Noroviruses Cause 1 in 5 Cases of Acute Gastroenteritis
Prevalence proves the need for vaccines, study says
Noroviruses are a leading cause of acute gastroenteritis across all age groups, responsible for almost a fifth (18%) of all cases worldwide. The new estimates, published in The Lancet Infectious Diseases, highlight the importance of developing norovirus vaccines, say the authors.
"Including data from 48 countries and involving more than 187,000 gastroenteritis cases worldwide, these new estimates are the largest analysis of norovirus infection and disease to date. There has been a proliferation of research on norovirus globally in the last five years, and we harnessed that data for this study," says lead author Dr. Benjamin Lopman of the Centers for Disease Control and Prevention.
"Norovirus spreads from person to person and through contaminated food or water and contact with contaminated surfaces. The virus is so contagious that as few as 18 viral particles may be enough to infect a healthy person, while more than a billion viruses can be found in a single gram of an infected person's stool. Currently, there is no vaccine or treatment for norovirus."
Lopman and colleagues analyzed 175 published reports to compile data on the prevalence of norovirus in individuals with acute gastroenteritis between 1990 and 2014. They found that norovirus tended to be more common in cases of acute gastroenteritis in the community (24%) and outpatient settings (20%) than in emergency department visits and hospitalizations (17%), supporting the notion that norovirus is a more common cause of mild disease. However, because of its sheer frequency, norovirus causes a substantial amount of severe disease.
Norovirus was also found in a considerable proportion of cases of acute gastroenteritis in both developing countries (14–19%) and developed countries (20%). "This highlights that norovirus, unlike bacterial and parasitic pathogens, cannot be controlled just by improved water and sanitation," explains Lopman.
"Our findings show that norovirus infection contributes substantially to the global burden of acute gastroenteritis, causing both severe and mild cases and across all age groups,” he concludes. “Diarrhea remains one of the leading causes of death of children in developing regions of the world. We have much to learn about norovirus in those settings, and how it can best be controlled."
Source: The Lancet Infectious Diseases; June 27, 2014.