Objective: To make an epidemiological investigation on malaria in Motuo County, Linzhi Prefecture of Tibet.
Methods: In July of the year 2006, the following activities were conducted in 2 selected villages from each of the three townships, i.e., Motuo, Dexing and Beibeng: malaria history survey among inhabitants in recent 2 years; collection of blood samples of inhabitants for examining malaria parasites, IFAT and detecting G6PD, respectively; mosquito collection in human dwellings and cattle shelters at night and various resting sites at day-time; mosquito collection by outdoor human baiting capture; classification and composition calculation of mosquito species and man biting rates; ELISA for detecting sporozoite infection of Anopheles.
Results: The mean rate of two-year malaria history was 8.98% (118/1314) and the parasite rate was 3.13% (38/1216, all P. vivax) in the inhabitants. The parasite positive rate among the feverish patients was 7.14% (3/42). IFAT revealed a malaria antibody rate of 40.24% (472/1173). The G6PD deficiency rate was 1.74% (21/1208). Five hundred and thirteen anopheline mosquitoes were caught. They were An. maculatus (474) which occupied 92.4% (474/513), An. peditaeniatus (35), An. kochi (3) and An. sinensis (1). The mean indoor density of An. maculatus was 4.75/night in human houses, and 69.5/night in cattle shelters. The outdoor human biting rate was 22.75/half-night/person, and the sporozoite rate of An. maculatus in anopheline saliva glands was 0 by ELISA.
Conclusion: Motuo County is an endemic area of vivax malaria with An. maculatus as the potential vector.