Spirometra infections in humans in Asia and Oceania.

The genus Spirometra (Cestoda: Diphyllobothriidae) is a group of tapeworms distributed worldwide and includes important species that cause sparganosis and spirometrosis in humans. Traditionally, it has been accepted that non-proliferative sparganosis is caused by Spirometra erinaceieuropaei and proliferative sparganosis by Sparganum proliferum. However, recent molecular studies have revealed that the species present in Asia are Spirometra mansoni and the recently described Spirometra asiana, not S. erinaceieuropaei endemic to Europe. It is questionable whether Spa. proliferum is a valid species: proliferative sparganosis cases in Asia might be caused by S. mansoni. Some human cases of multiple infections with plerocercoids of non-proliferative species may have been mistaken for proliferative sparganosis. This review focuses on sparganosis and spirometrosis in Asia and Oceania and overviews the molecular phylogeny, geographic distribution, current situation, innovative diagnostic methods and future perspectives for work on these species. Whether the species referred to as Spa. proliferum in Asia and Spa. proliferum in South America are conspecific is also discussed. Concerning S. asiana, little is known about its biology, biogeography and pathogenicity in humans. Accurate identification of these etiological agents through DNA analysis is important for the reliable assessment of zoonotic relevance and further understanding of the biology and epidemiology of these tapeworms.