BOTULISM, AVIAN - USA (07): (MICHIGAN) AQUATIC BIRDS
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Date: Wed, 5 Sep 2012
Source: Harbor Light [edited]
<http://www.harborlightnews.com/atf.php?sid=15036&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+wdinNewsDigestGeoRSS+%28Wildlife+Disease+News+Digest+GeoRSS+Feed%29&utm_term=wdinNewsDigestGeoRSS>
After a relatively quiet season in 2011, dead birds are again appearing on the Lake Michigan shoreline, and this year much earlier than anticipated. "Calls have been coming in for the past two weeks with reports of migratory waterfowl washing up on local beaches" said Kevin Cronk, Research and Monitoring Coordinator for Tip of the Mitt Watershed Council. "While the numbers are small, it is much earlier in the season than usual. We don't typically have this many reports until late September to early October. We are just at the beginning of 'avian botulism season' and calls this early may indicate a dramatic increase in bird mortality in the next few months."
Bird mortality caused by ingestion of a toxin produced by the bacterium _Clostridium botulinum_ has been periodically reported on the Great Lakes since the 1960s. However, the recent increase in avian botulism in the Great Lakes is believed due to alterations to the aquatic ecosystem brought on by invasive zebra and quagga mussels. The feeding behavior of the invasive mussels creates environmental conditions in the water that allow a common bacterial species to produce the botulism toxin. The mussels ingest the toxin, which is then passed through to fish and birds that feed upon the mussels or on fish that have become intoxicated by botulism. Low lake levels and high water temperatures may also play a key role in the outbreaks.
Since 2007, Tip of the Mitt Watershed Council has taken the initiative to educate the public and coordinate monitoring activities in order to better understand the extent and gravity of avian botulism outbreaks.
Volunteers from Emmet County Lakeshore Association, Petoskey Regional Audubon Society, other organizations, and the general public are assisting the Watershed Council to track the number and types of birds and fish dying from botulism. However, additional volunteers are always needed.
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[Avian botulism is a paralytic disease caused by ingestion of a toxin produced by the bacteria _Clostridium botulinum_. These bacteria are widespread in soil and require warm temperatures, a protein source, and an anaerobic (no oxygen) environment in order to become active and produce toxin. Decomposing vegetation and invertebrates combined with warm temperatures can provide ideal conditions for the botulism bacteria to activate and produce toxin. There are several types of toxin produced by strains of these bacteria; birds are most commonly affected by type C and to a lesser extent type E. Outbreaks of botulism in wild aquatic birds are a natural phenomenon in North America. Botulism epidemics typically occur in late summer or autumn and often recur at the same locations year after year.
There is no risk to people clearing up the carcasses.
A map of the affected area can be accessed at <http://healthmap.org/r/3o4y>. - Mod. PMB]
[It would be interesting to know the species of the dead birds. - Mod.JW]
[see also:
Botulism, avian - USA (06): (MD) aquatic birds 20120829.1271009 Botulism, avian - USA (05): (WY) pheasants 20120824.1262052 Botulism, avian - USA (04): (CA) waterfowl, susp. 20120802.1225667 Botulism, avian - USA (03): (OH) waterfowl, susp 20120706.1192230 Botulism, avian - USA (02): (HI) 20120624.1178706 Botulism, avian - USA: (CA) 20120430.1117985 Botulism, avian - New Zealand: (CB) susp 20120213.1040575
2011
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Botulism, avian - USA: (CO) 20110914.2797 2010
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Botulism, avian - USA (05): (FL) susp. 20100817.2848 Undiagnosed die-off, avian - USA (08): (CA) botulism susp.
20110923.2878]
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