Survey on scrapie in Japanese : detection of PrP^<Sc> and studies on the distribution of the PrP genotypes in sheep.

1.绵羊PrP基因的限制性片段长度多态性（RFLP）：为了研究PrP基因的RFLP类型，使用限制性内切酶EcoRI和HindIII以及绵羊PrP的编码区作为探针，分析了从日本不同地区收集的绵羊组织的染色体DNA。绵羊分为6个类型。I型至III型对应于英国报道的类型。近半数羊瘙痒病属于Ⅰ型，Ⅱ型羊瘙痒病的发生率较低。日本不同地区的类型分布存在一定的差异.日本羊瘙痒病感染绵羊的调查：为了调查日本羊瘙痒病感染的发病率，<Sc>在从日本不同地区获得的总共197只绵羊脑、脾和淋巴结中进行PrP^的检测。在<Sc>北海道采集的16只绵羊和从其他地区采集的2只绵羊中检测到PrP^。然而，这两只羊也是在北海道生产的。这些发现表明，在日本羊瘙痒病的污染仅限于在北海道生产的羊。

1. Restriction fragment length polymorphism (RFLP) on the sheep-PrP gene : To investigate the RFLP types on the PrP-gene, chromosomal DNAs from sheep tissues collected from various districts in Japan were analyzed using restriction endonucleases EcoRI and HindIII and the coding region of sheep PrP as a probe. Sheep were classified into 6 types. Types I to III corresponded to the types reported in England. Nearly half of the scrapie sheep belonged to type I and the frequency of type II in scrapie sheep was low. Distribution of the types in different parts of Japan showed some variations.2. Survey of scrapie infected sheep in Japan : To survey the incidence of scrapie infection in Japan, detection of PrP^<Sc> in a total of 197 sheep brains, spleens and lymph nodes obtained from various districts in Japan was carried out. PrP^<Sc> was detected in 16 sheep collected in Hokkaido and in 2 obtained from other districts. However, these two sheep had also been produced in Hokkaido. These findings suggest that contamination with scrapie in Japan is restricted to sheep produced in Hokkaido.