The effect of ivermectin, a broad spectrum antihelminthic on the sperm functions of animal models have
been extensively studied, however data on humans are very scanty hence this present study. In this study
we screened a total of 385 patients who were diagnosed of onchocerciasis. Out of which, 37 (9.6%) were
eligible for further tests, as their sperm counts were normal while the remaining patients had very low
sperm counts and were therefore not used for further tests or were too weak after the preliminary
screening tests and were not considered eligible for further test/studies. We therefore investigated the
effects of ivermectin therapy on the sperm functions of these eligible 37 diagnosed patients of
onchocerciasis who were of ages between 28 and 57 years. The sperm functions were assessed via
seminal fluid analysis using standard procedure and the following parameters were measured: sperm
counts, sperm motility, sperm morphology, sperm volume, sperm viscosity and sperm liquefaction time.
The above parameters were measured before and after the patients were treated with 150μg/kg body wt
of ivermectin for eleven months and the results were compared and also with normal control reference
range. We observed significant reduction in the sperm counts and sperm motility of the patients tested.
On the morphology there was significant increase in the number of abnormal sperm cells. This took the
forms of two heads, double tails, white (albino) sperms and extraordinarily large heads. It is suspected
that the above alterations in the already determined parameters of the patients’ sperm cells could only
have occurred as a result of their treatment with ivermectin. However, we could not record any
significant change or alteration in the sperm viscosity, sperm volume, and sperm liquefaction time of the
patients. We therefore suggest that caution be seriously exercised in the treatment of male onchocerciasis
patients with ivermectin to avoid the adverse effects it has on the patients’ sperm functions.