NEWCASTLE DISEASE, WATER BIRDS - USA: (MINNESOTA)
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Date: 6 Aug 2010
Source: Twin Cities [edited]
<http://www.twincities.com/ci_15696596?nclick_check=1>
Almost 1000 double-crested cormorants and ring-billed gulls have died on a western Minnesota lake from Newcastle disease, the Minnesota Department of Natural Resources (DNR) said Friday [6 Aug 2010]. As of Wednesday (4 Aug 2010), about 500 cormorants and 400 ring-billed gulls had been found dead on Marsh Lake near Appleton in Big Stone County.
More testing is being done to determine the strain of the viral disease, which most commonly infects cormorants, but also has been found in gulls and pelicans. Clinical signs in wild birds are often neurologic and include droopy head or twisted neck, lack of coordination, inability to fly or dive and complete or partial paralysis. Juveniles are most commonly affected.
Newcastle disease can sometimes affect people, generally causing conjunctivitis, a relatively mild inflammation of the inner eyelids.
It's spread to people through close contact with sick birds.
Another die-off of 50 cormorants, meanwhile, has been discovered on Wells Lake in Rice County, south of the Twin Cities metro area.
Samples are being tested, but the specific cause of the birds'
illness is unknown.
The DNR and the U.S. Department of Agriculture's Wildlife Services staff are cleaning up the sites and collecting swab and carcass samples for lab analysis.
Newcastle disease is not new to Minnesota. The last outbreak covered a 7-county area in 2008, when 2400 birds died. In 1992, several outbreaks occurred across the Great Lakes, Upper Midwest, and Canada, killing an estimated 35 000 birds.
[Byline: Dennis Lien <dlien@pioneerpress.com>]
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[Newcastle disease is an acute viral disease of domestic poultry and many other bird species. It is a worldwide problem that presents primarily as a respiratory disease, but depression, nervous manifestations, or diarrhea may be the predominant clinical form.
Mortality is variable. Occurrence of a virulent form of the disease is reportable and may result in trade restrictions.
Virulent NDV strains are endemic in poultry in most of Asia, Africa, and some countries of North, Central, and South America. Other countries, including the USA and Canada, are free of those strains and maintain that status with import restrictions and eradication by destroying diseased poultry. Cormorants, pigeons, and imported psittacine species have also been sources of virulent NDV infections of poultry. Low virulence NDV is prevalent in poultry and wild birds, especially waterfowl. Infection of domestic poultry with low virulence NDV contributes to lower productivity.
Infected birds shed virus in exhaled air, respiratory discharges, and feces. Virus is shed during incubation, during the clinical stage, and for a varying but limited period during convalescence. Virus may also be present in eggs laid during clinical disease and in all parts of the carcass during acute virulent infections. Chickens are readily infected by aerosols and by ingesting contaminated water or food.
Infected chickens are the primary source of virus, but other domestic and wild birds may be sources of NDV. Transfer of virus, especially in infective feces, by the movement of people and contaminated equipment is the main method of spread between poultry flocks.
Onset is rapid, and signs appear throughout the flock within 2-12 days (average 5) after aerosol exposure. Spread is slower if the fecal-oral route is the primary means of transmission, particularly for caged birds. Young birds are the most susceptible. Observed signs depend on whether the infecting virus has a predilection for respiratory, digestive, or nervous systems. Respiratory signs of gasping, coughing, sneezing, and rales predominate in low virulence infections. Nervous signs of tremors, paralyzed wings and legs, twisted necks, circling, clonic spasms, and complete paralysis may accompany, but usually follow, the respiratory signs in neurotropic velogenic disease.
Nervous signs with diarrhea are typical in pigeons, and nervous signs are frequently seen in cormorants and exotic bird species.
Respiratory signs with depression, watery-greenish diarrhea, and swelling of the tissues of the head and neck are typical of the most virulent form of the disease, viscerotropic velogenic Newcastle disease (VVND, also called exotic Newcastle disease), although nervous signs may also be seen. Varying degrees of depression and inappetence are observed.
Portions of this comment have been extracted from:
<http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/203702.htm&word=newcastle>
- Mod.TG]
[For a picture of a double crested cormorant, see <http://www.enature.com/fieldguides/enlarged.asp?imageID=16948>
For a picture of a ring billed gull, see <http://www.nps.gov/prsf/naturescience/ring-billed-gull.htm>
For the interactive HealthMap/ProMED map of Minnesota, see <http://healthmap.org/r/00DI>. - Mod.MPP]
[see also:
2003
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Newcastle disease, cormorants - USA (NY, VT) 20031009.2534 Newcastle disease, game fowl, plty - USA (west) (20) 20030714.1733 Newcastle disease, game fowl, pltry - USA (West) (19) 20030712.1717 Newcastle disease, game fowl, pltry - USA (West) (18) 20030702.1631 Newcastle disease, game fowl, plty - USA (west) (17) 20030604.1370 Newcastle disease, game fowl, plty - USA (west) (16) 20030527.1297 Newcastle disease, game fowl, plty -- USA (west) (15) 20030519.1236 Newcastle disease, game fowl, plty - USA (west) (14) 20030515.1212] ....................sb/tg/ejp/mpp
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