High prevalence of SARS-CoV-2 in wildlife populations

Study sites play a crucial role in wildlife research, providing valuable insights into the interactions between animals and their environment. In a recent study conducted across 43 counties in Virginia and Washington D.C., researchers collected nasopharyngeal or oropharyngeal samples from wildlife to investigate the presence of SARS-CoV-2. The study sites included wildlife rehabilitation centers in Boyce, Roanoke, and Waynesboro, VA, as well as various locations spanning a rural to urban gradient in Giles, Montgomery, Roanoke, and Wythe counties.

The researchers actively captured wildlife at eight sites between 2022 and 2023, using live traps to trap animals. Different sized live traps were used, depending on the size of the animals, and traps were set and baited in the evening before being checked the following morning to ensure the animals did not overheat. Larger animals were anesthetized using a bucket chamber or a clear box chamber, while smaller animals were anesthetized in a small plastic canister. Each captured animal was marked with aluminum ear tags and morphometric data, sex, and reproductive status were recorded.

For RT-qPCR detections, animals were swabbed with polyester swabs, and the swabs were placed in tubes with transport media to preserve the samples. Blood samples were also collected for antibody screening. All samples were stored in the refrigerator and processed within five days of collection. The researchers also collected samples from wildlife rehabilitation centers in Virginia and analyzed them within 45 days of collection.

To ensure the safety of personnel and prevent contamination, all individuals working with the samples wore N95 respirators and gloves. Equipment was sterilized between each animal, and traps were sterilized between trapping sessions. Personnel were tested regularly to confirm they were negative for SARS-CoV-2.

The study also involved RNA extraction and the detection of SARS-CoV-2 viral RNA using RT-qPCR. The researchers used a novel isoflurane anesthesia induction system for larger animals and a portable medical oxygen cylinder for anesthesia. Samples were processed shortly after collection, and RNA was purified and subjected to synthesis and amplification.

Serology data was obtained from additional samples to compare seropositivity prior to the emergence of SARS-CoV-2. Plaque reduction neutralization assays were performed to assess neutralizing antibody levels in the samples.

The study also involved urbanization and human presence variables, with estimates of urban imperviousness and population density obtained from various sources. Human presence at the study sites was also assessed, and the population within each site’s area was calculated.

Overall, the study sites provided valuable data on the presence of SARS-CoV-2 in wildlife populations and the interactions between animals and their environment. The detailed methods and analyses conducted at these sites have contributed to our understanding of the dynamics of the virus in wildlife populations.