Expansion in the latitudinal distribution of <i>Rhipicephalus sanguineus</i> sensu stricto (Acari: Ixodidae) to southern Chile

Abstract

<i>Rhipicephalus sanguineus</i> is a species complex with a challenging diagnosis. There are two main lineages: a temperate lineage—now recognized as <i>R. sanguineus</i> sensu stricto (s.s.)—and a tropical lineage. In the Americas, several studies examined the distribution of both lineages. Meanwhile, in Chile, the distribution of the tropical lineage was reported from 18° to 22° S and <i>R. sanguineus</i> s.s. from 20° to 33° S; the morphological diagnosis located <i>R. sanguineus</i> in south-central Chile. In this study, we assessed the morphological and genetic identity of ticks collected from 47 dogs in southern Chile. Six dogs (12.8%) were parasitized by ticks that were morphologically and genetically assigned to <i>R. sanguineus</i> s.s. This finding would represent the southernmost record of this species in the country, located at over 308 km further south than the previous record, suggesting a latitudinal expansion of its distribution. Experimental studies are further required to understand how this tick survives extreme weather conditions when compared to other <i>R. sanguineus</i> s.s. from lesser latitudes.