D Traversa, H. Yin, Domenico Otranto, C Boulard, Dd Colwell, G Guan, Annunziata Giangaspero, Bio-Agresseurs, Santé, Environnement [Nouzilly] (UR BASE), Institut National de la Recherche Agronomique (INRA), and ProdInra, Migration
Cattle and yak hypodermosis in China is caused by Hypoderma bovis and H. lineatum, with a prevalence reaching up to 98-100% of the animals and maximum intensities exceeding 400 warbles for each animal. A third species, H. sinense ,i s also considered by Chinese researchers to affect livestock. The molecular characterization of the most variable region of the mitochondrial cytochrome oxidase I gene and of the ribosomal 28S gene has been performed for the third-stage larvae collected from cattle and yaks in China and identified (on the basis of the spinulation on the ventral side of the 10th segment) as H. bovis, H. lineatum, and H. sinense. Amplicons were digested with the HinfI and BfaI restriction enzymes, which provided diagnostic profiles to simultaneously differentiate the 3 Hypodermaspecies. Third-stage larvae of H. sinense were also examined by scanning electron microscopy, which revealed proper morphological characteristics different from those of H. bovis and H. lineatum. The molecular and morphological evidence herein reported support the existence of a third species of Hypoderma affecting cattle and yaks in China, and the results provide new tools for unequivocal identification of this species and present key components for the evaluation of its endogenous cycle and pathogenicity in animals and humans. Larvae of Hypoderma spp. (Diptera, Oestridae) cause myia- sis to develop in warbles under the skin of domestic and wild ruminants (Zumpt, 1965). The most common species are Hy- poderma bovis (Linnaeus, 1758) and Hypoderma lineatum(De Villers, 1789), mainly affecting cattle, Hypoderma diana Brauer, 1858, Hypoderma actaeonBrauer, 1858, and Hypoder- ma tarandi (Linnaeus, 1758), affecting cervids (roe deer, red deer, and reindeer, respectively). Myiasis caused by larvae of Hypoderma spp. greatly impairs livestock production and wild ruminant welfare by inducing mechanical damage to internal organs and skin and by down- regulating the host's immune system (Boulard, 1989; Chabaudie and Boulard, 1992; Scholl, 1993; Nicolas-Gaulard et al., 1995; Boulard, 2002). In addition to the 5 species noted above, 2 other species have been described by Zumpt (1965), i.e., Hypoderma capreola Rubtzov, 1939, which has also been considered as synonymous of H. diana (see Grunin, 1962), and Hypoderma moschiferi Brauer, 1863. An eighth species, H. sinense, was described by Pleske (1926), but the author did not make comparisons between the adult flies and those of the other species (Grunin, 1969) and did not deposit holotypes. Furthermore, this species has long been considered a synonym of H. lineatum (see Zumpt, 1965), thought to affect animals living in mountainous regions (Grun- in, 1969). Identification of third larval stages (L3) of Hypoderma spp. is currently performed using 3 morphological keys (James, 1947; Zumpt, 1965; Sugar, 1976) on the basis of the presence or absence of the spines on the ventral surface of the 10th segment or on the structure of the posterior spiracles. A com- parative description of H. bovis, H. lineatum, H. diana, H. ac- taeon, and H. tarandi has been made using scanning electron