Virus Causing Vomiting Spreads Across Much of the U.S.: What You Need to Know
· Telemundo McAllen (KTLM)
While flu season may largely be behind us, an unpleasant and highly contagious stomach virus is on the rise. In recent weeks, hikers in Southern California have been affected by norovirus, according to the Pacific Crest Trail Association. Outdoor enthusiasts along this iconic trail are not the only ones suffering. Recent wastewater surveillance reveals a rising trend of 'high' levels of norovirus across much of the country, with rates currently increasing in the Northeast. Between August 1 and May 7, the CDC's NoroSTAT program recorded 1,194 outbreaks, compared to 2,534 during the same period last year, a figure that aligns with historical averages. 'Nationally, norovirus remains in the HIGH category due to elevated concentrations detected in the last 21 days,' said Amanda Bidwell, scientific programs manager at WastewaterSCAN, an academic program from Stanford University in collaboration with Emory University. Often referred to as the 'winter vomiting bug,' norovirus outbreaks can persist into late spring, Bidwell explained. Wastewater data also highlight a norovirus outbreak in the San Francisco Bay Area, although national figures remain within the usual average for this time of year, noted Dr. Linda Yancey, an infectious disease specialist at Memorial Hermann in the Houston area. 'There is nothing unusual about this particular outbreak in California,' Yancey added. 'They just had bad luck.' According to the CDC, national levels are not 'unusually high' compared to previous seasons; however, the agency's tracking system relies on confirmed cases reported by state agencies, meaning it may not capture a significant number of cases of the illness. 'Wastewater surveillance is very useful for this highly contagious virus, as there is not much clinical data to characterize outbreaks since most people recover at home without needing to see a healthcare professional,' Bidwell stated. Currently, several strains of norovirus are circulating, including GII.4—a common strain that has been around for years—and GII.17, a more mutated strain that partially evades previously acquired immunity, as the population has not been exposed to it as frequently, Yancey explained. During the 2024-25 season, the GII.17 variant surpassed GII.4 as the predominant strain in the U.S., causing approximately 75% of outbreaks. Both variants cause very similar symptoms, although the virus is known to mutate rapidly, Yancey noted. 'The newest variant is not inherently more contagious,' she added. 'It may spread more easily because fewer people have partial immunity to it; thus, more will get sick and transmit the virus.' Seasonal travel and extreme heat could be responsible. Although primarily a winter illness, norovirus cases can see a spike in late spring, said Aaron Glatt, chief of infectious diseases at Mount Sinai South Nassau in Long Island, New York. Additionally, the virus spreads easily among people, he added. Like measles, norovirus is one of the most contagious diseases known; infected patients can transmit the virus to an average of up to seven other people, Yancey indicated. Seasonal travel and extreme heat could be contributing factors. Increased traffic during holidays brings large groups of people into close contact, accelerating viral transmission; meanwhile, rising temperatures force people indoors, facilitating rapid spread in crowded spaces, said Dr. Scott Roberts, associate medical director of infection prevention at Yale School of Medicine in Connecticut. 'I haven't seen any evidence of a new strain; however, as with all viruses, evolution occurs, and unfortunately, our immunity to norovirus is not long-lasting,' Roberts added. How does norovirus spread? 'Norovirus can occur at any time of the year, but in the Northern Hemisphere, it is most commonly seen between November and May,' Bidwell noted. It typically spreads in environments where many people gather—such as cruise ships—either through direct contact with an ill person or by touching a contaminated surface and then bringing hands to the mouth. Often, people contract the infection through contaminated food—for example, when an ill cook prepares food and then serves it to diners—or by drinking untreated water. Those who consume ready-to-eat cold foods that are contaminated—such as salads and sandwiches—are at greater risk. Symptoms of norovirus and treatments to avoid. Norovirus is the most common cause of foodborne illness in the United States. Symptoms—vomiting, diarrhea, and stomach cramps—usually appear between 12 and 48 hours after exposure to the virus. Some people may only experience diarrhea or vomiting; however, a distinguishing feature of norovirus is the intensity of vomiting compared to other stomach viruses. The virus can be detected through a stool sample; however, doctors typically diagnose the condition without laboratory testing. Most healthy adults recover on their own within a few days, although they can continue to transmit the infection for up to two weeks, even after feeling better. There is no specific treatment for norovirus, and antibiotics are ineffective, as the infection is caused by a virus and not by bacteria. Experts recommend consuming oral rehydration solutions—rather than sports drinks—to replenish essential nutrients and minerals lost due to vomiting and diarrhea; however, drinks like Gatorade can be helpful in cases of mild dehydration. However, when dehydration becomes severe, the patient may require intravenous fluids to replenish lost volume. Vulnerable populations, such as young children and the elderly, should watch for warning signs of dehydration, including: decreased urination, dry mouth, dizziness when standing, and crying with few tears. To protect against norovirus, avoid consuming raw shellfish (especially oysters) and always wash hands thoroughly with soap and water. Hand sanitizers are often ineffective against this virus; therefore, clean surfaces using EPA-registered disinfectants specifically labeled to eliminate it. This article was originally published in English by NBC News.
AI summary · Source: Telemundo McAllen (KTLM) →
