<figure id="attachment_416312" class="wp-caption alignnone" style="width: 1024px;" aria-describedby="caption-attachment-416312"><a href="#" data-ident_hash="01d8ff00"><img src="https://res.cloudinary.com/fridaydigital/image/private/t_article_image/wpmedia/2025/03/b295e41dc2f1e46a27aabaf37894cbc0.jpg" alt=""></a><figcaption id="caption-attachment-416312" class="wp-caption-text">Last summer, a group infection of norovirus occurred during river activities.</figcaption></figure>
<h2>Infectivity is at its strongest level ever</h2>
Norovirus is raging.
Group infections are occurring one after another nationwide, and in Toyama Prefecture, a &#8220;Norovirus Food Poisoning Alert&#8221; was issued for the first time in 13 years. On social media, terms like family wiped out, three days of being best friends with the toilet, and the hellish stomach flu relay are appearing, indicating that the situation is worsening.
&#8220;Norovirus is a highly infectious virus that can spread with just 10 to 100 virus particles,&#8221; warns Dr. Hirokatsu Kinoshita (57), Chairman of Azabu Juban Jaguar Clinic.
&#8220;When one person in a household gets infected, it&#8217;s like passing the baton, starting a stomach flu relay. The infection is so strong that family members fall ill one after another. A typical case starts with sudden severe abdominal pain and vomiting, followed by repeated diarrhea.
Due to dehydration, the body becomes severely weakened, so frequent hydration is necessary, and symptomatic treatment is provided for nausea and fever. While adults often recover in a few days, during that time, it’s truly hell. For children and the elderly, dehydration can lead to hospitalization.&#8221;
Dr. Kinoshita himself was infected by his son last year. &#8220;It was the worst symptoms I’ve had in the past 20 years,&#8221; he said.
&#8220;My son experienced severe abdominal pain, vomiting, and diarrhea, and for about two days, he could barely do anything but go back and forth between the toilet and bed. Although he managed to stay hydrated, it was really tough. About two days after my son started to recover, I became infected. The abdominal pain and diarrhea were so bad that I couldn&#8217;t sleep at night.&#8221;
However, they managed to avoid a complete &#8220;family wipeout.&#8221; The only one who escaped infection was his wife, Jaguar Yokota (63).
&#8220;My wife lived in a separate room from me and used a separate toilet, so it was essentially a form of reverse quarantine. This might have been what prevented the spread of infection within our family. I realized that separating toilets and living spaces is an effective measure to prevent household infections.&#8221;
The frightening thing about norovirus is that even after recovery, the infected person continues to shed the virus for a week to a month. Without realizing it, they can spread the infection to those around them. Dr. Kinoshita points out that shared toilets are particularly dangerous.
&#8220;Norovirus is resistant to cold and drying, and the virus can remain infectious on surfaces like doorknobs and towels for long periods.
A particular point of concern is using smartphones in the bathroom. The virus expelled during vomiting or diarrhea can remain in the toilet, and if the phone is brought into the bathroom, it can get contaminated. By continuing to touch the phone afterward, the virus can transfer to the hands and unknowingly be carried to the mouth.&#8221;
If an infected person vomits and the vomit is not properly cleaned, the virus can spread into the air.
&#8220;Vomit can dry, become fine particles, and be dispersed into the air. Infection can occur when inhaling the virus particles, so it&#8217;s crucial to handle vomit carefully,&#8221; Dr. Kinoshita warned.
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<div data-friday-nextpage-lead="Disinfecting with alcohol is ineffective."></div>
<figure id="attachment_416313" class="wp-caption alignnone" style="width: 1155px;" aria-describedby="caption-attachment-416313"><a href="#" data-ident_hash="fc09bead"><img src="https://res.cloudinary.com/fridaydigital/image/private/t_article_image/wpmedia/2025/03/eb011605f2fd6bc19a84c7edf96a8df5.png" alt=""></a><figcaption id="caption-attachment-416313" class="wp-caption-text">Toyama City&#8217;s website notifying the issuance of advisories.</figcaption></figure>
<h2>What are really effective countermeasures?</h2>
&#8220;Since the COVID-19 pandemic, more people have been using alcohol-based sanitizers, but alcohol does not work on norovirus,&#8221; says Dr. Kinoshita.
&#8220;Norovirus can only be inactivated by chlorine-based disinfectants like bleach (sodium hypochlorite). If vomit from an infected person is wiped up and not properly disinfected, there&#8217;s a risk that the virus will dry out and spread into the air.&#8221;
With group outbreaks continuing this winter, there&#8217;s also a chance of infection in public restrooms. What can we do to protect ourselves from this invisible virus?
&#8220;Make sure to wash your hands for at least 30 seconds. It&#8217;s important to lather soap well and wash not only your palms but also between your fingers, under your nails, and up to your wrists. Be especially thorough after using the toilet and before eating.
If you do become infected, receive appropriate treatment and be mindful of preventing the spread to others. Particularly for those who handle food, there&#8217;s a risk of causing mass food poisoning. Such cases have already been reported this season. To get through this winter, I encourage everyone to reassess their preventive measures now.&#8221;
There’s no end in sight for this powerful norovirus. We can only protect ourselves and our families.

 Food poisoning caused by norovirus is raging throughout Japan. Once infected, the virus can spread to all family members, and is characterized not only by its virulence but also by its infectivity. A doctor shares his own experience and teaches how to deal with the disease.

Doctor Warns: Using Smartphones in the Bathroom Could Spread Deadly Norovirus

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