Field application of PCR-based assays for monitoring Wuchereria bancrofti infection in Africa.

Approximately 50 million people in Egypt and sub-Saharan Africa have bancroftian filariasis and together they represent about a third of all cases of lymphatic filariasis (LF) world-wide. Currently, the Global Programme to Eliminate Lymphatic Filariasis, which was launched by the World Health Organization (WHO) in 1998, is largely based on repeated annual cycles of mass drug administration (MDA) to endemic populations. Also, some countries, including Egypt, are taking steps to improve LF vector-control interventions, to break the transmission cycle more effectively than is achievable with MDA alone. New tools and strategies for monitoring and evaluating elimination campaigns are needed. The last 20 years have witnessed dramatic advances in the diagnosis of LF for epidemiological purposes. The recent introduction and development of molecular technologies have moved parasite-detection systems from traditional methods (that are labour-intensive, tedious and often impractical) to improved PCR-based assays that have considerable potential for field use. The present article highlights the strengths and limitations of the PCR-based assays when used to detect filarial infections in mosquitoes (particularly for the xenomonitoring of elimination campaigns).