An epidemiological study of recent outbreaks of gumboro disease in Ghana

A study to assess the epidemiological factors responsible for the recent outbreaks of infectious bursal disease (IBD) in Accra and Kumasi, between October and December 2002 and January to April 2003, was conducted. Case report records at Veterinary Diagnostic Laboratories were examined for IBD cases. Farm investigations were carried out using a combination of questionnaire and interviews to obtain information on the disease situation on farms, where the outbreaks had occurred. The highest occurrence of the disease was recorded between March and April 2003, with Accra showing the highest number of cases in March, coinciding with the Easter season. Day-old chicks imported into the country succumbed more easily to the disease than those produced locally. There was an association between IBD and the chicken type that was significant (P < 0.05) in cockerels and layers. Chickens vaccinated twice were more likely to be protected from the disease than those not vaccinated or vaccinated only once. The prevalence of the disease was also influenced by the age of the chickens with a rise in susceptibility with age from 3 weeks to 6 weeks old. The results of the study indicate that the factors studied, namely source of day old chicks, bird type, vaccination history, and age of chicks at the time of outbreak influenced outbreaks of IBD and are likely to contribute to the endemicity of infectious bursal disease in the poultry producing areas of Ghana. It is recommended that stringent biosecurity measures be observed on poultry farms to control the disease in the country.