title: The potential of canine sentinels for reemerging Trypanosoma cruzi transmission.
abstract: BACKGROUND
  Chagas disease, a vector-borne disease transmitted by triatomine bugs and caused by the parasite Trypanosoma cruzi, affects millions of people in the Americas. In Arequipa, Peru, indoor residual insecticide spraying campaigns are routinely conducted to eliminate Triatoma infestans, the only vector in this area. Following insecticide spraying, there is risk of vector return and reinitiation of parasite transmission. Dogs are important reservoirs of T. cruzi and may play a role in reinitiating transmission in previously sprayed areas. Dogs may also serve as indicators of reemerging transmission.
  
  
  METHODS
  We conducted a cross-sectional serological screening to detect T. cruzi antibodies in dogs, in conjunction with an entomological vector collection survey at the household level, in a disease endemic area that had been treated with insecticide 13 years prior. Spatial clustering of infected animals and vectors was assessed using Ripley's K statistic, and the odds of being seropositive for dogs proximate to infected colonies was estimated with multivariate logistic regression.
  
  
  RESULTS
  There were 106 triatomine-infested houses (41.1%), and 45 houses infested with T. cruzi-infected triatomine insects (17.4%). Canine seroprevalence in the area was 12.3% (n=154); all seropositive dogs were 9 months old or older. We observed clustering of vectors carrying the parasite, but no clustering of seropositive dogs. The age- and sex-adjusted odds ratio between seropositivity to T. cruzi and proximity to an infected triatomine (≤50m) was 5.67 (95% CI: 1.12-28.74; p=0.036).
  
  
  CONCLUSIONS
  Targeted control of reemerging transmission can be achieved by improved understanding of T. cruzi in canine populations. Our results suggest that dogs may be useful sentinels to detect re-initiation of transmission following insecticide treatment. Integration of canine T. cruzi blood sampling into existing interventions for zoonotic disease control (e.g., rabies vaccination programs) can be an effective method of increasing surveillance and improving understanding of disease distribution.
authors.affiliation: Center for Clinical Epidemiology & Biostatistics - Department of Biostatistics & Epidemiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA; Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru. Electronic address: rcastillo@jhu.edu.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Castillo-Neyra
authors.affiliation: Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Lily
authors.initials: L
authors.lastname: Chou Chu
authors.affiliation: Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Victor
authors.initials: V
authors.lastname: Quispe-Machaca
authors.affiliation: Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Jenny
authors.initials: J
authors.lastname: Ancca-Juarez
authors.affiliation: Dirección Regional del Ministerio de Salud, Arequipa, Peru.
authors.forename: Fernando S
authors.initials: FS
authors.lastname: Malaga Chavez
authors.affiliation: Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Milagros
authors.initials: M
authors.lastname: Bastos Mazuelos
authors.affiliation: Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Cesar
authors.initials: C
authors.lastname: Naquira
authors.affiliation: School of Medicine, University of California, San Francisco, CA, USA.
authors.forename: Caryn
authors.initials: C
authors.lastname: Bern
authors.affiliation: Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.affiliation: Center for Clinical Epidemiology & Biostatistics - Department of Biostatistics & Epidemiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA. Electronic address: mzlevy@mail.med.upenn.edu.
authors.forename: Michael Z
authors.initials: MZ
authors.lastname: Levy
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D014355:Chagas Disease / Q000453:epidemiology / Q000469:parasitology / Q000635:transmission / Q000662:veterinary*; D003430:Cross-Sectional Studies; D004283:Dog Diseases / Q000453:epidemiology* / Q000469:parasitology / Q000635:transmission; D004285:Dogs; D019353:Endemic Diseases / Q000662:veterinary*; D005260:Female; D007303:Insect Vectors / Q000469:parasitology*; D008297:Male; D010568:Peru / Q000453:epidemiology; D015995:Prevalence; D018571:Sentinel Surveillance / Q000662:veterinary*; D016036:Seroepidemiologic Studies; D062206:Spatial Analysis; D014224:Triatoma / Q000469:parasitology*; D014349:Trypanosoma cruzi / Q000302:isolation & purification*
chemical_list: D000913:Antibodies, Protozoan
keywords: Dog; ELISA; Sentinel surveillance; Spatial analysis; Triatoma infestans; Trypanosoma cruzi