Noroviruses May Boost Stomach Flu

Battled a bout with stomach flu in the last year? You're not alone. The CDC says reported cases of stomach flu are on the rise, possibly because of two new stomach bugs.

Stomach flu is often caused by viruses called noroviruses, which can spread through food, from person to person, or via contaminated surfaces.

Last October, the CDC started hearing from state health departments about a perceived increase in outbreaks of stomach flu, which doctors call acute gastroenteritis.

The CDC investigated and found that there was a "widespread increased frequency of norovirus-like illness outbreaks" from October 2006 through June 2007. That's right about the time that two new strains of norovirus emerged. Those strains are called Minerva and Laurens.

Are Minerva and Laurens to blame for the rise in stomach flu? The CDC says that's definitely a possibility, but health officials don't test every case of stomach flu to identify its cause.

CDC data show that 24 states together reported 1,316 cases of stomach flu from October 2006 to December 2006. That's an increase of at least 18% over the same period in 2005.

Many of those patients lived in nursing homes. Nationwide, 19 patients in long-term care or other health care facilities died of stomach flu during 2006, according to the CDC.

The CDC doesn't hear about every case of stomach flu, so those numbers may be on the low side.

Tips to Prevent Norovirus Infection

The norovirus report, published today in the CDC's "Morbidity and Mortality Report," includes these tips for preventing norovirus infection:

The CDC also recommends that nursing homes and other health care facilities keep patients with stomach flu — and staff who work with those patients — temporarily away from others in the facility.

By Miranda Hitti
Reviewed by Louise Chang, M.D.
© 2007, WebMD Inc. All rights reserved