Biology subjects

Harris, M. J.

Publications and source records attributed to Harris, M. J..

3 recordsLinked to original sources

bioRxiv2023

Surveillance of Vermont wildlife in 2021-2022 reveals no detected SARS-CoV-2 viral RNA

Previous studies have documented natural infections of SARS-CoV-2 in various domestic and wild animals. More recently, studies have been published noting the susceptibility of members of the Cervidae family, and infections in both wild and captive cervid populations. In this study, we investigated the presence of SARS-CoV-2 in mammalian wildlife within the state of Vermont. 739 nasal or throat samples were collected from wildlife throughout the state during the 2021 and 2022 harvest season. Data was collected from red and gray foxes (Vulpes vulples and Urocyon cineroargentus, respectively), fishers (Martes pennati), river otters (Lutra canadensis), coyotes (Canis lantrans), bobcats (Lynx rufus rufus), black bears (Ursus americanus), and white-tailed deer (Odocoileus virginianus). Samples were tested for the presence of SARS-CoV-2 via quantitative RT-qPCR using the CDC N1/N2 primer set and/or the WHO-E gene primer set. Our results indicate that no sampled wildlife were positive for SARS-CoV-2. This finding is surprising, given that most published North America studies have found SARS-CoV-2 within their deer populations. The absence of SARS-CoV-2 RNA in populations sampled here may provide insights in to the various environmental and anthropogenic factors that reduce spillover and spread in North Americans wildlife populations.

microbiology↗

bioRxiv2020

Quantifying signal persistence in the T cell signaling network using an optically controllable antigen receptor

T cells discriminate between healthy and infected cells with remarkable sensitivity when mounting an immune response. It has been hypothesized that this efficient detection requires combining signals from discrete antigen-presenting cell interactions into a more potent response, requiring T cells to maintain a memory of previous encounters. To quantify the magnitude of this phenomenon, we have developed an antigen receptor that is both optically and chemically tunable, providing control over the initiation, duration, and intensity of intracellular T-cell signaling within physiological cell conjugates. We observe very limited persistence within the T cell intracellular network on disruption of receptor input, with signals dissipating entirely in ~15 minutes, and directly confirm that sustained proximal receptor signaling is required to maintain active gene transcription. Our data suggests that T cells are largely incapable of integrating discrete antigen receptor signals but instead simply accumulate the output of gene expression. By engineering optical control in a clinically relevant chimeric antigen receptor, we show that this limited signal persistence can be exploited to increase the activation of primary T cells by ~3-fold by using pulsatile stimulation. Our results are likely to apply more generally to the signaling dynamics of other cellular networks.

biochemistry↗

bioRxiv2018

Climate drives spatial variation in Zika epidemics in Latin America

Between 2015 and 2017, Zika virus spread rapidly through populations in the Americas with no prior exposure to the disease. Although climate is a known determinant of many Aedes-transmitted diseases, it is currently unclear whether climate was a major driver the of Zika epidemic and how climate might have differentially impacted outbreak intensity across locations within Latin America. Here, we estimated force of infection for Zika over time and across provinces in Latin America using a time-varying Susceptible Infectious Recovered model. Climate factors explained less than 5% of the variation in weekly transmission intensity in a spatiotemporal model of force of infection by province over time, suggesting that week to week transmission within provinces may be too stochastic to predict. By contrast, climate and population factors were highly predictive of spatial variation in the presence and intensity of Zika transmission among provinces, with pseudo R2 values between 0.33 and 0.60. Temperature, temperature range, rainfall, and population size were the most important predictors of where Zika transmission occurred, while rainfall, relative humidity, and a nonlinear effect of temperature were the best predictors of Zika intensity and burden. Surprisingly, force of infection was greatest in locations with temperatures near 24{degrees}C, much lower than previous estimates from mechanistic models, potentially suggesting that existing vector control programs and/or prior exposure to other mosquito-borne diseases may have limited transmission in locations most suitable for Aedes aegypti, the main vector of Zika, dengue, and chikungunya viruses in Latin America.

ecology↗