Evaluating the risk of SARS‐CoV‐2 transmission to bats in the context of wildlife research, rehabilitation, and control

Abstract

Preventing wildlife disease outbreaks is a priority for natural resource agencies, and management decisions can be urgent, especially in epidemic circumstances. With the emergence of SARS‐CoV‐2, wildlife agencies were concerned whether the activities they authorize might increase the risk of viral transmission from humans to North American bats, but had a limited amount of time in which to make decisions. We describe how decision analysis provides a powerful framework to analyze and reanalyze complex natural resource management problems as knowledge evolves. Coupled with expert judgment and avenues for the rapid release of information, risk assessment can provide timely scientific information for evolving decisions. In April 2020, the first rapid risk assessment was conducted to evaluate the risk of transmission of SARS‐CoV‐2 from humans to North American bats. Based on the best available information and relying heavily on expert judgment, the risk assessment found a small possibility of transmission during summer work activities. Following that assessment, additional knowledge and data emerged, such as bat viral challenge studies, that further elucidated the risks of human‐to‐bat transmission and culminated in a second risk assessment in the fall of 2020. We updated the first SARS‐CoV‐2 risk assessment with new management alternatives and new estimates of little brown bat ( Myotis lucifugus ) susceptibility, using findings from the fall 2020 assessment and other empirical studies. We found that new knowledge led to an 88% decrease in the median number of bats estimated to be infected per 1,000 encountered when compared to earlier results. The use of facemasks during, or a negative COVID‐19 test or vaccination prior to, bat encounters further reduced those risks. Using a combination of decision analysis, expert judgment, rapid risk assessment, and efficient modes of information distribution, we provided timely science‐based support to decision makers for summer bat work in North America.

Oral Sampling of Little Brown Bat (Myotis lucifugus) Maternity Colonies for SARS-CoV-2 in the Northeast and Mid-Atlantic, USA

“…Protecting maternity colonies of little brown bats is of the utmost importance to longterm viability as the species continues to make, at best, only modest population increases (5-10%) following the long-running WNS-induced mortality event [28,[54][55][56][57][58]. Results here, while regionally specific and limited in scope, indicate that little brown bat maternity colonies may not serve as reservoirs for SARS-CoV-2 and therefore likely do not represent a threat for human infection [18,59,60]. However, expanding both sample size and time period of surveillance would be prudent.…”

“…Due to the current status of little brown bat populations, these findings are, thus far, encouraging from both the conservation and human health perspective. However, spillover is a function of exposure, and wildlife professionals that work with bats are recommended to follow protocols intended to decrease the likelihood of transmission [17,18,45]. Initial modeled estimates of susceptibility based on expert-opinion risk assessments predicted a range of likelihoods between 0.01-0.20 for little brown bats to potentially become infected by humans during summer fieldwork if no personal protective equipment precautions were taken [45].…”

“…Initial modeled estimates of susceptibility based on expert-opinion risk assessments predicted a range of likelihoods between 0.01-0.20 for little brown bats to potentially become infected by humans during summer fieldwork if no personal protective equipment precautions were taken [45]. Updated, median estimates of these initial models indicate that 0.83, 1.56, and 0.47 individuals per 1000 little brown bats could become infected with SARS-CoV-2 when exposed during research/monitoring, rehabilitation, and other encounters with infected humans, respectively [18]. Although estimates of human transmission to little brown bats are low, these results suggested a 33% probability of spread within bat populations given SARS-CoV-2 infection [17].…”

“…However, expanding both sample size and time period of surveillance would be prudent. In order to best protect bat and human health, however, following the guidelines set forth by Cook et al (2022) [18] are essential; that is negative COVID-19 tests and vaccinations prior to bat interactions, as well as the proper use of N95 respirators when working directly with bats or in close proximity to bats are critical.…”

“…At present, SARS-CoV-2 has not been detected in wild North American bats, suggesting that spillover from humans has not occurred [18], as it has with other domestic and wild animals in close proximity to humans [19][20][21][22][23][24][25]. For example, ferrets (Mustela furo) and cats (Felis catus) have been found to be permissive to SARS-CoV-2 infection with cats demonstrating susceptibility to airborne infection [21].…”