Selected diseases and antimicrobial resistance in feral swine in west Texas

Abstract: Feral swine are present in 215 of 254 Texas counties. They are also known to harbor diseases transmissible to other animal species and humans. The objective of this study was to determine the antibody prevalence of two pathogens in Texas feral swine populations. Overall prevalence of antibodies to Francisella tularensis and Brucella spp. were 27.8% and 4.1% respectively. Prevalence rates between males and females for either antibody were not significant (P = 0.6475 for tularemia, P = 1.0 for brucellosis). Conversely, prevalence rates for antibodies against tularemia between adults and juveniles, 81.5% and 18.5% respectively, were significant (P = 0.0012). Seropositive samples for either antibody were sent to Lubbock’s Bioterrorism laboratory for screening using real-time polymerase chain reaction (RT-PCR). Three samples from Crosby County were determined presumptive positive. These data indicate that Texas feral swine populations may be reservoirs of these two zoonotic diseases.

Abstract: Antibiotic resistance in commensal bacteria of domestic livestock is well documented. A few studies have also examined resistance in bacteria isolated from wildlife interacting with domestic livestock. The aim of this study was to identify the presence of antibiotic resistance in Escherichia coli isolated from feral swine occurring in close proximity to domestic livestock. Feral swine were sampled over a five month period from a ranch in Crosby County, Texas. Rectal swabs (n = 20) were collected and cultured for Escherichia coli. Three isolates from each confirmed sample (n = 13) were pooled and examined for susceptibility to four antibiotics. Resistance to the antibiotics tested (ampicillin, erythromycin, gentamicin, or penicillin) was not detected in any isolate.