Resurgence of malaria and drug resistance in plasmodium falciparum and plasmodium vivax species in Bombay.

Malaria had been well controlled in Bombay, through control of mosquito breeding sites and legal provisions. However in the past 2-3 years there has been a marked increase in incidence of malaria in Bombay. The objective of the present study was to assess the incidence of drug resistance of malarial parasite to standard drugs. The study was an outpatient study, but drug administration was supervised, blood smear was read by experienced technicians counting at least 100 fields. Follow up was done upto day 14 as beyond that, smear positivity due to reinfection cannot be ruled out. Two hundred cases; 56 of P. falsiparum, 139 of P. vivax and 5 with mixed infection were investigated. The public health department strategy of administering single dose of (10 mg/kg) chloroquine found to be largely effective in the past was now found to be only partially effective, with 20/56 Pl. falciparum, 7/139 P. vivax and 1/5 mixed infection cases showing smear positive on day 6 or day 14. These patients, resistant to single dose chloroquine, were then treated with full dose of (25 mg/kg) chloroquine. Three out of 20 cases of P. falciparum and 1/7 P. vivax cases did not respond to full dose (25 mg/kg) of chloroquine. These 3 chloroquine resistant cases of P. falciparum responded to Sulfadoxinepyrimethamine while the single case of chloroquine resistant P. vivax did not respond to quinine or sulfadoxinepyrimethamine.