Both variants cause very similar symptoms, even though the virus is known to mutate rapidly, Yancey said.<\/p>\n
\u201cThe newer variant isn\u2019t more contagious in and of itself,\u201d she added. \u201cIt can spread more easily because fewer people have partial immunity to it, so they will get sick and spread the virus.\u201d<\/p>\n
How travel and the heat may be to blame<\/strong><\/h2>\nAlthough primarily a winter illness, norovirus can spike in the late spring, said Aaron Glatt, chief of infectious diseases at Mount Sinai South Nassau on Long Island, New York.<\/p>\n
And the virus spreads easily between people, he added.<\/p>\n
Like measles, norovirus is one of the most contagious known illnesses, with infected patients spreading the virus to up to seven other people on average, Yancey said.<\/p>\n
Seasonal travel and extreme heat may also be to blame.<\/p>\n
Increased holiday traffic brings large groups into close contact, accelerating viral transmission, while rising temperatures force people indoors, facilitating rapid spread in crowded rooms, said Dr. Scott Roberts, the associate medical director of infection prevention at Yale School of Medicine in Connecticut.<\/p>\n
\u201cI have not seen any evidence of a new strain, but as with all viruses, evolution occurs, and unfortunately, our immunity to norovirus is not long-lasting,\u201d Roberts added.<\/p>\n
How does norovirus spread?<\/strong><\/h2>\n\u201cNorovirus can occur year-round, but in the Northern Hemisphere it is most commonly seen from November through May,\u201d Bidwell said.<\/p>\n
It commonly spreads in settings where many people are clustered together, like cruise ships, through direct contact with a sick person or by touching a contaminated surface and transferring it to the mouth.<\/p>\n
People often get the infection from contaminated food, like when a sick cook prepares food and then serves it to people, or by drinking water that is not adequately treated.<\/p>\n
Those who consume contaminated ready-to-eat cold foods, such as salads and sandwiches, are at higher risk.<\/p>\n
Symptoms of norovirus and treatments to avoid<\/strong><\/h2>\nNorovirus is the most common cause of food poisoning in the U.S.<\/p>\n
Vomiting, diarrhea and stomach cramps usually start 12 to 48 hours after exposure. Some people only complain of diarrhea or vomiting, but a hallmark of norovirus is intense vomiting compared to other stomach bugs.<\/p>\n
It\u2019s possible to test a person\u2019s stool for the virus, but generally doctors diagnose the condition without testing.<\/p>\n
Most healthy adults recover on their own within several days but still can spread the infection for up to two weeks, even after they feel better.<\/p>\n
There is no specific treatment, and antibiotics don\u2019t work since the infection is caused by a virus, not a bacterium.<\/p>\n
Experts recommend oral rehydration fluids rather than sports drinks to replace important nutrients and minerals lost to vomiting and diarrhea \u2014 although drinks like Gatorade may help with mild dehydration.<\/p>\n
But when some get too dehydrated, they may require intravenous fluids to replace what they\u2019ve lost. Vulnerable populations, like young children and older adults, should monitor for warning signs of dehydration, including:<\/p>\n
\n- Decreased urination<\/li>\n
- Dry mouth<\/li>\n
- Feeling dizzy when standing up<\/li>\n
- Crying with minimal tears<\/li>\n<\/ul>\n
To protect against norovirus, avoid raw shellfish (especially oysters) and always wash your hands thoroughly with soap and water. Hand sanitizers are often ineffective against this virus, so clean surfaces using EPA-registered disinfectants specifically labeled to kill it.<\/p>\n<\/div>\n