Different transmission assessment methods for lymphatic filariasis in urban settings

• To determine the most appropriate methodology to evaluate the presence of W. bancrofti transmission in urban conurbations in West Africa to establish if MDA is necessary for the elimination of W. bancrofti

The efforts deployed to date by endemic countries and a multiplicity of partners to eliminate lymphatic filariasis (LF) as a public health problem have been hampered, particularly in West Africa, by the presence of large and growing conurbations. Such urban areas are heterogeneous in terms of population and are the focus of rural-urban migration. It is difficult in these environments both to make effective treatment decisions and, where necessary, to implement mass drug administration (MDA) with high coverage. In general, WHO recommends MDA implementation in districts where antigenemia prevalence is >1% and at least 5 MDA rounds should be conducted to interrupt LF transmission. Urban areas are often subsumed in the treatment decisions and assessments of otherwise rural districts, often with little evidence of either transmission or disease prevalence.

This project will conduct an assessment of the level of W. bancrofti transmission in Monrovia, Liberia focused on the detection of the infective stage (L3) in mosquitos as well as an immunological monitoring approach of confirmatory mapping. Finally, a combination approach will utilise the results from both methods. The study will form a comprehensive evidence base for the Ministry of Health treatment decision in Monrovia, as well as inform development of a standardised and recommended protocol for taking similar decisions within urban conurbations of the West African region where there are expanding urban populations and ongoing in-migration from rural areas.