natural infection

• 自然感染

natural infection的用法和样例：

例句

1. This is the first report of the presence of FMDV in bull semen due to natural infection in China.
   这也是我国首次证实自然感染牛的精液被口蹄疫病毒污染。
2. Pathological observation on Cervus elaphus yarkandensis naturally infected with Sarcocystis sp.
   塔里木马鹿自然感染住肉孢子虫病的病理学观察。