Sociodemographic and regional determinants of rabies submission bias in North Carolina

Abstract

AbstractWith North Carolina's human population and urban development rapidly expanding, spread of zoonotic disease is of concern to both wildlife managers and public health officials. Between 2008 and 2018, 300−1,000 wild terrestrial animals were submitted for rabies testing each year, however, only 30−46% of total submissions tested positive for rabies annually. Given the low percentage of positive tests and high number of submissions in some counties, we used one‐way ANOVAs to determine if a submission bias, that is, healthy wildlife being submitted for rabies testing for undetermined reasons (e.g., fear, lack of knowledge), may exist in some counties or throughout North Carolina. Using multiple regression analyses and data from all 100 counties, we investigated if income, age, education, gender, ethnicity, population density, housing density, and geographical region influenced total submissions and percent positive cases. Statewide, annual total submissions averaged 765 ± 56.0 (x̄ ± SE throughout) and the percent positive cases averaged 35% ± 1%, however variation existed among counties for both metrics (F98−99,947−1088 = 3.77−23.07 P < 0.001) indicating submission bias. Counties that are in the Piedmont region and/or have lower percentages of Black residents (Std. β = −0.17) and counties with denser human populations, housing density, and/or more tourism income (β = 0.71) had the largest number of total submissions for rabies testing. Alternatively, counties that had higher percentages of residents who had attended some college submitted fewer animals for testing (Std. β = −0.18). Counties with a higher percent of Black residents also had a higher percentage of positive cases (Std. β = 0.33) and, as expected based on the ethnic composition of each region, there were lower percentages of positive cases in the Mountain region compared to the Piedmont and Coastal Plain regions. The percent of self‐reported Hispanic residents in a county also positively affected (Std. β = 0.30) the percentage of positive cases. This variable was negatively correlated with median age indicating counties with older residents have a lower percentage of positive cases. We suggest rabies education should be focused on the Mountain region, White residents, and older individuals in North Carolina since these groups of residents were more likely to request rabies testing on non‐rabid wildlife. Specifically, counties with higher populations of White individuals had higher annual total submissions, but fewer positive tests for rabies, indicating this demographic group had the most bias and they, as well as local and county animal control departments, should be the focus for targeted educational programs.