Does Increasing Treatment Frequency Address Suboptimal Responses to Ivermectin for the Control and Elimination of River Blindness?

作者：Frempong Kwadwo K; Walker Martin; Cheke Robert A; Tetevi Edward Jenner; Gyan Ernest Tawiah; Owusu Ebenezer O; Wilson Michael D; Boakye Daniel A; Taylor Mark J; Biritwum Nana Kwadwo; Osei Atweneboana Mike; Basanez Maria Gloria^*

来源：Clinical Infectious Diseases, 2016, 62(11): 1338-1347.

DOI：10.1093/cid/ciw144

• onchocerciasis
• ivermectin
• biannual treatment
• suboptimal responses
• elimination

Background. Several African countries have adopted a biannual ivermectin distribution strategy in some foci to control and eliminate onchocerciasis. In 2010, the Ghana Health Service started biannual distribution to combat transmission hotspots and suboptimal responses to treatment. We assessed the epidemiological impact of the first 3 years of this strategy and quantified responses to ivermectin over 2 consecutive rounds of treatment in 10 sentinel communities.
Methods. We evaluated Onchocerca volvulus community microfilarial intensity and prevalence in persons aged >= 20 years before the first, second, and fifth (or sixth) biannual treatment rounds using skin snip data from 956 participants. We used longitudinal regression modeling to estimate rates of microfilarial repopulation of the skin in a cohort of 217 participants who were followed up over the first 2 rounds of biannual treatment.
Results. Biannual treatment has had a positive impact, with substantial reductions in infection intensity after 4 or 5 rounds in most communities. We identified 3 communities-all having been previously recognized as responding suboptimally to ivermectinwith statistically significantly high microfilarial repopulation rates. We did not find any clear association between microfilarial repopulation rate and the number of years of prior intervention, coverage, or the community level of infection.
Conclusions. The strategy of biannual ivermectin treatment in Ghana has reduced O. volvulus microfilarial intensity and prevalence, but suboptimal responses to treatment remain evident in a number of previously and consistently implicated communities. Whether increasing the frequency of treatment will be sufficient to meet the World Health Organization's 2020 elimination goals remains uncertain.

• 出版日期2016-6-1
• 单位河北医科大学