Published Date: 2005-12-09 23:50:00
Subject: PRO/AH/EDR> Waterfowl die-off - Mexico (AG): botulism susp.
Archive Number: 20051209.3555
WATERFOWL DIE-0FF - MEXICO (AQUASCALIENTES): BOTULISM SUSPECTED
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Date: 6 Dec 2005
From: Mary Marshall <firstname.lastname@example.org>
& A-Lan Banks <A-Lan.Banks@thomson.com>
Source: Reuters [edited]
The sudden death of more than 1000 ducks at a lake in Mexico was not caused
by bird flu, the government said on Monday, but scientists are still trying
to uncover why the birds mysteriously died.
An Agriculture Ministry spokesman said the condition of the dead birds,
found by a lake in central Aguascalientes state, showed they had been dying
over a period of days or weeks.
Scientists are trying to work out if the birds died of botulism, a rare but
deadly illness caused by toxic bacteria, or from pollution, the ministry said.
The ministry would not say what species of duck had been hit in the mass
death, or how it had ruled out bird flu as a cause of death.
Although Mexico has had some cases of a low pathogenic strain of the flu,
which presents no known risk to humans, it has so far been successful at
keeping out the highly contagious and deadly H5N1 strain of the virus.
Migratory birds like ducks are seen as a possible cause of cross-border
infection since flu was detected in birds in Russia, Turkey and Romania.
H5N1 is endemic in poultry in parts of Asia, where it has killed almost 70
people. Experts fear the virus could mutate into a form which can be
transmitted easily from person to person, sparking a pandemic in which
millions of people could die.
Some environmental activists in Mexico say the virus could enter the
country via a thriving trade, both illegal and legal, in exotic birds such
as parrots. Mexico prohibits the import of all birds and bird products from
countries with confirmed outbreaks of the virus.
But environmental groups want a blanket ban, arguing the nature of trade in
exotic birds makes it hard to determine their origin.
Date: 6 Dec 2005
From: A-Lan Banks<A-Lan.Banks@thomson.com>
Source: El Universal Online, Mexico, 6 Dec 2005 [edited]
Hundreds of aquatic birds turned up dead along the shores of El Niagara
reservoir, 15 km east of Aguascalientes, victims of an apparent mass infection.
The dead birds, most of them ducks and coots, were reported by citizens
late last Friday and state officials began to recover and examine the
animals over the weekend.
"So far, it looks like botulism, although we can't rule anything out yet,"
said state environment chief Juan Solorio Tlazeca, who said that the
affected birds were still being examined at a state animal pathology
Enriqueta Medellin, president of the local Ecological Conscience civic
organization, said that she was reserving judgement on the case until test
results were available.
"It could be botulism, although it is notable to me that they did not find
much bird excrement, and botulism causes diarrhea," she said. "So another
possible cause might be water pollution."
[Aquatic birds are prone to botulism, generally type C, although such birds
as loons may be affected by type E. The causative organism is _Clostridium
botulinum_. If the carcasses are not disposed of, the maggots that tend to
form also harbor the toxin. Other birds will eat the maggots from the
carcasses and become intoxicated. Generally botulism does not cause
diarrhea or other increase in bird excrement, but it does cause a condition
commonly known as "limberneck." The botulism toxin causes a paralysis of
the muscles and the bird is unable to hold the head upright. Many birds
actually drown because they cannot lift their head out of the water. The
paralysis also renders the birds unable to use their wings or their legs
and often even the eyelids are unable to be raised.
Other diseases such as duck plague may cause the carcass to be soiled with
excrement. However, with coots being affected, it is unlikely to be duck
Since there are indications that the birds have been dying for some period
of time, it is unlikely that the cause is Avian cholera (caused by
_Pasteurella multocida_), as this disease causes rapid death.
If only 2 types of birds (ducks and coots) are affected, it is unlikely to
be water contamination. However, all of this remains speculative until
results are received from the lab. We look forward to an authoritative
report on the laboratory results. - Mod.TG]