Differences between Bacterial Fever and Viral Fever

A fever is a normal response by the body’s immune system, although a very high fever can become a serious health problem in and of itself. For this reason, it is important to monitor fevers in sick people, determine their causes, and treat them when necessary. The fever may be caused either by a bacterial infection or a viral infection. The difference between a bacterial fever and a viral fever is that bacterial fevers are usually higher and last longer. There are also differences in treatment: bacteria can be treated with antibiotics, but usually there is nothing to do in the case of a viral infection except to relieve symptoms and wait for the body’s immune system to take care of it on its own.

Fever is defined as a body temperature rising above the normal range of 97.7-99.5 degrees Fahrenheit, or 36.5-37.5 degrees Celsius in countries which use the metric system. Whether it is a bacterial fever or a viral fever, the person suffering the fever will usually feel quite cold, until the fever breaks and body temperature begins to decline back to normal, at which point they will feel hot. People suffering from fevers of any source may also experience depression, fatigue, and confusion, depending on its severity.

According to Dr. Betty Staples of Duke Health, viral fevers can be caused by infections like the common cold and influenza. Viral fevers tend to be “low-grade,” and usually resolve quite quickly, in a matter of days. In most cases, it is not possible to directly treat viral infections directly, but severe symptoms, including fevers, can be relieved with medication. Medications which reduce fever are called antipyretics. Over-the-counter pain relief medications, like ibuprofen (Advil), aspirin, and paracetamol or acetaminophen (Tylenol), have antipyretic effects.

In contrast, a bacterial fever is caused by a bacterial infection like strep throat, urinary tract infections, pneumonia, ear infections, or emergency conditions like sepsis and bacterial meningitis. Dr. Staples says that bacterial fevers can be higher-grade than viral fevers, and also tend to last longer – as long as 10 days to 2 weeks. Bacterial infections can be diagnosed by tests, and then treated using antibiotics. It is important to complete the full course of any prescribed antibiotics to ensure the infection is eradicated and reduce the possibility of drug resistance.

If you have a fever which lasts more than a brief period of time, or is particularly severe, you should report it to your doctor. Doctors will also assess additional aspects of the fever, such as whether the increased temperature is constant or fluctuates. If an infant or young child has a fever, monitor them carefully, give plenty of fluids, and be careful not to cover them with too many blankets or heavy clothing. Seek immediate medical attention if the fever is accompanied by a seizure, or if your baby is less than 2 months old.