Browsing by Autor "Catherine Bourguinat"

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Genetic polymorphism of the β-tubulin gene of <i>Onchocerca volvulus</i> in ivermectin naïve patients from Cameroon, and its relationship with fertility of the worms
(Cambridge University Press, 2005) Catherine Bourguinat; Sébastien D. S. Pion; Joseph Kamgno; Jacques Gardon; N. Gardon-Wendel; B. O. L. Duke; Roger K. Prichard; Michel Boussinesq
Observations of low response of patients infected with Onchocerca volvulus to ivermectin suggest that the parasite may be under a selection process toward potential resistance. To limit the extension of this phenomenon, it is crucial to characterize the genes of O. volvulus that are involved. For this, O. volvulus adult worms collected before the introduction of ivermectin in an onchocerciasis endemic area of central Cameroon were genotyped for beta-tubulin. To derive a baseline to investigate the selective pressure of ivermectin, we analysed (1) the frequency distribution of the beta-tubulin alleles, and (2) the relationship between the different beta-tubulin related genotypes and the fertility status of the female worms. The frequency of allele b of the beta-tubulin gene was very low, as it was observed in West Africa. We observed a deficit of heterozygous female worms leading to Hardy Weinberg disequilibrium, which might be explained by a shorter life-span of these worms compared to the homozygous worms. Unexpectedly, our results also show that the heterozygous female worms were much less fertile than the homozygotes: more than two thirds of the homozygotes were fertile, whereas only 37% of the heterozygotes were fertile. These results will be further considered when analysing post-treatment data.
Genetic Selection of Low Fertile Onchocerca volvulus by Ivermectin Treatment
(Public Library of Science, 2007) Catherine Bourguinat; Sébastien D. S. Pion; Joseph Kamgno; Jacques Gardon; B. O. L. Duke; Michel Boussinesq; Roger K. Prichard
The results indicate that ivermectin is causing genetic selection on O. volvulus. This genetic selection is associated with a lower reproductive rate in the female parasites. We hypothesize that this genetic selection indicates that a population of O. volvulus, which is more tolerant to ivermectin, is being selected. This selection could have implications for the development of ivermectin resistance in O. volvulus and for the ongoing onchocerciasis control programmes.
P-glycoprotein-like protein, a possible genetic marker for ivermectin resistance selection in Onchocerca volvulus
(Elsevier BV, 2008) Catherine Bourguinat; Bernadette F. Ardelli; Sébastien D. S. Pion; Joseph Kamgno; Jacques Gardon; B. O. L. Duke; Michel Boussinesq; Roger K. Prichard