Arbovirology - Research & Development

Host-Virus Interactions

Arboviruses are unique in that they require infection, replication and transmission from taxonomically diverse vertebrate and invertebrate hosts. Characterizing the complexity of these diverse interactions is critical to our understanding of arbovirus emergence and maintenance and is therefore among the primary research goals of the Wadsworth Center Arbovirus Laboratory.

West Nile virus is maintained primarily by Culex species mosquitoes and the focus of studies in this area is characterizing interactions in this system. Studies in recent years have begun to reveal the complexity and specificity of mosquito-virus interactions. Particular areas of interest include assessing temporal and spatial variability in vector competence, quantifying the effect of arbovirus infection on mosquito life history traits, identifying mechanisms of resistance, and characterizing interactions between arboviruses and the mosquito microbiome.

Arbovirus Evolution & Adaptation

Studies investigating the causes and consequences of genomic change of arboviruses are a focus of the Wadsworth Center Arbovirus Laboratory. Arboviruses are almost exclusively RNA viruses which replicate rapidly and are exceedingly error-prone. The resultant genetic diversity affords these pathogens vast evolutionary and adaptive potential that can have direct implications for their capacity to spread and cause human disease. Although arboviruses are often noted as being remarkably genetically stable, they are in fact in constant flux both within and among hosts.

Ongoing studies utilizing both natural virus isolates and laboratory-adapted strains combine traditional and next-generation sequencing and molecular tools with experimental infections and passaging to advance our understanding of evolutionary pressures and arbovirus fitness. Included in this are experimental evolution studies in both cell culture and natural hosts, phylogenetic studies assessing both geographic and temporal genetic change, studies assessing the phenotypic importance of intra-host diversity, and studies assessing host-specific selective pressures and the potential for host-range expansion. Although this work has focused on West Nile virus, additional studies have been completed or are ongoing with Zika virus, St. Louis encephalitis virus, Eastern equine encephalitis virus, Powassan virus, La Crosse virus and Dengue virus

Impact of Temperature on Arbovirus Transmission

Among the most important consequences of climate change are alterations in patterns of pathogen transmission. Arboviruses and invertebrate vectors are particularly sensitive to the effects of temperature and therefore studies assessing the effects of temperature on viral and mosquito fitness are a focus of the Wadsworth Center Arbovirus laboratory.

Current areas of interest include quantifying species and population-specific effects of temperature on West Nile virus transmission in Culex mosquitoes and assessing the capacity for mosquito and virus populations to adapt to rising temperatures. Experimental data are combined with surveillance and climate data to inform novel predictive transmission models. The overarching goal of these studies is to gain insight into how changing climates alter arbovirus risk and ultimately use these data to inform public health measures.

Antivirals

Despite the global disease burden associated with arboviruses, there are very few therapeutics approved for the treatment of arboviral infections. The Arbovirus Laboratory is involved in testing novel antiviral compounds, including toxicity and efficacy studies against a range of arboviruses including: West Nile virus, dengue virus, Powassan virus, Zika virus, and chikungunya virus. These studies are performed both on cell culture and using vertebrate models of disease.

Tick-borne Virus Surveillance and Research

New York State is a major focus of tick-borne pathogens. The etiologic agents responsible for Lyme disease, Anaplasmosis, Babesiosis, and Powassan encephalitis are transmitted by Ixodes scapularis (black-legged or “deer” ticks). The ticks and pathogens they transmit are expanding north- and west-ward from the original epicenter of the lower Hudson River Valley. Recently, Amblyomma americanum (lone-star) ticks have been expanding their range from the southeastern and midwestern United States and into Long Island and southern NYS. This tick is capable of transmitting the agent responsible for Ehrlichiosis as well as Heartland and Bourbon Viruses.

The Arbovirus Laboratory has partnered with the Bureau of Communicable Disease Control to establish a surveillance and research program to understand the geographic distribution of Powassan (Deer Tick virus, DTV), Heartland, and Bourbon viruses in NYS by testing ticks collected in the spring and fall each year and testing vertebrate sera for the presence of antibody. The laboratory has documented DTV throughout the Hudson River Valley, determined co-infection rates of DTV and bacterial pathogens in adult and nymphal ticks collected in Dutchess and Putnam Counties, and has led to the discovery of novel viral agents in ticks collected across NYS. In 2018 and 2019 respectively, the laboratory documented Heartland and Bourbon viruses in ticks collected on Long Island, NY, representing the first time these pathogens have been isolated outside the known endemic areas of the Midwest. The Arbovirus Laboratory’s tick research and surveillance component complements our proficient mosquito-borne virus program.