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Explanation for differences between skin repopulation rates

Posted by luccoffeng on 16 Apr 2013 at 09:42 GMT

Dear authors,

Thank you for this interesting work, I enjoyed reading it. One of your main findings is the worms in multply-treated individuals seem to be less productive in terms of mf quantity, although they start producing earlier after ivermectin treatment. One of the possible explanations you discuss is genetic selection. I would just like to share my thoughts on this point.

Suppose that the duration of the embryostatic effect of ivermectin is not (entirely) determined by genetic selection but (also) by the magnitude of the plug of dead mf in the uteri of adult female worms. The more productive a worm at the time of exposure to ivermectin, the more clogged up the uteri get, and the longer it takes for the plug to resolve. After resolution of the plug can female worms be inseminated and produce mf again. Such a mechanism could explain why the multiply-treated individuals show earlier skin repopulation with mf, assuming that the worms in those individuals are less productive (through non-cumulative or cumulative effects of ivermectin). This would also fit the observation of relatively low mf skin densities in the multiply-treated individuals 180 days after ivermectin.

Kind regards,

Luc Coffeng

No competing interests declared.