Duck virus enteritis an Old World disease--in the New World

Historic, Archive Document

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'duck virus enteritis

I an old world disease
... in the new world

U.S.Department of Agriculture P A — 9 2 5

DUCK VIRUS ENTERITIS

an old world disease
... in the new world

Duck virus enteritis, or Dutch duck plague, is
a contagious disease of waterfowl that causes
internal bleeding and severe diarrhea and kills
many infected birds. Domestic and wild ducks,
geese, and swans are susceptible.

Before 1967, this foreign disease was unknown
in the United States. That year it suddenly ap-
peared in the heart of the commercial duck in-
dustry on Long Island. Prompt enforcement of
control measures confined the outbreak to New
York State.

Duck virus enteritis does not affect humans.

WHERE IT UUUUK6

Duck virus enteritis is established in the
Netherlands. Occasional outbreaks occur in a
small area, but the disease is not widespread.

It was described as a distinct disease in 1949.
Dutch scientists then learned that signs of duck
virus enteritis were observed in ducks in 1923,
1932, and 1942. However, the earlier outbreaks
had been mistakenly diagnosed as fowl plague.

Duck virus enteritis has also been reported in
Belgium, India, and China. The disease has not
become widespread, and it has not invaded
neighboring countries.

Duck infected with duck virus enteritis is unable to walk
normally. It creeps and stretches its wings listlessly.

Most U.S. outbreaks have occurred in commer-
cial duck flocks on Long Island. The disease has
also killed free-flying waterfowl on Long Island
and a small number of migratory birds raised
in captivity in New York State. Outbreaks have
occurred in free-flying waterfowl in Maryland
and Pennsylvania.

In spite of careful investigations, the source
of the original U.S. outbreak has not been de-
termined.

SPREAD

Some scientists think duck virus enteritis is
usually spread by infected waterfowl that shed
the virus in droppings.

The virus survives in water. It may be spread
through polluted, stagnant, and slow-moving
pools, ponds, and waterways. Waterfowl may
pick up the disease by drinking or swimming in
polluted water or eating contaminated feed. The

Necrotic lesions (raised grayish-white streaks) are seen in
the esophagus.

Darkened spleen (lower left) and hemorrhagic heart (upper
right) are results of duck virus enteritis.

virus may enter susceptible birds through the
mouth, nose, cloaca, or breaks in the skin.

The virus may possibly be spread in other
ways — on equipment ; through feathers, eggs,
manure, and offal; and by cats, rats, dogs, sea-
gulls, lice, mites, mosquitoes, and man. Some
people believe that migratory waterfowl may be
carriers.

Duck virus enteritis may occur at any season.
Many outbreaks are associated with extremes
of weather. A combination of stresses — over-
crowding of ducks, unsanitary pens, other dis-
eases, and bad weather — may increase the
severity of an outbreak.

The virus does not survive long in a clean, dry
environment. It is readily killed by heating and
disinfectants.

SUSCEPTIBLE WATERFOWL

The first outbreaks in the United States oc-
curred in breeder flocks of Pekin ducks from 3
months to 2 years old. Since that time, the dis-
ease has appeared in breeder and market ducks
of all ages — even in ducklings a few days old.

Duck virus enteritis has also been diagnosed
in noncommercial Muscovy ducks and mute
swans in the United States.

Hemorrhagic areas in the liver of a duck infected with
duck virus enteritis show up as red spots.

Dutch research workers found that many
ducks are susceptible — Pekin, Khaki Campbell,
Indian runner, garganey teal, gadwall, widgeon,
tufted, shoveler, common pochard, shell, com-
mon eider, Muscovy, and wood. Mute swans,
bean geese, and whitefronted geese are also sus-
ceptible.

There are some indications that free-flying
waterfowl may be carriers of the virus, even
though they do not show signs of infection. Sea-
gulls and mallards have been known to mingle
with commercial ducks shortly before some out-
breaks.

Duck virus enteritis is thought to affect only
ducks, geese, and swans.

SIGNS

Susceptible ducks may show signs of duck
virus enteritis 3 to 7 days after they are expos-
ed. Sometimes ducks are found dead without
signs of the disease having been observed.

Infected birds become listless, lose their ap-
petites, and develop a great thirst and watery
diarrhea. Occasionally, other signs are swollen
eyelids and drooping wings.

Egg production drops markedly in infected
breeder ducks. The eggs that are laid are usually
fertile ; hatchability is not affected. In birds that
recover, signs of disease disappear and egg pro-
duction slowly returns.

