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ABSTRACT: During a survey of the helminth community of several rodent species in the Morogoro region (Tanzania), Trichuris whipworms (Nematoda: Trichuridae) were found in the ceca of the Natal multimammate mouse, Mastomys natalensis and a gerbil, Gerbilliscus vicinus (both Rodentia: Muridae). The taxonomic literature regarding Trichuris from African native rodents describes 10 species, but includes few metric and morphologic characters that discriminate between some of the pairs. The whipworms we sampled in Tanzanian Natal multimammate mice and gerbils were morphologically identified, respectively, as Trichuris mastomysi Verster, 1960 and Trichuris carlieri Gedoelst, 1916 sensu lato, but with characters that overlap or partially overlap with the cosmopolitan Murinae whipworm, Trichuris muris, already reported from several rodents in Africa. To clarify our identification, we sequenced the ITS-1, 5.8S, and ITS-2 ribosomal DNA region of the worms' nuclear genome. The genetic analyses clearly distinguish the whipworms we found in M. natalensis from those found in the gerbil, and both of these from T. muris whipworm reference sequences. The overlap of morphological characters between rodent whipworms suggests that reports of T. muris from rodent species not closely related to Murinae in other parts of Africa should be treated with caution.
The whipworms, genus Trichuris Roederer, 1761, are among the most readily recognized nematode genus parasitic of mammals, though distinguishing species within the genus can be difficult. They are commonly found in rodents worldwide, with new species being recently described or redescribed in South America (Robles et al., 2006; Torres et al., 2011) and in Europe (Feliu et al., 2000). The genus is also commonly found in African rodents with at least 10 species described to date. The literature review of helminths of African vertebrates from 1800 to 1967 by Canaris and Gardner (2003) mentions only 2 species, Trichuris carlieri Gedoelst, 1916 and Trichuris vondwei Ortlepp, 1938. The compilation by Skrjabin et al. (1971) reports Trichuris contorta Rudolphi, 1819 and Trichuris parvispicularis Clapham, 1945. However, the systematic status of Trichuris parvispicularis was questioned by Vester (1960) who considered it as a synonym of T. vondwei. Seven potential species were omitted from these compilations: Trichuris petteri described by Quentin (1966), Trichuris gerbillis and Trichuris gundii described by Bernard (1969), Trichuris mastomysi, Trichuris pedetei, Trichuris procaviae described by Verster (1960), and Trichuris...