine before laying

Usual programme admin live vaccine at 8 wis of age follow by inact vaccineat 16-20 wks of age i’m to thigh muscle

India vaccinated with intermediate strainat 12 -14 daythru oro nasalroute Or dw and booster on 28 then again vaccinate with inact vaccine