title: A Comparative Assessment of Track Plates to Quantify Fine Scale Variations in the Relative Abundance of Norway Rats in Urban Slums.
abstract: Norway rats (Rattus norvegicus) living in urban environments are a critical public health and economic problem, particularly in urban slums where residents are at a higher risk for rat borne diseases, yet convenient methods to quantitatively assess population sizes are lacking. We evaluated track plates as a method to determine rat distribution and relative abundance in a complex urban slum environment by correlating the presence and intensity of rat-specific marks on track plates with findings from rat infestation surveys and trapping of rats to population exhaustion. To integrate the zero-inflated track plate data we developed a two-component mixture model with one binary and one censored continuous component. Track plate mark-intensity was highly correlated with signs of rodent infestation (all coefficients between 0.61 and 0.79 and all p-values < 0.05). Moreover, the mean level of pre-trapping rat-mark intensity on plates was significantly associated with the number of rats captured subsequently (Odds ratio1.38; 95% CI 1.19-1.61) and declined significantly following trapping (Odds ratio 0.86; 95% CI 0.78-0.95). Track plates provided robust proxy measurements of rat abundance and distribution and detected rat presence even when populations appeared 'trapped out'. Tracking plates are relatively easy and inexpensive methods that can be used to intensively sample settings such as urban slums, where traditional trapping or mark-recapture studies are impossible to implement, and therefore the results can inform and assess the impact of targeted urban rodent control campaigns.
authors.affiliation: Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St, New Haven, United States of America, CT 06511.
authors.forename: Kathryn P
authors.initials: KP
authors.lastname: Hacker
authors.affiliation: Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom, L69 7ZB.
authors.forename: Amanda
authors.initials: A
authors.lastname: Minter
authors.affiliation: Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom, L69 7ZB.
authors.forename: Mike
authors.initials: M
authors.lastname: Begon
authors.affiliation: Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St, New Haven, United States of America, CT 06511.|Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom, L69 7ZB.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Diggle
authors.affiliation: Instituto de Biologia, Universidade Federal da Bahia, UFBA, Salvador, Brasil, 40.110-040 (SS).
authors.forename: Soledad
authors.initials: S
authors.lastname: Serrano
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brasil, 40296-710.|Instituto de Saúde Coletiva, Universidade Federal da Bahia, UFBA, Salvador, Brasil, 40.110-040.
authors.forename: Mitermayer G
authors.initials: MG
authors.lastname: Reis
authors.affiliation: Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St, New Haven, United States of America, CT 06511.
authors.forename: James E
authors.initials: JE
authors.lastname: Childs
authors.affiliation: Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St, New Haven, United States of America, CT 06511.|Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brasil, 40296-710.
authors.forename: Albert I
authors.initials: AI
authors.lastname: Ko
authors.affiliation: Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St, New Haven, United States of America, CT 06511.|Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom, L69 7ZB.|Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brasil, 40296-710.|Instituto de Saúde Coletiva, Universidade Federal da Bahia, UFBA, Salvador, Brasil, 40.110-040.
authors.forename: Federico
authors.initials: F
authors.lastname: Costa
keywords: Rattus norvegicus; indirect abundance; track plates; urban slum; zero-inflated; zoonotic diseases