56 下列有關冠狀病毒（coronavirus）之敘述，何者正確？

 為最大之負股RNA病毒之一

傳統的冠狀病毒侵犯人體後，均會發生發燒的情形，病情在1周後就會痊癒，沒有後遺症

病毒感染引發普通感冒症狀（common cold）

此病毒感染之最適當溫度為37℃

answer C

it is a positive strand RNA

Coronaviruses primarily infect the upper respiratory and gastrointestinal tract of mammals and birds. Four to five different currently known strains of coronaviruses infect humans. The most publicized human coronavirus, SARS-CoV which causes SARS, has a unique pathogenesis because it causes both upper and lower respiratory tract infections and can also cause gastroenteritis. Coronaviruses are believed to cause a significant percentage of all common colds in human adults. Coronaviruses cause colds in humans primarily in the winter and early spring seasons. The significance and economic impact of coronaviruses as causative agents of the common cold are hard to assess because, unlike rhinoviruses (another common cold virus), human coronaviruses are difficult to grow in the laboratory.