Evaluation of change in canine diagnosis protocol adopted by the visceral leishmaniasis control program in Brazil and a new proposal for diagnosis

PLoS One. 2014 Mar 7;9(3):e91009. doi: 10.1371/journal.pone.0091009. eCollection 2014.

Abstract

The techniques used for diagnosis of canine visceral leishmaniasis (CVL) in Brazil ELISA and IFAT have been extensively questioned because of the accuracy of these tests. A recent change in the diagnosis protocol excluded IFAT and included the Dual-Path Platform (DPP). We evaluated the prevalence and incidence rates of Leishmania spp. before and after the change in the protocol. In addition, based on our results, we propose a new alternative that is less expensive for the screening and confirmation of CVL. Plasma samples were obtained from a serobank from dogs evaluated in a cross-sectional study (1,226 dogs) and in a cohort study of susceptible animals (n = 447), followed for 26 months. Serology testing was performed using ELISA, IFAT, and DPP. The incidence and prevalence of CVL were determined by using the protocol of the Visceral Leishmaniasis Control and Surveillance Program until 2012 (ELISA and IFAT using filter paper) and the protocol used after 2012 (DPP and ELISA using plasma). The prevalence was 6.2% and the incidence was 2.8 per 1,000 dog-months for the protocol used until 2012. For the new diagnosis protocol for CVL resulted in an incidence of 5.4 per 1,000 dog-months and a prevalence of 8.1%. Our results showed that the prevalence and incidence of infection were far greater than suggested by the previously used protocol and that the magnitude of infection in endemic areas has been underestimated. As tests are performed sequentially and euthanasia of dogs is carried out when the serological results are positive in both tests, the sequence does not affect the number of animals to be eliminated by the Control Program. Then we suggest to municipalities with a large demand of exams to use ELISA for screening and DPP for confirmation, since this allows easier performance and reduced cost.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brazil
  • Communicable Disease Control
  • Cross-Sectional Studies
  • Dog Diseases / diagnosis*
  • Dog Diseases / epidemiology*
  • Dog Diseases / parasitology
  • Dogs
  • Enzyme-Linked Immunosorbent Assay / veterinary
  • Fluorescent Antibody Technique, Indirect / veterinary
  • Incidence
  • Leishmania infantum / immunology
  • Leishmaniasis, Visceral / diagnosis*
  • Leishmaniasis, Visceral / epidemiology
  • Leishmaniasis, Visceral / parasitology
  • Leishmaniasis, Visceral / veterinary*
  • Molecular Typing / economics
  • Molecular Typing / methods
  • Molecular Typing / veterinary*
  • Prevalence

Grants and funding

This study was supported by the following grants: Federal University of Ouro Preto; Brazilian Ministry of Health; DECIT/MS/CNPq/BR/grant: 576062/2008-1; FAPEMIG/BR/grant: CBB-APQ-3073-4.01/07, CNPq/BR/grant: 472554/2007-7; PPSUS/MS/CNPq/FAPEMIG/SES-MG/grant CBB-APQ-00356-10; FAPEMIG/PPM and PNPD/Institutional/2011. The funders had no role in the study design, the data collection and analysis, the decision to publish the manuscript, or the preparation of the manuscript. ABR, MC, and RCO are grateful for CNPq fellowships. WCV is supported by a PNPD/CAPES postdoctoral fellowship.