title: Factors affecting carriage and intensity of infection of Calodium hepaticum within Norway rats (Rattus norvegicus) from an urban slum environment in Salvador, Brazil.
abstract: Urban slum environments in the tropics are conducive to the proliferation and the spread of rodent-borne zoonotic pathogens to humans. Calodium hepaticum (Brancroft, 1893) is a zoonotic nematode known to infect a variety of mammalian hosts, including humans. Norway rats (Rattus norvegicus) are considered the most important mammalian host of C. hepaticum and are therefore a potentially useful species to inform estimates of the risk to humans living in urban slum environments. There is a lack of studies systematically evaluating the role of demographic and environmental factors that influence both carriage and intensity of infection of C. hepaticum in rodents from urban slum areas within tropical regions. Carriage and the intensity of infection of C. hepaticum were studied in 402 Norway rats over a 2-year period in an urban slum in Salvador, Brazil. Overall, prevalence in Norway rats was 83% (337/402). Independent risk factors for C. hepaticum carriage in R. norvegicus were age and valley of capture. Of those infected the proportion with gross liver involvement (i.e. >75% of the liver affected, a proxy for a high level intensity of infection), was low (8%, 26/337). Sixty soil samples were collected from ten locations to estimate levels of environmental contamination and provide information on the potential risk to humans of contracting C. hepaticum from the environment. Sixty percent (6/10) of the sites were contaminated with C. hepaticum. High carriage levels of C. hepaticum within Norway rats and sub-standard living conditions within slum areas may increase the risk to humans of exposure to the infective eggs of C. hepaticum. This study supports the need for further studies to assess whether humans are becoming infected within this community and whether C. hepaticum is posing a significant risk to human health.
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.|Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
authors: R
authors: R
authors: Walker
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.|Institute of Integrative Biology, University of Liverpool, Liverpool, UK.|Instituto de Biologia, Universidade Federal da Bahia, UFBA, Salvador, Brazil.
authors: T
authors: T
authors: Carvalho-Pereira
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.
authors: S
authors: S
authors: Serrano
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.|Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
authors: G
authors: G
authors: Pedra
authors: 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: K
authors: K
authors: Hacker
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.|Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
authors: J
authors: J
authors: Taylor
authors: Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
authors: A
authors: A
authors: Minter
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.|Instituto de Biologia, Universidade Federal da Bahia, UFBA, Salvador, Brazil.
authors: A
authors: A
authors: Pertile
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.
authors: A
authors: A
authors: Panti-May
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.
authors: M
authors: M
authors: Carvalho
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.
authors: F N
authors: FN
authors: Souza
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.
authors: N
authors: N
authors: Nery
authors: Centro de Controle de Zoonoses, Secretaria Municipal de Saúde, Ministério da Saúde, Salvador, Brazil.
authors: G
authors: G
authors: Rodrigues
authors: Instituto de Ciências da Saúde, Universidade Federal da Bahia, UFBA, Salvador, Brazil.
authors: T
authors: T
authors: Bahiense
authors: 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: M G
authors: MG
authors: Reis
authors: 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: A I
authors: AI
authors: Ko
authors: Department of Epidemiology of Microbial Disease, Yale School of Public Health, New Haven, CT, USA.
authors: J E
authors: JE
authors: Childs
authors: Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
authors: M
authors: M
authors: Begon
authors: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Ministério da Saúde, Salvador, Brazil.|Institute of Integrative Biology, University of Liverpool, Liverpool, UK.|Department of Epidemiology of Microbial Disease, Yale School of Public Health, New Haven, CT, USA.|Instituto de Saúde Coletiva, Universidade Federal da Bahia, UFBA, Salvador, Brazil.
authors: F
authors: F
authors: Costa
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D002195:Capillaria / Q000302:isolation & purification*; D002353:Carrier State / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D017189:Enoplida Infections / Q000453:epidemiology / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*; D059208:Parasite Load; D011204:Poverty Areas; D015995:Prevalence; D051381:Rats; D012307:Risk Factors; D012376:Rodent Diseases / Q000453:epidemiology* / Q000469:parasitology* / Q000473:pathology
keywords: 
                 Calodium hepaticum
              ; 
                 Rattus norvegicus
              ; Brazil; infection intensity; prevalence