Household Environmental Risk Factors Associated with Ehrlichia spp. Infection in Dogs from Homes with Human Rickettsiosis Exposure in Northwestern Mexico.

Zoonotic diseases represent an increasing public health concern worldwide, particularly in endemic regions of northwestern Mexico. This study aimed to evaluate household-level environmental and behavioral risk factors associated with Ehrlichia spp. infection in dogs living in areas with documented human rickettsiosis cases in Culiacán, Sinaloa, Mexico. A cross-sectional study was conducted, including 105 canine blood samples collected from urban and rural areas, with previous human rickettsiosis cases reported between 2021 and 2023. Microscopic examination and PCR amplification targeting the 16S rRNA gene of Ehrlichia spp. were performed. Morphological detection revealed a prevalence of 33.33%, while molecular analysis showed a prevalence of 43.83%. Risk factors significantly associated with infection included household waste, soil-type environments, free-roaming behavior identified through epidemiological analysis, and limited knowledge of tick-borne diseases among dog owners. These findings provide evidence of Ehrlichia spp. infection in dogs from areas with documented human rickettsiosis cases and highlight the value of dogs as indicators of household-level exposure to tick-borne pathogens in endemic communities.