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CAMBODIA: Hope Emerges in Epicentre of Drug-resistant Malaria

Marwaan Macan-Markar

Bangkok, Jul 15 2010 (IPS) - In a western corner of Cambodia known for battles waged by the genocidal Khmer Rouge decades ago, a new war is being fought. Its target, this time, is the lethal malaria parasite that is resistant to the most effective drugs available today.

In the frontline are teams of village volunteers who fan out across the mountainous province of Pailin, close to the Thai-Cambodian border, to supply “free early diagnosis and treatment services” to vulnerable communities in this malaria-infested region.

“The village malaria workers in Pailin are part of 3,000 volunteers in the country who have been trained to help with early detection of malaria in the local communities,” said Nguon Sokomar of the Phnom Penh-based National Centre for Malaria Control. “Each village has two volunteers, often from the same household.”

The health volunteers have been active over the past year in seven Pailin villages to help screen close to 3,000 people in that malarial belt, Nguon said during a telephone interview from the Cambodian capital. “They are important to stop and eliminate the malaria-resistant parasite.”

Their work has not been in vain. The screening done by these volunteers — some are farmers, others run small businesses – is helping roll back malaria resistance to artemisinin, the active ingredient in the anti-malarial drug artesunate.

Of the 2,782 people screened in the seven villages, there were only two cases of falciparum malaria, the strain in which the artemisinin resistance has emerged, reveals the World Health Organisation’s (WHO) Cambodia office. Only last year, these seven villages in Pailin province were among the most malaria-affected in the border area, officials say.

Key to the progress in the anti-malarial campaign so far has been the speed by which blood samples taken from the men, women and children in villages such as Krochab Krom, Phnom Dambang and Krachab Leu are sent by taxi to the Pasteur Institute in Phnom Penh for tests, states the WHO.

“(The samples) are tested using sophisticated technology – Polymerase Chain Reaction – that can detect even one malarial parasite,” WHO documents said. “The new intense screening programme is part of a tool just introduced (in the region) that aims to find – and treat – any hidden cases of resistant malaria in the targeted villages.”

“The new testing regime tries to find the parasite, not the symptom of malaria,” said Steven Bjorge, WHO team leader on malaria in Cambodia. “We can do mass genetic testing of samples at the Pasteur Institute on a scale not done before.”

The use of a taxi to ferry the samples – only a day’s journey from Pailin to Phnom Penh – and the speed of securing the testing results has meant that villagers can learn about their malaria status in at least four days, Bjorge told IPS. “This is important, to treat people before they leave their villages.”

The ongoing project, which aims to eliminate drug-resistant malaria in villages along the Cambodian and Thai sides of the border, is part of a 22.5 million U.S. dollar programme funded by the Bill and Melinda Gates Foundation.

In 2008, there were 247 million reported cases of malaria spread across 109 countries, according to the Geneva-based WHO. That year also saw nearly one million deaths, mostly among children living in Africa, due to malaria.

Currently, artemisinin, which comes from the wormwood plant in China, is the most potent antidote to falciparum malaria, the form of malaria responsible for most deaths.

Artemisinin has replaced the once potent drug chloroqunine, following resistance to the drug by the malaria parasite that has spread across the world. Chinese scientists reportedly isolated artemisinin in 1972 as an anti- malarial ingredient, resulting in the production of artesunate.

What makes the western corner of Cambodia so pivotal in the battle against the disease is the fact that while the South-east Asian country may now have a low incidence rate of malaria cases – in 2009 it was 6.16 cases per 1,000 population – the malaria belt along the Thai-Cambodian border has been described as the “epicentre of drug-resistant malaria in the world.”

In fact, resistance to chloroquine first developed in Pailin and nearby areas along the Thai-Cambodian border before spreading across the world. This has added to the notoriety that Pailin already has as the last stronghold of the Khmer Rouge, responsible for the deaths of 1.7 million Cambodians during its reign of terror from April 1975 to January 1979.

But at the same time, alarm bells are going off within the international and local public health communities about the need to prevent the development of resistance as well to artemesinin, something that emerged along the Thai- Cambodian border at the beginning of 2009.

As a result, the WHO was prompted to warn that this drug-resistant parasite posed “a serious threat to global efforts to control malaria” if it spread to other parts of South-east Asia, South Asia and Africa.

“It is a concern and we have to eliminate this particular problem,” Francois Nosten, professor of tropical medicine at Oxford University, told IPS. “There has been no evidence of such resistance anywhere else in the world.”

“It is very specific to the western Cambodian border,” the don of the British university added. “There is no evidence so far that it has started to spread.”