Plagues, Pestilences and Diseases
FEATURE-Cambodia's Super Drug-resistant Malaria Worries Health Officials
Sat, Mar 6 2010
By Thin Lei Win
PAILIN, Cambodia, March 7 (Reuters) - In a dusty village near the
Thai-Cambodia border, 24-year-old Oeur Samoeun sits on a dark green
hammock recovering from a super bug strain of malaria that has resisted
the most powerful drugs available.
Ravaged by days of fever and chills, he is considered lucky: the
parasite has left his body. But for many others, the potentially deadly
disease never quite disappears.
His province of Pailin is the epicentre of strains of malaria that have
baffled healthcare experts worldwide, raising fears a dangerous new
form of malaria could already be spreading across the globe.
"The fear is what we're observing right now could be the starting point
for something worse regionally and globally," said Dr. Charles
Delacollette, Mekong Malaria Programme Coordinator at the World Health
Organisation.
A New England Journal of Medicine study last year showed that
conventional malaria-fighting treatments derived from artemisinin took
almost twice as long to clear the parasites that cause the disease in
patients in Pailin and others in northwestern Thailand, suggesting the
drugs were losing potency in the area.
That is echoed by U.S. development agency USAID, which says
artemisinin-based combination therapy is "now taking two to three times
longer to kill malaria parasites along the Thai-Cambodian border than
elsewhere." The agency has helped to monitor the situation in the area
for years.
The disease transmitted via mosquito bites kills more than 1 million
people worldwide each year and children account for about 90 percent of
the deaths in the worst affected areas of sub-Saharan Africa and parts
of Asia.
The studies shine a spotlight on the remote province of Pailin, a
former stronghold of ultra-communist Khmer Rogue rebels and once
reknown for blood-red rubies and lush forests.
MULTIPLIED AND DISPERSED
Pailin is the origin of three drug-resistant malaria parasites over the
past five decades. Thanks to prolonged civil conflict, dense jungles
and movement of mass migrants in the gem mines in the 1980s and 90s,
the strains multiplied and dispersed through Myanmar, India and two
eventually reached Africa.
Few can say why it is a hotbed for drug-resistant malaria but experts
point to a combination of sociological factors and a complicated
history spanning the Khmer Rouge era when 1.7 million people, nearly a
quarter of Cambodia's population, perished from execution, overwork or
torture during their 1975-79 rule.
Driven from the capital, the rebels waged an insurgency from western
Cambodia with Pailin one of their last holdouts until their defeat in
the late 1990s.
"During the Khmer Rouge era, people came here illegally and when they
get malaria, they go to the market, buy pills and self-medicate,"
Sophal Uth, a Pailin-based field officer for non-profit Malaria
Consortium said. "It was difficult for the government to control."
With weak public health infrastructure and rising malaria cases,
Cambodia made malaria drugs available over the counter more than a
decade ago. Most Cambodians don't have access to public health services
and rely on private medical centres.
The strategy carried risks. Easy access reduced the number of cases but
also led to incorrect dosages and substandard or counterfeit medicine,
which instead of killing the parasites only make them stronger.
For some like Oeur, a migrant worker who likely caught malaria on a
logging trip or while sleeping in his rickety shed without a mosquito
net, artemisinin-based medicine still works.
Artemisinin, derived from the sweet wormwood, or Artemisia annua plant,
is the best drug available against malaria, especially when used in
artemisinin combination therapy (ACT) medicines made by firms such as
Swiss drugmaker Novartis AG <NOVN.VX> and France's Sanofi-Aventis
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SASY.PA>.
MOST HAVE HAD MALARIA
After three days of ACT, Oeur is weak but parasite-free.
The Mekong River region of Thailand, Cambodia, Vietnam and Laos use
ACTs against the "falciparum" parasite, the most severe form of
malaria, as suggested by the World Health Organisation.
"Artemisinin is the most effective antimalarial we have left," Dr.
Chansuda Wongsrichanalai of USAID's office of public health in Bangkok
said. "We don't have any ideal alternatives available and ready to for
use in a control programme right now."
Pailin's gem mines are gone and so are most foreign migrants and the
troops. Severe deforestation has left most hill tops barren. Yet the
parasites are as virulent as ever. Most of its inhabitants have had
malaria at least once in their lives.
Malaria experts, weary of being called alarmists, are quick to point
out ACTs still work -- they are just taking longer. The WHO isn't even
calling it drug-resistance, they preferred to use the term "altered
response" or "tolerance to artemisinin."
"From a public health perspective, I don't think it really matters much
if it's resistance or something else given that at the end of the
month, patients are returning to the health facility with the same
malaria," Dr. John MacArthur, chief of the President's Malaria
Initiative at the U.S. Centres for Disease Control and Prevention said.
Potential fallout from ACT resistance led the Bill & Melinda Gates
Foundation to fund a $22.5 million containment programme. Cambodia will
also receive $102 million from The Global Fund to fight malaria in the
next five years.
The Gates Foundation programme aims to use screening, bed nets and
grass-roots muscle to contain the parasites along the border area and
eliminate them before they can spread further.
Last November, Malaria Consortium said studies show artemisinin
resistance already may be present in Myanmar, China and Vietnam, where
between 12-31 percent of patients still had the parasite in the system
after three days of treatment.
(Editing by Jason Szep and Bill Tarrant)