title: Vector biodiversity did not associate with tick-borne pathogen prevalence in small mammal communities in northern and central California.
abstract: Vector and host abundance affect infection transmission rates, prevalence, and persistence in communities. Biological diversity in hosts and vectors may provide "rescue" hosts which buffer against pathogen extinction and "dilution" hosts which reduce the force of infection in communities. Anaplasma phagocytophilum is a tick-transmitted zoonotic pathogen that circulates in small mammal and tick communities characterized by varying levels of biological diversity. We examined the prevalence of A. phagocytophilum in Ixodes spp. ticks in 11 communities in northern and central California. A total of 1020 ticks of 8 species was evaluated. Five percent of ticks (5 species) were PCR-positive, with the highest prevalence (6-7%) in I. pacificus and I. ochotonae. In most species, adults had a higher prevalence than nymphs or larvae. PCR prevalence varied between 0% and 40% across sites; the infection probability in ticks increased with infestation load and prevalence in small mammals, but not tick species richness, diversity, evenness, or small mammal species richness. No particular tick species was likely to "rescue" infection in the community; rather the risk of A. phagocytophilum infection is related to exposure to particular tick species and life stages, and overall tick abundance.
authors.affiliation: School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA. Electronic address: jefoley@ucdavis.edu.
authors.forename: Janet
authors.initials: J
authors.lastname: Foley
authors.affiliation: School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA.
authors.forename: Jonah
authors.initials: J
authors.lastname: Piovia-Scott
mesh_terms: D041081:Anaplasma phagocytophilum / Q000235:genetics / Q000302:isolation & purification*; D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology*; D044822:Biodiversity; D002140:California / Q000453:epidemiology; D004269:DNA, Bacterial / Q000235:genetics; D016873:Ehrlichiosis / Q000453:epidemiology / Q000382:microbiology*; D007312:Eulipotyphla / Q000382:microbiology*; D005260:Female; D006801:Humans; D018884:Ixodes / Q000382:microbiology*; D007814:Larva; D008297:Male; D009758:Nymph; D015995:Prevalence; D012376:Rodent Diseases / Q000382:microbiology*; D012377:Rodentia; D015047:Zoonoses
chemical_list: D004269:DNA, Bacterial
keywords: Amplification effect; Dilution effect; Granulocytic anaplasmosis; Rescue effect