Is It a Virus or a Bacterium? Know the Difference In general,
most colds and other respiratory infections are not serious for
adults in good health. It's just the hassle of dealing with
runny noses, coughing, sneezing, fever, headaches, aching
muscles, and fitful sleeping. But knowing whether your infection
is caused by a virus or a bacterium makes a difference in how it
is treated. Which is it? Bacteria are one-celled organisms that
multiply by simple division. They are linked to such respiratory
infections as otitis media (ear), tonsillitis (tonsils),
pneumonia (lungs), bronchitis (airways), sinusitis (sinuses),
pharyngitis (throat), and whooping cough (airways). Most
respiratory infections, however, are caused by viruses rather
than by bacteria. Viruses are some of the tiniest entities
known. Unlike bacteria, they do not divide and do not reproduce
on their own. Instead, when they invade a cell, they take over
the cell’s machinery, forcing the cell to reproduce the virus in
massive numbers. Viruses infect