Prophylactic Antimalarial Activity of DB289 in Volunteers

The primary endpoint of this study is the appearance of erythrocytic parasites (parasitemia), which indicates a prophylaxis failure. Parasitemia will be sought by multiple means, including blood culture, polymerase chain reaction (PCR), Quantitative Buffy Coat (QBC) analysis, and thick and thin blood smears (detailed methods,Appendix II). QBC and giemsa-stained blood smears will be analyzed in real time and a positive result in any one of them is sufficient to initiate chloroquine treatment. All positive QBC analyses or blood smears will be confirmed by two experienced observers. On smears, the location of parasites will be recorded using a stage micrometer, and slides will be archived and available for later re-examination. PCR samples will be collected and stored for later analysis; cultures will be inoculated at once and maintained for 70 days. A positive result in any one of these tests constitutes a drug failure.