Malaria infection among the migrant population along the Thai-Myanmar border area.

A population based case-control study was performed to determine factors associated with malaria infection among the migrant population, foreign nationals aged 15 years or over. Data were obtained from 217 malaria and 217 non-malaria patients attending the Vector-Borne Disease Control Units 6-9 (Thong Pha Phum and Sangkhla Buri districts) in Kanchanaburi Province and at the Vector-Borne Disease Control Units 1,9 (Mae Fa Luang and Mae Sai districts) in Chiang Rai Province, between June and December 2002. All study subjects were interviewed by trained interviewers using a structured interview form. The statistical analysis was carried out by the chi-square test and multivariate logistic regression: a p-value of less than 0.05 was considered to be statistically significant. The results showed that the study subjects were predominantly Thai-Yai and Myanmar. Plasmodium falciparum was the major type of the malaria (60.8%). Logistic regression analysis, controlling for possible confounding factors, revealed that residence located in the forest increased the risk of malaria infection by a factor of 6.29 (OR = 6.29, 95% CI = 1.56-25.42); outdoor stay < 7 and > 7 days prior to the blood examination also increased the risk by a factor of 4.34 and 4.13 respectively (OR = 4.34, 95% CI = 1.05-17.99; OR = 4.13, 95% CI = 1.29-13.13).