Gumboro IBD infectious bursal disease in poultry

Infectious bursal disease (Gumboro disease)

Infectious bursal disease (IBD, Gumboro) is an acute, highly contagious viral infection of chickens manifested by inflammation and subsequent atrophy of the bursa of Fabricius, various degrees of nephritis (inflammation of the kidneys) and immuno-suppression (Failure to resist infections).

IBD | Gumboro

Clinically the disease is seen only in broiler chickens older than 3 weeks and occurs in most parts of the world.

The feathers around the vent are usually stained with feces containing plenty of urates. The disease is usually associated with high economic losses due to deaths and delay in weight gains.

Etiology and Transmission:

Infectious bursal disease (IBD) is caused by infectious bursal disease virus (IBDV) that is most readily isolated from the bursa of Fabricius but may be isolated from other organs.

It is shed in the feces and transferred from house to house by fomites( articles that have been in contact with sick birds such as bedding, drinking and feeding equipment, attendants`` feet, clothing, hands).

The disease is highly contagious being spread very fast through contact of infected birds or material that has come into contact with sick birds and healthy birds.

The virus is very stable and difficult to eradicate from premises.

Clinical Signs (How to recognize the Disease)

The results of infection depend on age and breed of chicken and virulence of the virus. Two forms of the disease may occur:-

a. Sub-clinical Form

where infections may be present without the birds showing any signs. This is common in birds before 3 weeks of age.

This form of the disease is associated with severe economic losses due to the resulting immunosuppression, where young birds do not respond well to vaccination and are prone to other infections from bacteria and other organisms commonly in the environment.

b. Clinical Form

It occurs at 3–6 weeks where sudden appearance of clinical signs with a very high morbidity (several birds affected) approaching 100% and a low mortality (deaths) of 20-30% occurs.

The signs include, severe prostration, incoordination, watery diarrhea, soiled vent feathers, vent picking, and inflammation of the cloaca.

Deaths occur from day three of the clinical disease, with a characteristic pattern where the mortality peaks at day 5-7 and then declines so that at day 10 there is almost complete decline. Recovery occurs in less than one week but broiler weight gain is affected and delayed by 5-7 days.

Post Mortem Lesions:

The cloacal bursa is swollen, edematous, yellowish, and occasionally hemorrhagic. Congestion and hemorrhage of the pectoral, thigh, and leg muscles is common. Chickens that have recovered from IBDV infections have small, atrophied, cloacal bursas due to the destruction and lack of regeneration of the bursal follicles.

Treatment and Control:

There is no treatment for IBD. Rigorous disinfection of contaminated farms after depopulation has some limited success. Live vaccines of chicken embryo or cell-culture origin are administered by eye drop, drinking water, or Sub-Cutaneous routes (injection) at 1–21 days of age with some degree of protection.

High levels of maternal antibody during early brooding of chicks in broiler flocks and in some commercial layer operation) can minimize early infection.

Breeder flocks should be vaccinated one or more times during the growing period, first with a live vaccine and again just before egg production with an oil-adjuvant, inactivated vaccine.

The immune status of breeder flocks, however, should be monitored periodically so that if antibody levels fall, hens should be re-vaccinated to maintain adequate immunity in the progeny.

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