title: Mycoplasmal upper respiratory tract disease across the range of the threatened Mojave Desert tortoise: associations with thermal regime and natural antibodies.
abstract: Most research of upper respiratory tract disease (mycoplasmal URTD) in the threatened Mojave Desert tortoise (Gopherus agassizii) has worked under the hypothesis that the pathogen, Mycoplasma agassizii, has a relatively consistent and predictable effect on tortoise populations across their natural range. In contrast, we hypothesized that multiple factors influence the prevalence of disease and analyzed biological and environmental variables that vary significantly across the Mojave Desert. We used multiple regression models to analyze associations between mycoplasmal URTD and the genetic structure of 24 tortoise populations, levels of natural antibody (NAb) to M. agassizii in tortoises (one component of the innate immune system), precipitation, and colder thermal regimes. We detected a significant, positive association between mean levels of NAb and seroprevalence to M. agassizii. We hypothesized that NAbs may provide tolerance to mycoplasmal infections and that more tolerant populations may act as host reservoirs of disease. We also detected significant associations between colder winters and mycoplasmal URTD, suggesting that colder winters may depress tortoise immune resistance against M. agassizii or enhance conditions for the growth of M. agassizii.
authors.affiliation: Department of Biology MS 314, University of Nevada Reno, Reno, NV 89557, USA. fcsandmeier@gmail.com
authors.forename: Franziska C
authors.initials: FC
authors.lastname: Sandmeier
authors.forename: C Richard
authors.initials: CR
authors.lastname: Tracy
authors.forename: Bridgette E
authors.initials: BE
authors.lastname: Hagerty
authors.forename: Sally
authors.initials: S
authors.lastname: DuPré
authors.forename: Hamid
authors.initials: H
authors.lastname: Mohammadpour
authors.forename: Kenneth
authors.initials: K
authors.lastname: Hunter
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000235:genetics / Q000276:immunology; D015153:Blotting, Western; D003080:Cold Temperature / Q000009:adverse effects; D003889:Desert Climate / Q000009:adverse effects; D004199:Disease Vectors; D004797:Enzyme-Linked Immunosorbent Assay; D005838:Genotype; D006801:Humans; D008954:Models, Biological; D009174:Mycoplasma / Q000276:immunology / Q000472:pathogenicity; D009175:Mycoplasma Infections / Q000453:epidemiology / Q000235:genetics / Q000276:immunology*; D012044:Regression Analysis; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology*; D016036:Seroepidemiologic Studies; D015206:Southwestern United States / Q000453:epidemiology; D014426:Turtles / Q000235:genetics / Q000276:immunology / Q000382:microbiology*
chemical_list: D000907:Antibodies, Bacterial