Millions of Cambodians affected by the worst flooding in a decade are receiving insecticide-treated mosquito nets (ITNs) in Asia’s largest such distribution, funded by the Global Fund for AIDS, Tuberculosis and Malaria at a cost of US$14.5 million.

The National Malaria Control Centre, the World Health Organisation and partnering NGOs are in a race against time to distribute 2.7 million ITNs to more than 40,000 villages in 20 provinces.

This is in anticipation of an increase in malaria cases as malaria-carrying mosquitoes begin breeding in stagnant pools as floodwaters recede.

On November 7, the mass distribution of ITNs began in Chhlong district, in the remote northeastern province of Kratie, where villagers living in forest areas are at great risk from malaria.

Provincial health staff worked through the Water Festival holidays and, by the end of this month, 785,000 ITNs will have been distributed in six provinces, including three of those hit hardest by floods.

In December, more than 1.9 million ITNs will be distributed in 13 provinces.

This is a great achievement.

The goal is to ensure that every Cambodian at risk of contracting malaria has an insecticide-treated mosquito net by the end of this year. With regard to malaria prevention, ITNs have a track record of reducing malaria cases and deaths.

The anopheles mosquito, which transmits malaria, feeds only at night, so night-time coverage by an ITN is uniquely effective. Correct, consistent use of ITNs can decrease transmission in a community setting by as much as 90 per cent. Lice and bedbug elimination is an added benefit from insecticide treatment of the mosquito nets.

But having effective tools for malaria containment and elimination means nothing unless they are embraced, and fully understood, by rural communities and health providers.

Cambodia is fortunate in this respect. The World Health Organisation-led Containment Project, funded by the Bill and Melinda Gates Foundation to contain and eliminate multi-drug-resistant malaria parasites, implemented with the help of the National Malaria Centre and other partners, has trained about 3,000 volunteer village malaria workers (VMWs).

These VMWs are fully trained to sensitise community members on the advantages of sleeping under an insecticide-treated mosquito net, to diagnose malaria in a village using a rapid diagnostic test, and to provide patients with the appropriate drugs for free.

A good understanding of people’s perceptions of malaria and its cause, preventive action, and the value attached to ITNs, are important determinants of success in malaria control programs that promote ITN use. Through an observable reduction of nightly mosquito nuisance and malaria cases, people perceive the direct benefits of bed nets and are more motivated to use them.

Next month will be crucial in the mass distribution of these insecticide-treated nets in western Cambodia, especially in areas along the Thai-Cambodia border. This is the epicentre of artemisinin-resistant falciparum malaria – the most dangerous form of the disease, and one that kills rapidly if treatment is delayed.

Cambodia, and the world, cannot afford to lose artemisinin and artemisinin derivatives in the treatment of malaria, because there is no group of drugs that can replace them as effective first-line treatments. Fortunately, significant progress has been made in reducing falciparum malaria cases in western Cambodia over the past two years.

One important intervention has been the mass distribution of insecticide-treated nets, along with early diagnosis and appropriate treatment through VMWs, active case detection, the strengthening of management and surveillance systems and operational research. 

More than half a million insecticide-treated mosquito nets were distributed in the Containment Project’s target zones during June, 2009, together with a scaling-up in the number of  village malaria workers. Within two years, in the province of Pailin, which has the highest incidence of malaria in western Cambodia, cases of falciparum malaria had fallen from a monthly average of 135 to fewer than 20.

Eliminating malaria in Cambodia by 2025 is not a pipe dream.

There is genuine political will in this country, coupled with an excellent partnership between the National Malaria Control Centre, the World Health Organisation and, importantly, donors who have rendered their support for a malaria free Cambodia.

Dr Pieter JM Van Maaren is a representative of the World Health Organisation in Cambodia.