Following on from the postings re dead fish at Kellys/Jerrabomberra (early
January), this NSW item may be of interest.
Robin Hide
Date: Wed, 13 Feb 2013 18:20:49 -0500 (EST)
From: ProMED-mail<>
Subject: PRO/AH/EDR> Botulism, avian, fish - Australia (03): (NS) ducks
BOTULISM, AVIAN, FISH - AUSTRALIA (03): (NEW SOUTH WALES) DUCKS
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A ProMED-mail post
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ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
Date: Fri 8 Feb 2013
Source: South Coast Register [edited]
<http://www.southcoastregister.com.au/story/1287988/botulism-caused-duck-deaths/?cs=203>
Tests have confirmed that botulism caused the death of more than 200
wild ducks on 2 ponds in Nowra.
During December [2012] and January [2013] wild ducks were found dead
or dying on the ponds in Harry Sawkins and Marriott Parks.
Testing by the Environment Protection Authority ruled out chemical
poisoning, with the Cumberland Livestock Health and Pest Authority
discovering the birds had died from botulism.
LHPA [Livestock Health and Pest Authorities] senior district
veterinarian, Dr Keith Hart, said botulism is a paralytic disease
which is difficult to diagnose. "It is caused by the ingestion of a
toxin, in this case created through a combination of low water levels
and warm temperatures," he said.
"Several dead and dying ducks and a dying seagull were examined," he
said, adding that botulism was a difficult disease to identify.
"Swabs were also taken to exclude virulent avian influenza -- a
potentially serious viral disease that could show up initially as
water bird mortalities on or near the coast.
"My diagnosis has been based on the history and clinical signs
exhibited by the sick birds examined and described by council staff,
and the fact that botulism is a fairly common cause of waterbird
deaths under these conditions."
Dr Hart says while the recent rainfall and cooler weather will assist
in flushing out the toxins, people should stay away from any duck
carcasses. "It is important that the public don't touch duck carcasses
or allow dogs to touch them," he said.
- --
Communicated by:
ProMED-mail from HealthMap Alerts
<>
[From the text, is not entirely clear whether botulism was confirmed
by laboratory tests, or if the diagnosis was based on a presumption
after other possible causes have been ruled out
Avian botulism is a paralytic disease caused by ingestion of a toxin
produced by the bacterium_Clostridium botulinum_. Spores of 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.
From the NWHC (USGS National Wildlife Health Center) field manual
(Chapter 38):
"A presumptive diagnosis of avian botulism is often based on a
combination of signs observed in sick birds and the absence of obvious
lesions of disease when the internal organs and tissues of sick and
dead birds are examined. However, this initial diagnosis must be
confirmed by the mouse-protection or ELISA test to separate avian
botulism from algal poisoning, castorbean poisoning, and other toxic
processes that cause similar signs of disease." (...) "The most widely
used test for avian botulism is the mouse-protection test, although an
enzyme-linked immunosorbent assay (ELISA) for type C toxin has been
developed recently".
A map of the affected area can be accessed at
<http://healthmap.org/r/5mhm>. - Mod.PMB]
[see also:
Botulism, avian, fish - Australia (02): (NS) 20130127.1517277
Botulism, avian, fish - Australia: (QL) 20130124.1512183
2012
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