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A ProMED-mail post
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International Society for Infectious Diseases
Date: 17 Dec 2010
Source: BBC Earth News [edited]
Poisoning drives vulture decline in Masai Mara, Kenya
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Vulture populations in one of Africa's most important wildlife
reserves have declined by 60 percent, say scientists. The researchers
suggest that the decline of vultures in Kenya's Masai Mara is being
driven by poisoning. The US-based Peregrine Fund says farmers
occasionally lace the bodies of dead cattle or goats with a toxic
pesticide called furadan. [Furadan is a carbamate pesticide. - Mod.TG]
This appears to be aimed at carnivores that kill the livestock, but
one carcass can poison up to 150 vultures.
Munir Virani, who is director of the Peregrine Fund's Africa programs,
has called for use of Furadan to be banned in the region "to preserve
these keystone members of the scavenging community. People may think
of vultures as ugly and disgusting, but the birds are essential for
the ecosystem," he says.
Their taste for carrion actually makes them the landscape's clean-up
team -- ensuring the region is not littered with bodies, helping
contain the spread of disease and recycling nutrients.
The results of this latest survey of vultures are published in the
journal Biological Conservation. The terrible consequences of a
vulture population crash have already been demonstrated during a case
that became known as the Asian vulture crisis. Populations of Gyps
vultures in particular, in South Asia, crashed by more than 95 percent
over just a few years in the 1990s, primarily because farmers treated
their cattle with the pain-killing drug diclofenac [acid].
The pain-killer, it turned out, was lethal to the vultures, which fed
on the dead cattle. As well as driving 3 species of vulture to the
brink of extinction, the crisis provided a huge amount of food for
wild dogs, which moved in to take the place of the birds. This had the
devastating side-effect of increasing the spread of rabies. And Dr
Virani is concerned that a similar situation could happen in Kenya.
The solution in Africa though, could be much more straightforward than
in South Asia. By boosting the public image of vultures in the
country, the Peregrine Fund hopes to stop people from carrying out
these "revenge poisoning attacks."
Between 2003 and 2005, Dr Virani and his colleagues drove across the
expansive Kenyan landscapes, counting vultures. He and his colleagues
then compared the results of these surveys with the results of surveys
carried out in the 1980s. The comparison revealed a 60 percent decline
in vultures.
Corinne Kendal's work has taken this survey a step further. Ms Kendal
is a researcher from Princeton University in the USA, who has also
been working with the Peregrine Fund -- tracking and monitoring the
birds to investigate the extent of the poisoning.
"We attached the GPS trackers like little backpacks," she tells BBC
News. "There's a piece that sits on their chest and 2 loops around
each wing. But we had 4 out of 16 vultures killed in the 1st year and
3 of those were confirmed cases of poisoning. From a sample of 16,
it's difficult to know how representative that is, but it's extremely
worrying."
The transmitters also revealed that most of the poisoning happened
outside of the reserve, which is a protected area.
"If they stayed in the Mara Serengeti they would hardly ever get
poisoned," says Ms Kendall. "But, based on the transmitters, it
appears that the vultures that use the Masai Mara have very large home
ranges -- from 30 000 to 80 000 square kilometres [11 583 to 30 888
square miles], depending on the species." And the birds can travel
over 250km [155 miles] in a single day. This means that poisoning in
and around the Masai Mara could have an effect on the vulture
populations, not just in other parts of Kenya, but in other countries
in Africa.
Ms Kendall explains to BBC News that in the Mara ecosystem, the birds
consume 70 percent of all available meat. "If we lose vultures,
there's no other animal that will be able to consume the volume," she
says.
The reserve is a vast dining table for the birds, especially during
the annual wildebeest migration, when 1.5 million of the animals march
across the plains in search of grass.
"So without vultures, during the wildebeest migration you would have
carcasses lying everywhere and you would see lots of disease spread,"
said Ms Kendall.
Under threat
------------
In the last 3 months alone, Dr Virani says he has discovered 6 cases
where vultures have been poisoned.
The Peregrine Fund has now recommend that 3 vulture species -- the
African white-backed, Ruppell's, and hooded vultures -- be relisted as
Vulnerable on the IUCN Red List, an internationally recognized
compilation of threatened species.
