Molecular characterization of Trichuris spp. from captive animals based on mitochondrial markers

Monoxenous parasites may easily infect animals in captivity, and nematodes belonging to the genus Trichuris are commonly reported in zoological gardens worldwide. Infections in captive animals should be accurately monitored and the characterization of pathogens is highly advisable, as a tool to infer possible routes of intra- and interspecific transmission pathways and to assess the related zoonotic potential. Whipworms are usually identified on the basis of few morphological features of adults males and eggs and by an host-affiliation criterion. Given the strong morphological convergence of adaptive traits and the possible occurrence of hybridization and/or cross-infections events, the use of molecular methods is of great utility. Here, we analysed two partial mitochondrial loci, the cytochrome c oxidase I and the cytochrome b regions, in Trichuris spp. infecting four animal species hosted in the Bioparco Zoological Garden of Rome. Results from molecular systematics, compared to previous data, suggested that the five Trichuris taxa recovered were well separated, showing a significant degree of host affiliation (herbivorous, primates/swine and rodents/canids). The screw horn antelopes and the camels were infected with two variants of Trichuris ovis; Trichuris sp. similar to those observed in rodents from South America was infecting the Patagonian maras. Moreover, Trichuris from the ring-tailed lemur showed a great similarity to Trichuris infecting the Japanese macaque previously analysed from the same zoological garden, and clustering together with Trichuris trichiura, posing a potential zoonotic threat for visitors and workers.