Master of Public Health
First Committee Member
Patrick Maloney, PhD, MPH
Second Committee Member
David Brett-Major, MD, MPH
Third Committee Member
Bryan Buss, DVM, MPH, DACVPM
Background: Rabies is a zoonotic disease caused by a neurotropic virus that has been a public health issue for over 4,000 years, killing roughly 59,000 humans globally each year. This study examined the seasonality of bat-human exposures, the association between animal-human exposure types and animal rabies positivity, and using skunk monthly positivity rates to predict all non-skunk non-bat animal positivity rates with a lag time of six months, in Nebraska.
Methods: Animal rabies testing data from 2012-21 were extracted from Nebraska’s Electronic Disease Surveillance System. Animal tests that had a valid animal rabies test were included in the analyses. To examine the seasonality of bat-human exposures, we conducted an ANOVA test to assess the differences in monthly positivity rates and a T-test to assess the differences in positivity rates between hibernation (November-February) and non-hibernation (March-October) months. Four log-binomial regression analyses were conducted to assess the relationship between each reported exposure type and animal rabies testing outcome. A correlation analysis with a lag time of six months was run to examine the effect of skunk monthly positivity rates on all non-skunk non-bat monthly positivity rates.
Results: 12,113 animals were included for analysis. We found no significant differences between monthly positivity rates for bats (p=0.62). Positivity rates were also not significantly different between hibernation (1.3%) and non-hibernation (2.6%) months (p=0.12). Saliva contact was significantly associated with an increased risk of the exposing animals' test coming back positive in non-bat animals (RR: 9.4, 95% CI: [4.6, 19.3]), while proximity to bats was significantly associated with a decreased risk of the exposing animals' test coming back positive in bat specimen (RR: 0.4, 95% CI: [0.2, 0.6]). A weak positive association was observed between skunk monthly positivity rates and all non-skunk non-bat animal monthly positivity rates, with a lag time of six months (r=0.22, p=0.02).
Conclusion: We conclude that all potential exposures in Nebraska should be taken seriously, regardless of the season the exposure took place. Additionally, any potential exposure involving saliva contact should be reported and medical treatment should be sought immediately. Finally, a rise in skunk positivity can be used as an early warning sign, which can be used to know when to issue public warnings.
Theye, Elijah, "A Retrospective Analysis of Rabies Lyssavirus Animal Testing in Nebraska, 2012 through 2021" (2023). Capstone Experience. 253.
Available for download on Monday, April 29, 2024