Morphological and molecular analyses of Taenia and Mesocestoides species from red foxes (Vulpes vulpes) in northwestern China

Abstract

Background The red fox (Vulpes vulpes) is a geographically widespread predator species, occurring across the northern Hemisphere. It has high veterinary-medical significance, in part owing to its definitive host role in the life cycle of several tapeworm species, including zoonotic ones. However, there have been only few reports on cyclophyllid tapeworm (Cestoda: Cyclophyllidea) infection in red foxes from China. Methods In this study, 263 tapeworms were collected from eight road-killed red foxes in Xinjiang Uygur Autonomous Region (XUAR, northwestern China). The tapeworms were analyzed based on morphological characters and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequences. Results 83 Taenia and 180 Mesocestoides tapeworms were identified according to the presence or absence of rostellum, and the number, the length and the shape of the large rostellar hooks. The morphological and molecular analyses revealed that i) 180 Mesocestoides tapeworms, here named as Mesocestoides sp. Vulpes vulpes, showed 99.21% (378/381 bp) identity to Mesocestoides sp. reported from red fox in Mongolia; and ii) 83 Taenia tapeworms belonged to three species. The first Taenia species (n = 16, named as Taenia sp. Vulpes vulpes), based on the length of large rostellar hooks (337–342 µm) and its cox1 sequence, was identified as a potentially novel species, which is phylogenetically close to Taenia laticollis. The second species (n = 54, named as Taenia sp. Vulpes vulpes & Rhombomys opimus), was morphologically similar to Taenia endothoracicus according to the number (n = 52), the length (319–332 µm) and the shape of the large rostellar hooks. This species, infecting three red foxes, shared 100% cox1 sequence identity with Taenia sp. Rhombomys opimus genotype C found previously in great gerbils (Rhombomys opimus) in the same region. The third species (n = 13, named as Taenia polyacantha-like), had shorter large rostellar hooks (178–180 µm) and showed 96.27% (361/375 bp) sequence identity to Taenia polyacantha reported from red fox in Italy. In addition, co-infections with two Taenia species and with Taenia and Mesocestoides species were also demonstrated. Conclusions The “great gerbil-red fox” life cycle of Taenia sp. Vulpes vulpes & Rhombomys opimus, belonging to the mitochondrial lineage of T. endothoracicus, is confirmed. The T. polyacantha-like species and Mesocestoides sp. Vulpes vulpes were found for the first time in red fox in China. Taenia sp. Vulpes vulpes is a potentially novel species, which is close to Taenia laticollis based on its phylogenetic properties. The life cycle of Taenia sp. Vulpes vulpes and Mesocestoides sp. Vulpes vulpes should be further explored.