How much malaria occurs in urban Luanda, Angola? A health facility-based assessment.

We conducted a health facility-based survey of patients with fever during malaria transmission season to determine the proportion with laboratory-confirmed malaria in Luanda, Angola. We enrolled 864 patients at 30 facilities; each underwent a blood film for malaria and a questionnaire. Only 3.6% had a positive blood film. When stratified by distance of the facility to city center (< 15 km and > or = 15 km), the proportions were 1.5% (9/615) and 8.8% (22/249), respectively (P < 0.0001). Of patients traveling outside Luanda in the preceding 3 months, 6.8% (6/88) had malaria, compared with 3.2% (26/776) not traveling (P = 0.13). Children < 5 years of age were less likely to have malaria (2.4%; 12/510) than children ages 5-14 (8.7%; 9/104) and adults (4.0%; 10/250) (P = 0.03). The prevalence of laboratory-confirmed malaria in febrile patients in Luanda is very low, but increases with distance from the urban center. Prevention and treatment should be focused in surrounding rural areas.