title: Coastal development and precipitation drive pathogen flow from land to sea: evidence from a Toxoplasma gondii and felid host system.
abstract: Rapidly developing coastal regions face consequences of land use and climate change including flooding and increased sediment, nutrient, and chemical runoff, but these forces may also enhance pathogen runoff, which threatens human, animal, and ecosystem health. Using the zoonotic parasite Toxoplasma gondii in California, USA as a model for coastal pathogen pollution, we examine the spatial distribution of parasite runoff and the impacts of precipitation and development on projected pathogen delivery to the ocean. Oocysts, the extremely hardy free-living environmental stage of T. gondii shed in faeces of domestic and wild felids, are carried to the ocean by freshwater runoff. Linking spatial pathogen loading and transport models, we show that watersheds with the highest levels of oocyst runoff align closely with regions of increased sentinel marine mammal T. gondii infection. These watersheds are characterized by higher levels of coastal development and larger domestic cat populations. Increases in coastal development and precipitation independently raised oocyst delivery to the ocean (average increases of 44% and 79%, respectively), but dramatically increased parasite runoff when combined (175% average increase). Anthropogenic changes in landscapes and climate can accelerate runoff of diverse pathogens from terrestrial to aquatic environments, influencing transmission to people, domestic animals, and wildlife.
authors.affiliation: One Health Institute, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: VanWormer
authors.affiliation: EpiCentre, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
authors.forename: Tim E
authors.initials: TE
authors.lastname: Carpenter
authors.affiliation: Department of Civil Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Bachupally Nizampet (S.O), Hyderabad-500090, India.|Department of Land, Air, and Water Resources, University of California, Davis, 1 Shields Ave, Davis, CA, 95616, USA.
authors.forename: Purnendu
authors.initials: P
authors.lastname: Singh
authors.affiliation: One Health Institute, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.|Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, 1 Shields Ave, Davis, CA, 95616, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Shapiro
authors.affiliation: Department of Land, Air, and Water Resources, University of California, Davis, 1 Shields Ave, Davis, CA, 95616, USA.
authors.forename: Wesley W
authors.initials: WW
authors.lastname: Wallender
authors.affiliation: One Health Institute, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.|Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, 1 Shields Ave, Davis, CA, 95616, USA.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Conrad
authors.affiliation: Department of Environmental Science and Policy, University of California, Davis, Bodega Marine Laboratory, 2099 Westside Rd, Bodega Bay, CA, 94923, USA.
authors.forename: John L
authors.initials: JL
authors.lastname: Largier
authors.affiliation: Department of Geosciences, University of Montana, 32 Campus Dr. #1296, Missoula, MT, 59812, USA.
authors.forename: Marco P
authors.initials: MP
authors.lastname: Maneta
authors.affiliation: One Health Institute, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
authors.forename: Jonna A K
authors.initials: JA
authors.lastname: Mazet
mesh_terms: D000818:Animals; D002140:California; D002415:Cats; D017753:Ecosystem; D004784:Environmental Monitoring; D005618:Fresh Water; D005843:Geography; D006790:Host-Parasite Interactions; D009792:Oceans and Seas; D011891:Rain; D012623:Seawater; D014122:Toxoplasma / Q000502:physiology*