Frontiers in Medicine (Aug 2020)

In vitro Infectivity of Strains Isolated From Dogs Naturally Infected With Leishmania infantum Present a Distinct Pathogenic Profile in Hamsters

  • Lucilene Aparecida Resende,
  • Lucilene Aparecida Resende,
  • Rodrigo Dian de Oliveira Aguiar-Soares,
  • Nádia das Dores Moreira,
  • Nádia das Dores Moreira,
  • Nádia das Dores Moreira,
  • Sidney de Almeida Ferreira,
  • Sidney de Almeida Ferreira,
  • Mariana Ferreira Lanna,
  • Mariana Ferreira Lanna,
  • Jamille Mirelle de Oliveira Cardoso,
  • Fernando Augusto Siqueira Mathias,
  • Wendel Coura-Vital,
  • Wendel Coura-Vital,
  • Wendel Coura-Vital,
  • Wendel Coura-Vital,
  • Reysla Maria da Silveira Mariano,
  • Jaqueline Costa Leite,
  • Patricia Silveira,
  • Tatiane Furtado de Carvalho,
  • Renato Lima Santos,
  • Denise da Silveira-Lemos,
  • Denise da Silveira-Lemos,
  • Denise da Silveira-Lemos,
  • Olindo Assis Martins-Filho,
  • Walderez Ornelas Dutra,
  • Alexandre Barbosa Reis,
  • Alexandre Barbosa Reis,
  • Alexandre Barbosa Reis,
  • Rodolfo Cordeiro Giunchetti

DOI
https://doi.org/10.3389/fmed.2020.00496
Journal volume & issue
Vol. 7

Abstract

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Visceral leishmaniasis (VL) is a severe disease caused by Leishmania infantum. Dogs are the parasite's main reservoir, favoring its transmission in the urban environment. The analysis of L. infantum from infected dogs contributes to the identification of more virulent parasites, thereby supporting basic and applied studies such as vaccinal and therapeutic strategies. We proposed the in vitro and in vivo characterization of L. infantum strains from naturally infected dogs from a VL endemic area based on an infectivity and pathogenicity analysis. DH82 canine macrophages were infected in vitro with different strains for infectivity analysis, showing distinct infectivity profiles. The strains that showed greater and lesser infectivity using in vitro analyses (616 and 614, respectively) were used to infect hamsters for pathogenicity analysis. The group infected with strain 616 showed 100% survival while the group infected with strain 614 showed 50% after seven months of follow up. Furthermore, the 614 strain induced more noticeable clinicopathological changes and biochemical abnormalities in liver function, along with high inflammation and parasite load in the liver and spleen. We confirmed high variability of infectivity and pathogenicity in L. infantum strains from infected dogs. The results support the belief that screening for L. infantum infectivity using in vitro experiments is inadequate when it comes to selecting the most pathogenic strain.

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