Group Group I (dsDNA) Family Herpesviridae Genus Mardivirus | Order Herpesvirales Subfamily Alphaherpesvirinae | |
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Species Duck herpesvirus 1 (DHV-1) | ||
Duck plague (also known as duck viral enteritis) is a worldwide disease caused by duck herpesvirus 1 (anatid herpesvirus 1) of the family Herpesviridae that causes acute disease with high mortality rates in flocks of ducks, geese and swans. It is spread both vertically and horizontally—through contaminated water and direct contact. Migratory waterfowl are a major factor in the spread of this disease as they are often asymptomatic carriers of disease. The incubation period is three to seven days. DVE is not zoonotic.
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Clinical signs and diagnosis
Sudden and persistent increases in flock mortality is often the first observation of DVE. Symptoms in individual birds include loss of appetite, decreased egg production, nasal discharge, increased thirst, diarrhea, ataxia, tremors and a drooped-wing appearance. Most ducks that show symptoms eventually die—mortality may reach 90 percent.
Due to the formation of diptheroid plaques on the eyelids and the mucosae of the respiratory system and gastrointestinal system the bird may show ophthalmic signs and refuse to drink.
Diagnosis can usually be made based on the clinical signs and postmortem findings:
On post-mortem, petechial haemorrhage in the conjunctivae, mucous membranes, trachea, syrinx and intestine are pathognomonic for DEV.
Treatment and control
Vaccination for duck viral enteritis is now routine in the United States. Only attenuated vaccines are efficacious. Once DVE is present, depopulation, relocation and intensive disinfection are required to overcome an outbreak. Solid natural immunity develops in recovered birds.
Management practices such as preventing exposure to wild waterfowl and contaminated water and screening of new stock should be performed to prevent disease.