How do I know if my fever is contagious?


By definition, fever is an increase in body temperature above 38 ° C. It can be caused by an infection as well as by a central regulatory disorder. However, bacterial or viral infections are usually the main causes of fevers.

Fever itself is not contagious, but the pathogen that causes the fever can be passed on to other people.

How do I know if my fever is contagious?

Each illness can have different symptoms, with a fever being just one of many possible. It occurs when the body's own defense cells are activated and trigger an inflammatory reaction. Or if you want to put it another way, fever is nothing more than a reaction of the immune system to kill pathogens. The increase in temperature means above all that the defense process is in full swing and the infection has not yet been sufficiently contained by the body's own cells.
You can only determine it by measuring your body temperature - regardless of whether it is under the tongue or rectally. Sufferers can also use the severity of other existing symptoms to judge how sick they are. The more symptoms there are in an illness in addition to the fever, the higher the risk of infection. However, temperatures falling over days during the recovery process should also be viewed as critical in relation to the ability to work, since even a minimally increased body temperature still indicates an infection that has not completely healed. So in order not to unnecessarily infect his colleagues, the person affected should first return to work without a fever.
Conversely, this also applies to only a slightly increased body temperature at the beginning of an infection. This period of time until the actual outbreak of the disease is perhaps the most dangerous for infection. In the meantime, the invading pathogens multiply in the body and, for example, attack the mucous membranes of the person affected. Until the immune system identifies the pathogen as causing the disease and mobilizes and regenerates cells of the body's own defense system, the person concerned only suffers from subfebrile (= just below the fever limit of 38 ° C) temperatures. So the person concerned may feel a little reduced in performance, but not yet really sick.
For the pathogen, this means optimal conditions for spreading, since contact with other people is usually not yet avoided. The slight feeling of "glowing" or the "inner heat" should therefore be taken just as seriously as real fever in relation to infection.

You might also be interested in this topic: Fever with no other symptoms

Duration of the risk of infection

As already mentioned, strictly speaking, every fever and its associated illness are contagious. But it is not the increase in temperature that is itself contagious. Rather, it is the pathogens that trigger them. This makes the fever a good indicator of the healing process for an infection. If the person concerned is free of fever again and has no further serious complaints, he can no longer be seen as contagious. In contrast, every increase in fever and every stagnant fever must be classified as potentially infectious.
For employees or children who visit public institutions, this means staying away from work or school until a full recovery has occurred. This protects the others from a possible infection and the affected person from a possible deterioration or delay in his healing process. Too early exposure can weaken the immune system. The best assessment parameter here is one's own perception of illness in combination with a progress check of the body temperature. As annoying and uncomfortable as it may seem. If, according to the fever measurement, there is no fever for more than two days, there is no longer any risk of infection.

Also read the article on the topic: How can you lower a fever?

Am I contagious during the incubation period?

The incubation period in particular is a highly contagious phase when a fever occurs accompanied by a sore throat, runny nose, coughing, headache, vomiting or diarrhea. If pathogens enter the body via the mucous membrane, for example, they will find an optimal nutrient medium. As a result, they multiply rapidly. Those affected notice this as decreased performance, drowsiness and slightly increased body temperatures. In themselves, however, they do not yet have a real disease value.
If symptoms such as sneezing or coughing become more pronounced, the pathogens can then simply be transmitted via droplet infection. However, one speaks of a disease only when the mucous membrane becomes visibly inflamed and further symptoms occur. However, the risk of infection is highest during the asymptomatic incubation period. Social contacts are not avoided during you - and that is exactly what makes the risk of infection so great.

How contagious are different types of fever?

How contagious is nettle rash?

Nettle rash is caused by the popularly known "hives". It is a skin disease that can have many causes. However, their physical expression is independent of the cause.The name already suggests that this disease is characterized by wheals and redness on the skin, as they normally occur after contact with a nettle (also: nettle).
They also cause the same symptoms as severe itching and a feeling of heat on the skin. The accompanying fever can be explained by the inflammatory reaction caused by this disease. However, it is usually not contagious. This is based on the fact that the wheals are not caused by pathogens.
Rather, it is factors such as stress, sun exposure or medication that lead to an allergic reaction. The immune system is activated like a normal infection, but it is directed against the consequences of physical stimuli or ingredients and not against components of bacteria or viruses. Thus, no transmission can take place and infection is excluded as long as the person concerned does not suffer from an additional infection.

Read more on the topic: Hives

How contagious is the 3 day fever?

3-day fever is a typical childhood disease that is characterized by a high fever that lasts for three days. With the rapid defrosting on the fourth day, a characteristic rash appears all over the body. The disease is caused by herpes viruses. In itself, infections with herpes viruses are very contagious if there is sufficient physical contact with the person concerned.
However, one must consider that the infection rate in the population with this virus is very high. In principle, a child with a 3-day fever is highly contagious during the fever interval. Theoretically, most parents have already been in contact with the herpes virus and are no longer infected with their sick children. However, kindergartens and schools should not be visited during the illness phase, especially since the high fever makes those affected feel extremely ill.

Read more on the topic: Three days of fever- How contagious is it?

How contagious is dengue fever?

Dengue fever is a tropical disease that has to be taken seriously. It is transmitted to humans by mosquitoes. Person-to-person infection is not common. The only possible infection here is the transmission of infected blood products. There is another way for a person affected to avoid infecting their loved ones with the virus. Nonetheless, the fever is no less dangerous as it can lead to life-threatening symptoms in those affected.
The combination of the high body temperature and the effect of the virus on the blood components usually leads to serious circulatory problems. If you want to protect yourself from the virus, you have to take prophylactic measures. There is no vaccination. The use of anti-mosquito spray and mosquito nets are therefore the only effective measures to prevent illness. Anyone who cares for or wants to visit someone who is sick is advised to pay attention to the environment. On the one hand, mosquito repellent should be applied when staying in endemic areas and, on the other hand, care should be taken not to come into contact with blood products or objects contaminated with blood.

Further information on the subject can be found at: Dengue fever

How contagious is Mediterranean fever?

Mediterranean fever is a genetic disease. It is characterized by repetitive attacks of fever with accompanying symptoms such as joint or muscle pain. Pathogens such as bacteria or viruses play no role here. The cause lies namely in a changed genetic material of the person concerned. Infection is therefore ruled out, since “internal factors” alone lead to a fever.

Read more on the topic: Familial Mediterranean fever

How contagious is rheumatic fever?

Rheumatic fever develops after an infection with streptococci. It is important to know that the rheumatic fever does not arise from a renewed infection with the bacteria, but rather as a reaction to the one that has gone through. The bacteria that previously caused disease are therefore usually not to be found here. Rather, it is the lasting effect of the infection that leads to the fever. Because of the similarity of bacterial components and the body's own characteristics, the body falsely starts an autoimmune reaction. This causes the fever and can also damage the heart valves or the kidneys.
Rhythmic fever is not contagious. Only the underlying infection of the upper respiratory tract by bacteria (streptococci) is contagious. This can be transmitted by a droplet infection or smear infection.

Read more on the topic: Rheumatic fever