Changing response of Plasmodium falciparum to chloroquine in West Bengal during 1980-1988.

A total of 314 cases of Plasmodium falciparum malaria studied during 1980-88 in nine times monitoring revealed three RIII foci i.e. two in Jalpaiguri and one in Purulia districts. The studies showed a parasite clearance of 40 per cent and 32 per cent of P. falciparum cases within seventh day in Purulia and Jalpaiguri districts respectively, with a dosage of 25 mg per kg body weight, spread over three days in divided doses. Increase in transmission potential and prolonged drug pressure with single drug have been noted in association with development of resistance. Malaria parasite clearance time (MPCT) value of sensitive and resistant cases reach parallelism and malaria parasite recrudescence time (MPRT) value starts declining, giving an indication of stabilisation of genetic change in the parasite.