title: Patterns in Leptospira Shedding in Norway Rats (Rattus norvegicus) from Brazilian Slum Communities at High Risk of Disease Transmission.
abstract: BACKGROUND
  We address some critical but unknown parameters of individuals and populations of Norway rats (Rattus norvegicus) that influence leptospiral infection, maintenance and spirochetal loads shed in urine, which contaminates the environment ultimately leading to human infection.
  
  
  RESULTS
  Our study, conducted in Salvador, Brazil, established the average load of leptospires in positive kidneys to be 5.9 x 10(6) per mL (range 3.1-8.2 x10(6)) genome equivalents (GEq), similar to the 6.1 x 10(6) per ml (range 2.2-9.4 x10(6)) average obtained from paired urines, with a significant positive correlation (R2=0.78) between the two. Based on bivariate and multivariate modeling, we found with both kidney and urine samples that leptospiral loads increased with the age of rats (based on the index of body length to mass), MAT titer and the presence of wounding/scars, and varied with site of capture. Some associations were modified by sex but trends were apparent. Combining with data on the demographic properties and prevalence of leptospiral carriage in rat populations in Salvador, we estimated that daily leptospiral loads shed in the urine of a population of 82 individuals exceeded 9.1 x 10(10) leptospires.
  
  
  CONCLUSIONS
  These factors directly influence the risk of leptospiral acquisition among humans and provide essential epidemiological information linking properties of rat populations with risk of human infection.
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil; Instituto de Saúde Coletiva, Universidade Federal da Bahia (UFBA), Salvador, Brazil; Department of Epidemiology of Microbial Disease, Yale School of Public Health, New Haven, Connecticut, United States of America; Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Federico
authors.initials: F
authors.lastname: Costa
authors.affiliation: Department of Epidemiology of Microbial Disease, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Elsio A
authors.initials: EA
authors.lastname: Wunder
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.
authors.forename: Daiana
authors.initials: D
authors.lastname: De Oliveira
authors.affiliation: Department of Epidemiology of Microbial Disease, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Vimla
authors.initials: V
authors.lastname: Bisht
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: 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, Connecticut, United States of America.
authors.forename: Mitermayer G
authors.initials: MG
authors.lastname: Reis
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, Connecticut, United States of America.
authors.forename: Albert I
authors.initials: AI
authors.lastname: Ko
authors.affiliation: Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Mike
authors.initials: M
authors.lastname: Begon
authors.affiliation: Department of Epidemiology of Microbial Disease, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: James E
authors.initials: JE
authors.lastname: Childs
mesh_terms: D000367:Age Factors; D000372:Agglutination Tests; D000704:Analysis of Variance; D000818:Animals; D057138:Bacterial Shedding / Q000502:physiology; D001938:Brazil / Q000453:epidemiology; D007668:Kidney / Q000382:microbiology; D007922:Leptospirosis / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary*; D015233:Models, Statistical; D011204:Poverty Areas; D015995:Prevalence; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D012376:Rodent Diseases / Q000453:epidemiology* / Q000382:microbiology* / Q000635:transmission; D014556:Urine / Q000382:microbiology