Malaria disaster looming as drug resistance develops in northwest

Photo by: Sovann Pilong
A young girl is taught how to apply mosquito repellent. In the high risk northwest, mosquito nets are the repellant of choice.

The Phnom Penh Post
http://www.phnompenhpost.com/

Written by CHRISTOPHER SHAY
Friday, 29 May 2009

As a breeding ground for malaria strains immune to the latest drugs, Cambodia is hosting an ‘unprecedented’ containment strategy designed to completely eradicate the killer bug

FAKE drugs, improper treatments and mobile populations along the Thai-Cambodian border threaten to unleash a rogue strain of malaria that can resist even the most powerful medicines.

"When the parasite is fully resistant, it will be a disaster," said Dr Duong Socheat, the director of the National Centre for Malaria (NCM).

But with funding from the Bill and Melinda Gates Foundation, Cambodia and its partners are racing to contain the increasingly drug resistant parasite with an "unprecedented" containment strategy.

"We're doing things as fast as possible," said Dr Najibullah Habib, the World Health Organisation's (WHO) Malaria Containment Project Manager. "This is a unique and unprecedented project, because we're going for 100 percent elimination."

Artemisinin, a drug first isolated from Chinese wormwood in 1965 but only recently adopted internationally, is the front line defence against malaria. In Cambodia, it is the only viable drug against the most lethal malaria strain, Plasmodium falciparum.

But in recent years along the Thai-Cambodian border, artemisinin is taking longer to clear the parasite, signaling an increased resistance.

According to an article published in the Malaria Journal in February by a team of international scientists, the only way to contain the artemisinin-resistant malaria is to eliminate it completely from western Cambodia.

If there is no intervention, the researchers say, "by 2030, ... the prevalence of malaria will have doubled compared to 2008 and resistance to the artemisinins will be approaching 100 percent".

But the resistant strain does not just threaten people along the Thai-Cambodian border. In the past, drug resistant strains have spread across the world.

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Everyone agrees that if it were to spread to Africa it would be a disaster.
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"Migrants go from here to Burma, from there to India, and then on to Africa," Dr Habib said, saying that this is what happened to chloroquine, an anti-malarial that is largely ineffective in Cambodia.

Dr Ros Seyha from the WHO added: "Everyone agrees that if it were to spread to Africa it would be a disaster."

In 2006, the year with the latest available data, Africa accounted for more than 90 percent of the world's malaria cases with about 801,000 deaths, according to the WHO. Malaria killed 207 people last year in Cambodia.

Philanthropic funds
The WHO received a two-year grant from the Bill and Melinda Gates Foundation for more than $22 million to fight malaria, with Cambodia's NCM receiving a substantial chunk of that money.

In order to prevent an international disaster where malaria spreads unchecked, the WHO and the NCM have developed an expensive, multi-pronged attack to all but eliminate the disease by 2015.

The main aspect of Cambodia's prevention strategy is the distribution of hundreds of thousands of long-lasting, treated bed nets, according to Duong Socheat.

The NCM has divided the area into two zones - one zone that includes much of Pailin province and has been designated a high-risk area, and a second zone at moderate risk.

Zone one has a population of just under 500,000, and zone two has a population of nearly 2 million, according to Duong Socheat.

Despite receiving the Gates Foundation funds in February, the NCM has only been able to distribute about 200,000 treated bed nets. It is hoping to hand out between 100,000 and 200,000 more.

"That is not enough," Duong Socheat said. "We have more than two million in the population; 200,000 is still very few."

In order to reach the remote areas of the region, the NCM and WHO have developed a network of about 2,000 village health volunteers who distribute both information about malaria and treated bed nets.

Cambodia has also set up a network of about 600 village malaria workers who are trained to diagnose and treat the disease. They are primarily located in high risk areas, far from public health clinics.

Shortcuts on care
But many Cambodians still seek treatment from private providers who may not prescribe a full treatment or supply counterfeit drugs.

"Among the poor, the majority buy their drugs from private health providers," Habib said.

The NCM, with the help of the WHO, has been educating private pharmacists about the importance of a full course of treatment, Duong Socheat said, but it was an uphill battles without affordable medicine. "People buy according to their pocketbook, not according to the dose," he said.

The danger is that suboptimal doses will not clear out the parasite completely, leaving only the most resistant parasites. Fortunately, Cambodia is eligible for Global Fund support to make a full course of medicines more affordable, Ros Seyha said.

Along with its prevention and education strategies, the WHO and NCM have started a pilot mass screening effort in the high risk zone one.

Duong Socheat said the program aims to screen up to 200,000 people in zone one, testing blood samples of every person in selected villages.

If a person tests positive in one of these screenings, the person will not receive the normal artemisinin combination therapy but will instead receive Malarone, a treatment that is normally prohibitively expensive for poor countries.

"We don't want to put more pressure on the parasite to become drug resistant," Najib said.

Duong Socheat explained that avoiding artemisinin as part of a combination therapy was only temporary. "It's a special case and will only be for two years. Because one component of Malarone is that the parasite develops resistance to it very quickly."

He added that every malaria case would be followed and that other therapies would be prescribed if the Malarone treatment was ineffective.

Moving fast
In addition to the mass screenings, when a case of particularly resistant malaria is found, the WHO will target the entire village where the person is from, in hopes of nipping the spread of the malaria strain early, Duong Socheat said.

Eliminating malaria will not be easy, but Dong Socheat was optimistic that Cambodia could all but rid itself of the disease by 2015 with adequate funding. "If we have enough money and motivation, we can contain the parasite by 2015," he said.

According to February's Malaria Journal article, the last remaining parasites will be the most resistant, meaning if the WHO and NCM fail to contain the parasite, there would be a far more resistant population than before.

"We cannot stop midway," Duong Socheat said.