Modeling the Impact of Climate Change on Cervid Chronic Wasting Disease in Semi-Arid South Texas

Abstract

Chronic wasting disease (CWD) is a spongiform encephalopathy disease caused by the transmission of infectious prion agents. CWD is a fatal disease that affects wild and farmed cervids in North America with few cases reported overseas. Social interaction of cervids, feeding practices by wildlife keepers and climate effects on the environmental carrying capacity all can affect CWD transmission in deer. Wildlife deer game hunting is economically important to the semi-arid South Texas region and is affected by climate change. In this paper, we model and investigate the effect of climate change on the spread of CWD using typical climate scenarios. We use a system of impulsive differential equations to depict the transmission of CWD between different age groups and gender of cervids. The carrying capacity and contact rates are assumed to depend on climate. Due to the polygamy of bucks, we use mating rates that depend on the number of bucks and does. We analyze the stability of the model and use simulations to study the effect of harvesting (culling) on eradicating the disease, given the climate of South Texas. We use typical climate change scenarios based on published data and our assumptions. For the climate indicator, we calculated and utilized the Standard Precipitation Evapotranspiration Index (SPEI). We found that climate change might hinder the efforts to reduce and effectively manage CWD as it becomes endemic to South Texas. The model shows the extinction of the deer population from this region is a likely outcome.

Error in demographic ratios from aerial surveys of white‐tailed deer in semi‐arid rangelands

“…The recent emergence of chronic wasting disease in white‐tailed deer and mule deer in Texas, USA (Texas Parks and Wildlife Department 2022) has brought increased attention to population monitoring (Figure 1). The disease is fatal and poses serious long‐term implications for management (Williams et al 2002, Uehlinger et al 2016, DeVivo et al 2017), especially for populations in semi‐arid regions, where population growth rate is low because of variable precipitation (Foley et al 2016, DeYoung et al 2019, Islam et al 2022).…”

Cap. 8. Ecosistemas, servicios ecosistémicos y biodiversidad. En: La Quinta Evaluación Nacional del Clima.

“…Impacto del clima en el riesgo de enfermedades en seres humanos y en la vida silvestre LEYENDA: Numerosas enfermedades en seres humanos y en la vida silvestre (KM 15.1) se están extendiendo a nuevas zonas y especies y se están haciendo más comunes a medida que el cambio climático amplía las áreas de distribución de los vectores y modifica las interacciones entre especies y las preferencias de hábitat. Fuentes: Islam et 152,153,155,156,157 .…”