The death rate from duck virus enteritis has
reached 60 percent of infected waterfowl in some
flocks. In other flocks, only a few of the infected
birds died. Losses are higher in flocks kept in
unsanitary pens and among waterfowl affected
with other diseases.

POST MORTEM LESIONS

Post mortem lesions most often noted are
spots of dead tissue in the esophagus and cloaca.

Hemorrhages usually occur in the thymus
gland, esophagus, liver, and in the small intes-
tine, including the lymphoid rings. Not infre-
quently hemorrhages take place in other internal
organs, including the male and female reproduc-
tive tracts. The infected spleen is uniformly
dark in color and may be smaller than normal.

HOW TO GET A DIAGNOSIS

If you suspect duck virus enteritis in your
flock — or if you have w^aterfowl that die from
a disease that is unknown to you — notify your
veterinarian, your county agricultural agent, or
a State or Federal disease-control official at once.
Officials may arrange to send blood or live water-
fowl showing signs of disease to a diagnostic
laboratory.

TREATMENT

Successful treatment for duck virus enteritis
has not yet been developed.

VACCINATION

Efforts are continuing to develop a vaccine
that will protect waterfowl without spreading
duck virus enteritis. Such a vaccine — when
available — may be used to help control the dis-
ease.

The hemorrhagic spots in the intestinal walls and the
darkened, swollen band (top center) are typical of duck
virus enteritis.

CONTROL

When Pekin ducks in a commercial flock began
dying from an unidentified cause in January
1967, the Long Island producer sent them to the
Long Island Duck Research Laboratory. The
disease was tentatively diagnosed as duck virus
enteritis. The USDA's Plum Island Laboratory
confirmed the diagnosis. This was the first time
duck virus enteritis had been diagnosed in the
United States.

Immediately, a cooperative State-Federal pro-
gram was launched. University scientists joined
government veterinarians in an attempt to con-
trol and eradicate the disease.

In the first outbreak all waterfowl and eggs
were destroyed and buried; State and Federal
indemnities were paid. Contaminated premises
were thoroughly cleaned and disinfected.

Later, quarantines were established for do-
mestic waterfowl and their products originating
in Suffolk County, Long Island, N.Y. In 1969,
only ducklings from approved flocks were per-
mitted to move interstate from the quarantine
area. An approved flock is one that has been in-
spected, tested, and found not infected. Main-
tenance inspections and tests are conducted in
approved flocks at regular intervals to make
certain the disease does not appear.

HOW THE U.S. GUARDS AGAINST IT

Since duck virus enteritis has been reported in the
Netherlands, Belgium, India, and China, no waterfowl
from these countries are permitted to enter this country.

Any other country — except Canada — that wants to im-
port waterfowl into the United States can do so only
upon the issuance of an import permit. This same regula-
tion also applies to chickens, turkeys, pigeons, doves,
pheasants, grouse, partridges, quail, guinea fowl, and
peafowl of all ages. Such waterfowl and poultry are
entered at the ports of New York, Miami, and Honolulu
for quarantine.

Watch for signs of disease in your flock.

Report signs of disease and unexplained deaths of
domestic and wild waterfowl on your premises to your
veterinarian, your county agricultural agent, or State
or Federal disease-control officials.

Cooperate with State and Federal officials. Observe
quarantine.

Keep your pens and premises clean. Run-off" water
from moats should be treated by antipollution measures.
Do not overcrowd birds.

Get your replacement birds only from flocks known to
be free of duck virus enteritis.

Isolate new birds for 10 days before adding them to
your flock.

Whenever possible, keep market ducks in same pen.
Clean and disinfect pens thoroughly after flock is
marketed.

Collect dead ducks as soon as you find them. If car-
casses are not to be sent to a laboratory, burn or bury
them promptly-

If you dress or eviscerate wild waterfowl in the field,
bury all offal.

Keep visitors out of any area where waterfowl are
raised.

Do not visit other w^aterfowl farms.

TJiis is one of a series of publications designed to
acquaint American livestock and poultry producers with
foreign diseases. If you want more information, contact
your local veterinarian, your county agent, or State or
Federal animal disease-control officials.

Prepared by Animal Health Division,
Animal Disease and Parasite Research Division,
and Veterinary Biologies Division
Agricultural Research Service
Washington, D.C. Revised July 1970

■si- U.S. GOVERNMENT PRINTING OFFICE :1970—O-385-177