A Survey on Risks of Malaria Infection among Different Populations in the Yuanjiang River Basin

Abstract

Abstract

In order to understand the risks of malaria infection among populations at different altitudes in the Yuanjiang River Basin, a cross-sectional survey of malaria prevalence was performed with parasitological and serological methods. The data were analyzed by stratification. The results of IFAT indicated: a) taking permanent residence in the foothills (<1,200 m) as the reference, the risk ratios (RR) were 4.5 (95%CI: 3.4-5.8), 8.4 (95%CI: 6.4-10.9) and 6.3 (95%CI: 4.9-8.1), respectively, for mobile populations in different areas; b) for residents living at the altitudes 1,200-1,600 m and >1,600 m, taking the age group of younger than 15 years old as the reference, the RR was 2.8 (95%CI: 2.4-3.8) for the labor age group who were 15-60 years old. Analysis of parasite rates showed that, compared with permanent residents in the foothills, the RR was 20.6 (95%CI: 4.8-89.6) for one- or two-day workers who had no shelters and stayed outdoors overnight. It is concluded that malaria transmission is still serious and primarily occurs in the foothill zone, and that staying overnight in the field and lack of personal protective measures are risk factors of malaria infection in the region.

Keywords : malaria, Yuanjiang River Basin, cross-sectional survey, risk ratio