Bedbug-related consultations in the major Japanese metropolitan areas of Tokyo and Osaka have surged this year to hit their highest numbers on record, according to pest control associations in the two prefectures, with experts warning that infestations are spreading nationwide.

The sudden resurgence of the bloodsucking pests in Japan follows reports of similar outbreaks in countries like South Korea and France, raising alarm among the public as domestic and international travel rebounds following the coronavirus pandemic.

Bedbugs, which are around 5 millimeters long and nocturnal relatives of the stink bug, hide in cracks and gaps in furniture during the day, coming out to feed on humans at night. Their bites can trigger an allergic reaction in some people, resulting in intensely itchy welts.

A bedbug. (Photo courtesy of Masaru Natsuaki, Hyogo Medical University)(Kyodo)

Difficulties in detecting the tiny critters and a female's ability to lay hundreds of eggs in her lifetime mean that infestations can easily spread if they hitch rides on clothing or belongings.

While bedbugs have been present in Japan since the late 19th century and were once rampant throughout the country, their numbers sharply decreased around 1970 with the widespread use of potent insecticides. However, from around 2000, some of the bugs began to develop resistance to the insecticides.

According to Tokyo's pest control association, the capital has received 306 bedbug-related consultations as of November, already eclipsing the total 247 consultations in 2022.

Major Tokyo-based insecticide manufacturer Earth Corp. also said consultations about bedbugs surged eightfold in November compared to the same period last year.

Meanwhile, Osaka has received 307 consultations as of the end of November, about 50 percent more than last year. In late November, a report of a bedbug on the Osaka Metro spread on social media, prompting its operator to clean all 1,380 of its trains.

Nationwide, consultations in fiscal 2022 increased around fivefold from fiscal 2009 to 683, with people asking for referrals to exterminators and help in getting rid of bedbugs, among other requests.

According to Masaru Natsuaki, president of the Japan Society of Medical Entomology and Zoology and a professor of dermatology at Hyogo Medical University, bedbug infestations are occurring even outside of urban areas.

"(People are getting bitten) in various parts of the country, and nowhere can be considered safe. I want people to have the mindset that it can happen anywhere in the country," said Natsuaki.

Waves of outbreaks have also been reported overseas, with the South Korean government declaring war on the pests in November, prompting extermination campaigns in lodgings, public transport and other public areas.

In France, recent reports of bedbug sightings in trains, cinemas and schools have caused a national panic, with fears that the image of Paris, set to host the Olympic Games next year, could be damaged.

Natsuaki recommends sealing clothes and other belongings in plastic bags and placing them as far away from the bed as possible when traveling. But he adds that hysteria is unnecessary.

"Although their bites cause intense itching, bedbugs do not transmit diseases. If you take preventive measures, there is no need for excessive fear," he said.

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