Health A mysterious cold-like illness has reportedly been spreading in Fukuoka.

[Hiroyuki Nagashima]

A mysterious cold-like illness has reportedly been spreading in Fukuoka

"Mysterious Cold" in Fukuoka: Sore Throat and Runny Nose, But No Fever — Medical Association Testing Samples
Since May, an increasing number of patients in Fukuoka Prefecture have been visiting medical institutions complaining of symptoms such as throat discomfort and runny noses. The condition has become a topic of discussion on social media, where it is being referred to as a "mysterious cold."
According to the Fukuoka Prefectural Medical Association, the exact cause remains unknown, and posts about the "mysterious cold" have been increasing on social media.
Tsuyoshi Inamitsu, Executive Director of the Fukuoka Prefectural Medical Association:
"It typically begins with a sore throat, followed by worsening runny nose and coughing. The symptoms appear in a consistent pattern, so we believe it is likely some kind of infectious disease or viral infection."
The Medical Association stated that samples have been collected from affected patients and are currently undergoing detailed testing. However, it may take some time before the results become available.
The Association also warned that the number of people being transported to hospitals due to heatstroke is increasing and urged residents to take preventive measures early.
This is Hitomori, bringing you some additional information about the "mysterious cold."
Many people are reporting respiratory symptoms such as runny noses and sore throats, but the exact cause remains unclear, especially since many patients do not develop a fever.
The Fukuoka Prefectural Medical Association says it first became aware of these symptoms in early May, but laboratory test results may take one to two months to complete.
Dr. Yukiko Harada of Fukuoka City Hospital believes that one possible factor is allergies.
The Kyushu region is currently in the season for grass pollen (particularly from the Poaceae family).
As temperatures rise, people are opening their windows more frequently, allowing pollen to enter homes and potentially trigger symptoms. In some cases, symptoms can persist for more than a week, and treatment with prescription anti-allergy medications may be necessary.
A second possible cause is a viral infection.
One candidate is human metapneumovirus (hMPV), which is more common from spring through summer. The virus may infect the throat after it has been irritated by yellow dust (Asian dust) or air pollutants such as PM2.5 particles.
In such cases, symptoms often resolve within a week, and adequate rest is considered the most effective treatment.
In any event, if symptoms worsen or persist, other underlying causes may be involved. Individuals are advised to seek medical evaluation from a healthcare professional.
Last Updated: May 20, 2026, 4:52 PM (JST)

I experienced the same symptoms starting in the first half Golden Week holiday. I never developed a fever, but I had a severe sore throat and a persistent cough that made it difficult to sleep at night.
The cough finally subsided yesterday, and my symptoms have now disappeared. However, the illness lasted quite a while and left me feeling exhausted, having drained a significant amount of my energy.

 

[thomas]

Glad you're feeling better, @Hiroyuki Nagashima!

 

[mdchachi]

Something very similar is going on with my son but we are nowhere near Fukuoka let alone Japan. He has a sore throat/cough for over a week now. No fever as far as I know. It also seems to have progressed from a throat irritation to an irritating, disruptive cough. We did a home combination test for Covid, RSV and Flu A/B and none of them came up positive.

 

[Hiroyuki Nagashima]

Glad you're feeling better, @Hiroyuki Nagashima!

Thank you for your kind words.
During a company web meeting, I learned that several employees in Tokyo are experiencing the same symptoms and have been visiting doctors as well. Since many people traveled during the May holidays, the illness may have spread to Tokyo and other areas.

In any case, the symptoms seem to last for a long time, so I recommend taking good care of your throat by using an antiseptic gargle or mouthwash with antibacterial properties.

 

[Ukigumo]

Could it be a cold?

 

[mdchachi]

Could it be a cold?

It's very likely a cold. But cold is an imprecise term. The cause of a cold could be rhinoviruses, coronaviruses, adenoviruses, RSV and others.

 

[Hiroyuki Nagashima]

Something very similar is going on with my son but we are nowhere near Fukuoka let alone Japan. He has a sore throat/cough for over a week now. No fever as far as I know. It also seems to have progressed from a throat irritation to an irritating, disruptive cough. We did a home combination test for Covid, RSV and Flu A/B and none of them came up positive.

I'm sorry to hear about your son's symptoms. I hope he makes a full recovery as soon as possible.

Since I didn't have a fever at the beginning, I was quite optimistic and only took an anti-inflammatory throat medicine from the pharmacy. However, my coughing became so severe at night that I couldn't sleep. After consulting with a pharmacist, I started taking a traditional herbal medicine before bedtime, which helped improve my symptoms somewhat.

At work, I was constantly using throat lozenges containing CPC (cetylpyridinium chloride hydrate), so I ended up going through a huge number of them.

In Fukuoka, there have also been warnings about tuberculosis cases, and some of the symptoms can be similar to those of this illness, so people are being advised to stay alert.

Tuberculosis Cases Triple Compared to the Previous Week in Fukuoka

It has been reported that the number of tuberculosis (TB) cases in Fukuoka Prefecture has increased compared to last year. The prefectural government is urging people to seek medical attention promptly if they experience a cough or phlegm lasting more than two weeks.

According to the Fukuoka Prefectural Government, 18 tuberculosis cases were reported by medical institutions across the prefecture during the week ending May 17, which is three times the number reported the previous week.

From December 29 of last year through May 17 of this year, a total of 286 tuberculosis cases were reported, an increase of 24 cases compared with the same period the previous year.

Because the early symptoms of tuberculosis can resemble those of a common cold, infected individuals may not realize they have the disease during the initial stages. Tuberculosis can spread through the air when an infected person coughs or sneezes.

The Fukuoka Prefectural Government advises anyone who has had a cough or phlegm for more than two weeks, or who continues to experience a low-grade fever or persistent fatigue, to seek medical care as soon as possible.

Last updated: May 21, 2026, 7:14 PM.

 

[johnnyG]

TB usually also involves a fever--night sweats are a classic sign. Of course a cough and phlegm, but sore throat would not be typical.

I'd certainly have to brush up on it, but I was a TB control worker in the peace corps in korea, from '74-76, where it was endemic. Kind of yukky, but I helped collect lots of sputum samples and do the lab testing on those. I generally avoided the needle work--PPDs and BCGs for 1st and 6th graders when visiting elementary schools, but was able to give a minor health talk (in Korean) before or after that. And the same to family members when the health center I was at was visiting patients. One challenge was keeping people on the two-year course of treatment--after some initial treatment symptoms disappear (a couple months), and then patients would stop coming in for drugs, only to return six months or more later with the return of symptoms, and some drug resistance. One angle on it was that if a foreigner (presumably a specialist) was saying to keep taking the medicine, that might keep a few more people on treatment that might otherwise have stopped.

Japan had its own TB problem. Tho he recovered, my wife's father had TB and was in a sanatorium for a couple years, which also meant he wasn't eligible/taken for military service.