title: The impact of five years of annual ivermectin treatment on skin microfilarial loads in the onchocerciasis focus of Asubende, Ghana.
abstract: Following the registration of ivermectin (Mectizan) for human use in the treatment of onchocerciasis, in 1987 the Onchocerciasis Control Programme in West Africa (OCP) begun a series of trials in order to determine the safety of the drug when used on a large scale and its potential for morbidity control. This paper reports the changes in skin microfilarial loads during the first 5 years of annual treatment in the holoendemic focus of Asubende in Ghana, which was the largest trial area and which also had the longest series of follow-up surveys. The general observed pattern was a marked reduction of microfilarial loads shortly after each treatment followed by a steady repopulation of the skin until a subsequent treatment round. The overall reduction of microfilarial loads observed between the base line survey and one year after the last treatment was 90% for the total population examined and over 93% for a cohort which received the drug at all 5 treatment rounds. In contrast, there was only a very gradual decrease in the prevalence of infection in the population after subsequent treatments. The study further emphasizes that even a single treatment with ivermectin has a significant medium-term impact on microfilarial loads. Microfilarial counts barely increased after 14-16 months of treatment and stabilized around 55% of pre-treatment counts 2-4 years after a single treatment.
authors.affiliation: Onchocerciasis Control Programme in West Africa, Ouagadougou, Burkina Faso.
authors.forename: E S
authors.initials: ES
authors.lastname: Alley
authors.forename: A P
authors.initials: AP
authors.lastname: Plaisier
authors.forename: B A
authors.initials: BA
authors.lastname: Boatin
authors.forename: K Y
authors.initials: KY
authors.lastname: Dadzie
authors.forename: J
authors.initials: J
authors.lastname: Remme
authors.forename: G
authors.initials: G
authors.lastname: Zerbo
authors.forename: E M
authors.initials: EM
authors.lastname: Samba
mesh_terms: D000818:Animals; D000977:Antiparasitic Agents; D005869:Ghana / Q000453:epidemiology; D006801:Humans; D007300:Insect Control; D007559:Ivermectin / Q000627:therapeutic use*; D008842:Microfilariae / Q000302:isolation & purification*; D009855:Onchocerciasis / Q000188:drug therapy* / Q000453:epidemiology / Q000635:transmission; D015995:Prevalence; D012867:Skin / Q000469:parasitology*; D012876:Skin Diseases, Parasitic / Q000453:epidemiology / Q000469:parasitology; D013997:Time Factors
chemical_list: D000977:Antiparasitic Agents; D007559:Ivermectin