Differentiation of Trichuris species using a morphometric approach

Trichuris trichiura is a nematode considered as the whipworm present in humans and primates. The systematics of the genus Trichuris is complex. Morphological studies of Trichuris isolated from primates and humans conclude that the species infecting these hosts is the same. Furthermore, numerous molecular studies have been carried out so far to discriminate parasite species from humans and Non-Human Primates using molecular techniques, but these studies were not performed in combination with a parallel morphological study. The hypothesised existence of more species of Trichuris in primates opens the possibility to revise the zoonotic potential and host specificity of T. trichiura and other putative new species of whipworms. In the present work, a study of Trichuris Roederer, 1761 (Nematoda:Trichuridae) parasitizing C. g. kikuyensis, P. ursinus, Macaca sylvanus, Pan troglodytes, and Sus scrofa domestica has been carried out using modern morphometric techniques in order to differentiate populations of Trichuris isolated from four species of captive NHP from different geographical regions, and swine, respectively. The results obtained revealed strong support for geometrical morphometrics as a useful tool to differentiate male Trichuris populations. Therefore, morphometrics in combination with other techniques, such as molecular biology analyses, ought to be applied to further the differentiation of male populations. On the other hand, morphometrics applied to female Trichuris species does not seem to contribute new information as all the measurements combinations of obtained from females always showed similar results.