FALCIPARUM-MALARIA AND CLIMATE-CHANGE IN THE NORTHWEST FRONTIER PROVINCE OF PAKISTAN

Following a striking increase in the severity of autumnal outbreaks of Plasmodium falciparum during the last decade in the Northwest Frontie r Province (NWFP) of Pakistan, the role of climatologic variables was investigated. A multivariate analysis showed that during the transmiss ion season of P. falciparum, the amount of rainfall in September and O ctober, the temperature in November and December, and the humidity in December were all correlated (r(2) = 0.82) with two measures of P. fal ciparum, the falciparum rate (percent of slides examined positive for P. falciparum) since 1981 and the annual P. falciparum proportion (per cent of all malaria infections diagnosed as P. falciparum) since 1978. Climatologic records since 1876 show an increase in mean November and December temperatures by 2 degrees C and 1.5 degrees C, respectively, and in October rainfall. Mean humidity in December has also been incr easing since 1950. These climatologic changes in the area appear to ha ve made conditions for transmission of P. falciparum more favorable, a nd may account for the increase in incidence observed in the NWFP in r ecent years.