Study of Baylisascaris procyonis larva migrans : Pathological and parasitological analysis and development of serological diagnosis.

由常见的浣熊蛔虫引起的幼虫迁徙是一种在北美极为重要的人畜共患疾病。我们在一个小型野生动物园的家兔中遇到了日本首次证实的这种疾病爆发。在这个公园里，浣熊已经被饲养了9年，其中一只浣熊是在兔子爆发前8周由宠物主人捐赠给公园的。间接证据表明，捐赠的浣熊很可能是此次疫情的源头。此外，我们还调查了在日本感染原yonb.s幼虫迁移的家兔中枢神经损伤的细节。在本研究中，我们发现在23只被诊断为原yonis幼虫迁移的动物中，只有8只存在蛔虫幼虫。由于不可能总是检测到幼虫，因此必须认真考虑原芽孢杆菌幼虫迁移的可能性。此外，原生殖道双歧杆菌会导致人类严重的视网膜病变。病变称为弥漫性单侧亚急性神经视网膜炎（DUSN）。为了解沙鼠原结肠双胞杆菌的发病机制，我们将原结肠双胞杆菌胚卵接种于蒙古沙鼠体内，用检眼镜对其眼底进行监测。组织病理学检查显示视盘区血管周围炎、色素细胞炎性增生、玻璃体炎多见。这些发现与人类DUSN病例相似，表明沙鼠可能是了解人类原生殖道芽胞杆菌感染发病机制的有用模型。

Larva migrans caused by the common raccoon ascarid, Baylisascaris procyonis, is a zoonotic disease of critical importance in North America. We encountered the first proven outbreak of this disease in Japan in domestic rabbits in a small wildlife park. In this park, raccoons had been kept for 9 years, and one raccoon was donated to the park by a pet owner 8 weeks prior to the occurrence of an outbreak in rabbits. Circumstantial evidence indicates that the donated raccoon is the likely source of this outbreak. Also, we investigated the details of the central nervous lesion in the rabbits affected with B.procyonis larva migrans in Japan. In this study, we demonstrated ascarid larvae in only eight out of 23 animals diagnosed as B.procyonis larva migrans. Since it is not always possible to detect the larvae, the possibility of B.procyonis larva migrans must be given serious consideration to the characteristic lesions. Also, B.procyonis causes a severe retinal lesion in humans. The lesion is termed as diffuse unilateral subacute neuroretinitis (DUSN). To understand the pathogenesis of B.procyonis in gerbils, we inoculated the embryonated eggs of B.procyonis into Mongolian gerbils, and monitored their fundi with an ophthalmoscope. Histopathological examination revealed perivasculitis in the optic disk region, inflammatory proliferation of the pigment cells, and vitreitis in most cases. These findings were similar to those in human cases of DUSN, suggesting that gerbils might be a useful model for understanding the pathogenesis of B.procyonis infection in humans.