Babesia vulpes infection rates in Texas shelter dogs

Abstract

Canine babesiosis is an emerging tick-borne disease of worldwide distribution, caused by protozoa of the genus Babesia, and characterized by hemolytic anemia. In the United States (US), Babesia vogeli, Babesia gibsoni, Babesia conradae, and Babesia vulpes have been recognized as the main species causing babesiosis in dogs, the latter species also infecting foxes and raccoon dogs across Europe, Asia, and North America. In this study, we evaluated the prevalence of Babesia spp. infections in shelter dogs from Central Texas. Genomic DNA was extracted from blood samples (n = 446) of dogs, followed by conventional PCR targeting the 18S ribosomal RNA gene and sequencing of positive amplicons. The association between demographic variables (i.e., age, sex, breed group) and the outcome (B. vulpes positivity) was evaluated through univariate Pearson's chi-squared tests. We found an overall prevalence of 6.28% (n = 28; CI 95% 4.39-9.20) within this shelter dog population. A total of 12 distinct haplotypes were identified among these isolates. No statistical association between the positivity of B. vulpes and demographic variables was identified. This study highlights the haplotypic diversity of B. vulpes isolates circulating in a single regional population of domestic shelter dogs. These findings suggest a heterogenous transmission dynamic which may involve ticks associated with owned, sheltered, and wild canids, as well as other transmission routes. Finally, data herein corroborates the current geographical distribution of B. vulpes in Central Texas, reinforcing the need to monitor shelter dogs for vector-borne pathogens and deploy the use of tick preventive products year-round.