Duck plague, also known as Duck Virus Enteritis (DVE), is a severe and often fatal viral disease. It primarily affects ducks, geese, and swans. This highly contagious illness is caused by Anatid herpesvirus 1. Outbreaks of DVE can lead to very high mortality rates, sometimes reaching 100% in affected flocks. This can cause significant financial losses for domestic duck farms due to high mortality and declines in egg production.
Recognizing the Signs
Symptoms of duck plague vary by virus strain, species, and immune status. Often, the first indication is sudden, unexpected deaths within a flock, with birds appearing healthy one day and found dead the next.
Affected birds show a range of behavioral and physical changes. They might display weakness, depression, and ruffled feathers. A loss of appetite, extreme thirst, partially closed eyelids, and sensitivity to light are frequently observed. Incoordination, known as ataxia, and tremors can also occur, making it difficult for birds to stand or fly.
Digestive issues are common, with birds experiencing severe watery or bloody diarrhea. Nasal discharge and blood-stained bills are also indicators. A drooped-wing appearance is a characteristic sign, and in male ducks, a prolapsed penis may be observed. In young ducklings, additional signs include tearing eyes, weight loss, and blue-colored beaks.
How Duck Plague Spreads
Duck plague spreads primarily through direct contact with infected birds that shed the virus in feces, saliva, and nasal secretions. Contaminated water is a significant route of transmission, as birds can contract the disease by drinking or swimming in it.
The virus can also spread indirectly through contaminated food or equipment. Migratory waterfowl play a substantial role, acting as asymptomatic carriers that introduce the virus to new areas. They can shed the virus periodically, even for years, maintaining the infection cycle. The virus can persist in moist environments for up to 60 days, especially in stagnant or slow-moving water.
Protecting Poultry from Duck Plague
Preventing duck plague involves strict biosecurity measures and vaccination. Live attenuated vaccines are commonly used in commercial duck farming to prevent the disease. These vaccines are typically administered to young birds, with booster vaccinations every four to six months for ongoing protection.
Biosecurity practices are important to limit virus spread. Maintaining clean water sources and limiting contact between domestic and wild birds are recommended. Isolating any new birds before introducing them to an existing flock helps prevent virus introduction.
Regular cleaning and disinfection of equipment and facilities are also important for prevention. If duck plague is suspected, consult a veterinarian for diagnosis, which may involve virus isolation or molecular tests like PCR. Affected birds should be isolated to prevent further transmission.