Michael H Reiskind-Research Interests
STATEMENT OF RESEARCH OBJECTIVES
I. Research Objectives
Broadly, I am interested in connections between vector ecology and disease. My interests span the breadth of this interaction, and therefore scale from the landscape to the vector habitat to the pathogen. Understanding disease vector biology has important impacts in controlling widespread pathogens, such as malaria and dengue fever virus and in understanding emergent pathogens, including West Nile and chikungunya viruses. Historically, with the possible exception of yellow-fever vaccination, most of the advances in controlling vector-borne disease have come from detailed studies of vector ecology and vector-host interactions, yet the connections between vector ecology and epidemiology remain under explored. One of the benefits of working with a widespread family is that the questions I ask are amenable to diverse situations, and could be done in almost any locality in the world, with only small adjustments for specific mosquito species.
II. Current and Future Research
A. The ecology of invasive vectors: landscape level investigations of Aedes aegypti and Aedes albopictus distributions in southern Florida. In today’s global economy and changing climate, disease vectors have the opportunity to invade new regions with unprecedented frequency, and with concomitant impacts on global human health. Preparedness and prevention requires integrating knowledge of invasion biology and vector ecology. To this end, Dr. L. Phil Lounibos and I are currently investigating the spatial and temporal distributions of two important, potential disease vectors in Palm Beach County, Florida. Aedes aegypti has been established in Florida since the colonial period, but A. albopictus is a newly invasive species. In many parts of the historical range of A. aegypti, Aedes albopictus has completely replaced it, successfully establishing populations in much of the southeastern United States, and as far north as Illinois and Maryland. However, in a few places, especially urban locations in Florida, A. aegypti has resisted invasion, and seems to be stably persistent. To understand this ecological phenomenon, we are determining the mechanisms of coexistence of these two species along an urban gradient, and testing predictions of seasonal abundances of the two species. As these two species have different capacities to transmit different pathogens, this ecological interaction has important epidemiological consequences.
B. Breeding habitat and vectorial capacity: effects of larval competition on adult mosquito characteristics. Larval competition, a ubiquitous phenomenon in container breeding mosquitoes, may have important effects on adult characteristics, such as susceptibility to infection and survival. These adult characters, in turn, determine the vectorial capacity (the overall ability of a population of vectors to transmit disease), and therefore the epidemic potential of a vector-borne pathogen. However, the interaction between competition and adult characteristics has been a neglected area of research in medical entomology. Dr. Lounibos, Dr. Barry Alto (currently at Yale University), Dr. Christopher Mores, and I have been examining how larval competition in A. aegypti and A. albopictus affects mosquito susceptibility to infection by dengue fever virus (Flaviviridae), an important human pathogen. In addition, I have been investigating how the outcomes of larval competition affect adult survival (a crucial component of vectorial capacity) under stressful and benign conditions, comparing these two species of Aedes mosquitoes.
C. Breeding habitat and vectorial capacity: diet diversity, larval performance and oviposition behavior. Mosquito larvae encounter a diverse array of resource conditions in their aquatic habitats. However, most experimental approaches with mosquitoes have used artificial diets, or at most one leaf type as a resource base, leaving the effects of diet quality on vectorial capacity an open question. I am examining the impact of leaf diversity and specific leaf type on two species of container dwelling mosquitoes (Aedes triseriatus and A. albopictus). I have extended this work to include oviposition behavior, thus linking larval population ecology with the behavioral ecology of egg-laying females, the primary vectors of mosquito-borne diseases. Although utilizing different mosquito species, many of the ideas concerning optimal oviposition strategies were developed as part of my doctoral dissertation.
D. Anticipating emerging diseases: vector competence to novel viruses. Since the 1970’s, vector-borne emerging diseases have arisen as major public health issues throughout the world. Recent outbreaks of West Nile virus in North America and chikungunya virus in the Indian Ocean have emphasized the need for continued research examining the ability of these viruses to spread to new regions. As such, I have been examining the susceptibility of Florida mosquitoes to viruses they have thus far not encountered in Florida. Along with two PhD students and a colleague (Dr. Mores), I am examining how mosquitoes from Florida respond to infection with chikungunya virus (Alphaviridae). We have extended this work to examine basic biological parameters of infection by chikungunya virus in Florida mosquitoes, including the minimum infectious titer and the extrinsic incubation period. Through this research, I have mastered numerous virological techniques, and I am certified to work with live material in containment facilities (Biosafety Level-3, with respirator, on select agents).
E. Pathogen-vector interactions: impact of viral infection on mosquito survival and fecundity. I will be investigating the harmful effects of vectoring viruses on mosquitoes in preparation for a NIH proposal. I plan to quantify interspecfic (between A. aegypti and A. albopictus) differences in deleterious effects of infection with dengue and chikungunya viruses, and relate them to vectorial capacity. I am also interested in using this approach to examine populations of mosquitoes from areas of intense disease transmission and from areas with no recent history of disease transmission, and to compare the mosquitoes’ interactions with dengue and chikungunya virus. The likelihood of a disease emerging in a new region critically depends on how it interacts with novel vectors, and this will add in our understanding of these processes.