Seroepidemiological study of malaria in a rural population of Chandigarh.

A total of 1689 peripheral blood smears and serum samples were collected from healthy subjects from four villages of U.T. Chandigarh during the pre-monsoon season (February to May 1987) while 1809 such samples were collected during the post-monsoon season (October 1987-January 1988). None of the peripheral blood smears examined by Giemsa and acridine-orange stains showed malarial parasite. Out of 1689 serum samples tested by indirect haemagglutination (IHA) test during pre-monsoon season, 81 per cent showed malarial antibody titres of less than 1:8 and only 19 per cent showed titres of 1:8 or above. In contrast, out of 1809 serum samples tested during post-monsoon season, 58.3 per cent showed antibody titres of less than 1:8 while 41.6 per cent samples showed titres of 1:8 and above. Total number of malaria cases from these villages from June 1987 to January 1988 was also low (total 65 cases) as compared to corresponding period of previous year (total cases 191). Serological findings independent of positive cases of malaria suggest that though, no proved clinical cases of malaria were observed in the population surveyed, malaria transmission had certainly taken place as evidenced by higher antibody titres observed during the post-monsoon season compared to pre-monsoon season.