A Reevaluation of the Tolerability and Effects of Single-Dose Ivermectin Treatment on Onchocerca volvulus Microfilariae in the Skin and Eyes in Eastern Ghana

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  • 1 School of Public Health, University of Health and Allied Sciences, Ho, Ghana;
  • | 2 St. Thomas Eye Hospital, Accra, Ghana;
  • | 3 Hohoe Municipal Hospital, Hohoe, Ghana;
  • | 4 Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri;
  • | 5 Department of Ophthalmology, Washington University School of Medicine, St. Louis, Missouri;
  • | 6 Infectious Diseases Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri;
  • | 7 Center for Global Health and Diseases, Case-Western Reserve University, Cleveland, Ohio

Mass administration of ivermectin (IVM) has significantly reduced onchocerciasis prevalence, intensity, and morbidity in most endemic areas. Most IVM clinical trials were performed long ago in persons with high-intensity infections that are uncommon in West Africa today. This cohort treatment study recruited participants from a hypoendemic area in eastern Ghana to reevaluate the efficacy and tolerability of IVM with a special focus on the kinetics of microfilaria (Mf) clearance. Mf in the skin and anterior chambers (ACs) were assessed by skin snip and slit lamp examinations at baseline and at 3 and 6 months after treatment with IVM 150 μg/kg. Out of 231 people, 79 enrolled were treatment-naïve. The baseline geometric mean skin Mf count was 12.67/mg (range 3–86). Although persons with MfAC at baseline (64/231, 27%) had significantly higher skin Mf counts than people without MfAC, 7 of 39 (15%) of persons with skin Mf counts in the range of 3–5 Mf/mg had MfAC. Skin Mf were detected in 14% (31/218) and 45% (96/216) of participants 3 and 6 months after IVM treatment, respectively. MfAC were detected in 12 of 212 (5.7%) study participants at 6 months 81% (187 of 231) of participants experienced 439 adverse events within 7 days after treatment; all adverse events were mild (96.1%) or moderate. This study has provided new data on the kinetics of Mf in the skin and eyes after IVM treatment of persons with light to moderate intensity Onchocerca volvulus infections that are common in Africa at this time.

Author Notes

Address correspondence to Gary J. Weil, Infectious Diseases Division, Washington University School of Medicine, 4444 Forest Park, St. Louis, MO 63108. E-mail gary.j.weil@wustl.edu

Financial support: This study was supported by a grant from the Bill & Melinda Gates Foundation (OPP GH5342) to Washington University. The funder had no role in the study design, data collection/analysis, decision to publish, or preparation of the manuscript.

Authors’ addresses: Nicholas O. Opoku, School of Public Health, University of Health and Allied Sciences, Ho, Ghana, E-mail: noopoku@uhas.edu.gh. Michael E. Gyasi, St. Thomas Eye Hospital, Accra, Ghana, E-mail: mikegiasi67@gmail.com. Felix Doe, Hohoe Municipal Hospital, Hohoe, Ghana, E-mail: felixdoedr@yahoo.com. Daphne Lew, Division of Biostatistics, Washington University School of Medicine, St. Louis, MO, E-mail: daphne.lew@wustl.edu. Augustine R. Hong, Department of Ophthalmology, Washington University School of Medicine, St. Louis, MO, E-mail: ahong22@wustl.edu. Sithembele Chithenga, Infectious Diseases Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, E-mail: s.chithenga@wustl.edu. Christopher L. King, Center for Global Health and Diseases, Case-Western Reserve University, Cleveland, OH, E-mail: cxk21@case.edu. Gary J. Weil, Infectious Diseases Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, E-mail: gary.j.weil@wustl.edu.

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