An endemic Taenia from South America: validation of T. talicei Dollfus, 1960 (Cestoda: Taeniidae) with characterization of metacestodes and adults

Abstract

Taenia talicei is redescribed based on new data from polycephalic, fimbriocercus and cysticercus metacestodes found in Ctenomys spp. (Rodentia: Ctenomyidae) from Argentina. Strobilate adult specimens, derived from experimental infections in domestic dogs, are described for the first time. Identity of the adult and metacestodes stages is based on the number of rostellar hooks (44–50 hooks in 2 rows), their dimensions (large hooks= 232–242; small= 150–187) and shape. Taenia talicei is distinguished from those species that occur naturally in Neotropical Felidae and from those cosmopolitan species that circulate in synanthropic cycles with rodents (or lagomorphs) and domestic hosts such as cats and dogs in South America based on the structure of the metacestode, dimensions and numbers of rostellar hooks and a suite of specific characters of the genital system in strobilate adults. This species is the first that can be considered endemic to South America. Origins of an endemic Taenia species or taeniid assemblages in South America would have relationships to either North American or Eurasian placental carnivores. In these instances, the expansion of Taenia may have resulted from geographic colonization of South America, radiation in both felids (and canids), and host switching by tapeworms to caviomorphs, prior to the emergence of the Panamanian Isthmus. Taenia talicei is capable of development in domestic dogs, and metacestodes in species of Ctenomys were found in urban or semi-urban environments. These factors may establish a role for synanthropic cycles linked to definitive hosts including dogs and cats as a route for exposure of humans to infection by this taeniid.