Understanding the basic pharmacology of praziquantel tailored to paediatric setting and developing a treatment access plan for this age class
Helping increase and sustain the scale-up of preventive chemotherapy campaigns in West and Central Africa
Impact of Malaria Vector Control & Status of Lymphatic Filariasis Transmission in the Lake Zone of Tanzania
To assess filarial exposure in the study population and mosquito infection status prior to and after the start of intensified malaria control interventions.
Determination of the prevalence of LF infection in districts not included in LF control activities and of the basis for integrated implementation of LF - onchocerciasis elimination strategies in potentially co-endemic areas
Field validation of the diagnostic performance of the Wb123/Ov16 biplex rapid diagnostic test and Wb123 ELISA, compared to the filariasis test strip (FTS) in a setting initially found to be non-endemic for lymphatic filariasis, in which clinical cases have been identified.
To compare the performance of antigen (FTS) and antibody (Wb123 monoplex) tools in programmatic settings (TAS).
Preliminary Findings and Lessons Learned
The goal of this study is to compare the performance of antigen (FTS) and antibody (Wb123 monoplex, Wb123 ELISA, multiplex) tools in programmatic settings (TAS). In order to strengthen the existing TAS platform we need to better understand which diagnostic indicator(s) are best-suited for making programmatic decisions. The TAS was conducted in Trou de Nord and Plaisance EUs. Both EUs passed the TAS, but positive FTS were identified (4 and 2, respectively). However the Wb123 RDT found ZERO positive children, of the over 2000 tested. While the Wb123 ELISA testing is still ongoing, this initial result agrees with findings from other studies, all of which suggest that the Wb123 RDT is too insensitive a tool to be of programmatic use.
To evaluate strategies to improve the sensitivity of the TAS for detecting evidence of recent lymphatic filariasis transmission in an evaluation unit (EU). The TAS Strengthening Study in American Samoa is designed to assess additional indicators that may be added to the current TAS platform in order to strengthen the resulting stopping or surveillance decisions. A comprehensive analysis will be conducted to understand the correlation between antigen and antibody in adults and children with the mosquito data. A spatial analysis looking at microfoci of infection will also be conducted. Xenomonitoring work to assess Aedes mosquitoes is underway.
Preliminary Findings and Lessons Learned
The ultimate goal of this study is to strengthen the existing TAS platform so that the programs can be more confident with their stopping and surveillance decisions. In order to strengthen the existing TAS platform we need to better understand which target population(s) and diagnostic indicator(s) are best-suited for identifying areas with persistent transmission that is not expected to cease on its own, knowing that the answer may vary according the primary vector and stage of the program. In the selected sites a community-based TAS was conducted using the standard sampling of 6-7 year olds while a community TAS (individuals >8 years) was conducted concurrently. All samples were tested via FTS and DBS (for Wb123 ELISA). In these same communities a molecular xenomonitoring study will take place and the mosquitoes will be tested for filarial DNA to relate back to the human specimens. To date human sampling has been completed in all sites and laboratory analysis of the specimens is complete. Mosquito collection has been completed in Haiti and Tanzania and the PCR analysis has been completed in Haiti and is planned for Tanzania (pending the arrival of a new PCR machine). In American Samoa xenomonitoring has been delayed due to weather conditions and arbovirus outbreaks; work is expected to commence spring 2018.
- To define a cost-effective and accurate method to map ivermectin-naïve districts for Onchocerciasis, Lymphatic Filariasis and Loiasis and identify districts eligible for safe treatment with ivermectin MDA.
- To validate a statistical model of Loiasis prevalence and intensity by comparing the model results to data from a prevalence assessment.
To assess the relationships between the prevalence of the clinical sign TF compared to prevalence of infection and antibody in Chikwawa and Mchinji districts
Determine whether current or historic C. trachomatis (Ct) infection can be detected, and whether it is associated with clinical signs of ‘trachomatous inflammation – follicular’ (TF) in Vanuatu and Kiribati
Determine the utility of infection testing as a tool for operational surveillance and impact assessment in trachoma-endemic environments.
To study the feasibility of LF and Oncho (Filariases) integrated transmission assessment survey (iTAS) according to both LF and Onchocerciasis WHO elimination guidelines