Infectious bursal disease (IBD) is a highly contagious, worldwide disease that primarily infects young chickens of about three to eight weeks of age and can also infect turkeys and wild birds. It was first discovered in 1962 in Gumboro, Delaware USA.
It has two serotypes and, depending on the strain, can have an incubation period of three to four days, with flock morbidity at 100% and a mortality rate ranging from 5% to over 60%. In recent years even more virulent strains have emerged.
Cause
The disease is caused by the infectious bursal disease virus. It infects the immune system causing immunosuppression and so leaves infected birds vulnerable to secondary infections such as salmonella, E Coli and mycoplasma.
Transmission
The virus is extremely infectious and is easily spread from bird to bird where there is a high density of birds. It’s transmitted by droppings, through infected water, food and close contact. It can be transferred from house to house and farm to farm on infected clothing and equipment.
Clinical signs
Common signs of infectious bursal disease are listlessness, depression, ruffled feathers, huddling and watery diarrhoea. Other signs include slow trembling walking, pecking other chickens and reduced eating or anorexia. These signs typically show between three to eight weeks of age. The increased susceptibility to secondary infections, like Inclusion Body Hepatitis, can have a negative impact economically.
Diagnosis
Serology can detect antibodies from recovering chicks, however, most of them will already have maternal antibodies. Post mortem examination can show, in acute cases, a swollen and bloody bursa of Fabricius. An initial diagnosis can be made by observing gross lesions in the cloacal bursa and can be confirmed by the identification of the viral genome in bursa tissue.
Treatment and control
There is no treatment for Infectious bursal disease. There are a range of live and inactivated vaccines and a new generation of recombinant vaccines have been developed. One of the best methods of control is the vaccination of breeder flocks as this ensures protective antibodies are passed on to their offspring. Young chicks can also be vaccinated to prevent any disease taking hold.
As the virus is difficult to eradicate from a premises, prevention with stringent biosecurity measures is always the best action to take. Keeping houses clean and disinfected while ensuring feed and drinking water is fresh helps reduce the risk of incursion.
Expert advice from the experts
Livetec are the industry leaders in biosecurity. We create bespoke plans that are designed to mitigate the risk of infection and protect the welfare of your flock and your farm business.
We also offer our unique Biosecurity Advisory Service. Backed by years of on-farm experience and evidence based research one of our experts conducts an on-site review of your operations and advises you on implementing the most effective biosecurity measures.
To find out more about how our services can help you, click here.