Impact of long-term treatment of onchocerciasis with ivermectin in Kaduna State, Nigeria: First evidence of the potential for elimination in the operational area of the African Programme for Onchocerciasis Control
African Programme for Onchocerciasis Control, WHO/APOC, P. O. Box: 01 B.P. 549, Ouagadougou 01, Burkina Faso; SightSavers Regional Office for Africa, Dakar, Senegal; Sightsavers Nigeria Country Office, 1 Golf Course Road, Kaduna, Nigeria; No. 8 Somto Anugwom Close. Ekulu West, G.R.A. Enugu, Enugu State, Nigeria; Sightsavers, PO Box 181909, Airport, Accra, Ghana; London School of Hygiene and Tropical Medicine, London, United Kingdom; Sightcare International, Secretariat Main Office, P.O. Box 29771, Ibadan, Oyo State, Nigeria; APOC, 120 Rue des Campanules, 01210 Ornex, France
Background. Onchocerciasis can be effectively controlled as a public health problem by annual mass drug administration of ivermectin, but it was not known if ivermectin treatment in the long term would be able to achieve elimination of onchocerciasis infection and interruption of transmission in endemic areas in Africa. A recent study in Mali and Senegal has provided the first evidence of elimination after 15-17 years of treatment. Following this finding, the African Programme for Onchocerciasis Control (APOC) has started a systematic evaluation of the long-term impact of ivermectin treatment projects and the feasibility of elimination in APOC supported countries. This paper reports the first results for two onchocerciasis foci in Kaduna, Nigeria. Methods. In 2008, an epidemiological evaluation using skin snip parasitological diagnostic method was carried out in two onchocerciasis foci, in Birnin Gwari Local Government Area (LGA), and in the Kauru and Lere LGAs of Kaduna State, Nigeria. The survey was undertaken in 26 villages and examined 3,703 people above the age of one year. The result was compared with the baseline survey undertaken in 1987. Results. The communities had received 15 to 17 years of ivermectin treatment with more than 75% reported coverage. For each surveyed community, comparable baseline data were available. Before treatment, the community prevalence of O. volvulus microfilaria in the skin ranged from 23.1% to 84.9%, with a median prevalence of 52.0%. After 15 to 17 years of treatment, the prevalence had fallen to 0% in all communities and all 3,703 examined individuals were skin snip negative. Conclusions. The results of the surveys confirm the finding in Senegal and Mali that ivermectin treatment alone can eliminate onchocerciasis infection and probably disease transmission in endemic foci in Africa. It is the first of such evidence for the APOC operational area. © 2012 Tekle et al; licensee BioMed Central Ltd.
ivermectin; adolescent; adult; article; child; eradication therapy; feasibility study; female; human; infant; infection control; major clinical study; male; Microfilaria; Nigeria; nonhuman; Onchocerca volvulus; onchocerciasis; preschool child; prevalence; school child; Adolescent; Adult; Animals; Antiparasitic Agents; Child; Child, Preschool; Disease Eradication; Female; Humans; Infant; Ivermectin; Male; Middle Aged; Nigeria; Onchocerca volvulus; Onchocerciasis; Prevalence; Public Health; Young Adult