SALMONELLOSIS, REDPOLL FINCHES - USA (MINNESOTA): SUSPECTED
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A ProMED-mail post
http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
http://www.isid.org>

Date: Sat, 5 Mar 2005
From: ProMED-mail 
Source: Minneapolis-St. Paul Star Tribune, 4 Mar 2005 [edited]
http://www.knoxstudio.com/shns/story.cfm?pk=BIRDPLAGUE-03-04-05&cat=AN>


This winter, common redpolls -- small red-capped finches that flock at
feeders -- have swarmed into Minnesota from Canada, delighting
birdwatchers.
But in the past 3 weeks, birds have been dropping dead near feeders all
over
the state, victims of salmonella.

People are being urged to remove finch feeders, clean them with a mild
bleach
or vinegar solution and not replace them for a while to force the birds
to
forage more widely, lessening the spread of the disease.

"Probably in the next 2 to 3 weeks they'll be moving north, spreading
out
over thousands of miles of northern forest, and that will help
greatly," said
Carrol Henderson, supervisor of non-game wildlife programs for the
Minnesota
Department of Natural Resources.

Henderson urged cat owners to keep their pets inside for a while. Cats
that
catch and eat sick birds can catch salmonella and become seriously ill.

Common redpolls are brownish finches with pale bellies and bright
cherry-
colored caps. Males have rosy breasts. Usually full-time Canadian
residents,
they move south in large numbers every 5 or 6 years during the winter
because
of food shortages, Henderson said.

The birds are "beautiful little things and feed in swarms," thrilling
birdwatchers and driving up sales of thistle seed and ground peanut
hearts,
he said. But last month, people all over Minnesota began reporting that
redpolls, some pine siskins and even a few native goldfinches were
dying. The
Park Rapids area, in the northern part of the state, has seen evening
grosbeaks affected by the mystery disease.

Tests revealed the culprit to be salmonella B, a bacterial disease
transmitted by contact from bird to bird, from infected feeders and
from
droppings that fall on seed on the ground. Henderson recommended
cleaning up
the ground below feeders to reduce chance of transmission. Dead birds
should
be disposed of.

It's a coincidence that the salmonella outbreak coincided with one of
the
redpoll's periodic migrations into the United States, Henderson said.
Similar
die-outs have been reported from Quebec to New York to Virginia and
North
Carolina, he said. But he said the overall population should be fine
because
birds that survive have more resistance and because they will scatter
when
they migrate north again.

[Byline: Mary Jane Smetanka]

- --
ProMED-mail


[This information seems strikingly similar to a previous posting on
redpoll
finch mortality in Alaska (see ref).

A possible spread of Salmonella by finches should worry public health
folks
at least to the same degree as it seems to worry cat lovers. Among the
Salmonella group B bacteria there are notorious pathogens such as _S.
typhimurium_, _S. agona_, _S. heidelberg_ and _S. brandenburg_.

If this is salmonellosis, are the bacteria the primary, direct cause of
disease and mortality among the birds, affecting all or most of them,
or just
a secondary finding? Interestingly, during the 1997-1998 epizootic of
salmonellosis affecting several species of songbirds over a large area
of the
eastern North American continent, the common redpoll (_Carduelis
flammea_)
was found to be the species most often affected. (Daoust et al, 2000.
Salmonellosis in songbirds in the Canadian Atlantic provinces during
winter-
summer 1997-98. Can Vet J. 41(1):54-59.)

1st-hand information from professional investigators and the veterinary
laboratories involved, including identification of the bacteria, will
be
helpful. - Mod.AS]

[To quote from the post on the Alaska outbreak (ref. below):
"... if the Washington lab does not get a salmonella culture, it will
continue to work on the sample until it isolates the cause. Whatever
the
outcome, ... it is likely the culprit is being passed from bird to bird
at
feeders and that bird enthusiasts should continue to take precautions
as if
the outbreak was salmonella. That includes cleaning feeders frequently
and
disposing of dead birds so that pets do not become infected."  Meaning
that
the birds could be salmonella carriers but that salmonella is not the
cause
of death. I suppose they should have the lab results by now. - Mod.JW]



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