Randomized, controlled, double-blinded field trial to assess Leishmania vaccine effectiveness as immunotherapy for canine leishmaniosis

Angela Toepp, Mandy Larson, Geneva Wilson, Tara Grinnage-Pulley, Carolyne Bennett, Adam Leal-Lima, Bryan Anderson, Molly Parrish, Michael Anderson, Hailie Fowler, Jessica Hinman, Eric Kontowicz, Jane Jefferies, Marvin Beeman, Jesse Buch, Jill Saucier, Phyllis Tyrrell, Radhika Gharpure, Caitlin Cotter, Christine Petersen

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

Better tools are necessary to eliminate visceral leishmaniasis (VL). Modeling studies for regional Leishmania elimination indicate that an effective vaccine is a critical tool. Dogs are the reservoir host of L. infantum in Brazil and the Mediterranean basin, and therefore are an important target for public health interventions as well as a relevant disease model for human VL. No vaccine has been efficacious as an immunotherapy to prevent progression of already diagnostically positive individuals to symptomatic leishmaniasis. We performed a double-blinded, block-randomized, placebo-controlled, vaccine immunotherapy trial testing the efficacy of a recombinant Leishmania A2 protein, saponin-adjuvanted, vaccine, LeishTec® in owned hunting dogs infected with L. infantum. The primary outcome was reduction of clinical progression, with reduction of mortality as a secondary outcome. Vaccination as an immunotherapy reduced the risk of progression to clinically overt leishmaniasis by 25% in asymptomatic dogs (RR: 1.33 95% C.I. 1.009–1.786 p-value: 0.0450). Receiving vaccine vs. placebo reduced all-cause mortality in younger asymptomatic dogs by 70% (RR: 3.19 95% C.I.: 1.185–8.502 p-value = 0.0245). Vaccination of infected-healthy animals with an anti-Leishmania vaccine significantly reduced clinical progression and decreased all-cause mortality. Use of vaccination in infected-healthy dogs can be a tool for Leishmania control.

Original languageEnglish (US)
Pages (from-to)6433-6441
Number of pages9
JournalVaccine
Volume36
Issue number43
DOIs
StatePublished - Oct 15 2018
Externally publishedYes

Keywords

  • Canine
  • Immunotherapy
  • Leishmania
  • Zoonoses

ASJC Scopus subject areas

  • Molecular Medicine
  • General Immunology and Microbiology
  • General Veterinary
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases

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