Cats shedding pathogenic Leptospira spp.-An underestimated zoonotic risk?

PLoS One. 2020 Oct 22;15(10):e0239991. doi: 10.1371/journal.pone.0239991. eCollection 2020.

Abstract

Shedding of DNA of pathogenic Leptospira spp. has been documented in naturally infected cats in several countries, but urinary shedding of infectious Leptospira spp. has only recently been proven. The climate in Southern Chile is temperate rainy with high annual precipitations which represents ideal preconditions for survival of Leptospira spp., especially during spring and summer. The aims of this study were to investigate shedding of pathogenic Leptospira spp. in outdoor cats in Southern Chile, to perform molecular characterization of isolates growing in culture, and to assess potential risk factors associated with shedding. Urine samples of 231 outdoor cats from rural and urban areas in southern Chile were collected. Urine samples were investigated for pathogenic Leptospira spp. by 4 techniques: qPCR targeting the lipL32 gene, immunomagnetic separation (IMS)-coupled qPCR (IMS-qPCR), direct culture and IMS-coupled culture. Positive urine cultures were additionally confirmed by PCR. Multilocus sequence typing (MLST) was used to molecularly characterize isolates obtained from positive cultures. Overall, 36 urine samples (15.6%, 95% confidence interval (CI) 11.4-20.9) showed positive results. Eighteen (7.8%, 95% CI 4.9-12.1), 30 (13%, 95% CI 9.2-18), 3 (1.3%, 0.3-3.9) and 4 cats (1.7%; 95% CI 0.5-4.5) were positive in qPCR, IMS-qPCR, conventional culture, and IMS-coupled culture, respectively. MLST results of 7 culture-positive cats revealed sequences that could be assigned to sequence type 17 (6 cats) and sequence type 27 (1 cat) corresponding to L. interrogans (Pathogenic Leptospira Subgroup 1). Shedding of pathogenic Leptospira spp. by cats might be an underestimated source of infection for other species including humans. The present study is the first one reporting growth of leptospires from feline urine in culture in naturally infected cats in South-America and characterisation of culture-derived isolates. So far, very few cases of successful attempts to culture leptospires from naturally infected cats are described worldwide.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Outer Membrane Proteins / isolation & purification
  • Bacterial Shedding / physiology*
  • Cat Diseases / microbiology
  • Cat Diseases / pathology*
  • Cat Diseases / transmission
  • Cats
  • DNA, Bacterial / metabolism
  • Female
  • Leptospira / genetics
  • Leptospira / isolation & purification
  • Leptospira / pathogenicity*
  • Leptospirosis / microbiology
  • Leptospirosis / pathology*
  • Leptospirosis / transmission
  • Leptospirosis / veterinary
  • Lipoproteins / genetics
  • Lipoproteins / isolation & purification
  • Male
  • Multilocus Sequence Typing
  • Real-Time Polymerase Chain Reaction
  • Risk Factors
  • Urine / microbiology

Substances

  • Bacterial Outer Membrane Proteins
  • DNA, Bacterial
  • LipL32 protein, Leptospira
  • Lipoproteins

Grants and funding

The Bavarian Academic Center for Latin America supported the study by paying for travel expenses (between Valdivia and Munich on two occasions) for planning the study. The Dirección de Investigación y Desarollo of the Universidad Austral de Chile supported the study by covering part of the costs for the material necessary for sampling and part of additional costs, e.g. transport and compensation of owners for study participation. For compensation, all included cats were vaccinated and dewormed. MSD Animal health provided the resources for sampling, clinical investigation of cats and laboratory investigations. Part of the laboratory work was funded by Proyecto FIC 15-8 (código BIP 30421496) del Gobierno Regional de Los Ríos, Chile.