Gastroenteritis: Incubation period
The incubation period describes the time between infection with a disease and the appearance of the first symptoms. The incubation period for gastroenteritis is usually very short (a few hours). For some pathogens, however, it can last for days or weeks. Usually the gastrointestinal flu incubation period is between one and seven days, but a different period is typical for each pathogen:
- Norovirus and rotavirus: ten to 50 hours
- Salmonella: five to 72 hours (depending on the amount of salmonella absorbed)
- EHEC: usually three to four days
- Campylobacter: two to five days
- Shigella (bacterial dysentery): one to four days
- Entamoeba histolytica (amoebic dysentery): one to four weeks
- Food poisoning: one to six hours (Staphylococcus aureus), eight to 16 hours (Clostridium perfringens)
Gastroenteritis: duration of symptoms
The typical symptom of gastroenteritis is diarrhea with vomiting. The vomiting usually starts before the diarrhoea and subsides after one or two days. Diarrhoea, on the other hand, lasts longer, usually between two and ten days. Diarrhoea that lasts longer than three weeks is called chronic diarrhoea. It can occur, for example, in patients with an immune deficiency: The impaired body defences can considerably prolong the duration of gastroenteritis. Diarrhoea lasting for weeks or even months is also possible with a gastrointestinal infection caused by parasites such as amoebas and lamblia.
How long the symptoms ultimately persist depends – like the incubation period – on the respective pathogen. If salmonella is the trigger, the duration of the gastrointestinal infection is usually only a few days. A typical viral gastro-enteritis is also often severe, but lasts only for a relatively short time. Three days after the beginning of a noro- or rotavirus infection, digestion usually returns to normal. A gastro-intestinal flu caused by Cambylobacter usually lasts a little longer: the symptoms usually last four to five days, but occasionally up to two weeks.
Gastroenteritis: How long is it contagious?
As soon as someone is infected with the pathogens of a stomach flu, they are also contagious for others. This means that it can transmit the disease even before the first symptoms appear, i.e. during the incubation period. Those affected by gastro-enteritis do not know at this stage that they are already ill.
Even after the signs of the disease have subsided, those affected still excrete the causative germs with their stool for some time. As a result, there is still a risk of infection a few days, sometimes even weeks after the perceived recovery:
- Noroviruses can still be measured in 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 there are pathogens in the stool, infection is potentially possible, but the longer the patient subjectively feels healthy again, the less likely it is. In the acute phase of a gastroenteritis, the pathogen load in the body is at its highest and thus also the amount that is excreted with the stool. By fighting through the immune system, the pathogens become fewer and fewer and thus the risk of infection decreases.
Especially with highly infectious pathogens such as the Norovirus, however, special attention should still be paid to hygiene after each visit to the toilet, at least a few days after recovery. This not only reduces the risk of infecting other people, but also reduces the risk of reinfecting yourself.
Special case of permanent eliminators
Permanent eliminators are people who still eliminate bacteria or viruses after more than ten weeks, even though they have long since stopped showing symptoms. Those affected often know nothing about it and therefore represent a permanent risk of infection for other people. This condition can be temporary (temporary “permanent” eliminator), but it can also persist for life (permanent eliminator).
However, the probability of becoming a permanent eliminator after a stomach flu is low. With some pathogens, however, a certain residual risk always remains: In salmonellosis, for example, about one to four percent of those affected become symptomless permanent eliminators. Age seems to be a negative factor, i.e. older people are more likely to become permanent dropouts than younger ones. Antibiotics can be used as therapy for bacteria.
A well-known permanent eliminator in the history of medicine was Mary Mallon. The Irish-American cook is said to have infected more than 50 people with typhoid fever at the beginning of the 20th century and was therefore also called “Typhoid Mary” by the press. But this fate is one that very few people with gastroenteritis share: the duration of the illness is usually short.