rickettsiae

例句：

1. 1. Rickettsia is a bacterium that causes the disease.
   立克次体是一种引起疾病的细菌。
2. 2. The researcher discovered a new strain of Rickettsia in the sample.
   研究人员在样本中发现了一种新的立克次体菌株。
3. 3. Rickettsia can cause severe illnesses, such as meningitis.
   立克次体可以引起严重的疾病，如脑膜炎。