Abstract:
Human enteric viruses are responsible for the majority of acute waterborne diseases. Most people affected are children under five years old. Symptoms of disease can include diarrhea, gastroenteritis, and paralysis. However, human infections can also be asymptomatic, which allows viruses to go undetected and circulate within the environment. Environmental surveillance is a tool that can supplement disease-based surveillance by sampling, concentrating, and analyzing sewage and other environmental surface waters for pathogens. Polioviruses and group A rotaviruses are enteric viruses of major global public health concern and water has been implicated in their transmission. Environmental surveillance for the detection of poliovirus has expanded in recent years to supplement clinical detection of wild polioviruses and vaccine-derived polioviruses in support of polio eradication efforts. Surveillance of other enteric viruses typically relies on disease-based surveillance and any environmental surveillance employed is for a limited sampling period. Recently, the introduction of new live, attenuated rotavirus vaccines has created a need for environmental monitoring to characterize rotavirus strains in wastewater. The epidemiology of these strains is useful to inform vaccine efficacy. This research focused on addressing environmental sampling needs. First, the evaluation and optimization of a secondary concentration step for improved detection of poliovirus in wastewater is presented. Next, environmental surveillance sampling is applied to enable molecular characterization of group A rotavirus strains in circulation in three communities in Nairobi, following the introduction of the Rotarix® vaccine in Kenya. A skimmed-milk flocculation (5%) method is identified as an economically feasible, time efficient, and high recovery secondary concentration method for poliovirus detection. Genetic characterization in selected Nairobi communities reveals a diversity of rotavirus strains in post-vaccine Kenya, with the emergence of serotype G3. Environmental surveillance for non-polio enteric viruses is often ad hoc to support outbreak investigations or inform vaccine efficacy. Though, it is expected to expand in coming years as better detection methods are developed and the global community pursues eradication of more vaccine preventable diseases. URI http://hdl.handle.net/1773/40096