I just found this site, and I am thrilled. How exciting to find such a chat room. I love Latin, and set aside time each morning to study it.

Others wrote about declining nouns in Latin. Virus is a masculine noun and is declined as follows:
Singular = Nom Case Virus; gen case, viri; dative case,viro; accusative case = virum; ablative case = viro.

Plural: Nom. viri; gen = virorum; dat = viris; accusative = viros; ablative = viris.