In-Vivo Response of P. Falciparum to Antimalarial Treatment in HIV-Infected and HIV-Uninfected Adults

Overview

Plasmodium falciparum malaria and HIV are among the most important infectious diseases in sub-Saharan Africa. Approximately two-thirds of the estimated 35 million HIV infected persons live in sub-Saharan Africa. Of the 300-500 million annual cases of malaria infection occurring worldwide, about 90% of P. falciparum infections occur in sub-Saharan Africa, resulting in approximately 1 million deaths, mostly in children under five years of age. It is clear that HIV and malaria are responsible for substantial disease, suffering, and an enormous economic burden on the people who can least afford it. Although a study in 1993 in Tanzania showed significantly higher prevalence of malaria infections in HIV-positive compared to HIV negative adults, until recently there have been few studies showing any association between the two infections. We conducted a study to measure the efficacy of the then-first line antimalarial drug (sulfadoxine-pyrimethamine) among patients in three study arms: those who were HIV negative, those who were HIV infected with CD4 cell counts \< 200, and among HIV infected patients with CD4 cell counts \>= 200. Our hypothesis is that patients with HIV infection and low CD4 cell count will not respond to antimalarial therapy as well as patients who are HIV infected with higher CD4 cell counts or who are HIV negative.

The study was conducted at Siaya District Hospital, in Nyanza Province, Kenya. Non-pregnant adults who provided consent to participate, who were found to have pure Plasmodium falciparum malaria parasitemia with at least 500 asexual parasites per microliter, and who agreed to undergo HIV counseling and testing were eligible for participation. Clients were then followed with repeat physical examinations and blood smears on day 1,2,3,4,7,14,21 and 28 and any non-scheduled day when they were sick. Those that failed therapy were treated with quinine to clear parasitemia. Samples were also taken to measure reinfection vs. recrudescence, pharmacokinetics, and antifolate resistance markers.