Incidence Of Trypanosomosis Research Articles

Evaluation of insecticide-treated cattle as a barrier to re-invasion of tsetse to cleared areas in northeastern Zimbabwe.

A field trial in Zimbabwe investigated the efficacy of insecticide-treated cattle as a barrier to prevent the re-invasion of tsetse, Glossina morsitans and G. pallidipes (Diptera: Glossinidae), into cleared areas. The original tsetse barrier consisted of insecticide-treated odour-baited targets, at an operational density of four to five targets per km2, supported by insecticide-treatments of cattle with either deltamethrin dip (Decatix, Coopers) at two-weekly intervals, or deltamethrin pouron (Spoton, Coopers) at monthly intervals, in a band approximately 20 km wide from the re-invasion front. Tsetse catch, and trypanosomiasis incidence in nine sentinel herds was recorded for 7-8 months, respectively, before the targets were removed, leaving only the insecticide treatment of the local cattle to stem the re-invasion of tsetse. After the removal of the target barrier, the tsetse readily invaded the trial area and the incidence of trypanosomiasis in sentinel herds increased, while their PCVs decreased. After seven months without the targets in place, trypanosomiasis prevalence in the local stock had reached alarmingly high levels; the trial was terminated prematurely and the target barrier re-deployed. Immediately after the re-deployment of the target barrier, the tsetse catch in the trial area reverted to acceptable levels along the re-invasion front, and trypanosomiasis incidence in the sentinel cattle decreased. It is concluded that, under the conditions of the field trial, the insecticidal treatment of local cattle did not in itself form an effective barrier to tsetse re-invasion. By contrast, the target barrier performed as was predicted by mathematical and experimental analysis, and readily cleared the tsetse infestation and reduced trypanosomosis incidence in the trial area.

Utilisation du test ELISA de détection des antigènes circulants de trypanosomes dans le cadre d'un suivi épidémiologique dans la zone de Sidéradougou, Burkina Faso

Des plasmas, prélevés lors d'un suivi parasitologique sur la trypanosomose bovine, ont été testés a posteriori à l'aide du test de détection des antigènes circulants. Le but était d'évaluer l'intérêt de ce test pour l'épidémiosurveillance, en comparant les résultats obtenus à ceux d'un diagnostic parasitologique usuel (examen du buffy cool). L'étude a porté sur une cohorte de 297 bovins dont 216 provenaient de quatre villages de la zone pastorale de Sidéradougou, région indemne de glossines à la suite d'un vaste programme d'éradication. Les taux d'incidence de la trypanosomose bovine obtenus avec le test de détection des antigènes circulants sont faibles dans les cheptels situés au centre de la zone. Ils diminuent proportionnellement à la distance entre le lieu de prélèvement et la limite de la zone infestée. Les résultats du diagnostic parasitologique sont concordants sauf pour un village situé en bordure de la zone traitée. L'utilisation du test de détection des antigènes circulants confirme donc la faible incidence de la trypanosomose dans le centre de la zone de Sidéradougou après la campagne d'éradication.