Gerbil Disease?

[Mike Dolan]

One of my gerbils just died, he was three years old. I had him in a tank with
his son and I want to put another gerbil in with him but I don't know if he
is infected. The fathers symptoms were: He was hardly able to move couldn't
really open his eyes and shaked alot. Please get back to me as soon as
possible because i don't want to leave the gerbil single in the tank for a
long time. Thanks. If anymore info is needed to determine what will happen
please e-mail me and i will do the best I can.