Malaria Survey in the Tak Province Refugee Camps

According to the World Malaria Report, there were significant decreases in the number of P.falciparum (PF) malaria cases worldwide in the past decade. On the Thai-Myanmar border where transmission is low and seasonal and where incidence of Multi-drugs resistant P.falciparum parasites is the highest, the same trend has been observed with a clear decline in malaria episodes and the ratio of P. falciparum/P. vivax (PF/PV).

Economic development, unprecedented financial support, renewed efforts in vector control, a wider use of rapid diagnosic tests (RDTs) for malaria and the deployment of artemisinin based combination treatments (ACT) are the main contributing factors to those successes against malaria.

However the emergence in Cambodia and on the Thai-Myanmar border of P.falciparum isolates that exhibit resistance to artesunate is threatening those gains . This is characterized by a slow parasite clearance rate observed in patients treated with artesunate.

At the same time, recent SMRU surveys along the Thai-Burmese border using a new cutting-edge technology i.e. highly sensitive quantitative Real Time PCR (RT-PCR) able to detect very low parasitaemia (10 parasites per ml), found up to a 3-5 fold increase in the prevalence of malaria compared to what is found with the usual diagnostic tools such as microscopy, RDT or even conventional PCR.

It seems that a large number of asymptomatic carriers with very low parasites counts (a large potential malaria reservoir) go undetected. If confirmed, this might pose the greatest obstacle for malaria elimination in the region and containment of artemisinin resistance.

The purpose of the survey is to further study and understand the epidemiology of malaria in the refugee camp population using cutting-edge technology (RT-PCR) .

The necessity of research in Humans With the double mission of malaria elimination and artemisinin-resistance containment, there are intensive malaria activities currently implemented in the refugee camps in the Tak province (a province in Thailand that is on the Thai-Burmese border). The malaria risk among the refugee camp is higher than the Thai residences inside Thailand.

To avoid resource wastage, it is thus essential to conduct a simple questionnaire to understand the current situation of malaria prevention in the camps, especially information regarding the mosquito net ownership and usage (mosquito net distribution has been a major malaria prevention activity among the NGOs in the camps).

PCR method is being used more and more in recent year due to its sensitivity compared to slide reading. PCR is considered being able to capture more cases with sub-microscopic infection. However, the current PCR methods conventionally used in malaria survey usually use finger prick to obtain only few microliters of capillary blood , the detectable level of parasitaemia is therefore limited due to minimal amount of blood from which Plasmodium DNA can be extracted. Thus the RT-PCR method proposed here using 2ml venous blood well compensates these shortcomings.

The comparison of test results of conventional microscopy (currently still as the universal golden standard in the clinics) and RT-PCR will not only enable detection of both symptomatic and asymptomatic malaria cases but help define the epidemiology apart from our conventional understanding of malaria.

Thus this study is necessary and is strategically important for the next roadmap development of malaria elimination and resistance containment.