Bacterial Versus Viral Infections: Know The Differences

Distinguishing viral from bacterial infection can be difficult clinically, especially in the initial stages of infection. This may explain why patients are sometimes started on antibiotics while waiting for laboratory test results.

The Indian Medical Association recently directed doctors to not prescribe antibiotics unnecessarily in the wake of surging flu cases in the country. The fundamental reason behind this call is to fight antibiotic resistance which mostly happens due to the overuse of these drugs. Antibiotics are drugs primarily used to treat bacterial infections and are ineffective at treating illnesses caused by other microbes such as viruses and fungi. Sometimes the distinction between infections caused by bacteria and viruses is not very obvious clinically and this can sometimes lead to antibiotic misuse.

Both viruses and bacteria are disease-causing microbes. They differ from each other on many grounds such as shape, size, structure and methods of reproduction. Clinically, the two are difficult to separate and your doctor might do the diagnosis on basis of your symptoms.

Bacterial versus viral infections

Viruses are microorganisms that are made up of genetic material and a protein coat. When they enter a human body, they become alive, start replicating and gradually take over the body. Bacteria, on the other hand, are large microorganisms that don't necessarily need a host to reproduce. They can survive in many environments and already does exist inside our system. Some bacteria cause sickness in humans and are also known to secrete toxins that can damage body cells. Diseases like food poisoning and pneumonia are often caused by bacteria whereas most common colds, COVID-19, flu and others are mostly caused by viruses.

Sometimes, distinguishing viral from bacterial infection can be difficult clinically, especially in the initial stages of infection. This may explain why patients are sometimes started on antibiotics while waiting for laboratory test results.

In some circumstances, antibiotics are appropriate when the viral infection compromises your immune response and this allows harmful bacteria to attack your body easily. Sometimes what starts off as a viral infection can also develop secondary, co-bacterial infection. So, your attending doctor usually gives you an antibiotic to treat these secondary bacterial infections and not a viral infection.

Differences in the symptoms

The differences between a bacterial infection and a viral infection can be understood in terms of symptoms and how an infected person might respond to some medicines. Mostly in a bacterial infection, symptoms can last longer than 10-14 days, and fever can become exceptionally high and usually gets worse with time. On the contrary, in a viral infection, the body's response gets better with antiviral drugs, fever is not very high and usually eases with time.