| Urbanization of natural habitats may produce concentrations of resources that increase the population densities of urban adapted species, resulting in increased rates of disease transmission and infection in both urban adapted and non-urban adapted wildlife. Trichomonas, Salmonella , and Listeriaare all pathogens known to infect birds, but infection rates in wild bird populations are poorly documented. This study documents infection rates of the three pathogens in wild bird populations in Southeast Texas and tests predictions about how infection rates are expected to vary among sites representing a suburban to rural gradient. Birds were sampled at five sites in Southeastern Texas representing rural (<1 house/ha), exurban (∼1 house/ha), and suburban (∼10 houses/ha) habitat types. Birds were captured in mist nets and pathogen samples were taken from the oral cavity, crop, and vent. Pathogen samples were screened for Trichomonas by examining wet mounts under a light microscope, while pathogens samples were screened for Salmonella and Listeria by examining colonies grown on agar plates. Pathogens detected during the initial screening were positively identified by PCR and DNA sequencing. Infection rates for Trichomonas, Salmonella, and Listeria were 9%, 17%, and 5%, respectively. The distributions of infection rates across habitats (rural, exurban, rural), feeding categories (feeder bird or non-feeder bird), and seasons (spring, summer, fall, winter), did not differ significantly from the expected null distributions for any of the three pathogens; however, the data suggested some interesting patterns that should be confirmed with a larger dataset. Infection rates for Trichomonas and Salmonella were highest at the suburban sites, while the infection rate for Listeria was highest at the rural site, albeit not statistically significant. Feeder birds were more likely to be infected by all three pathogens than non-feeder birds Small sample sizes make definitive conclusions regarding variation in infection rates along the suburban to rural gradient unpredictable, but the results suggest that pathogens followed the predicted patterns. This study presents the first report of infection rates of these pathogens in wild population of many of the bird species sampled in Southeast Texas. |
