natural infestation的用法和樣例：
例句
- This is the first report of the presence of FMDV in bull semen due to natural infection in China.
這也是我國首次證實自然感染牛的精液被口蹄疫病毒污染。 - Because natural rotavirus infection was not associated with intussusception, they reasoned their vaccine would similarly not increase the risk of this complication.
由於自然感染輪狀病毒並不會造成腸套疊，因此他們認為新疫苗也不會增加這種併發症的風險。
