Acta tropica
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Comparative Study
Blood schizontocidal activity of WR 238605 (Tafenoquine) against Plasmodium cynomolgi and Plasmodium fragile infections in rhesus monkeys.
A new 8-aminoquinoline antimalarial WR 238605 (Tafenoquine), developed initially as a primaquine alternative for prevention of Plasmodium vivax relapses was evaluated for blood schizontocidal activity against two simian malaria infections namely Plasmodium cynomolgi B and Plasmodium fragile in rhesus monkeys. Treatment with WR 238605 at a dose of 3.16 mg(base)/kg/day x 7 days cured established trophozoite induced infections in monkeys with both these parasites. ⋯ Primaquine was only partially curative at 10.0 mg(base)/kg/day x 7 dose regimen against both these infections. The potent blood schizontocidal activity of tafenoquine adds to the armoury of antimalarial drugs.
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While the distribution of schistosomiasis has changed over the last 50 years and there have been successful control programmes, the number of people estimated to be infected or at risk of infection has not been reduced. Today, 85% of the number of infected people are estimated to be on the African continent where few control efforts are made. ⋯ WHO has now developed a dual strategy for the control of schistosomiasis: a strategy for morbidity control adapted to the public health context in high burden areas, and a strategy to consolidate control in areas where a low endemic level has been reached and elimination may be feasible. Related to this new vision, some research needs are pointed out.
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Comparative Study
Tegumental changes in adult Schistosoma mansoni harboured in mice treated with praziquantel enantiomers.
Praziquantel administered to the host causes damage to the tegument of Schistosoma mansoni. In this study, the effects of racemic praziquantel (Pra) and its enantiomers, levo-praziquantel (L-Pra) and dextro-praziquantel (D-Pra) were compared using scanning electron microscopy (SEM). Mice infected with S. mansoni for 49 days were treated with a single dose of Pra (300 mg/kg), L-Pra (150 mg/kg) or D-Pra (150 or 600 mg/kg). ⋯ The study thus clearly showed that L-Pra was more active than D-Pra in causing tegumental damage. D-Pra showed a qualitatively similar activity at a higher concentration. It is possible that this effect was due at least to some extent to the small amount of L-Pra (<2%) which was present in the preparation of D-Pra used.
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CATT/Trypanosoma brucei (T.b.) gambiense is an antibody detection test currently used in field surveys on Gambian sleeping sickness. The screening test is usually performed on a drop of freshly collected heparinized blood, followed by a more specific confirmation test on diluted blood, plasma or serum. This approach may be biased by the occurrence of a complement-mediated prozone phenomenon causing lower test sensitivity at lower sample dilutions. A simple remedy is by addition of a Ca2+ chelating agent such as EDTA.