The purpose of this study is to determine differences between cure rates vs re-infection levels. The fundamental question is to see what the prevalence and intensity are before MDA, and then, see what those are 7 to 8 weeks after MDA. Since there are villages that continue to have high prevalence from year to year, we will determine if this primarily represents reinfection occurring since the last annual MDA or if it is related more to treatment efficacy.
A selected number of 5 villages near Lake Victoria shown to maintain very high levels of infection with S. mansoni following at least three rounds of annual praziquantel chemotherapy will be compared with 5 villages where infection rates have been much more responsive to similar levels of treatment, with respect to the following general considerations and questions:
1) What is the general situation for each village with respect to proximity of water bodies where intensive human contact occurs?
2) For each village, what is the role of each major habitat in transmission, as assessed by three separate techniques: water filtration; use of sentinel mice; and standard snail survey techniques?
Develop a mobile reader application for use at the point-of care for the POC-CCA assay used for mapping and surveillance of Schistosoma mansoni. The reader apk will provide results consistent with the visual human reading of the test. Distinguishing intensity bands and reading 'Trace' results can be problematic and leads commonly to 'false positive' readings. The apk being developed will utilize a testing algorithm to better distinguish between true positive and false positive "Trace" test results.
What is the the impact of riverine prawns on infections in humans? Studies are to be conducted on interrupting seasonal transmission of Schistosomiasis and ecologic assessment of riverine prawns on infections in humans.
This study will include comparing 1) MDA as usual 2) double treatment with two closely-spaced MDAs (consistent with the recommendation based on mathematical models) 3) twice yearly MDA and 4) double MDA plus snail control.
(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)?
How do villages which do not show substantial decreases in the prevalence of schistosomiasis despite repeated, high coverage mass drug administration (persistent hot-spot villages) differ from villages which show substantial decrease in prevalence across various factors (declining prevalence villages)?
Will providing enhanced MDA at the community level while achieving treatment coverage of 75% or greater in children (5-17) and adults substantially decrease S. mansoni infection in previously identified persistent hot-spot communities?