AsianScientist (Mar. 5, 2014) – Efforts are being scaled up to stem a further spread of drug-resistant malaria in Southeast Asia.
“The emergence of resistance… threatens worldwide malaria control and treatment since there is no alternative to this drug if its efficacy decreases further and the resistance spreads outside the region,” wrote the Global Fund to Fight AIDS, Tuberculosis and Malaria, which is providing some US$150 million for malaria prevention and elimination programmes in the Greater Mekong sub-region within the next two years.
The region includes southern China, Laos, Vietnam, Cambodia and Myanmar.
In 2008, artemisinin-resistant malaria was first discovered in Cambodia’s Pailin Province along the Thai border, which immediately alarmed health experts.
About 60 years earlier, malaria strains had also developed resistance against chloroquine, then the most common drug to treat malaria. A spread of resistance could not be stopped, and several years later, chloroquine was deemed useless globally.
Now, as the parasite’s most deadly strain, Plasmodium falciparum, is proving resistant to drugs not based on artemisinin, the government – with the World Health Organization (WHO), the US government-funded Control and Prevention of Malaria (CAP-Malaria) and other development partners – is trying to stop a further spread in the region.
One fear is that, like before, drug resistance will reach sub-Saharan Africa, where the majority of malaria deaths occur.
“In the last year, it got worse, and we also found resistance in locations including [Cambodia’s northwestern provinces of] Oddar Meanchey and Preah Vihear, so it’s getting a bigger and bigger concern and we need to contain this,” said Nguon Sokomar, country director for CAP-Malaria based in Phnom Penh.
Between 2003 to 2011, the number of malaria cases diagnosed in Southeast Asia dropped from almost 6 million to 3.4 million, a decrease of 43 percent, while the number of deaths declined by 68 percent during the same time period.
But during that time, resistance was spreading.
“The findings show that the number of resistant strains is increasing. In a percentage of treatment failures, it’s about 40 percent in Oddar Meanchey, bordering Thailand,” Sokomar said.
As part of an emergency response, WHO established a regional malaria hub in Phnom Penh in April 2013, following the success of Cambodia’s village malaria workers, said Sonny Krishnan, communications officer for WHO’s Emergency Response to Artemisinin Resistance.
Village malaria workers – trained individuals who educate and screen other villagers – have been a best practice model in Cambodia, where 1,500 village malaria workers have been trained in priority areas.
To “confuse” the parasite and hinder the development of resistance, different drugs are being used in combination with artemisinin in different provinces.
The regional hub is now also coordinating efforts to reach out to ethnic minorities in Laos and Vietnam, who speak minority languages and have to be educated through signs, as they are commonly overlooked in malaria interventions.
In addition, WHO has established a three-tier system, where Tier 1 is regions with evidence of artemisinin resistance, Tier 2 has an inflow of migrant workers from Tier 1 regions, and Tier 3 is areas with no evidence of artemisinin resistance.
The Global Fund said it has allocated $100 million (in addition to its $150 million pledge) to fight artemisinin resistance in Tier 1 and Tier 2 regions in Southeast Asia, as mobile migrant workers are of particular concern.
Migrant workers part of the problem?
Legal migrants can be monitored and governments of provinces along the Lao-Cambodian and the Thai-Cambodian border are cooperating with each other to screen workers.
“There is a good cooperation between Chanthaburi [Thailand] and Pailin [Cambodia] where they screen people crossing the border. The moment you cross the border, there are also bilingual posters about malaria,” Krishnan said.
Undocumented migrants, however, can only be reached through village malaria workers.
“It’s a serious problem because there are more and more illegal migrant workers,” Krishnan said.
Due to low surveillance and the country’s only recent opening, drug-resistant malaria has not been confirmed in Myanmar yet, but is of concern.
“We don’t know if there is a resistance yet, but there is a strong belief that there could be, and there are studies being done now,” he said.
Despite efforts to stop the spread of artemisinin-resistant strains, overall joint operations in the region need to be scaled up further, Sokomar said.
The mosquito-borne disease causes more than half a million deaths annually globally.
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