The epidemiological study of artemisinin tolerant malaria parasites along the Thai-Cambodian border using the geographic information syste

Abstract

Malaria remains one of the infectious diseases with highest burden in developing countries. In Greater Mekong Sub-region (GMS), there is an increasing evidence that artemisinin resistant malaria parasites are present on the Thai-Cambodian border. Therefore, a project of a strategy for the containment of artemisinin tolerant malaria parasites in South-East Asia has been implemented to contain artemisinin-resistant malaria in the Thai-Cambodian border since 2009. This analysis using data from a newly-developed surveillance information system describes malaria epidemiology in the containment area for the first time, estimates the rate of Day3+, and explores risk factors associated with Day3+. Surveillance data from 1^st  January 2009 to 30^th June 2011 are used to describe the malaria epidemiology in the containment area with a focus on Plasmodium falciparum (Pf). The rates of follow-up are calculated and the pattern is descried. Based on followed cases, the  rate of Day3+ is calculated. Multivariate logistic regressions are used to investigate risk factors for Day3+. In the containment area, malaria demonstrates similar pattern like elsewhere among Thai with an increasing species ratio (Plasmodium vivax/Plasmodium falciparum) and proportion of foreign migrants. The follow-up rate at Day3 is estimated to be less than 61%. Although Pf cases have dropped dramatically, the rate of Day3+among those followed shows slightly increasing trend. Residing in Si Sa Ket is associated with higher of Day3+ while residing in Pf-endemic Ubonatchatani is very unlikely to be Day3+. There is a strong evidence that malaria cases detected by A