Learn about Alexandra Michelle: her birthday, what she did before fame, her family life, fun trivia facts, popularity rankings, and more. Fun facts: before fame, family life, popularity rankings, and more.
Viruses cause such respiratory infections as the common cold (rhinovirus), the flu (influenza), some pneumonias and bronchiolitis (respiratory syncytial virus, or RSV). It can be difficult to determine whether you have a viral or bacterial infection because the symptoms are often similar.
The most common virus is the common cold, which is actually caused by several different families of viruses. Even though you may experience upper-respiratory symptoms associated with a bacterial infection, most cases of the common cold are not caused by bacteria-which make antibiotics useless against them.