RESISTANCE OF FALCIPARUM-MALARIA TO CHLOROQUINE AND SULFADOXINE-PYRIMETHAMINE IN AFGHAN REFUGEE SETTLEMENTS IN WESTERN PAKISTAN - SURVEYS BY THE GENERAL HEALTH-SERVICES USING A SIMPLIFIED IN-VIVO TEST

Surveys of drug resistant falciparum malaria were conducted in several Afghan refugee settlements, distributed over a 700 km range in wester n Pakistan, during the transmission seasons of 1994 and 1995. Symptoma tic malaria patients were recruited by a process of passive case detec tion at the refugees' basic health units. To facilitate follow-up by l ocal health workers, a modified version of the WHO extended in vivo te st was adopted in which blood smears were taken from each subject, and clinical symptoms recorded, at weekly intervals. Resistance to chloro quine and sulfadoxine-pyrimethamine was identified in every settlement . The frequency of chloroquine resistance ranged from 18% to 62%. Resi stance occurred mostly as RI, with RII resistance never exceeding 11%. Resistance to sulfadoxine-pyrimethamine occurred at much lower freque ncies, ranging from 4% to 25%. There was a resumption of clinical symp toms at the onset of parasite recrudescence in over 90% of cases. The policy of using chloroquine as first-line treatment might be changed i n favour of sulfadoxine-pyrimethamine in most camps and areas of weste rn Pakistan. The modified in vivo test was almost as accurate as che n ormal WHO in vivo test in identifying the grade of resistance, and sho uld prove a useful tool for the monitoring of resistance to common ant imalarials by district health services.