Rachel Fay

All Publications

• Rising temperatures contribute to West Nile virus diversification and increased transmission potential. Scientific reports Fay, R. L., Cruz-Loya, M., Maffei, J. G., Mordecai, E. A., Ciota, A. T. 2025; 15 (1): 25016

  Abstract

  West Nile virus (WNV), the most common mosquito-borne disease in the continental United States, is vectored by Culex spp. mosquitoes. Since its introduction to New York State (NYS) in 1999, WNV has become endemic. NYS temperatures have risen by 0.14 °C per decade since 1900, with larger increases linked to increased WNV transmission. In this study, we asked if increases in temperature in NYS influence virus diversification and adaptation, leading to shifts in thermal sensitivity. More specifically, do contemporary WNV strains have increased transmission potential at higher temperatures compared to historic strains? Using surveillance and sequencing data of WNV isolated from mosquitoes in NYS, we found a significant correlation between rising temperatures, increased WNV genetic diversity, and higher prevalence. We then analyzed genetically distinct WNV strains from mosquitoes collected during recent warm summers (2017 and 2018) and cooler historic summers (2003 and 2004). Assessing Culex pipiens dissemination efficiency and calculating the relative R₀ at 20 °C, 24 °C, and 28 °C, we found that contemporary strains exhibit higher transmission potential at increased temperatures. Our results show that contemporary WNV strains possess greater phenotypic and genotypic diversity, suggesting that climate warming in concert with viral adaptation may facilitate the emergence of strains with enhanced transmission potential.

  View details for DOI 10.1038/s41598-025-09284-5

  View details for PubMedID 40646045

  View details for PubMedCentralID PMC12254422

• Population-specific thermal responses contribute to regional variability in arbovirus transmission with changing climates. iScience Fay, R. L., Cruz-Loya, M., Keyel, A. C., Price, D. C., Zink, S. D., Mordecai, E. A., Ciota, A. T. 2024; 27 (6): 109934

  Abstract

  Temperature is increasing globally, and vector-borne diseases are particularly responsive to such increases. While it is known that temperature influences mosquito life history traits, transmission models have not historically considered population-specific effects of temperature. We assessed the interaction between Culex pipiens population and temperature in New York State (NYS) and utilized novel empirical data to inform predictive models of West Nile virus (WNV) transmission. Genetically and regionally distinct populations from NYS were reared at various temperatures, and life history traits were monitored and used to inform trait-based models. Variation in Cx. pipiens life history traits and population-dependent thermal responses account for a predicted 2.9°C difference in peak transmission that is reflected in regional differences in WNV prevalence. We additionally identified genetic signatures that may contribute to distinct thermal responses. Together, these data demonstrate how population variation contributes to significant geographic variability in arbovirus transmission with changing climates.

  View details for DOI 10.1016/j.isci.2024.109934

  View details for PubMedID 38799579

  View details for PubMedCentralID PMC11126822

• Experimental Evolution of West Nile Virus at Higher Temperatures Facilitates Broad Adaptation and Increased Genetic Diversity VIRUSES-BASEL Fay, R. L., Ngo, K. A., Kuo, L., Willsey, G. G., Kramer, L. D., Ciota, A. T. 2021; 13 (10)

  Abstract

  West Nile virus (WNV, Flaviviridae, Flavivirus) is a mosquito-borne flavivirus introduced to North America in 1999. Since 1999, the Earth's average temperature has increased by 0.6 °C. Mosquitoes are ectothermic organisms, reliant on environmental heat sources. Temperature impacts vector-virus interactions which directly influence arbovirus transmission. RNA viral replication is highly error-prone and increasing temperature could further increase replication rates, mutation frequencies, and evolutionary rates. The impact of temperature on arbovirus evolutionary trajectories and fitness landscapes has yet to be sufficiently studied. To investigate how temperature impacts the rate and extent of WNV evolution in mosquito cells, WNV was experimentally passaged 12 times in Culex tarsalis cells, at 25 °C and 30 °C. Full-genome deep sequencing was used to compare genetic signatures during passage, and replicative fitness was evaluated before and after passage at each temperature. Our results suggest adaptive potential at both temperatures, with unique temperature-dependent and lineage-specific genetic signatures. Further, higher temperature passage was associated with significantly increased replicative fitness at both temperatures and increases in nonsynonymous mutations. Together, these data indicate that if similar selective pressures exist in natural systems, increases in temperature could accelerate emergence of high-fitness strains with greater phenotypic plasticity.

  View details for DOI 10.3390/v13101889

  View details for Web of Science ID 000717066500001

  View details for PubMedID 34696323

  View details for PubMedCentralID PMC8540194

• Visual Detection and Avoidance of Pathogenic Bacteria by Aphids CURRENT BIOLOGY Hendry, T. A., Ligon, R. A., Besler, K. R., Fay, R. L., Smee, M. R. 2018; 28 (19): 3158-+

  Abstract

  Aphids are diverse sap-sucking insects [1] that can be serious agricultural pests and vectors of plant disease [2]. Some species, including pea aphids (Acyrthosiphon pisum), are susceptible to infection by epiphytic bacteria that are commonly found on plant surfaces [3-5]. Pea aphids appear unable to recover from these infections, possibly because pea aphids are missing apparent orthologs of some immune response genes [6], and these aphids exhibit relatively low immune responses after pathogen exposure [7]. We therefore tested the ability of pea aphids to use avoidance as a non-immunological defense against Pseudomonas syringae, a widespread plant epiphyte and aphid pathogen [8, 9]. Pea aphids avoided highly virulent strains of P. syringae, but not all strains, and avoidance led to a significant reduction in infection among aphids. We found that aphids can use visual cues to detect the ultraviolet (UV)-based fluorescence of the bacterial siderophore pyoverdine [10] produced by virulent strains. Avoided epiphytic bacteria caused light leaving the surface of leaves to be richer in wavelengths that were tightly linked to both aphid visual sensitivities and the fluorescent emission spectra of pyoverdine, suggesting that pyoverdine fluorescence mediates avoidance and may be a visual cue used by aphids to detect epiphytic pathogens. Although pyoverdine production in Pseudomonas species may be a broadly reliable indicator of bacterial virulence within the phyllosphere, it was not directly responsible for virulence to aphids. Aphids may be under selection to avoid fluorescence on leaves, a phenomenon with potential use for the control of agricultural pest insects.

  View details for DOI 10.1016/j.cub.2018.07.073

  View details for Web of Science ID 000446693400033

  View details for PubMedID 30270187