Recently, over 300,000 individuals in Taiwan sought medical treatment for diarrhea at outpatient and emergency departments during one week (February 2-8)—the highest numbers in the last ten years. Additionally, over the past month, almost 400 "diarrhea cluster infections" were reported to Taiwan's Centers for Disease Control, setting another record as the highest numbers in a five-year period. Officials at Taiwan's CDC Epidemic Intelligence Center Director explain that almost all of the cluster infections that were tested turned out to be norovirus, and most occurred in the restaurant and hospitality industries (yikes!).
Norovirus is also currently ripping through the United States. There was a massive outbreak of norovirus recently on the Holland America cruise ship the "Rotterdam" that sailed out of Fort Lauderdale, Florida—152 passengers (of 2,614) and 17 crew members (of 989) became ill during the ship's recent voyage. And according to the WastewaterSCAN dashboard, the majority of sites that track norovirus are currently in the "high" category. The CDC also provides some data on norovirus, but wastewater data seems more reliable, because currently, state, local, and territorial health departments are not required to report individual cases to the CDC.
The National Capital Poison Center explains that norovirus can cause nausea, vomiting, cramps, fever, and diarrhea, and can last up to ten days. It's highly contagious and as few as 18 particles can cause infection (compare this to the thousands of viral particles that are necessary to cause influenza!). Norovirus spreads through direct contact with an infected person's vomit or feces—for instance if someone with the virus prepares, handles, or serves food without properly washing their hands after going to the bathroom or cleaning up their vomit. It can also spread indirectly through surfaces—say, for instance, if you touch a doorknob in a bathroom after someone infected with the virus has touched it—where the virus can live up to 50 days. The virus is also spread through aerosolized viral particles that float through the air—so, if you enter a bathroom after someone with the virus has vomited or pooped, you can breathe in their viral particles (this is EXACTLY why I wear a mask in public restrooms). You can also catch norovirus by eating contaminated shellfish, or by eating fresh fruits and vegetables that were grown with irrigation water contaminated with the virus (this is why I always wash my fruits and veggies).
Unfortunately, it's not just norovirus that's out of control right now. WasterwaterSCAN also reports that the majority of SARS-CoV-2, RSV, and Influenza A sites are also in the "high" category. In fact, we're currently in the one of the worst flu seasons in the last two decades. Time reports that at least 24 million people in the U.S. have caught flu so far during this season, and we're nowhere near finished.
More cases of bird flu are popping up in humans, as well, and the CDC recently began recommending more increased subtyping of influenza patients to look for H5N1. And let's not forget that measles is making a comeback (especially among the unvaccinated), along with tuberculosis (which I never imagined I'd be reporting on in 2025, sigh).
Luckily, wearing a mask works against all of these pathogens, so it's always a good idea. Here's a great resource about how to keep yourself and those around you healthy—it provides information about air ventilation, CO2 monitors, masks, nasal sprays, mouthwash, testing and isolation, vaccines, and more.
Be careful out there friends! Mask up, clean your air, and wash your hands—remember, norovirus isn't killed by hand sanitizer, only soap and water!
