The vervet monkey (Chlorocebus aethiops) as an experimental model for Trypanosoma brucei gambiense human African trypanosomiasis: a clinical, biological and pathological study.

It has long been known that the vervet monkey, Chlorocebus (C.) aethiops, can be infected with Trypanosoma rhodesiense, but this model has not been described for T. gambiense. In this study, we report the development of such a model for human African trypanosomiasis. Twelve vervet monkeys infected with T. gambiense developed chronic disease. The duration of the disease ranged between 23 and 612 days (median 89 days) in five untreated animals. Trypanosomes were detected in the blood within the first 10 days post-infection and in the cerebrospinal fluid, with a median delay of 120 days (n = 4, range 28-348 days). Clinical changes included loss of weight, adenopathy, and in some cases eyelid oedema and lethargy. Haematological alterations included decreases in haemoglobin level and transitory decreases in platelet count. Biological modifications included increased gamma globulins and total proteins and decreased albumin. Pathological features of the infection were presence of Mott's cells, inflammatory infiltration of either mononuclear cells or lymphocytes and plasma cells in the brain parenchyma, and astrocytosis. These observations indicate that the development of the disease in vervet monkeys is similar to human T. gambiense infection. We conclude that C. aethiops is a promising experimental primate model for the study of T. gambiense trypanosomiasis.

Sulfadoxine-pyrimethamine for the treatment of Plasmodium falciparum malaria in Gabonese children.

Chloroquine can no longer be recommended as the first-line treatment for falciparum malaria in several parts of Africa, given the increasing resistance of Plasmodium falciparum to this drug. The sulfadoxine-pyrimethamine combination (SP) is obviously an alternative candidate, that has already been selected as first-line antimalarial treatment by a few African countries. However, the extent of resistance to SP appears to be highly variable within Africa. Therefore, we investigated the efficacy of SP to treat uncomplicated malaria attacks in children from south-east Gabon. Sixty-six children presenting with a P. falciparum malaria attack were given a standard regimen of SP, and were followed at Days 3, 7, 14, and 21. No RIII response was observed, but relatively high prevalences of RII (18.2%) and RI (12.1%) were present. Moreover, analysis of the clinical outcome according to CDC criteria showed that initial clinical response was lacking in 8.5% of children, and that clinical failure occurred in 9.1%.