Therapeutic response of multidrug-resistant Plasmodium falciparum and P. vivax to chloroquine and sulfadoxine-pyrimethamine in southern Papua, Indonesia

To determine the level of antimalarial drug resistance in southern Papua, Indonesia, we assessed the therapeutic efficacy of chloroquine plus sulfadoxine-pyrimethamine (CQ+SP) for Plasmodium falciparum infections as well as CQ monotherapy for P. vivax infections. Patients with P. falciparum failing therapy were re-treated with unsupervised quinine+/-doxycycline therapy and those with P. vivax with either unsupervised quinine+/-doxycycline or amodiaquine. In total, 143 patients were enrolled in the study (103 treated with CQ+SP and 40 with CQ). Early treatment failures occurred in four patients (4%) with P. falciparum and six patients (15%) with P. vivax. The failure rate by Day 28 for P. vivax was 65% (95% CI 49-81). After PCR correction for re-infections, the Day 42 recrudescence rate for P. falciparum infections was 48% (95% CI 31-65). Re-treatment with unsupervised quinine+/-doxycycline resulted in further recurrence of malaria in 48% (95% CI 31-65) of P. falciparum infections and 70% (95% CI 37-100) of P. vivax infections. Eleven patients with recurrent P. vivax were re-treated with amodiaquine; there were no early or late treatment failures. In southern Papua, a high prevalence of drug resistance of P. falciparum and P. vivax exists both to first- and second-line therapies. Preliminary data indicate that amodiaquine retains superior efficacy compared with CQ for CQ-resistant P. vivax.

Interethnic genetic differentiation in Africa: HLA class I antigens in The Gambia

A total of 752 individuals from The Gambia, west Africa who are representative of the major ethnic groups in the capital, Banjul, were serologically typed for HLA-A, -B, and -C antigens. Although all were typically "African" in their antigenic profiles, some marked frequency differences were found between the ethnic groups. Genetic distance comparisons with several other African populations showed that, although these west African populations clustered closely together, the positions of the various ethnic groups in The Gambia were consistent with historical and linguistic evidence of their affinities with one another and with other African populations. Despite the potential confounding effects both of selection by infectious diseases and of genetic drift caused by local differences in population structure, HLA frequencies appear to be of value in measuring inter- and intraregional population affinities in sub-Saharan Africa.