Fever can support the immune system's attempt to gain advantage over infectious agents, such as viruses and bacteria, and it makes the body less favorable as a host for replicating viruses and bacteria, which are temperature sensitive. Infectious agents are not the only causes of fever, however.
Your sister's grandson is your great nephew. You are his great aunt (if you are a woman) or his great uncle (if you are a man).
Our Little Persian Cousin E. Cutler Shedd. The agha's daughter was transformed in the eyes of her guest. A Soldier of the Legion C. N. Williamson. Certainly Bey, on my head and eyes be it, said the obliging agha; and this was the form in which the hint arrived.