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Viability and fertility of adult Onchocerca volvulus after 6 years of treatment with ivermectin
Author(s) -
Kläger S. L.,
Whitworth J. A. G.,
Downham M. D.
Publication year - 1996
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/j.1365-3156.1996.tb00083.x
Subject(s) - ivermectin , onchocerca volvulus , onchocerciasis , population , medicine , sierra leone , helminthiasis , fertility , onchocerca , biology , veterinary medicine , immunology , environmental health , development economics , economics
Summary Onchocerca volvulus nodules were removed from 77 fully compliant patients in a longitudinal study of ivermectin treatment in Sierra Leone. The patients had participated in a randomized controlled trial and received either 4 annual doses of ivermectin or 10 6‐monthly doses over 6 years. Worms were examined 9 months after the last treatment for evidence of changes in morphology, viability and reproductivity. The findings were compared with results for the 2 groups obtained at earlier surveys of the same study population. Repeated treatment at 6 and 12‐month intervals has resulted in a marked ageing of the male worm population profile and a significant reduction in the proportion of live female worms found in the nodules. In addition, there has been a reduction in reproductivity of 90% or more. However, most of the worms found were still alive and potentially fertile, underlining the need for the continuation of regular ivermectin treatment to maintain the benefits achieved.