Epidemiological link between canine monocytic ehrlichiosis caused by Ehrlichia canis and the presence of Rhipicephalus sanguineus sensu stricto in Argentina

Abstract

In this work, we analyze data that support an epidemiological link between cases of canine monocytic ehrlichiosis (CME) by Ehrlichia canis and the presence of Rhipicephalus sanguineus sensu stricto as vector in an endemic area for this tick in Argentina. In a blood sample of a 1-year-old toy poodle with CME compatible clinical signs, which showed CME typical morulae in monocytes in Giemsa-stained blood smear, DNA of E. canis was detected by PCR. Further, DNA of E. canis was also detected in a female of R. sanguineus s.s. collected on the infected dog. Rhipicephalus sanguineus s.s. is the only member of the R. sanguineus group that prevails in the study area. The results of this study suggest that R. sanguineus s.s. may play a more important role in the transmission of E. canis than it was assumed so far. The epidemiological link between CME cases and R. sanguineus s.s. as vector in temperate areas of Argentina described in this work contrast previous studies which found that R. sanguineus sensu lato "tropical lineage" (which is absent in the study area) is competent to transmit E. canis but not R. sanguineus s.s.

Rhipicephalus sanguineus Complex in the Americas: Systematic, Genetic Diversity, and Geographic Insights

“…However, no tests have been carried out to verify the vectorial capacity of this linage. Otherwise, R. sanguineus s.s. can be naturally infected by E. canis in Argentina [24,25]. For this reason, in regions where both lineages are sympatrically distributed, it is possible to assume that a high richness of tick-borne pathogens could be circulating.…”

Amblyomma triste (Acari: Ixodidae): nuevos registros en la provincia de Buenos Aires, Argentina

“…En Argentina, se ha detectado R. massiliae en R. sanguineus s.s. de Ciudad Autónoma de Buenos Aires (CABA), Bahía Blanca (provincia de Buenos Aires) y Mendoza (Cicuttin, 2014;Monje et al, 2016) y también se ha reportado un caso humano de rickettsiosis por R. massiliae en CABA (García-García et al, 2010). Ehrlichia canis y A. platys se encuentran ampliamente distribuidas en el país (Sebastian et al, 2021;Cicuttin et al, 2015).…”