Assessing the Presence of Wuchereria bancrofti Infections in Vectors Using Xenomonitoring in Lymphatic Filariasis Endemic Districts in Ghana

Abstract

Mass drug administration (MDA) is the current mainstay to interrupt the transmission of lymphatic filariasis. To monitor whether MDA is effective and transmission of lymphatic filariasis indeed has been interrupted, rigorous surveillance is required. Assessment of transmission by programme managers is usually done via serology. New research suggests that xenomonitoring holds promise for determining the success of lymphatic filariasis interventions. The objective of this study was to assess Wuchereria bancrofti infection in mosquitoes as a post-MDA surveillance tool using xenomonitoring. The study was carried out in four districts of Ghana; Ahanta West, Mpohor, Kassena Nankana West and Bongo. A suite of mosquito sampling methods was employed, including human landing collections, pyrethrum spray catches and window exit traps. Infection of W. bancrofti in mosquitoes was determined using dissection, conventional and real-time polymerase chain reaction and loop mediated isothermal amplification assays. Aedes, Anopheles coustani, An. gambiae, An. pharoensis, Culex and Mansonia mosquitoes were sampled in each of the four study districts. The dissected mosquitoes were positive for filarial infection using molecular assays. Dissected An. melas mosquitoes from Ahanta West district were the only species found positive for filarial parasites. We conclude that whilst samples extracted with Trizol reagent did not show any positives, molecular methods should still be considered for monitoring and surveillance of lymphatic filariasis transmission.

Prevalence of Wuchereria bancrofti infection in human and vector populations from Center-East, East and South-West regions of Burkina Faso: preliminary results

“…These results were con rmed two years after in the same areas by Kima et al [5] who had also noti ed many cases of W. bancrofti in human populations con rming thus the hotspot status of this transmission belt. Compared to Ghana a neighboring country experiencing the elimination of LF, the infection of W. bancrofti in human population was rare or absent after 11 to 16 MDAs that lead to conduct post TAS evaluation studies [8]. Here in Burkina Faso many investigations are still needed before decision making to stop the MDA.…”

“…The detection of Wuchereria bancrofti L3 within mosquitoes was realized by conventional PCR [8,16,17] using DNA from heads and thoraces of mosquitoes grouped by pool before PCR processes. This technique permitted to analyze the An.…”

“…gambiae s.l. [8] integrating this technique can be a complementary way for the monitoring and evaluation of post TAS validation in Burkina Faso. Additionally, the same DNA extracts can be used for malaria detection in the vectors if one wants to have a co-infection pro le in these endemic areas [9].…”

Low transmission of Wuchereria bancrofti in cross-border districts of Côte d’Ivoire: A great step towards lymphatic filariasis elimination in West Africa

“…Although some species belonging to Anopheles, Aedes, Culex and Mansonia mosquito genera have been found to carry W. bancrofti DNA or parasite depending on the geographic location [11], An. gambiae is known as the main LF vector in West Africa [14,15], while Cx. quinquefasciatus mostly transmits the worm in East Africa [46].…”

“…gambiae and Cx. quinquefasciatus are known as the primary vectors of W. bancrofti [13][14][15]. Togo (West Africa) became the first country in sub-Saharan Africa to receive WHO validation of EPHP [4], while others like Benin and Ghana are advanced at transmission assessment survey (TAS) phase [16].…”