A new study has predicted that even if Cambodia manages to eradicate so-called “human” strains of malaria by 2025 – a key government goal – it will continue be at “high risk” of infections from a strain of the parasite more typically found in wild monkeys and transmissible to humans.
The peer-reviewed research, published earlier this month in the scientific journal PLOS Neglected Tropical Diseases, created the first map of plasmodium knowlesi malaria risk to identify priority areas of surveillance based on regions with sparse data and high estimated risk.
P. knowlesi is a malaria parasite commonly found in wild monkeys and can infect humans via mosquitoes that pick up the strain from the primates. It can lead to severe and fatal symptoms in humans.
“The geographical distribution of this disease is largely unknown because it is often misdiagnosed as one of the human malarias,” the study reads. “Understanding the geographical distribution of p. knowlesi is important for identifying areas where malaria transmission will continue after the human malarias have been eliminated.”
Human infections of this parasite have already been reported in nine Southeast Asian countries, including Cambodia, the report says. But Huy Rekol, director of the National Malaria Centre, last week denied that claim.
However, professor Francois Nosten, director of the Shoklo Malaria Research Unit, a field station for tropical medicine faculty at Mahidol University in Bangkok, said p. knowlesi is a “very big threat” for the country.
He also expressed scepticism that the Kingdom could be human malaria-free by 2025. “It’s very unlikely, not because of knowlesi, but because of resistance in falciparum,” he said.
Falciparum is the malaria parasite that first emerged in Cambodia in 2008 and is resistant to the most potent anti-malarial drugs. However, Rekol maintained that eliminating malaria by 2025 was part of the national strategic plan.
“Now we use [a fixed-dose combination of drugs] without any resistance, yet,” he said.
So far this year, there’s been a total of 13,370 malaria cases, but no deaths, he noted. Last year, there were 27,661 cases and four deaths.
Nosten said the government needs to focus on eliminating the drug-resistant parasite as soon as possible, but he remained doubtful that the issue was receiving enough attention.
“The people who really know about malaria are worried about malaria in Cambodia, but nobody else is,” he said.