Most people erroneously call it “stomach flu” and think of it as an unpleasant nuisance, but the vomiting and diarrhea caused by inflammation of the stomach and intestines — gastroenteritis – can be lethal, and appears to be growing deadlier.
The number of people of all ages who died from gastroenteritis more than doubled from 1999 to 2007 in the United States, according to the Centers for Disease Control and Prevention (CDC), and most of the deaths from infectious causes can be attributed to two stomach bugs — Clostridium difficile and norovirus.
While C. diff continues to be the leading cause of deaths from gastroenteritis here and throughout the world, a new study shows for the first time that norovirus is likely the second leading infectious cause of gastroenteritis deaths.
The analysis, presented by the CDC Wednesday at the International Conference on Emerging Infectious Diseases in Atlanta, used data from the National Center for Health Statistics.
Over the eight-year study period, the CDC said, gastroenteritis-associated deaths from all causes ballooned from nearly 7,000 to more than 17,000 per year.
Adults over 65 years old accounted for 83 percent of those deaths.
Norovirus was associated with about 800 deaths annually, though the CDC said there were 50 percent more deaths in years when epidemics were caused by new strains of the virus. Norovirus fatalities are often a result of severe dehydration.
Norovirus is the leading cause of gastroenteritis in the U.S., and about half of all food poisoning cases are caused by norovirus. Highly contagious, it spreads through person-to-person contact and through food, water and surfaces contaminated with vomit or feces. Although people can get norovirus illness throughout the year, the incidence generally peaks from December through February.
Norovirus is said to cause about 70,000 hospitalizations each year in the U.S.
People infected with norovirus are contagious as soon as they feel ill and can remain contagious for about three days and up to two weeks after they recover, the CDC says. So far there is no specific vaccine or treatment, but a nasal spray vaccine is being tested and at least one other vaccine and an antiviral medication are in development.
Cooking foods — especially oysters and other shellfish — and carefully washing fruits and vegetables to be eaten raw, cleaning and disinfecting kitchen and bathroom surfaces and frequent hand washing are the basic ways to prevent the spread of norovirus.
Exposure to Clostridium difficile (bacteria often referred to as C. diff) occurs most often in hospitals and other health care settings, although a recent CDC report said that overall, health care associated infection levels have actually fallen as the medical profession has worked to prevent the bacterium’s spread.
Nevertheless, there has been a fivefold increase in deaths from C. diff, from approximately 2,700 to 14,500 per year. Much of the recent increase in the incidence and mortality of C. difficile is attributed to the emergence and spread of a hypervirulent, resistant strain known as North American pulse-field type 1 (NAP1), according to the CDC.
About one-quarter of C. diff cases are linked to hospitals, but in the other 75 percent the symptoms first surfaced in nursing home patients or people who recently had received care at a doctor’s office or clinic. Often those stricken have been taking antibiotics.
To reduce C. diff infections, the CDC recommends prescribing and using antibiotics carefully; isolating infected patients; using gloves and gowns, even when performing routine care; using bleach or other spore-killing products to clean surfaces; and notifying other facilities when sick patients are transferred.
People who seek medical treatment because of profuse diarrhea and vomiting are sometimes told they have gastroenteritis and sent home. The way to determine if the symptoms are caused by norovirus, C. diff., Shiga-toxin producing E. coli, Salmonella, Shigella, Campylobacter, Staphylococcus and other bugs is through a stool anaylsis.
Because gastroenteritis is a major cause of death, “by knowing the causes of gastroenteritis-associated deaths and who’s at risk, we can develop better treatments and help health care providers prevent people from getting sick,” noted Dr. Aron Hall, DVM, MSPH, the CDC’s lead author of the gastroenteritis study.