Historical review of surveillance methods, insecticide spray, and epidemiology of malaria in Bannu zone, Khyber Pakhtunkhwa, Pakistan.

Historical review and epidemiology of disease contribute to effective planning against any disease. The present study aimed to evaluate case detection methods and the historic prevalence and seasonality of malaria and to assess the effectiveness of insecticide sprays to reduce the malaria rate in the Bannu zone during 1965–97. It is a cross-sectional study consisting of both laboratory and official data. Data on malaria/case detections and insecticide spray and the number of houses sprayed were collected from the official record. Active case detection remained the dominant method during 1966–89 and was replaced by passive case detection. Malaria rates remained low during 1966–74, increased to a peak in 1975, and suddenly declined in 1977. Malaria showed a steady increase from 1989 with a peak in 1995 followed by a reduced rate in 1996. Plasmodium vivax malaria was much more prevalent than Plasmodium falciparum malaria throughout the study period. Slide positivity rates of different surveillance methods were comparable up to 1977. Slide positivity rates of Plasmodium vivax and Plasmodium falciparum were comparable based on combined data. Slide positivity rates and annual parasite incidence were fairly well correlated up to 1985 and followed by good correspondences based on the combined data. Transmission of malaria occurred from August to December of the same year. The estimated number of the sprayed houses exceeded the recorded. Five insecticides were used annually in variable quantities over the study that demonstrated a correlation with reduced malarial rates during 1966–88, except in 1975. The malaria showed seasonality characterized by Plasmodium vivax malaria that remained dominant, and the prevalence rate revealed fluctuation over the period. Active case detection was dominant for the most of period. Insecticide spray effectively contributed to reducing the rate of malaria in the study area. [ABSTRACT FROM AUTHOR]