Vector species, including mosquitoes and ticks, are responsible for transmitting some of the world’s most dangerous pathogens. We study vector-pathogen-host interactions, ranging from the molecular to the population level, with the aim of limiting the impact of disease.
Malaria, induced by a parasite transmitted by mosquitoes, is one of the leading causes of morbidity and mortality globally. In the last decade the spread of mosquito borne viruses like dengue and Zika is being spurred on by urbanization, global travel and changes in climate. In parallel, new and emergent pathogens transmitted by ticks are becoming more common (e.g. Lyme disease, Babesiosis, Powassan, Bourbon, and Heartland viruses). Effective vaccines are not available for these pathogens, in part because their complex biology has challenged vaccine development or because of their very recent emergence. Much of the historical success in vector-borne disease control has resulted from control of vectors themselves. While decreasing mosquito breeding habitat is helpful, the cornerstone of these practices has been the use of insecticides in outdoor spraying, treatment of surfaces in houses or the use of bed nets. The long-term efficacy of these approaches is at risk, as resistance against insecticides emerges and spreads in vector populations. While similar levels of resistance to acaricides have not been detected in ticks, there are concerns over long-term applications of synthetic chemicals to the landscape and the effect on non-target organisms and environmental quality. In response to these challenges, other control practices are being explored including genetic modification of vectors, the use of biological control agents including bacteria and fungi, and novel pesticide delivery strategies based on a better understanding vector ecology and behavior.
Examples of specific questions that we are trying to address at CIDD include (1) What makes a vector a good transmitter of pathogens and what are the relative roles of genes and environment in determining transmission? (2) How do interactions between vectors and their natural bacterial biota (including gut bacteria and endosymbionts) affect their ability to serve as vectors? (3) What are the molecular mechanisms of vector immunity in response to pathogens? (4) What host characteristics drive vector choice? (5) How does evolution of insecticide resistance impact transmission and how can resistance be managed? (6) What are the best environmentally sound, integrated ways to manage vectors at a landscape level? The answers to these questions are helping to improve understanding of the dynamics and distribution of vector borne diseases and to develop more effective and sustainable control strategies.