Despite high-risk exposures, no evidence of zoonotic transmission during a canine outbreak of leptospirosis

Zoonoses Public Health. 2019 Mar;66(2):223-231. doi: 10.1111/zph.12557. Epub 2019 Jan 7.


Leptospirosis is a bacterial zoonosis that affects many mammals, including humans and dogs; dogs can transmit the bacteria to humans, but the frequency of transmission and highest risk exposures are poorly understood. During 2016-2017, the Maricopa County Department of Public Health, Arizona Department of Health Services and Centers for Disease Control and Prevention investigated the zoonotic potential of a canine leptospirosis outbreak in the Phoenix metro area. We identified symptomatic persons exposed to canine leptospirosis cases by conducting active and passive surveillance. We tested dog owners (n = 9) and animal care providers (n = 109) for serological evidence of Leptospira spp. infection (via the microscopic agglutination test [MAT]) and interviewed these persons about their specific exposures to canine cases and general exposures to canine blood and urine. Through surveillance, seven symptomatic persons were identified; six were tested and all were negative by MAT, and of these six, four persons were negative by PCR (two did not have PCR testing). All serosurvey participants (n = 118) were also seronegative. Among animal care providers, bare skin contact with urine/blood from a canine case was reported by 23.2%; two persons reported dog urine splashing in their face. Veterinary technicians were more likely to have bare skin contact with blood from a canine case compared to veterinarians and boarding facility staff (p < 0.001). Infection control practices were inconsistent; when working with specimens from a canine leptospirosis case, 44.6% of participants reported always wearing gloves when working with urine (i.e., collecting specimens), and 54.5% always wore gloves when working with blood. Veterinary technicians were also most likely to engage in all activities involving potential urine/blood contact, such as conducting laboratory tests (p < 0.01). We therefore recommend that veterinary technicians specifically receive targeted education about infection control practices. Our results suggest that dog-to-human transmission of leptospirosis is uncommon.

Keywords: infection control; leptospirosis; occupational exposure; serology; veterinary clinics; zoonoses.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Animal Technicians / statistics & numerical data
  • Animals
  • Antibodies, Bacterial / blood
  • Arizona / epidemiology
  • Disease Outbreaks / veterinary*
  • Dog Diseases / epidemiology*
  • Dog Diseases / microbiology
  • Dog Diseases / transmission
  • Dogs / microbiology
  • Female
  • Humans
  • Infection Control
  • Leptospira / immunology
  • Leptospirosis / epidemiology
  • Leptospirosis / transmission
  • Leptospirosis / veterinary*
  • Male
  • Middle Aged
  • Occupational Exposure / statistics & numerical data
  • Ownership
  • Pets
  • Skin / microbiology
  • Young Adult
  • Zoonoses / epidemiology*
  • Zoonoses / microbiology
  • Zoonoses / transmission


  • Antibodies, Bacterial