Molecular evidence of Rickettsia typhi infection in dogs from a rural community in Yucatán, México.

Introduction: Rickettsia typhi causes murine or endemic typhus, which is transmitted to humans primarily through flea bites contaminated with feces. Synanthropic and domestic animals also contribute to the infection cycle of R. typhi. Cases of murine typhus in humans were reported in the rural community of Bolmay, Yucatán, México, between 2007 and 2010. 

Objective: To identify the presence of R. typhi and estimate the frequency of infection in dogs from Bolmay, México, a locality with previous reports of murine typhus in humans. 

Materials And Methods: Whole blood samples were taken from 128 dogs. Total DNA was extracted for use in the polymerase chain reaction (PCR) to amplify fragments of the 17 kDa and omp B genes and confirms the presence of Rickettsia spp. The reaction products were sequenced, and alignment analysis was performed using the BLAST tool. 

Results: The frequency of R. typhi infection in dogs was 5.5 % (7/128). The alignment identified 99% and 100% homology to the R. typhi 17 kDa and omp B genes, respectively. 

Conclusion: We confirmed the presence of R. typhi in dogs in the studied community but at a low frequency. However, there is potential risk of transmission to humans.