Clinical aspects of malaria in the Asir Region, Saudi Arabia.

Three hundred and thirty-four cases of confirmed malaria seen in the Asir Central Hospital, Abha, in southwestern Saudi Arabia, were studied retrospectively. Two hundred and eighty-two of these (84.4%) were Saudis and the majority (72.2%) were living in the lowlands of Tihama. Transmission was found to occur throughout the year, with peaks following the rainy season and in the summer. In Saudis, falciparum malaria is more common than vivax (97.2% vs. 2.8%), while vivax malaria is more commonly seen in expatriates (46.2%). Poor response of falciparum malaria to chloroquine was more prevalent in expatriates than in Saudis (46.4% vs. 23%). Most of the expatriates gave a history of recent travel to countries known to be endemic with resistant malaria. The possibility of the emergence of chloroquine-resistant malaria in the southwestern region of Saudi Arabia was discussed.