Virus or Bacteria? What’s the Difference?

Bacterial cell structure
Bacterial cell structure

Many human illnesses are caused by diseases that are from viruses or bacteria. It is important to know what is making you sick, however, is difficult to tell which is the culprit. Symptoms of both bacterial and viral infections are very similar, yet treatment is different for each.


Viruses contain genetic material inside them. They are much smaller than bacteria. Viruses cause diseases such as the common cold, flu and warts. They also cause severe illnesses such as HIV/AIDS, smallpox, measles, and hemorrhagic fevers. Viral infections are difficult to treat because antibiotics which work on bacterial infections do not work on viral infections. The current medicines against future viral infections come in the form of vaccines as well as a few anti viral medications. Rest is very important when sick with a virus.

A common symptom of a viral disease that is not seen in bacterial disease is clear and/ or cloudy mucous, as well as wide-spread symptoms. Viral illnesses also last from 2-10 days and sometimes but not always produce a fever.


Bacteria are one-celled organisms that multiply by simple division. They cause respiratory infections, tonsillitis, pneumonia, bronchitis, sinusitis, pharyngitis, and whooping cough.

A common symptom of a bacterial disease that is not seen in viral disease is colored phlegm. Symptoms are usually in one specific area such as the sinuses, throat, or chest. Bacterial illnesses also last 10 days or more and are notorious for producing a fever. Luckily, most bacterial infections can be cured with a full course of antibiotics.

Knowing the difference between a viral and bacterial illness may save you time and money. Remember, a cold and cough is usually always viral, while something localized such as an ear infection is usually always bacterial and can be treated with antibiotics. Only your doctor will be able to confirm what is making you sick and follow up with proper medication.


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