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CHYTRID FUNGUS, FROG - PHILIPPINES: (LUZON)
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A ProMED-mail post
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International Society for Infectious Diseases
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Date: Thu 21 May 2009
Source: Business Mirror [edited]
<http://businessmirror.com.ph/component/content/article/53-agri-commodities/10657-scientists-find-deadly-fungus-in-luzon.html>
Scientists find deadly fungus in Luzon
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Scientists conducting frog surveys in 2 areas in Luzon have discovered a
deadly fungus that could send amphibians -- particularly frogs -- to
extinction.
The discovery of the chytrid fungus has prompted the Department of
Environment and Natural Resources (DENR) to sound the alarm, and DENR
secretary Lito Atienza has ordered the Protected Areas and Wildlife Bureau
(PAWB) to formulate a national strategy for monitoring frog populations
throughout the country. "We cannot discount the possibility that global
warming is promoting the spread of this fungus because according to
studies, rising temperature allows it to enter places where these
amphibians reside," Atienza said.
The infection was discovered by scientists who just concluded a 2 year
joint US-Philippine survey of chytrid fungus in 20 different sites in the
Philippines. Scientists said 18 of the sites are currently free of the
deadly fungus, which indicates that the infection isn't massive and could
still be prevented, says Mae Diesmos, assistant professor at University of
Santo Tomas and leader of the team sampling live frogs' skin for the past 2
years.
Five endemic species of frogs, Luzon striped frog (_Rana similis_), Luzon
stream frog (_Rana luzonensis_), Luzon fanged frog (_Limnonectes woodworth_
and _Limnonectes macrocephalus_) and Puddle frog (_Occidozyga laevis_) --
found in Mount Labo, Camarines Norte, and Mount Palay-palay Cavite province
were infected with the fungus scientifically known as _Batrachytrium
dendrobatidis_, the agent causing chytridiomycosis, a frog disease. It is
an infectious and often lethal disease that triggered the extinctions of
hundreds of species of frogs throughout the world.
Chytrid fungus causes deformities in tadpoles and interferes with the skin
of adult frogs and toads. When infection levels are high, catastrophic
die-offs can occur, wiping whole populations and even entire species of
amphibians.
At least one of the infected frog species may be declining but scientists
said further monitoring of the population of the said species is needed to
come up with such conclusion in the coming years. Scientists said a
combination of habitat disturbance and forest destruction, and climate
change may have triggered the rapid spread of the fungus. While evidence or
proof of such fungus infection in frogs have been found in Cavite and
Camarines Norte, scientists fear it may be found in other places or could
spread throughout the country. Previously unrecorded in Asia, the chytrid
fungus has recently been reported in Japan and Indonesia, Atienza said.
A third of the 5743 known species of frogs, toads, and other amphibians are
classified as threatened, the Global Amphibian Assessment survey revealed,
and the continuous spread of the deadly fungus is very alarming, Atienza
said. "We are looking at a possible mass extinction if we don't do
something about it," Atienza said. A total of 592 of the country's 1137
endemic species of amphibians, birds, and mammals have been declared as
threatened or endangered, Atienza said.
Dr Rafe Brown, a professor of Biology in the University of Kansas and a
collaborator in the study, said the fungus is a very serious threat to
amphibian biodiversity in the Philippines.
A curator of amphibians and reptiles in the University of Kansas
Biodiversity Institute said the Philippines is home to an incredibly
diverse amphibian fauna. He blamed forest destruction, pollution, and
climate change for the infection of the frogs, and warned that it may turn
out to be "the final blow" that could spark major amphibian extinctions in
the archipelago.
His counterpart in the Philippines, Dr Arvin Diesmos, curator of amphibians
and reptiles at the National Museum of the Philippines emphasized that one
of the most disturbing findings was the fact that the pathogen is
apparently present at middle to high elevations in relatively pristine forests.
Mount Labo and Mount Palay-palay Mataas na Gulod National Park are both in
the southern part of Luzon, the largest and most populated island in the
Philippines.
Dr Vance Vredenburg, assistant professor at the San Francisco State
University and member of the team that identified the fungus using
molecular data, said of the nearly 6500 species of amphibians in the world,
more than one-third are threatened by extinction and many hundreds of Asian
species are now in jeopardy.
Several studies in recent years have linked the rapid disappearance of many
of the world's frogs and toad species to global warming. Amphibians, in
particular, have suffered more species loss than any other animal group due
to the deadly fungus. According to scientists, the disease has already
wiped out hundreds of frogs, toad, and salamander species, and is spreading
across the globe, in part because of climate change but also through
international trade -- much of it illegal -- in wildlife. Scientists are
still scrambling to find a cure that will work in the wild even as more
species disappear.
[byline: Jonathan Mayuga]
--
communicated by:
HealthMap Alerts via
ProMED-mail <promed@promedmail.org>
[Chytridiomycosis is a key example of an emerging infectious disease in
wildlife. The most important factor driving the emergence of such wildlife
diseases is the anthropogenic (humanborne) introduction of pathogens into
new geographic areas (pathogen pollution). Following its introduction,
confining the disease indoors is a complex, or almost unattainable goal.
For a detailed description of the disease signs, subscribers are referred
to Mod.TG's commentary in 20080928.3065.
Further reading
---------------
1. Chytrid Fungus page in the Amphibian Ark website
<http://www.amphibianark.org/chytrid.htm>.
2. Che Weldon et al. Origin of the amphibian chytrid fungus. EID, 10, (12),
December 2004, available at
<http://www.cdc.gov/ncidod/eid/vol9no8/03-0030.htm>. - Mod.AS
Pictures:
Luzon striped frog (_Rana similis_):
<http://polillo.mampam.com/Images/Amphibianspeciesguide/Frogextrapics/images/Rana%20similis3.jpg>
Luzon stream frog (_Rana luzonensis_):
<http://www.gulf-times.com/mritems/images/2009/5/20/2_291894_1_248.jpg>
Luzon fanged frog
_Limnonectes woodworthi_:
<http://polillo.mampam.com/Images/Amphibianspeciesguide/Frogextrapics/images/Ranawoodworthi2.jpg>
and
_Limnonectes macrocephalus_:
<http://www.herpwatch.org/images/species/macroceph.Balbalasang.jpg>
Puddle frog (_Occidozyga laevis_):
<http://polillo.mampam.com/Images/Amphibianspeciesguide/Frogextrapics/images/Occidozyga%20laevis2.jpg>
The HealthMap/ProMED-mail interactive map of the Philippines is available
at <http://healthmap.org/r/00dc>. - CopyEd.MJ]
[see also:
2008
---
Chytrid fungus, frogs - Panama 20081014.3246
Climate change, disease impact: amphibians 20081003.3124
Chytrid fungus, frogs - Spain (Majorca) 20080928.3065
2007
---
Chytrid fungus, frogs - Japan (02): wild frogs 20070613.1924
Chytrid fungus, frogs - Japan 20070113.0176
2006
---
Chytrid fungus, amphibian - worldwide 20061027.3077
Chytrid fungus, frogs - worldwide: possible source 20060524.1463
Chytrid fungus, frogs - South Africa 20060203.0344
2005
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Chytrid fungus, frogs - UK (England) 20050916.2741
Undiagnosed die-off, toads - Germany (03) 20050515.1337
2004
---
Iridoviruses, amphibian deaths - USA 20041212.3292
.................arn/mj/sh
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