Fever is a normal response to infections where there is an increase in body temperature. Elevation of body temperature over 370C would be classified as fever. Fever can be caused due to viruses, bacteria, drugs, chronic illnesses, or tumors.
An increase in temperature stimulates the natural killer cell activity as well as stimulates the activity of macrophages and dendritic cells against pathogenic organisms that have invaded the body. There is also increase in inflammatory molecules like cytokines and nitric oxide. Increase in interferons is also seen that have antiviral and antibacterial effects during fever.
Elevated body temperatures are also useful against bacteria or other viruses that would invade our body. Raised temperatures also prevent this pathogenic organisms from reproducing. It also helps increase white blood cells and help in recognition of pathogens. These responses also work effectively in high temperatures, hence a fever might not be necessarily bad.
According to a study published in the 2004 edition of the Journal of Allergy and Clinical Immunology, children who developed a fever in the first year had lesser cases of allergies in their later childhood than children who did not develop a fever. In another study performed in mice published in 2000 at the Journal of microbiology, it was seen that mice that were feverish had improved survival rate, increased host defenses, and better maintenance of core temperature.
Temperatures ranging from 37.10C -37.8oC are characterized as low-grade fevers. Low-grade fevers are nothing to worry about but if there is discomfort, rashes, vomiting, lethargy, stiff neck seen it is important to contact a doctor.