Systematic review of the prevalence of environmental and host-related risk factors and the zoonotic potential of leptospirosis in domestic dogs in regions impacted by environmental changes.

Abstract

Background: Leptospirosis is a globally distributed zoonosis with significant public and veterinary health implications. Domestic dogs serve both as sentinels and reservoirs, particularly in ecologically dynamic settings influenced by urbanization and climate change. However, the global understanding of canine leptospirosis remains fragmented due to inconsistent diagnostic practices and variable regional data.

Objectives: To synthesize global evidence on the seroprevalence, dominant serovars, and risk factors associated with Leptospira infection in domestic dogs, and to evaluate the implications for public health within a One Health framework.

Methods: Following PRISMA guidelines, a systematic review was conducted across four databases (PubMed, Scopus, Web of Science, and WeLib) for studies published between 2000 and 2024. Observational studies using the Microscopic Agglutination Test (MAT) on domestic dogs were included. Data were extracted on seroprevalence, serovar distribution, and environmental, behavioral, and socio-economic risk factors. The Newcastle-Ottawa Scale was used for quality assessment. A narrative synthesis was conducted due to heterogeneity in methodologies.

Results: The systematic search identified 1,842 records, with 26 studies included, involving 13,827 dogs across 12 countries. Seroprevalence ranged from 9.1% to 75.0%, with higher rates in South America and Asia due to tropical climates. Dominant serovars included Leptospira interrogans serovar Canicola and Leptospira interrogans serovar Icterohaemorrhagiae, while Leptospira borgpetersenii serovar Sejroe emerged in specific regions. Environmental (e.g., water proximity, OR = 1.5-5.1), behavioral (e.g., rodent hunting, OR = 2.4-4.5), and socioeconomic (e.g., poverty, OR = 2.5-4.0) risk factors were identified. Dogs served as sentinels and reservoirs, guiding One Health interventions.

Conclusions: Canine leptospirosis is shaped by environmental, behavioral, and socio-economic drivers, with marked regional disparities. Dogs play a dual role as sentinels and reservoirs, necessitating integrated One Health interventions including targeted vaccination, environmental control, and community education. Standardization of diagnostics and expanded surveillance in underrepresented regions are critical for effective global leptospirosis control.