Duck Viral Enteritis:
Symptoms and how to get help
Duck Viral Enteritis is not a common disease in the UK. It seems to be more prevalent in S E Asia, probably because of the climate and environmental conditions and possibly because large flocks of domestic ducks are kept commercially. Nevertheless, there is the odd case in the UK which causes a lot of grief. Information is hard to come by because the incidence of the disease is rare, so we thought that the information gained from last year's enquiries, and research for solutions, could be useful on the web pages.
Cases from the UK
The cases that we have been aware of in the last few years have been in Scotland, Lancashire and Eastern England. The incidence of DVE is perhaps most likely where there is a large migrant bird population, and/or large numbers of mallard. The disease tends to arrive in spring and may be associated with migrant birds. The disease is viral, and can affect, and be carried by, geese (Anser anser), ducks (Anas p.platyrhynchos) and the Muscovy duck (Cairina moschata). It also affects wildfowl.
Strangely, in the limited number of cases reported in the UK, not all of the waterfowl flock is affected. In one case the heavy ducks had high mortality but the Call ducks and geese were all right. In another the light ducks died and the Call ducks also survived. Perhaps the unaffected birds had natural immunity.
Muscovies are generally thought to be at greatest risk and are probably an early indicator that something is wrong. Worryingly, it is reported that affected birds which survive can be carriers of the disease. In these carriers, there may be a 'cold sore' lesion under tongue (hence the term herpes virus). The sore may be intermittent; also oral swabs for testing may find the virus, but on other occasions the virus may not be found (info from a sample page from Wildpro).
In a case reported from Taiwan, 50-95% of the infected ducklings died. Death occurred within 3-4 days of the first appearance of the symptoms, and survivors were stunted; some showed physical abnormalities. In the first reported case, only young ducklings were affected. Adults presumably were over the time the disease spread (Y K Liao et al., The Outbreak and Control of Duck Viral Disease in Taiwan, 1989-90, Provincial Research Institute for Animal Health, Tansui, R.O.C on Taiwan).
Reported from Taiwan: ducks lose their appetite and stand around with ruffled feathers. Watery diarrhoea is excreted. Birds become unable to stand; some have tremors of the head, neck and body. Birds fall on their side, occasionally paddle with their legs, and die with their heads drawn back.
In addition to this, other writers describe a greenish-yellow diarrhoea which is sometimes blood-stained. Birds are sensitive to light, and thirsty. They may stand at the water's edge. The bill may turn blue. Feathers around the eyes may be sticky, and the eyes stuck shut. In laying ducks, there is a marked drop in egg production. Dead birds have blood-stained feathers around the vent and blood dripping from the nostrils. Internally, there are haemorrhages throughout the body. Note that some birds may just die suddenly with no obvious external symptoms.