With the transition from summer to monsoon around the corner, there will be an upsurge of infections in people caused by bacteria and viruses. The impact of such infections is greater in children than in adults, owing to their developing immunity. It is thus vital to understand the difference between bacterial and viral infections as well as provide the correct treatment to aid recovery.
Happiest Health spoke to experts who explain the differences between bacterial and viral infections, how to prevent them and why antibiotics should not be used to treat a viral infection.
Bacterial infection
A bacterial infection develops slowly before showing symptoms. “It has an insidious onset, where obvious symptoms are not seen initially as it takes time for them to manifest,” says Dr Chetan Rao Vaddepally, pulmonologist, Yashoda Hospitals, Hyderabad.
Symptoms of bacterial and viral infections that overlap include fever, cough and a runny nose, among others. “A runny nose is more common in viral infections, while a persistent cough is usually noticed in bacterial infections,” says Dr Washim Khot, infectious diseases specialist, Global Hospitals, Mumbai. However, cough was a telltale sign of COVID-19 (a viral infection) during the pandemic.
“Even a high-grade fever and yellow or green phlegm can point towards a bacterial infection,” says Dr Khot, cautioning that there is no hard and fast rule for differentiating between a bacterial and viral infection. “Only clinical signs [detected during a doctor’s examination] and lab tests can help differentiate between the two,” he adds.
Viral infection
Each virus has its own pattern of infection, says Dr Khot. “While some of them can cause upper respiratory infections, others can bring about pink eye, diarrhea or just generalised fever.”
Viral infections have a rapid onset and progression of symptoms. “Even if you are totally fine in the morning, you can develop a high-grade fever at night,” explains Dr Vaddepally.
Symptoms of a viral infection include fever, runny nose, sneezing, body aches, cough and headache.
How are bacterial and viral infections transmitted?
Although both bacteria and viruses are airborne, Dr Khot says that the rate of transmission is higher for viruses than for bacteria. “If many people in a household fall sick, chances are it is a viral infection,” he explains.
Viruses can also spread through vectors like mosquitoes, which cause infections like dengue and malaria. “Bacteria from different places (skin, soil, etc.) can enter the mouth through the hands if proper hand hygiene is not maintained,” explains Dr Khot.
Differentiating bacterial and viral infections
Differentiating between bacterial and viral infections, Dr Behram Pardiwalla, internal medicine specialist, Wockhardt Hospitals, Mumbai, explains, “One can recover from a viral flu infection within a week. However, if symptoms like fever and cough persist for a longer period, it can be a sign of bacterial infection.”
A blood test can reveal the type of infection and the parameters that vary with it. “The WBC [white blood cell] count is higher in bacterial infections than in viral infections. Thus, a blood test is vital to understand if an infection is bacterial or viral,” adds Dr Pardiwalla.
Co-infection: When bacteria and viruses attack simultaneously
Bacterial and viral infections tend to occur together at times, which is referred to as co-infection. “If you have a viral upper respiratory tract infection, a bacterial infection might be superimposed, leading to a co-infection,” explains Dr Pardiwalla.
Anupam (name changed), a Hyderabad-based medical college student, presented with unspecific symptoms of gastroenteritis and fever in May 2023. He tested positive for typhoid, a bacterial infection.
However, his condition deteriorated. He was not responding to antibiotics and was admitted to the ICU. His fever persisted, and the WBC count went below normal ranges. Even his platelet count declined. Upon further investigation, he also tested positive for dengue, which is a viral infection. “After we started treating both infections, his condition improved,” mentions Dr Vaddepally, who treated Anupam.
Bacterial vs viral infection: Treatment and prevention
Some basic measures that should be taken (especially during flu season) to prevent both bacterial and viral infections include:
- Maintaining hygiene through social distancing and masking
- Having a healthy diet
- Exercising regularly
- Maintaining immunity through a healthy diet and an active lifestyle
- Getting vaccinated
Vaccines like the pneumococcal vaccine (administered for pneumonia caused by the bacteria Streptococcus pneumoniae) and the yearly influenza vaccine will help in decreasing the incidence and severity of infections, says Dr Vaddepally.
“The major line of treatment for a bacterial infection is administering antibiotics,” says Dr Vaddepally. However, viral infections cannot be treated with antibiotics. It has become a regular practice in most households to take antibiotics for treating any infection without diagnosing its cause, thereby leading to antibiotic resistance, he adds.
“Misuse of over-the-counter antibiotics is leading to the development of resistance in bacteria, making it difficult to treat upper respiratory tract infections with the antibiotics available. This is referred to as antibiotic resistance. Thus, it is vital to consult your physician and treat the condition accordingly,” says Dr Vaddepally.
“To manage fever and cold during a viral infection, put a cold towel over your head to manage the temperature and consult a doctor. Ensure adequate hydration and do not take antibiotics on your own,” advises Dr Pardiwalla.
Takeaways
- Symptoms of a viral infection manifest rapidly, while those of a bacterial infection have a slow progression. However, the symptoms can sometimes overlap.
- Certain symptoms persisting for a longer period can indicate a bacterial infection, as those of a viral infection usually subside within a week.
- Antibiotics should not be used to treat any infection without knowing its cause, as it leads to the development of antibiotic resistance.
