Human cystic echinococcosis: first molecular identification of Echinococcus canadensis G7 in Brazil

Echinococcus granulosus sensu lato (s.l.) is a species complex with the potential to cause cystic echinococcosis (CE). Contact with the feces of domestic dogs (Canis familiaris) fed with raw viscera of intermediate livestock hosts is a risk factor for this infection in the southern region of Brazil. Although the region has been considered endemic to CE for many years, molecular data regarding the species of the complex causing CE in humans are scarce. This study aimed to perform a molecular analysis of the biological fluid from a human liver cyst to investigate the species responsible for CE. Genetic material obtained from the hydatid fluid of a hepatic cyst from a human with CE was subjected to PCR to amplify mitochondrial and nuclear DNA sequences. The phylogenetic analysis confirmed the human infection by Echinococcus canadensis G7 in the state of Paraná, Brazil. This is the first molecular record of E. canadensis G7 infecting a human in Brazil, and it is important to reiterate the risk of human CE caused by this species in South America, as reported by a previous study in Patagonia, Argentina. From the epidemiological point of view, this finding is of great relevance for the southern region of Brazil, since this parasite has previously only been detected in pigs in the state of Rio Grande do Sul, neighboring Paraná. The finding points to the importance of this identification in the molecular epidemiology of E. granulosus s.l., especially in South America.