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).
My great grandmother (Ann Mitchell BALFOUR who married William WATSON) was one of nine children born to William and Helen (nee MITCHELL) BALFOUR. Annâs sister Julia married John CAMPBELL on 16th January 1885 at Ferry Port on Craig, Fife, Scotland.