Rev. sci. tech. Off. int. Epiz., 1996, 15 (3), 1053-1060 Epidemiology of inclusion body hepatitis in poultry in northern India from 1990 to 1994 A. SINGH *, M.S. OBEROI **, S.K. JAND ** and B. SINGH *** Summary: The epidemiology of inclusion body hepatitis (IBH) was studied in poultry in northern India, from April 1990 to March 1994, to evaluate the various factors responsible for causing and determining the severity of the disease. Broiler chicks and Japanese quail (Coturnix coturnix japonica) were the species examined. The factor observed to be most commonly associated with IBH was the presence of aflatoxins in the feed at higher than permissible levels, i.e. 20 parts per billion. Avian adenovirus-1 was isolated from the livers of affected birds. In the final year of the study, a number of outbreaks of IBH caused heavy mortalities among three to five-week-old broiler chicks, which displayed typical IBH lesions in addition to hydropericardium. KEYWORDS: Aflatoxin - Avian adenoviruses - Epidemiology - Hydropericardium - Inclusion body hepatitis - India - Poultry diseases - Viral diseases. INTRODUCTION Avian adenoviruses have been shown to cause various diseases in different species of birds. In India the diseases caused by avian adenoviruses, particularly inclusion body hepatitis (IBH), threaten the viability of the poultry industry. This is particularly important in view of the fact that poultry farming has become an important livestock industry in India. India is ranked fifth in the world for egg production, and the production of broiler chickens has increased from four million in 1971 to 275 million in 1994. Thus, from April 1990 to March 1994, studies were conducted in northern India on the epidemiology of IBH, to evaluate the roles of various field conditions in the causation and severity of the disease, in order to develop and recommend various preventive measures. * Department of Veterinary Public Health and Epidemiology, College of Veterinary Science, Punjab Agricultural University, Ludhiana-141 004, India. ** Veterinary Bacteriology and Virology, College of Veterinary Science, Punjab Agricultural University, Ludhiana-141 004, India. *** Veterinary Pathology, College of Veterinary Science, Punjab Agricultural University, Ludhiana-141 004, India.