Systematic Veterinary Virology

INTRODUCTION

• Duck hepatitis is caused by at least three different viruses, namely duck hepatitis virus (DHV) types I, II and III.
• The most common is DHV type I is an enterovirus.
• DHV type II is an astrovirus, and
• DHV type III is considered to be a picornavirus.
• The more prevalent and internationally mentioned duck viral hepatitis is the duck hepatitis virus (DHV) type I, which is an enterovirus that causes a highly lethal, acute, contagious infection in ducklings upto 6 weeks of age. This infection is not seen in older birds.
• DHV type II is caused by an astrovirus. The infection occurs in ducklings from 10 days to 6 weeks of age, and caused pathological changes similar to those of DHV type I
• DHV type III is reported only in the United States of America. It causes similar liver lesions in young ducklings, but is less virulent than DHV type I. It is believed to be a picornavirus, serologically unrelated to type I virus.
• The viruses that cause hepatitis in ducklings should not be confused with duck hepatitis B virus, a hepadnavirus infection of older ducks.