title: Using fine-scale spatial genetics of Norway rats to improve control efforts and reduce leptospirosis risk in urban slum environments.
abstract: The Norway rat (Rattus norvegicus) is a key pest species globally and responsible for seasonal outbreaks of the zoonotic bacterial disease leptospirosis in the tropics. The city of Salvador, Brazil, has seen recent and dramatic increases in human population residing in slums, where conditions foster high rat density and increasing leptospirosis infection rates. Intervention campaigns have been used to drastically reduce rat numbers. In planning these interventions, it is important to define the eradication units - the spatial scale at which rats constitute continuous populations and from where rats are likely recolonizing, post-intervention. To provide this information, we applied spatial genetic analyses to 706 rats collected across Salvador and genotyped at 16 microsatellite loci. We performed spatially explicit analyses and estimated migration levels to identify distinct genetic units and landscape features associated with genetic divergence at different spatial scales, ranging from valleys within a slum community to city-wide analyses. Clear genetic breaks exist between rats not only across Salvador but also between valleys of slums separated by <100 m-well within the dispersal capacity of rats. The genetic data indicate that valleys may be considered separate units and identified high-traffic roads as strong impediments to rat movement. Migration data suggest that most (71-90%) movement is contained within valleys, with no clear source population contributing to migrant rats. We use these data to recommend eradication units and discuss the importance of carrying out individual-based analyses at different spatial scales in urban landscapes.
authors.affiliation: Department of Biology Providence College Providence RI USA.
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Richardson
authors.affiliation: Department of Biology Providence College Providence RI USA.
authors.forename: Mary K
authors.initials: MK
authors.lastname: Burak
authors.affiliation: Department of Ecology & Evolutionary Biology Yale University New Haven CT USA.
authors.forename: Christian
authors.initials: C
authors.lastname: Hernandez
authors.affiliation: Department of Ecology & Evolutionary Biology Yale University New Haven CT USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Shirvell
authors.affiliation: Department of Ecology & Evolutionary Biology Yale University New Haven CT USA.
authors.forename: Carol
authors.initials: C
authors.lastname: Mariani
authors.affiliation: Centro de Pesquisas Gonçalo Moniz Fundação Oswaldo Cruz Ministério da Saúde Salvador Brazil.
authors.forename: Ticiana S A
authors.initials: TS
authors.lastname: Carvalho-Pereira
authors.affiliation: Centro de Pesquisas Gonçalo Moniz Fundação Oswaldo Cruz Ministério da Saúde Salvador Brazil.
authors.forename: Arsinoê C
authors.initials: AC
authors.lastname: Pertile
authors.affiliation: Centro de Pesquisas Gonçalo Moniz Fundação Oswaldo Cruz Ministério da Saúde Salvador Brazil.
authors.forename: Jesus A
authors.initials: JA
authors.lastname: Panti-May
authors.affiliation: Centro de Pesquisas Gonçalo Moniz Fundação Oswaldo Cruz Ministério da Saúde Salvador Brazil.
authors.forename: Gabriel G
authors.initials: GG
authors.lastname: Pedra
authors.affiliation: Centro de Pesquisas Gonçalo Moniz Fundação Oswaldo Cruz Ministério da Saúde Salvador Brazil.
authors.forename: Soledad
authors.initials: S
authors.lastname: Serrano
authors.affiliation: Centro de Pesquisas Gonçalo Moniz Fundação Oswaldo Cruz Ministério da Saúde Salvador Brazil.
authors.forename: Josh
authors.initials: J
authors.lastname: Taylor
authors.affiliation: Centro de Pesquisas Gonçalo Moniz Fundação Oswaldo Cruz Ministério da Saúde Salvador Brazil.
authors.forename: Mayara
authors.initials: M
authors.lastname: Carvalho
authors.affiliation: Centro de Controle de Zoonoses Secretaria Municipal de Saúde Ministério da Saúde Salvador Brazil.
authors.forename: Gorete
authors.initials: G
authors.lastname: Rodrigues
authors.affiliation: Instituto de Saúde Coletiva Universidade Federal da Bahia, UFBA Salvador Brazil.
authors.forename: Federico
authors.initials: F
authors.lastname: Costa
authors.affiliation: Department of Epidemiology of Microbial Disease Yale School of Public Health New Haven CT USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Childs
authors.affiliation: Centro de Pesquisas Gonçalo Moniz Fundação Oswaldo Cruz Ministério da Saúde Salvador Brazil; Department of Epidemiology of Microbial Disease Yale School of Public Health New Haven CT USA.
authors.forename: Albert I
authors.initials: AI
authors.lastname: Ko
authors.affiliation: Department of Ecology & Evolutionary Biology Yale University New Haven CT USA.
authors.forename: Adalgisa
authors.initials: A
authors.lastname: Caccone
keywords: epidemiology; favela; individual‐based sampling; intervention; landscape genetics; population genetics; public health; reservoir host; spatial scale; urban ecology; vector control