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).
Symptoms
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.
