Breaking Down the Basics of Infectious Bursal Disease: Symptoms, Causes, and Treatment Options
Infectious bursal disease (IBD), also known as Gumboro disease is a highly contagious and immunosuppressive disease of young chickens caused by IBD virus (IBDV) which is responsible for major economic losses in the poultry industry worldwide. IBDV is a double-stranded RNA virus belonging to the genus Avibirnavirus of the family Birnaviridae. The IBD virus is a lymphotropic virus that can destroy B lymphocytes (immature) rapidly and cause immunosuppression in poultry. The currently known IBD-causing virus consists of 2 serotypes, namely serotype 1 and serotype 2, which can infect chickens and turkeys. Serotype 1 first discovered is called the classic strain pathogens and strains found then in the Americas it is a variant strain very malignant, namely very virulent IBD (vvIBD).
IBD was discovered in Delaware, America in 1956, then spread to various parts of the world in America, Europe, Africa, Australia, and Asia, including Indonesia which is caused by the classic IBD virus or vvIBD. Mortality reached 56.09% in broilers and 25.08% in laying hens. The mortality rate is higher in winter than in spring or summer and rainy season. This is understandable because extreme temperatures (too cold or too hot) cause chickens to stress easily, so chickens are easily infected by viruses.
The clinical symptoms seen depend on the virus strain that infects the chicken, the amount of virus, the age, the strain of the chicken, the route of inoculation, and the presence of neutralizing antibodies. Clinical symptoms caused by IBD infection are lethargic chickens, lost appetite, and wings hanging down. In addition, symptoms of diarrhea are also often found, as well as dirt that sticks to the cloaca. In young chickens without maternal antibodies, clinical symptoms began to appear 48 hours post-infection, and clinical symptoms worsened at 56-72 hours post-infection. Meanwhile, on vaccinated chickens, clinical symptoms appeared 3 days after being challenged, and the chickens died after 2 – 3 days of showing clinical symptoms. For chickens that survive, growth becomes inhibited, and often found secondary infections such as Newcastle Disease, Colibacillosis, and Coccidiosis.
Anatomical pathological changes in chickens infected with the IBD virus depend on the chicken strain and virus isolate used. In the early stages, edema is found 2-7 days post-infection, in the form of a gelatinous liquid that covers the serous layer. The bursa then enlarged at the age of 10 days post-infection due to exudate in the lumen of the bursa which was initially reddish in color, at a later stage it became yellowish in color and spots of bleeding in the spleen. Bleeding was also found in the chest and thigh muscles from 2 to 7 days post-infection. At 7 days after infection, the bursa of Fabricius of chickens infected with vvIBDv looked smaller compared to the bursa of Fabricius of normal chickens, as well as at 14 days post-infection. If healing occurs, the size of the bursa returns to normal by 21 days post-infection.
The diagnosis of IBD can be established based on clinical symptoms, changes in anatomic pathology, and histopathology. Pathognomonic signs are the changes found on Bursa Fabricius. Nevertheless, the diagnosis of IBD as The primary cause needs to be supported with techniques the other diagnosis is due to symptoms of IBD virus infection similar to ND or other disease causes immunosuppressive. Diagnosis of IBD can also be done in this way virus isolation, Virus neutralization test technique, ELISA, and RT-PCR.
Effective control of IBD disease is by carrying out a regular vaccination program accompanied by a biosecurity program, followed by the detection of antibody titers to determine the success of vaccination by serum neutralization test or ELISA. Vaccination of breeding hens is the most essential step in controlling IBD because the antibodies produced by the parents will be passed on through the eggs to the offspring. Maternal antibodies with good titers will protect chickens against IBD. Another prevention is by vaccinating using a vaccine that is homologous to the specific virus. Vaksimune IBD M+ is a live freeze-dried vaccine of infectious bursal disease of intermediate plus strain, propagated in embryonated specific pathogen-free (SPF) chicken eggs.
To obtain protection titers in commercial laying hens, a minimum of 2 times vaccinating. The First vaccine schedule is around days 6-8 of age, and then the second is around days 18-20 of age. Vaccination before the outbreak is to protect immunity against IBD Virus.
by drh. Yasir Hamdani Dalimunthe