title: Prevalence and factors associated with Leishmania infantum infection of dogs from an urban area of Brazil as identified by molecular methods.
abstract: BACKGROUND
  Various factors contribute to the urbanization of the visceral leishmaniasis (VL), including the difficulties of implementing control measures relating to the domestic reservoir. The aim of this study was to determine the prevalence of canine visceral leishmaniasis in an urban endemic area in Brazil and the factors associated with Leishmania infantum infection among seronegative and PCR-positive dogs.
  
  
  METHODS
  A cross-sectional study was conducted in Belo Horizonte, Minas Gerais, Brazil. Blood samples were collected from 1,443 dogs. Serology was carried out by using two enzyme-linked immunosorbent assays (Biomanguinhos/FIOCRUZ/RJ and "in house"), and molecular methods were developed, including PCR-RFLP. To identify the factors associated with early stages of infection, only seronegative (n = 1,213) animals were evaluated. These animals were divided into two groups: PCR-positive (n = 296) and PCR-negative (n = 917) for L. infantum DNA. A comparison of these two groups of dogs taking into consideration the characteristics of the animals and their owners was performed. A mixed logistic regression model was used to identify factors associated with L. infantum infection.
  
  
  RESULTS
  Of the 1,443 dogs examined, 230 (15.9%) were seropositive in at least one ELISA, whereas PCR-RFLP revealed that 356 animals (24.7%) were positive for L. infantum DNA. Results indicated that the associated factors with infection were family income<twice the Brazilian minimum salary (OR 2.3; 95%CI 1.4-3.8), knowledge of the owner regarding the vector (OR 1.9; 95%CI 1.1-3.4), the dog staying predominantly in the backyard (OR 2.2; 95%CI 1.1-4.1), and a lack of previous serological examination for VL (OR 1.5; 95%CI 1.1-2.3).
  
  
  CONCLUSIONS
  PCR detected a high prevalence of L. infantum infection in dogs in an area under the Control Program of VL intervention. Socioeconomic variables, dog behavior and the knowledge of the owner regarding the vector were factors associated with canine visceral leishmaniasis (CVL). The absence of previous serological examination conducted by the control program was also associated with L. infantum infection. It is necessary to identify the risk factors associated with CVL to understand the expansion and urbanization of VL.
authors.affiliation: Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Wendel
authors.initials: W
authors.lastname: Coura-Vital
authors.forename: Marcos José
authors.initials: MJ
authors.lastname: Marques
authors.forename: Vanja Maria
authors.initials: VM
authors.lastname: Veloso
authors.forename: Bruno Mendes
authors.initials: BM
authors.lastname: Roatt
authors.forename: Rodrigo Dian de Oliveira
authors.initials: RD
authors.lastname: Aguiar-Soares
authors.forename: Levi Eduardo Soares
authors.initials: LE
authors.lastname: Reis
authors.forename: Samuel Leôncio
authors.initials: SL
authors.lastname: Braga
authors.forename: Maria Helena Franco
authors.initials: MH
authors.lastname: Morais
authors.forename: Alexandre Barbosa
authors.initials: AB
authors.lastname: Reis
authors.forename: Mariângela
authors.initials: M
authors.lastname: Carneiro
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D016054:DNA, Protozoan / Q000235:genetics; D004283:Dog Diseases / Q000453:epidemiology* / Q000469:parasitology*; D004285:Dogs; D019353:Endemic Diseases; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D018314:Leishmania infantum / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D007898:Leishmaniasis, Visceral / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D008297:Male; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D012959:Socioeconomic Factors
chemical_list: D000913:Antibodies, Protozoan; D016054:DNA, Protozoan