PARASITES OF AN ENDANGERED HARVEST MOUSE (REITHRODONTOMYS RAVIVENTRIS HALICOETES) IN A NORTHERN CALIFORNIA MARSH

Sadie N Trombley; Laureen M Barthman-Thompson; Melissa K Riley; Sarah A Estrella; Katherine R Smith; Deana L Clifford; Patrick Foley; Janet Foley; Douglas A Kelt

doi:10.7589/JWD-D-21-00059

PARASITES OF AN ENDANGERED HARVEST MOUSE (REITHRODONTOMYS RAVIVENTRIS HALICOETES) IN A NORTHERN CALIFORNIA MARSH

J Wildl Dis. 2022 Jan 1;58(1):122-136. doi: 10.7589/JWD-D-21-00059.

Authors

Sadie N Trombley^{1

2}, Laureen M Barthman-Thompson², Melissa K Riley^{1

2}, Sarah A Estrella², Katherine R Smith^{1

3}, Deana L Clifford^{4

5}, Patrick Foley⁶, Janet Foley⁴, Douglas A Kelt¹

Affiliations

¹ Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
² California Department of Fish and Wildlife, Bay Delta Region (3), 2109 Arch Airport Road, Stockton, California 95206, USA.
³ WRA Inc., 2169-G E San Francisco Boulevard, San Rafael, California 94901, USA.
⁴ Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, 944 Garrod Drive, Davis, California 95616, USA.
⁵ California Department of Fish & Wildlife, Wildlife Investigations Lab, 1701 Nimbus Road Suite D, Rancho Cordova, California 95670, USA.
⁶ Department of Biological Sciences, California State University, Sacramento, 6000 J Street, Sacramento, California 95819, USA.

PMID: 34814173
DOI: 10.7589/JWD-D-21-00059

Abstract

Disease may limit recovery of endangered species. We surveyed parasites in the federally endangered salt marsh harvest mouse (SMHM; Reithrodontomys raviventris halicoetes) and sympatric rodents in Suisun Marsh (Solano County, California, USA) from April 2018 through March 2019. We investigated individual SMHM risk factors (age, sex, reproductive status, and body condition) for infection and relationships among the estimated parasite prevalence and season and habitat management (natural tidal habitats versus diked, nontidal habitats). We captured 625 individual rodents, including 439 SMHM, and tested these for infection with Bartonella spp., Borrelia spp., Rickettsia spp., Francisella tularensis, Leptospira spp., Cryptosporidium spp., Giardia spp., and Toxoplasma gondii by PCR. Over one-third (34.6%, confidence interval [CI], 30.2-39.3%) of SMHM tested positive for at least one parasite. Four percent (CI, 2.8-6.3%) of SMHM were infected with F. tularensis holarctica, a virulent bacterium that causes mortality in rodents shortly after infection. Additionally, we detected three species of Bartonella (B. henselae, B. rochalimae, B. vinsonii arupensis), Leptospira borgpetersenii serovar Ballum, Cryptosporidium sp. (deer mouse [Peromyscus maniculatus] genotype), Cryptosporidium parvum, Giardia intestinalis, and an unidentified Borrelia sp. The only parasite that was associated with habitat management was Bartonella spp., which was more prevalent in diked than tidal areas. Male SMHM were more likely to be parasitized than females, and individuals in modestly poor body condition were most likely to be infected with Bartonella spp. The estimated sample prevalence of multiple parasites varied by season and by host species. This is the first major parasite assessment in a long-endangered species, and these results will assist managers to incorporate parasitic disease into recovery planning and provide a critical baseline for future investigations, including how climatically induced habitat and species composition changes could alter disease dynamics.

Keywords: Bartonella spp.; Cryptosporidium parvum; Francisella tularensis; Giardia spp.; Leptospira borgpetersenii serovar Ballum; endangered species; salt marsh harvest mouse; wildlife disease.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Animals
Bartonella* / genetics
Cryptosporidiosis* / epidemiology
Cryptosporidium*
Female
Male
Parasites*
Prevalence
Wetlands