Distribution and genetic variation of hymenolepidid cestodes in murid rodents on the Canary Islands (Spain)

Three species of hymenolepidids were identified: Hymenolepis diminuta, Rodentolepis microstoma and Rodentolepis fraterna. Hymenolepis diminuta (in rats) and R. microstoma (in mice) showed a widespread distribution in the Archipelago, and R. fraterna was the least spread species, appearing only on five of the islands. The hymenolepidids found on Fuerteventura, Lanzarote and La Graciosa were restricted to one area. The COI network of H. diminuta showed that the haplotypes from Lanzarote and Fuerteventura are the most distant with respect to the other islands, but clearly related among them.Founder effects and biotic and abiotic factors could have played important role in the presence/absence of the hymenolepidid species in determined locations. The haplotypes from the eastern islands (Fuerteventura and Lanzarote) seem to have shared an ancestral haplotype very distant from the most frequent one that was found in the rest of the islands. Two colonization events or a single event with subsequent isolation and reduced gene flow between western-central and eastern islands, have taken place in the Archipelago. The three tapeworms detected are zoonotic species, and their presence among rodents from this Archipelago suggests a potential health risk to human via environmental contamination in high risk areas. However, the relatively low prevalence of infestations detected and the focal distribution of some of these species on certain islands reduce the general transmission risk to human.Cestodes of the family Hymenolepididae (Cyclophyllidea) are ubiquitous and parasites from diverse birds, rodents, insectivores, Chiroptera and some other mammals. According to Czaplinski and Vaucher [1], there are ca. 230 and 620 species of hymenolepidids parasitizing mammals and birds, respectively. Some of the hymenolepidid species of rodents are of health interest, since they are zoonotic and can cause severe diseases in immunosuppressed individuals [2-4].The Canary Islands are considered a