"If we lost the vultures," says Dr Murani, "tourists would have to
travel around the reserve with face masks on, because the stench from
rotting wildebeest carcasses would be unbearable."
[Byline: Victoria Gill]
--
Communicated by:
HealthMap Alerts via ProMED-mail
[Furadan or Curater is the market name for carbofuran, a very toxic
carbamate pesticide. Carbofuran is a systemic plant insecticide
meaning the plant can take it up through the roots and the plant pests
are killed when they consume the plant. Carbofuran is also toxic to
insects via contact with them.
Carbamates are a class of chemicals that work by reversibly inhibiting
acetylcholine esterase, a nerve transmitter. In contrast,
organophosphates irreversibly inhibit acetylcholine esterase.
Carbofuran has been banned from use in Europe and Canada. The US EPA
(Environmental Protection Agency) announced its intention in 2009 to
stop use of the chemical on all crops produced for human consumption.
In essence, it has had the same effect as banning the chemical in the
USA.
Prior to the ban of the granular form of the chemical, one granule was
enough to kill a bird of substantial size. There is a liquid
formulation that is less harmful to birds. However 1 teaspoon of the
liquid is enough to kill a 70 kg [155 pound] human.
These formulations, however illegal, remain a major culprit for
wildlife deaths in Canada, the USA and Britain. Domestic animals in
these same countries are also targeted with this poison. Especially
the granular formulation and to a lesser extent the liquid formulation
has been used in Kenya to kill lions.
Photos of the African White-backed vulture (_Gyps africanus_) may be found at:
and
Photos of Ruppell's vulture (_Gyps ruepellii_ [that is NOT a typo])
may be found at:
Photos of hooded vultures (_Necrosyrtes monachus_) may be found at:
References:
-----------
CBS News 60 Minutes tv show:
BBC News:
Wobeser et al. 2004. Secondary poisoning of eagles following
intentional poisoning of coyotes with anticholinesterase pesticides in
Western Canada. Journal of Wildlife Diseases 40(2):163-172
US EPA/OPPTS; Reregistration Eligibility Decisions (REDs) Database on
Carbofuran (1563-66-2). EPA-738-R-06-031. August 2006
Environment New Service:
[Location map of Kenya:
Location map of Masai Mara Reserve:
-Mod.JW]
[see also:
2009
----
NSAID intoxication, vulture - Asia (03): ketoprofen, pot. hazard
20091213.4235
NSAID intoxication, vulture - Asia (02): ketoprofen, pot. hazard
20091211.4218
NSAID intoxication, vulture - Asia: ketoprofen, pot. hazard 20091210.4204
2008
----
Rabies, vulture die-off - India (02): link susp. 20080818.2576
Rabies, vulture die-off - India: link susp. 20080817.2554
2006
----
Vulture die-off - Africa, Asia (02) 20061110.3236
Vulture die-off - Africa, Asia 20060718.1978
2005
----
Vulture die-off - India (Gujarat) 20050612.1644
2004
----
West Nile virus, vulture - Russia (Vladivostok) 20040630.1744
Vulture die-off - India, Pakistan, Nepal 20040204.0415
2003
----
Vulture die-off - India, Pakistan, Nepal (02) 20030620.1515
Vulture die-off - India: etiology 20030613.1459
Vulture die-off - India: RFI 20030612.1447
Vulture die-off - India, Pakistan, Nepal 20030212.0375
Rabies and vulture die-off - India 20030207.0329
2002
----
Vulture die-off - India, Pakistan, Nepal (04) 20021018.5590
Vulture die-off - India, Pakistan, Nepal (03) 20021015.5557
Vulture die-off - India, Pakistan, Nepal (02) 20021014.5552
Vulture die-off - India, Pakistan, Nepal: RFI 20021010.5514
2001
----
Vulture die-off - India (04) 20010210.027
2000
----
Vulture die-off - India (03) 20000922.1637
Vulture die-off - India (02) 20000920.1619
Vulture die-off - India 20000530.0867
....................sb/tg/ejp/jw
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