Modeling human exposure to Babesia spp. utilizing a hunting dog cohort in the United States

Babesiosis is a disease caused by parasites of Babesia species that is spread through ticks. Babesiosis can affect humans and many other mammals all over the world. In the United States, babesiosis is mainly caused by Babesia microti with additional species of Babesia infecting dogs. Dogs have long been known to be a good indicator species for human tick-borne infection due to the shared spaces they have with humans and their tendency to explore and pick up diseases in the environment. This study used a group of hunting dogs to determine the presence of Babesia infection. The goal was to determine a predictive model for human infection. Infection was defined as having a positive antibody test or molecular test for Babesia species in blood samples. Blood samples were taken at two time points, tested, and compared. Statistical methods were used to analyze the results of the tests and compare them with variables such as region, gender, age, and other diseases the dogs were exposed to. Of 214 dogs, 56 had Babesia infections, with a prevalence rate of 26.2%. At the first time point the model showed age and infection with Anaplasma platys as being significant. At the 2nd time point, 29 dogs were lost to follow up, leaving a total of 185 dogs sampled with 63 testing positive for Babesia spp. The rate for the 2nd time point was 34.1%. No variables were found to be significant in the model for the 2nd time point. Despite differences in Babesia that infect humans and dogs, the hunting dog cohort reflects a model that validates the environmental exposures, coinfections, and demographic variables that affect transmission of the pathogen. Furthermore, findings of this study cast doubt on the ability of Ixodes scapularis to act as capable vector for canine-infecting Babesia species.