Bacterial and viral infections: what is the difference?

If you look at statistics, infections are the most common reason for seeking medical attention. Can be caused by a variety of pathogens: viruses, bacteria, fungus, etc. Viruses and bacteria can cause clinically similar infections but require different treatment. How bacterial and viral infections differ?

Basics of Microbiology

Bacteria are single-celled microorganisms that are strikingly diverse. They have many forms and characteristics, some of them are capable of surviving in unthinkable conditions.

The human microbiome has hundreds of species of bacteria and each performs certain functions, such as inhibiting the growth of pathogenic microorganisms, supporting metabolic processes and much more. Only 1% of bacteria are known to cause disease.

Viruses, even less than bacteria, need the host cells for normal functioning, where they can live and grow. Some viruses can destroy the cells where they develop.

Modes of transmission

There are many similarities in the ways infections are transmitted. The main route of transmission is from person to person through close contact, such as kissing.

Contact with human bodily fluids, e.g. during sexual intercourse, coughing and sneezing. Not only viral infections, such as HIV, SARS, and the new coronavirus infection, but also bacterial infections are transmitted this way. Some viruses and bacteria are transmitted by contact with contaminated surfaces, where viruses and bacteria live in biological media. Another possible route of transmission is through animal and insect bites.

Clinical picture

Viruses and bacteria cause similar illnesses in terms of symptoms: fever, runny nose, cough, headache, weakness and reduced performance. But upon closer examination and study, you will find a lot of differences that only a doctor would notice.

Viral infections are more common, so when symptoms appear, it is often assumed. The following differences and criteria help to differentiate one from the other:

• The incubation period for viruses is shorter than for bacteria. For example, bacterial infections – symptoms appear 7-10-14 days after infection, and sometimes more. Viral infections appear 1-5 days after infection.
• The clinical picture of viral infections is clearer, with all the characteristic symptoms appearing literally at once or a short period of time between their appearance. If we talk about bacterial infections, they develop more slowly, but with a full set of symptoms.

Viral infections can affect a healthy person, but bacterial infections develop against a background of weakened immunity or are a complication of a past illness.

Of course, the main difference is the ways and methods of specific treatment. Antibiotics have no effect on viruses, and antivirals on bacteria.

Peculiarities of diagnostics

In medicine there is such a concept as differential diagnosis – diagnostic methods that help to distinguish one disease from another with a similar clinical picture. Bacterial and viral infections can cause respiratory diseases, and to determine the cause, conduct a differential diagnosis – analysis of symptoms.

For example, nasal discharge in viral infections are liquid, transparent, often serous in nature. But with bacterial – thick, may have a yellow or green tint, which indicates the presence of a purulent process.

The body’s natural response to viral or bacterial infections is an increase in body temperature. With viral infections, the fever rises quickly and rapidly, and can last for several days. With bacterial infections, it rises gradually and the onset is difficult to track.

With viral infections, it is difficult to distinguish the affected area. Patients notice that everything hurts: throat, chest, muscles, head. However, with bacterial infections it is easy to identify the affected area: sore throat with angina, chest pain with bronchitis, pain during urination with cystitis, etc.

The duration of the disease also varies. For example, with viral infections, improvement comes on the 5th-7th day of the disease, but bacterial infections last longer.

Diagnostic features

In most cases, it is possible to make a preliminary diagnosis based on complaints, external and instrumental examination. Some viral and bacterial infections have very specific symptoms. When making a diagnosis, data on the epidemiological situation is also taken into account.

Still, more often with bacterial infections, additional testing methods are needed, including laboratory. In accordance with this, the doctor necessarily prescribes the following tests:

• general blood analysis;
• Examination of mucus, sputum secreted, other secretions and smears;
• analysis of urine, stool;
• skin scrapings;
• Study of cerebrospinal fluid in severe disease.

In bacterial infections, such studies are carried out to determine the type of pathogen, as well as its antibiotic sensitivity.

Features of treatment

Viral and bacterial infections are completely different diagnoses with specific clinical course as well as treatment. And, if there is a mistake in prescribing treatment, the likelihood of complications increases, the development of the underlying disease. Sometimes it poses a health and life threatening.

Treatment of bacterial infections

Antibiotics are a group of drugs prescribed exclusively for the treatment of bacterial infections. There are different types of antibiotics that specifically target bacteria of a certain class or broad spectrum. Broad spectrum antibiotics may be prescribed for acute illnesses with a serious and rapid course, and after the results of antibiotic sensitivity testing have been obtained, highly specialized drugs may be prescribed.

Uncontrolled, unreasonable taking of antibiotics, when the patient stops taking them early, this can lead to the formation of antibiotic-resistant flora and later treatment will be ineffective.

Treatment of viral infections

For many viral infections, there is no specific treatment. Symptomatic treatment is usually developed, aimed at eliminating symptoms, lowering fever. Still, treatment is determined by the specific virus and the disease it provoked.

For viral infections, the doctor prescribes antiviral drugs that inhibit the life cycle of some viruses.

Most importantly, it is worth remembering that some serious bacterial and viral infections can be prevented by vaccination.