Epidemiology of SARS-CoV-2 in white-tailed deer

In a recent study posted on research plaza*Preprint server, Researchers investigated the epidemiological factors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in white-tailed deer.

study: Epidemiological dynamics of SARS-CoV-2 in whitetail deer.IMage Credit: TonyCampbell/Shutterstock.com

*Important Notices: medrex sib We publish a non-peer-reviewed, preliminary scientific report and should not be taken as conclusive, to guide clinical practice/health-related actions, or to be treated as established information.

Background

SARS-CoV-2 was detected in white-tailed deer (WTD) in 2020. In 2021, it was demonstrated that regional SARS-CoV-2 spread in WTD via human-to-deer and deer-to-deer pathways.

WTD populations may become reservoirs for SARS-CoV-2, leading to persistence of variants due to endemic infection, emergence of new variants, and possible spillback into the human population.

During a pandemic, transspecies transmission could cause significant global health impacts. To avoid such consequences, it is important to understand the causes of zoonotic pathogens.

About research

In the present study, researchers measured the prevalence of SARS-CoV-2 infection in WTD in North America.

Between October 2021 and September 2022, 10,722 WTD samples were obtained from 27 states and Washington DC. WTD samples have been collected post-mortem from a variety of sources, including control events, hunter harvest samples, and opportunistic samples from death such as roadkill. The state Department of Natural Resources collected these samples.

The USDA Animal and Plant Health Inspection Service (USDA-APHIS), the Wildlife Service, and other agencies were involved. Management type and deer-specific indicators such as gender and age class were recorded in this study.

Samples were taken from the nose or mouth and analyzed for SARS-CoV-2 viral ribonucleic acid (RNA) using real-time reverse transcriptase polymerase chain reaction (rRT-PCR).

The team assessed population density in all counties. The proportion of land in each county that could support a WTD population was determined using the Gap Analysis Project (GAP) WTD species distribution model.

The New York Times Repository of SARS-CoV-2 Cases was used to calculate weekly human SARS-CoV-2 mortality rates in each county.

result

Between October 2021 and March 2022, 10,217 oral and nasal swab specimens from WTD were tested in 27 states and Washington, DC. Thirteen percent of the samples were positive for SARS-CoV-2 viral RNA.

This viral RNA was more common in males than females, although similar sample sizes were collected from both genders. Sampling was skewed toward adults, but detection rates were similar in juvenile and adult groups.

A significant interaction was observed between gender and management method, but no significant effect was found for age class or swab type. Male deer had higher infection rates than females in samples obtained by agency managers, but the difference was less pronounced in male deer obtained by hunters.

Human population density and deer habitat have a slightly positive effect, but not statistically significant. As population density increases from 10 to 100 people per square kilometer, the prevalence of WTD is expected to rise from 10% to 15% between October 2021 and March 2022. increase.

As the proportion of WTD habitat increases, the prevalence of WTD is also expected to increase from 10% to 15% between October 2021 and March 2022.

According to the model, there was a correlation between the prevalence of SARS-CoV-2 in WTD and the rate of infection in humans. In this model, we employed lag human SARS-CoV-2 mortality as a surrogate indicator of infection.

The model suggests that for every 11 additional deaths per 100,000 county residents, the prevalence of WTD increases by 13%. The model also revealed that approximately 10% of positive his-WTDs detected between October 2021 and March 2022 were due to human infectious pressure.

Average prevalence from October 2021 to March 2022 was higher on the East Coast than in the Midwest and Southwest.

The average county-level apparent prevalence was more extreme than the time-average estimates for counties with small sample sizes. Peak prevalence across the range of WTD assessed showed spatial variation.

Conclusion

Findings showed that SARS-CoV-2 was found in white-tailed deer populations in most counties where white-tailed deer are present. The estimated times of peak infection rates were comparable across the multiple counties sampled, indicating possible spread of human-to-deer spillover infections.

Quantifying disease dynamics and risk variables is critical for developing effective strategies to curb, monitor, and control zoonotic diseases. Models can be used to analyze surveillance data and estimate disease prevalence across space and time. This helps fill in the gaps in data collection.

Spatial analysis of reconstructed disease trajectories can help identify disease-affected areas, which may be at high risk for future outbreaks.

In conclusion, similar peak infection rate teams from various counties provide evidence of human-to-deer transmission. However, extensive estimates of regional epidemiological reproduction numbers suggest that deer-to-deer transmission is also likely. Research models estimated that 10% of his WTD infected was due to human infectious pressure.

*Important Notices: medrex sib We publish a non-peer-reviewed, preliminary scientific report and should not be taken as conclusive, to guide clinical practice/health-related actions, or to be treated as established information.