Microlevel epidemiological variations in malaria & its implications on control strategy.

Microlevel epidemiological variations in designing malaria control strategies were studied. Quantitative and qualitative variations were observed between two physiographic zones and between four different ecotypes within the zones of the Koraput district. While the peak transmission occurred in rainy season in the 600 m plateau (Jeypore zone), the same was observed in cold season in 150 m plateau (Malkangiri zone). The age specific parasite prevalence indicated a high degree of transmission and high level of acquired immunity in top- and foot-hill villages of both zones as compared to plain and riverine villages. Transmission was perennial in top-hill and foot-hill villages while it was of short period (indicated by infant parasite rate) in others. Since the period and intensity of transmission vary, an uniform residual insecticidal spray schedule as followed at present is not necessary. Majority of fever patients in top-hill villages were positive for Plasmodium falciparum and therefore may be treated for malaria without slide collection and examination. Evaluations may be done by sample surveys. These steps can optimize the malaria control operation in the district.