Incubation period | Three-day fever – is that dangerous?

Incubation period

The time between the virus entering the body and the onset of the first symptoms of three-day fever can be 5-15 days. During this time the virus tries to multiply itself by invading a body cell. It does this by infiltrating its own genetic material into the genetic material of the human body cell (host cell).

The virus first attacks the salivary gland cells. It multiplies in these cells and can then enter the entire body via the blood.If so many viruses have been created in this way that a certain threshold is exceeded, the body reacts to this and the symptoms of the disease appear. The incubation period comes to an end when the first symptoms appear. An infection can occur in the last three days of the incubation period, but also until the rash disappears.

Pathogen

Three-day fever is usually caused by Human Herpesvirus 6 (HHV6) and in rare cases by Human Herpesvirus 7 (HHV7). In the case of three-day fever caused by human herpes virus 7, the occurrence of febrile convulsions is more frequently observed. After absorption of the virus into the body via droplet infection, it takes about 5-10 days before the disease breaks out in the child (incubation period).

At first the child gets high fever with temperatures up to 40°C, which lasts for 3 to 5 days. During this time the child feels exhausted and very ill, it can appear nervous and irritable. In this phase of the disease, febrile convulsions may occur; headaches, coughing, and swelling of the cervical lymph nodes may also occur.

Further, inflammation of the mucous membranes (enanthema), swelling of the eyelids (lid edema) or inflammation of the intestines (enteritis) with abdominal pain are not uncommon side effects in children. In very rare cases, a severe course of the three-day fever can lead to pneumonia in the child (pneumonia), and even more rarely to inflammation of the brain (encephalitis). After up to a week, the high fever often ends abruptly and shortly afterwards (“subito”) a skin rash (exanthema) appears consisting of small red spots, which can sometimes “converge” to form larger spots.

As a rule, this non-itching rash mainly affects the trunk and the arms and legs (extremities), while the face is usually left out. Once the rash has appeared, the child is no longer considered contagious. After 1-3 days, the rash usually disappears with a three-day fever.

The disease is then over and the child is healthy again. When children are sick, many complaints project themselves into the abdomen and the children complain of abdominal pain. This can also be caused as an unspecific immune response of the body by a swelling of the lymph nodes in the abdomen.

In the case of three-day fever, abdominal pain may ultimately also occur. In some cases the children also suffer from diarrhoea. However, the symptoms subside of their own accord after a few days.

In the course of the three-day fever, there may also be irritation in the throat area. This then naturally provokes a cough. If the fever persists longer and the cough is increasingly productive with sputum, further clarification of the possible causes, such as pneumonia in the child, should be carried out. In the case of three-day fever, however, the children will be well again within a few days.