The problem is more severe in Cambodia than anywhere else in the world, says Steven Bjorge, the World Health Organization's malaria team leader in Cambodia. About 17 percent of all cases in the Cambodian-Thai border area of Pailin were drug-resistant in 2011, up from 10 percent the year before, according to Char Meng Chuor, director of the government’s National Malaria Center. He says the drug-resistant disease has also spread to parts of Preah Vihear and Pursat, border provinces in Cambodia’s north and west. Drug-resistant malaria first evolved in Cambodia in the 1950s and 1960s, according to Bjorge.
“Since then, every new drug seems to first become resistant in Cambodia or on the Thai-Cambodian border before anywhere else in the world,” he said. Drug resistance occurs when a patient infected with the Plasmodium falciparum parasite takes an incomplete or incorrect course of anti-malarial drugs. This allows the parasite to evolve resistance to that medicine, so patients must take another course of drugs under the supervision of a doctor, says Char Meng Chuor.
The problem is greatest in border towns with a lot of traffic. Here, migrant workers might buy the wrong drugs without seeing a doctor, or misuse treatment in other ways, says Uth Sophal, Pailin field officer for the health group the Malaria Consortium. “Migrant people move from one province to another, so when they come to Pailin, which already has resistant malaria, when the mosquitoes bite those people, they will get that parasite and pass it from one province to another province, from one country to another,” he said. With some help, health workers are hoping that will change.
The Malaria Consortium has created a network of volunteers at Pailin’s border crossing to check and evaluate migrant workers and treat them if they have malaria. “When Cambodians cross the border, we measure their temperature,” Uth Sophal said. “If they have any kind of illness, we have to immediately treat them.” University Research, a global health company fighting drug-resistant malaria in sub-Mekong Region countries, is trying to ensure migrant workers are given bed nets before they move through malaria-prone areas. It is also training local people to provide malaria.