Gulas-Wroblewski, Bonnie Electra (2021-04). Zoonotic Diseases of Texas Skunks (Mammalia: Mephitidae) Within a One Health Framework. Doctoral Dissertation.
Thesis
Zoonotic diseases of wildlife can have wide-ranging effects on public health, wildlife and conservation management, and ecosystem functions. Consequently, any investigation into the dynamics of these complex, adaptive systems necessitates a One Health approach. This thesis evaluates the disease ecology of Texas skunks (Mammalia: Mephitidae) within a One Health framework, the results of which can be practically applied to public health strategies and conservation planning for the promotion of both animal and human health. To this end, field surveillance of Trypanosoma cruzi (the etiological agent of Chagas disease) and the pathogenic agents of dermatophytosis were carried out in wild Texas skunks and assessed in relation to their impact on wildlife populations and human and domestic animal health. To ensure maximum extraction of DNA from the blood filter papers used in the T. cruzi surveillance of skunks, the extraction procedure for whole blood stored on Nobuto strips was optimized. Employing the resulting methodology, a PCR-based surveillance of T. cruzi in 235 wild skunks, representing four species, was conducted across 76 counties and ten ecoregions in Texas, USA, along with an evaluation of potential disease risk factors. An overall T. cruzi prevalence of 17.9% for all mephitid taxa was recovered, and the first cases of Chagas disease were reported in eastern spotted (Spilogale putorius), western spotted skunks (S. gracilis), and American hog-nosed skunks (Conepatus leuconotus). Although not statistically-significant, trends for juveniles to exhibit greater disease risk and for differential sex biases in T. cruzi prevalence between taxa were also recovered. Concordantly, an evaluation of cutaneous infections was performed in a population of eastern spotted skunks, from which the zoonotic fungal pathogen Microsporum canis was cultured. These first records of T. cruzi and M. canis were then incorporated into a comprehensive review of infectious diseases of eastern spotted skunks. The implications of these pathogens for current and future population health of the species were addressed with reference to the influences of anthropogenic processes. This thesis contributes key data for informing population viability analyses and epidemiologic models in addition to providing a One Health evaluation of skunks that can serve as a baseline for future disease ecology studies.
