Systematic Veterinary Virology

PATHOGENESIS

• Hosts affected: Ducks and gooses (young birds) are more commonly affected. The infection is seen in ducklings.
• Distribution: DHV I is present in Northern America, Europe and Asia, DHV II is restricted to the United Kingdom and III is restricted to the United States of America. It has not been reported in Pacific region.
• Transmission: The disease is very contagious and the virus excreted by faeces is transmitted by direct contact between birds or through fomites such as brooders, waterer, feeder and such other equipment. Recovered birds can shed the virus for up to 8 weeks. DHV can also be through import live ducks from an infected country. Introduction of virus into susceptible population is also possible through duck meat or duck product. Rats have also been described as a reservoir for DHV viruses.
• Incubation period: Incubation period is 18-48 hours.
• Morbidity and mortality: Morbidity is 100% and mortality is 80-95%.