Prevalence of Leptospiral Infection in Cats

George E. Moore, DVM, PhD, DACVIM (SAIM), DACVPM (Epi), Purdue University

ArticleLast Updated September 20233 min read
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In the Literature

Ricardo T, Azócar-Aedo L, Signorini M, Previtali MA. Leptospiral infection in domestic cats: systematic review with meta-analysis. Prev Vet Med. 2023;212:105851. doi:10.1016/j.prevetmed.2023.105851

The Research …

Studies of leptospirosis in cats have increased and commonly investigate serologic titers or PCR of urine samples in stray or free-roaming cats with limited patient history. Cats may have an underrecognized role in the epidemiology of leptospirosis.1,2

Authors of this systematic literature review screened 5 databases for studies published between 1979 and 2022 to estimate the prevalence of leptospiral infection in cats and identify risk factors for infection. Sixty-one studies that assessed seroprevalence of leptospiral antibodies and/or prevalence of pathogenic Leptospira spp in the urine or kidneys were included in one or more analyses.

Based on 55 studies (7,413 cats), global seroprevalence was 11.7%; however, geographic representation was not balanced, with fewer studies from North America compared with Asia, Europe, and South America (14.8% of studies were conducted in Brazil). Pooled estimation of prevalence of pathogenic Leptospira spp (typically assessed via PCR) was 3.7% in urine based on 15 studies (2,597 cats) and 12.8% in kidney tissue based on 8 studies (528 cats) with mostly shelter or stray cats.

Meta-analysis of risk factors was limited, as many studies did not include these data. Assessed factors included sex, stray versus owned status, contact with rodents, access to outdoors, age category, environment (eg, rural versus urban), and contact with other cats. Only cats with access to outdoors had significantly increased (2.74 times greater) odds of infection. Free-roaming status likely indicated increased exposure to infected water or infected prey.

Although study data were pooled for summary measures, there was variability in study design and significant statistical heterogeneity. In addition, studies measuring titers often did not examine for organisms, and studies assessing PCR results often did not assess titers or verify PCR-positive results with other molecular methods.

Correlation of these findings to cats in the United States may not be appropriate, as other US-based prevalence reports are much lower.3

… The Takeaways

Key pearls to put into practice:

  • Cats, particularly free-roaming or stray cats, may have serologic evidence of exposure to Leptospira spp.

  • Positive microscopic agglutination test (ie, MAT) titers may be present in some cats but are generally low (<1:400) and unlikely to cause a positive result on point-of-care antibody assays. Specific serovars of concern for feline infection have not been adequately researched.

  • Clinical signs of leptospiral infection and potential comorbidities were not described in this study and remain poorly defined.

  • Public health precautions should be taken when handling patient urine, as leptospirosis is a zoonotic disease.