Equitable access to Mass Drug Administration for trachoma elimination: an ethnographic study to understand factors associated with low coverage in Kenya and Tanzania
Main objectives are firstly to identify and understand better the factors behind low and unequal MDA coverage and compliance in trachoma endemic areas in Tanzania and Kenya with nomadic populations, secondly to prioritize factors in terms of amenability to intervention. The researcher will then use the evidence generated to design specific interventions that could improve the reach and impact of campaigns of Zithromax MDA in both countries. While there are contextual differences between nomadic societies throughout Africa, research among the Masai in Tanzania and Kenya should inform programme services in other settings with nomadic populations. Particular attention will be given to gender-sensitivity; that is, interventions that will improve access and use by women as well as men.
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 Tanzania 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. Because the EU is also endemic for onchocerciasis, the new Ov16 monoplex RDT was used in the field. The Wb123 and Ov16 antibodies were assessed via ELISA in the NIMR lab in Tanga and the results will soon be compiled. Xenomonitoring work to assess Culex and Anopheles mosquitoes, as well as black flies, 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.
Analyze the relationships between the prevalence of the clinical sign follicular trachoma (TF) and the prevalence of infection and antibody to determine whether it may be appropriate to consider one or more alternative indicators for deciding whether trachoma programs can stop MDA.
Demonstrate the utility of a new mapping strategy based on school cluster random sampling Using PPES. A secondary objective is to assess the value of laboratory-based antibody assays as confirmatory tests and additional diagnostic tools for measuring LF transmission.
Field validation of sampling strategies for integrating STH surveys into Transmission Assessment Surveys (Tanzania)
(1) Is it possible to eliminate schistosomiasis as a public health problem on Unguja in three years and to interrupt transmission in five years? (2) Is it possible to control schistosomiasis throughout Pemba (prevalence <10%) in three years and to eliminate it as a public health problem in five years? (3) What are the costs, successful strategies, barriers, etc. associated with three different interventions (MDA, vector control, and behavior change)?