Gastrointestinal Pathogens Are Highly Prevalent in Endangered Amargosa Voles (Microtus californicus scirpensis)

Disease can threaten endangered species by affecting fitness and survival, suppressing population growth and species recovery. Herein, we investigated three gastrointestinal pathogens-Giardia, Cryptosporidium, and Helicobacter-that could negatively affect the endangered Amargosa vole (Microtus californicus scirpensis). We used PCR testing to determine the presence of the target parasites in 76 fecal samples from 71 Amargosa voles collected during summer 2021 in four marshes in Tecopa, California, USA. Overall, 51 (72%) of 71 voles were PCR positive for Giardia microti, 48 (68%) of 71 for Cryptosporidium spp., and 100% for Helicobacter spp. There were no significant associations between G. microti infection and sex, body condition score, or source marsh. Cryptosporidium sp. infection was significantly more prevalent in smaller marshes. More than half of the individuals sampled (39/71, 55%) were PCR positive for both Giardia and Cryptosporidium spp. upon initial sampling. This study provides foundational information regarding environmentally transmitted parasites in populations of Amargosa voles. Further studies are needed to understand and manage the adverse effects of disease and other threats for the survival of the Amargosa vole.