Socio-economic and environmental protective/risk factors for severe malaria in Thailand

We conducted a cross-sectional study to identify the socio-economic and environmental protective/risk factors for severe malaria in Thailand. Forty-six cases of severe malaria, 72 cases of non-severe malaria with high parasite biomass and 40 mild malaria cases were included. When comparing severe malaria and non-severe malaria with high parasite biomass, specific logistic regression models showed a significant protective effect for helminths, adjusted odds ratio 0.24 (0.07–0.78) for low body mass index (BMI), adjusted odds ratio 0.11 (0.02–0.58). When comparing severe and mild malaria, a longer residence duration, adjusted odds ratio 0.36 (0.09–0.83) and the use of antimalarial self-medication, adjusted odds ratio 0.08 (0.009–0.84) were associated with protection from severe malaria. Using stepwise logistic regression with all the variables inserted in the model yielded similar results. These findings suggest specific immunity and self-medication control parasite multiplication whereas helminths and malnutrition more specifically affect the pathogenesis of severe malaria.