Short paper

Mass ivermectin treatment for Onchocerciasis: Lack of evidence for collateral impact on transmission of Wuchereria bancrofti in areas of co-endemicity

FO Richards Jr¹, A Eigege¹, D Pam², A Kal¹, A Lenhart¹, JOA Oneyka², MY Jinadu³ and ES Miri¹

¹  The Carter Center, One Copenhill, Atlanta GA 30307, USA

²  Department of Zoology, University of Jos, Jos, Plateau State, Nigeria

³  Room 913, Phase II, Federal Secretariat, Federal Ministry of Health, Lagos, Nigeria

Filaria Journal 2005, 4:6doi:10.1186/1475-2883-4-6

Published:	15 July 2005

Abstract

There has long been interest in determining if mass ivermectin administration for onchocerciasis has 'unknowingly' interrupted lymphatic filariasis (LF) transmission where the endemicity of the two diseases' overlaps. We studied 11 communities in central Nigeria entomologically for LF by performing mosquito dissections on Anopheline LF vectors. Six of the communities studied were located within an onchocerciasis treatment zone, and five were located outside of that zone. Communities inside the treatment zone had been offered ivermectin treatment for two-five years, with a mean coverage of 81% of the eligible population (range 58–95%). We found 4.9% of mosquitoes were infected with any larval stage of W. bancrofti in the head or thorax in 362 dissections in the untreated villages compared to 4.7% infected in 549 dissections in the ivermectin treated villages (Mantel-Haenszel ChiSquare 0.02, P = 0.9). We concluded that ivermectin annual therapy for onchocerciasis has not interrupted transmission of Wuchereria bancrofti (the causative agent of LF in Nigeria).