Gastroenteritis in Norwegian primary care - Time trends and a large waterborne outbreak

Abstract

Gastroenteritis is a common term for acute infection of the gastrointestinal tract and includes several conditions and specific infections. Gastroenteritis has to a great extent caused disease and death in humans through our history. Even the very foundation of epidemiology can be traced back to John Snow's work on identifying drinking water as source of the cholera epidemic in London in 1854. Gastroenteritis still occurs frequently in the community, but most people in our part of the world experience self-limiting symptoms and therefore only a small proportion seek the health care services. Of those seeking medical attention, only a few submit stool samples for microbiological diagnostics, and only those who are diagnosed with a notifiable microbe are included in the statistics of the notification systems of infectious diseases. The clinical features of gastroenteritis vary from asymptomatic cases to fatal disease, but diarrhea is common in cases who develop symptoms.

The clinical features in the individual gastroenteritis patient can give a hint as to whether there is a viral or bacterial cause. Correspondingly, using existing knowledge about seasonal variation and the epidemiology of the specific infections may give an indication of probable microbiological cause in gastroenteritis patients at group level. This is useful knowledge because laboratory verified diagnoses are rare. Our study of consultations for gastroenteritis in Norwegian primary care during a 10-year period shows a contact pattern similar to what characterizes viral gastroenteritis: Most consultations took place in the winter and children and young adults dominated among the patients. The findings contribute to increased knowledge of the normal situation regarding gastroenteritis patients’ use of health care services.

Since antibiotics became widely available in the years following World War II, antibiotic treatment has been central to the treatment of many infectious diseases. Gastroenteritis has been an exception, both because most are viral and because antibiotics only to a small extent have been shown to shorten the course of the disease and relieve symptoms also in most bacterial gastroenteritis. Antimicrobial resistance in bacteria causing gastroenteritis represent a growing concern in a European and global context, although the current situation in Norway is more favorable. Transmission between animals and humans, either directly or indirectly via food, makes resistance in zoonoses and food-borne microbes particularly challenging. Our study of antibiotic use in gastroenteritis in the Norwegian primary health care service over a 10-year period shows that antibiotics are rarely used compared with other countries. Further, there has been an even more favorable development after 2012 with a decrease in the use of resistance-driving antibiotics such as fluoroquinolones and macrolides.

Gastroenteritis tends to appear as outbreaks of various magnitude and public health importance. The outbreaks occur and spread either via direct contact between humans, directly between humans and animals, or as food-borne outbreaks where the microbe spreads to humans via food or drinking water. Gastroenteritis caused by the foodborne infection campylobacteriosis is an example of the latter, and in June 2019, more than 1 500 in the community became acutely ill during a major waterborne outbreak of Campylobacter infection in Askøy. Our population-based study of acute gastroenteritis during the outbreak shows a broader spectrum of symptoms, with less bloody stools and more tiredness and joint pain than previously described in laboratory-verified sporadic cases of Campylobacter infection. The study sheds light on the cases of gastroenteritis that occur in the interface between how they appear in the community, in the health care services, in the notification systems, and not least in the research literature.