【摘要】 本文对山羊蠕形螨Demodex caprae生活史各期形态特征及其对宿主的致病力进行了观察,生活史分为卵、幼虫、前若虫、若虫和成虫五期。虫体主要寄生于山羊的头颈部、背部和四肢内外侧的真皮内,感染部位可出现大小不等的圆形结节,给节内包含有生活史各期的大量虫体和可溶性类脂物,组织切片显示,由于虫体的大量繁殖而破坏局部组织,从而形成结节和空洞。更多还原

【Abstract】 Demodex caprae is parasitic on goats,which causes scab.It is one of the most common skin disease of goats. Notable economic losses due to infestation of this mite have been reported from several African nations, as well as in China.The present paper studies the morphology of life history stages and pathogenicity to host of this mite. Morphology:Ovum elongate-oval, 84.5 μ× 48.4 μ. Larva 56.3μ in length, boundary of gnathosoma and podosoma marked, but it is indistinct be-tween podosoma and opisthosoma.Protonymph 160. 1 μ, opisthosoma flattened, other structures similar to larva. Nymph 375. 4 μ long, opisthosoma gradually tapering to a point. Transverse striations on the surface of body apparent.Female 243.8μ long, gnathosoma long and protruding, hypostome apparent.Striations on dorsal surface of podosoma chrysanthemum like. Vulva a simple longitudinal slit. Male 232. 5 μ long, aedoe-agus 36. 1 μ ong, other structures similar to female.Pathogenicity:Infestations of the mites usually are confined to derma of neck, back and inner and lateral limbs of host body.In the infested sites there appears a large number of rough circular or ellipsoidal nodules, measuring from 0. 1cm to 1.8 cm in diameter. A nodu1e of 0.6 cm in diameter includes a lot of lipid substance and a large population of over 25549 mites. In heavy infestation the nodules are conjuncted with each other. Section of skin shows that derma and collagenous fibers, elastic fibers, reticulated connective tissue of subcutaneous layer are destroyed by the enormous number of mites.更多还原