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How to Know Whether It’s a Virus or Bacteria That’s Making You Sick

Here’s the problem with diagnosing and treating viral and bacterial infections—symptoms can look similar, but treatments are different. For example, say your child has a sore throat and fever. “Many people know that fever and sore throat can be a sign of strep throat. Strep throat is caused by a bacterium and will improve with antibiotics,” said Nathan B. Price, MD, a pediatric infectious disease specialist at Banner – University Medicine Pediatric Specialty Clinic in Tucson, AZ.

But what many people don’t realize is that most of the time, when a child has a sore throat and fever, it’s not strep throat. It’s due to a virus, and an antibiotic won’t help. Different types of germs can cause these similar symptoms. And antibiotics work for bacterial infections but not for viral infections.

How do you figure out whether you’re looking at a viral or bacterial infection? Most of the time, you can’t tell on your own. You’ll need additional evaluation from a health care professional, and often, lab tests to help sort out the difference.

How you can treat bacterial infections

Along with strep throat, other common bacterial infections include urinary tract infections, bronchitis, sinusitis, cellulitis, Lyme disease and tetanus. If your health care provider diagnoses a bacterial infection, they can determine whether you need an antibiotic. “Some bacterial infections get better on their own, but that’s rare,” Dr. Price said.

Most of the time, your doctor will prescribe an antibiotic. If that’s the case, it’s essential to take the entire course—even if you feel better, you need to take all of your medication to make sure you clear the infection.

How you can treat viral infections

Viruses cause infections such as colds, flu, COVID-19, chickenpox, measles and warts. Most of the time, there’s no treatment available for viral infections. You can alleviate the symptoms and wait for it to pass. “The best thing to do is to make sure to get good rest, hydration and nutrition,” Dr. Price said. “Fortunately, most viral infections are short-lived because our immune systems are good at fighting off this type of infection.”

For a few different viral infections, treatments are available. You might benefit from medication if you come down with the flu or COVID-19, for example. “Your medical provider can help decide if medicine is needed,” Dr. Price said.

When should you see a doctor?

Dr. Price’s advice is to trust your gut. “You should see a doctor if you are concerned about any infection,” he said. “It is hard to have definite rules about when to see a medical provider because every person is different. One person may get really sick with an infection while another may do just fine.”

That said, there are some symptoms you should have evaluated:

  • Trouble breathing
  • Severe cough
  • Not being able to keep fluids down/dehydration
  • Not waking up or not acting normally
  • Seizure with a fever
  • Fever that lasts for several days
  • Fever of 104 degrees or higher
  • Fever with a rash

How to prevent viral and bacterial infections

“A great way to prevent infections is to wash your hands and stay away from people when they are sick,” Dr. Price said. Wearing a mask when you’re around other people can help prevent the spread of COVID-19 and other viral infections.

“The most important thing that you can do is to make sure you get all the recommended vaccines,” Dr. Price said. “Vaccination is one of the most important lifesaving things we can do.”

The bottom line

Viral and bacterial infections may have similar symptoms, but they need different treatments. A health care professional can evaluate your symptoms and help determine what type of infection you have and what course of treatment might work. If you need evaluation for your symptoms, Banner Health can help you connect with a doctor.

Find out more about viral and bacterial infections with these articles:

Cold and Flu Infectious Disease