Published Date: 1999-11-09 23:50:00
Subject: PRO/AH/EDR> Botulism, waterfowl - Canada (Ontario)
Archive Number: 19991109.2009

BOTULISM, WATERFOWL - CANADA (ONTARIO)
**************************************
A ProMED-mail post
<http://www.healthnet.org/programs/promed.html>

See Also

Botulism, avian: cause & cure 990719215236
Date: Fri, 05 Nov 1999 18:42:00 -0500
From: Ian Barker <ibarker@ovc.uoguelph.ca>

Significant numbers of several species of mainly fish-eating birds have
died over the past 5 weeks on southeastern Lake Huron (between Kettle Point
and Grand Bend, approximately 50-80 km NE of Sarnia, Ontario), and along
north west shore of Lake Erie (between Point Pelee and Rondeau,
approximately 60-80 km SE of Windsor, Ontario).
On Lake Erie, minor mortality was noted throughout September, with an
increase about 28 Sep 1999 that persisted for a few days, and a larger
episode beginning 26 Oct 1999, that now is apparently subsiding. About 90%
of birds found sick or dead have been common mergansers, though common
loons, grebes, diving ducks, ring-billed gulls, herring gulls, and
Bonaparte's gulls also have been affected. Mortality is likely of the order
of 1000 birds, with 1-2 carcasses per 10 metres of beach in some
localities.
On Lake Huron, where beached carcasses were observed beginning about 14 Oct
1999, with a notable increase on 23-24 Oct 1999, approximately 90% of the
birds involved were common loons. Fewer common mergansers, grebes,
red-throated loons, some diving ducks, ring-billed gulls and Bonaparte's
gulls also were reported. The number of birds affected has not been
determined, but based on carcass counts, at least 700 loons died.
Type E botulism has been diagnosed in mergansers that died in late
September and late October on Lake Erie, and in loons from Lake Huron. Live
sick loons had flaccid paralysis, and some were successfully rehabilitated
and released following supportive care.
In late July and early August a large number of gulls and sanderlings were
found dead on the beaches at Point Pelee after a large fish die-off in the
area. We were unable to confirm botulism in these birds, but no other
disease was recognized, and the circumstances and reported behaviour (some
sick birds recovered and were released following supportive care) are
compatible with botulism.
Type E botulism is associated with fish, and the majority of birds involved
in these out breaks are fish-eaters or scavengers. Even diving ducks, which
are primarily mollusc feeders, had fish in their digestive tracts at the
time of death. At this time of year, large rafts of migrating loons,
mergansers and diving ducks are resting and feeding offshore in the
affected areas.
Episodes of Type E botulism are periodically recurrent in fish-eating
birds, especially loons, on the Great Lakes in late fall [see Brand, C.J.
et al., An outbreak of Type E botulism among common loons (_Gavia immer_)
in Michigan's Upper Peninsula. Journal of Wildlife Diseases 24: 471-476, 1
988. We diagnosed botulism as the cause of a smaller die-off of common
loons in the Kettle Point-Grand Bend area in fall 1998. What is unclear are
the circumstances under which fish become toxic. No unusual fish mortality
has been detected in association with the episodes on Lakes Erie and Huron
over the past 5 weeks, and loons, mergansers and grebes would not be
expected to consume dead fish.

--
G. Douglas Campbell, and Ian K. Barker
Ontario Region,
Canadian Cooperative Wildlife Health Centre,
Dept. of Pathobiology,
Ontario Veterinary College,
University of Guelph,
Guelph, Ontario Canada
e-mail: ibarker@ovc.uoguelph.ca
........................................tg/es
--
Send all items for posting to: promed@promedmail.org
(NOT to an individual moderator). If you do not give your
full name and affiliation, it may not be posted. Send
commands to subscribe/unsubscribe, get archives, help,
etc. to: majordomo@promedmail.org. For assistance from a
human being send mail to: owner-promed@promedmail.org.
##########################################################
##########################################################

*##########################################################*
ProMED-mail makes every effort to verify the reports that
are posted, but the accuracy and completeness of the
information, and of any statements or opinions based
thereon, are not guaranteed. The reader assumes all risks in
using information posted or archived by ProMED-mail. ISID
and its associated service providers shall not be held
responsible for errors or omissions or held liable for any
damages incurred as a result of use or reliance upon posted
or archived material.
************************************************************
Visit ProMED-mail's web site at <http://www.promedmail.org>.
Send all items for posting to: promed@promedmail.org
(NOT to an individual moderator). If you do not give your
full name and affiliation, it may not be posted. Send
commands to subscribe/unsubscribe, get archives, help,
etc. to: majordomo@promedmail.org. For assistance from a
human being send mail to: owner-promed@promedmail.org.
############################################################
############################################################