Characterizing the interaction between human and vector behaviors to enhance the impact of malaria control interventions in Uganda

University Of California, San Francisco, San Francisco CA

Investigators

Abstract

PROJECT SUMMARY/ABSTRACT Great progress was made in reducing the burden of malaria in sub-Saharan Africa from 2000 to 2015, with a majority of the cases averted attributed to the scale up of vector control with tools like insecticide-treated bednets. More recently, however, progress has stalled, and even reversed course in some high burden countries. The World Health Organization now recommends local tailoring of malaria control interventions to enhance their effectiveness. Few national malaria control programs have on hand malaria surveillance systems capable of producing the high-quality data necessary to tailor control interventions at the sub-national level. This creates an urgent public health need for enhanced malaria surveillance that can guide planning of control strategies by linking clinical outcomes to control interventions. Long-lasting insecticide-treated bednets (LLINs), the most widely used tool for malaria prevention, no longer seem as effective as they once were, likely as a result of resistance to pyrethroid-class insecticides and changes in the vector behaviors and species composition. Fur- thermore, human behaviors, such as lower rates of LLIN use and more time spent outdoors, may also be reduc- ing the effectiveness of vector control tools. Ultimately, it is the interactions between humans and vectors that determine the effectiveness of vector control. As a result, this proposal focuses on biological and behavioral factors that modulate interactions between humans and malaria vectors in the context of vector control interven- tions. Our central hypothesis is that there are gaps in protection despite the use of existing vector control tools (e.g. LLINs) which can only be elucidated by integrating human and vector monitoring data. Our proposed ap- proach will be to add rigorous human behavioral and entomological monitoring to our existing malaria surveil- lance network in 38 sites across Uganda. This network provides longitudinal estimates of clinical outcomes in- cluding malaria incidence and parasite prevalence from communities in target areas around government-run health facilities. Working in the context of “real-life” implementation of vector control interventions (e.g. LLIN distribution campaigns), our primary goal will be to link measures of human-vector interaction to epidemiological outcomes across geographic and transmission settings. Achieving this goal will enable us to answer fundamental questions about why malaria persists in the face of current control strategies and provide practical options for policy makers seeking evidence-based, targeted, interventions. In addition, this surveillance system will be ide- ally positioned to evaluate the impact of new vector-oriented interventions as they are implemented in the future. This proposal represents a unique opportunity to provide both actionable data for policymakers and also gener- ate fundamental insights for the many other countries throughout the world that rely on vector control to fight malaria. Our long term goal is to provide insights into how vector control tools affect clinical outcomes through reducing human-vector interaction and make progress in finding better ways to prevent malaria in the future.