Gastrointestinal flu: incubation period
The incubation period describes the duration between infection with an infectious disease and the appearance of the first symptoms.
On average, it takes between one and seven days for the first symptoms of gastroenteritis to appear after infection. With some pathogens, however, the first symptoms can appear within a few hours. With others, it can take weeks before the infected person notices anything.
The incubation period for an infection with common manganese influenza pathogens is approximately:
- Norovirus: six to 50 hours
- Rotavirus: one to three days
- Salmonella: six to 72 hours (depending on the amount of salmonella ingested)
- EHEC: two to ten days (three to four days on average)
- Campylobacter: two to five days
- Shigella (bacterial dysentery): twelve to 96 hours
- Entamoeba histolytica (amoebic dysentery): between three days and seven days, in some cases longer
- Food poisoning: one to three hours (Staphylococcus aureus), seven to 15 hours (Clostridium perfringens)
Gastroenteritis: duration of symptoms
Diarrhea that lasts longer than three weeks is what doctors call chronic diarrhea. It can occur, for example, in patients with immune deficiency: The impaired body defense can significantly prolong the duration of gastroenteritis. It is also possible for diarrhea to last for weeks or even months if parasites such as amoebae and lamblia cause the gastroenteritis.
How long the symptoms ultimately persist depends – like the incubation period – mainly on the pathogen in question. If salmonellae are the triggers, the gastrointestinal infection usually lasts only a few days.
A typical viral gastrointestinal flu is also often severe, but lasts only a relatively short time. Three days after the onset of a norovirus or rotavirus infection, digestion has usually returned to normal.
A gastrointestinal flu caused by Cambylobacter usually lasts somewhat longer: the duration of the symptoms here is usually four to five days. Occasionally, however, it can take up to two weeks for the patient to get back on his or her feet.
Gastroenteritis: How long is one contagious?
Even after the symptoms have subsided, those affected continue to excrete the causative germs in their stool for some time. As a result, there is still a risk of infection for several days, sometimes even weeks, after the perceived recovery:
- Noroviruses can still be measured in the stool one to two weeks after recovery.
- EHEC can be detected for up to three weeks,
- Shigella and Campylobacter even up to four weeks.
As long as pathogens are present in the stool, it is potentially possible to become infected. However, the probability of this decreases the longer the patient subjectively feels healthy again. In the acute phase of a gastrointestinal flu, the pathogen load in the body is at its highest and thus also the amount that the affected person excretes in the stool. As the immune system fights the pathogens, they steadily decrease, and so does the risk of infection.
Special case of persistent excretors
Persistent excretors are people who continue to excrete bacteria or viruses for more than ten weeks, even though they have long since ceased to show symptoms. Those affected are often unaware of this and therefore represent a permanent risk of infection for other people. This condition can be temporary (temporary permanent excretor), but can also remain lifelong (permanent excretor).
However, the probability of becoming a permanent excretor after a bout of gastroenteritis is low. For some pathogens, however, a certain residual risk remains: in the case of salmonellosis, for example, about one to four percent of those who fall ill become symptomless permanent excretors. Age appears to be a negative factor here. This means that older people are more likely to become permanent excretors than younger people.
