Cowpox virus

Japanese: 牛痘ウイルス - ぎゅうとうういるす

...It is well known that Jenner developed the vaccination method after getting the idea from a milkmaid who said, "I have had cowpox, so I don't have to worry about catching smallpox." The cowpox virus used in vaccination has been implanted in the skin of cattle and sheep for a long time, and is therefore different from the cowpox virus of today, and is called the vaccinia virus. It is thought that the human smallpox virus and the cowpox virus have undergone DNA recombination, resulting in almost no pathogenicity and strong immunogenicity. ...

From 【Vaccination】

… The smallpox virus belongs to the Orthopoxvirus genus in the Poxviridae family, and its only natural host is humans. Closely related viruses include the cowpox virus and vaccinia virus. The cowpox virus causes cowpox in cattle, which is localized to the udder. …

*Some of the terminology that mentions "cowpox virus" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…ジェンナーが〈牛痘にかかったから天然痘にかかる心配はない〉という乳搾りの娘の話からヒントを得て，種痘法を開発したことはよく知られている。種痘に用いられる牛痘ウイルスcowpox virusは，長い間ウシ，ヒツジなどの皮膚に植えついだものなので，現在の牛痘ウイルスとは異なってきており，ワクチニアウイルスvaccinia virusとよばれている。ヒトの天然痘ウイルスと牛痘ウイルスとのDNAの組換えが起こり，病原性がほとんどなく，免疫原性が強くなったものと考えられている。…