Current large-scale schistosomiasis treatment programs are a first step to reducing the global burden of Schistosoma-related disease, yet such programs may not significantly alter parasite transmission in high-risk areas. Consequently, the sustainability of these programs'initial benefits remains in doubt, as recurring low-level reinfection can be associated with persistent morbidity such as anemia, undernutrition, and diminished performance. Novel molecular tools for rapid, sensitive transmission monitoring are needed to obtain more informative surveillance of schistosome propagation over extended areas. In accord with the R21 program's developmental focus, this project will create and validate new technologies that can significantly advance knowledge of the environmental features of schistosome transmission, and will materially contribute to health-related implementation research for improved schistosomiasis control. The overall aim of the proposed study is to test the capacity of new S. haematobium DNA-detection molecular tools to efficiently monitor schistosomiasis transmission in multi-community campaigns. The parasite is widely prevalent in Africa and the Middle East, with 120 million persons currently infected. Effective 'xenomonitoring'snail sampling strategies can provide highly sensitive systems for monitoring transmission potential following implementation of parasite control campaigns. The present study's Loop-mediated Isothermal Amplification is a scalable approach can be adapted to provide low-tech DNA detection systems that regional and international control programs will be able use as a means to document their effectiveness and confirm attainment of schistosomiasis eradication.
The Specific Aims of the study are: 1. To validate the established 525 bp Sh110/SmSl PCR technique as a species-specific means to identify snails infected with S. haematobium in ecosystems where related schistosome species are sympatric. 2. To develop a low-tech detection of prepatent snail infection by adapting the Loop-Mediated Isothermal Amplification (LAMP) assay for amplifying the inter-repeat 525 bp Sh110/SmSL sequence of S. haematobium. 3. To validate the LAMP assay by examining laboratory infected snails and field snails collected from S. haematobium-endemic areas in Kenya. 4. To establish the LAMP as a working assay in a pilot field laboratory in Kenya and in a central reference laboratory for backup and quality control. 5. To evaluate S. haematobium-LAMP performance in an existing control setting in Kenya. Human schistosomiasis is a parasitic trematode infection that imposes a major health burden on the developing world and new strategies are needed for tracking its uneven transmission through the environment. This proposal develops new DNA detection systems to monitor parasite transmission (through local infested water bodies) among infected intermediate host snails. This tool will provide a highly useful method of directing schistosomiasis control programs, and could lead to much more effective targeted strategies for eradication of parasite transmission.
| Abbasi, Ibrahim; Webster, Bonnie L; King, Charles H et al. (2017) The substructure of three repetitive DNA regions of Schistosoma haematobium group species as a potential marker for species recognition and interbreeding detection. Parasit Vectors 10:364 |
| Hamburger, Joseph; Abbasi, Ibrahim; Kariuki, Curtis et al. (2013) Evaluation of loop-mediated isothermal amplification suitable for molecular monitoring of schistosome-infected snails in field laboratories. Am J Trop Med Hyg 88:344-51 |
| Abbasi, Ibrahim; Hamburger, Joseph; Kariuki, Curtis et al. (2012) Differentiating Schistosoma haematobium from related animal schistosomes by PCR amplifying inter-repeat sequences flanking newly selected repeated sequences. Am J Trop Med Hyg 87:1059-64 |
| Abbasi, Ibrahim; King, Charles H; Muchiri, Eric M et al. (2010) Detection of Schistosoma mansoni and Schistosoma haematobium DNA by loop-mediated isothermal amplification: identification of infected snails from early prepatency. Am J Trop Med Hyg 83:427-32 |
