Experts say the pests are highly resistant and difficult to exterminate on their own.
In Japan, dermatitis caused by the pest bed bugs was confirmed around ’05, and from ’15 to ’19, the number of bed bugs increased rapidly, and I felt that this would be a serious problem.
At that time, it was a period when the number of foreigners visiting Japan increased rapidly due to inbound travel. After that, the epidemic temporarily stopped because the movement of people was restricted due to the new corona, but it has increased again since the corona was classified as class 5.
Since May of this year, the number of patients has increased dramatically, and most of them seem to have brought it back from their travel destinations.
Most of the patients seem to have brought it back from their travel destinations,” said Dr. Masaru Xiaju, a professor at Hyogo Medical University and an expert on skin diseases caused by insects.
In France, where the Olympics will be held in Paris next summer, bed bugs have become a social problem due to the large number of bed bug infestations. Sightings of bed bugs have been reported at residences, hotels, movie theaters, and other locations throughout the city, and the situation seems to have become so serious that the National Assembly is considering countermeasures.
Bed bugs are pests that repeatedly reproduce by sucking human blood, and although they were once thought to have been drastically reduced, they have been confirmed again since 2005, and their damage has been increasing in Japan over the past few years. The reason for this is related to human traffic.
In Japan, the number of bed bugs increased around World War II, then declined sharply around 1970 due to the spread of insecticides and changes in living conditions. From then until around 2005, bed bugs were so rare in Japan that they could be called an endangered species,” says Dr. Masaru Natsuaki of Hyogo Medical University’s Department of Dermatology.
Bed bugs travel by burrowing into clothing, documents, and other luggage carried by people. They are spread by visitors to Japan who bring them with them to their accommodations, or by Japanese travelers who bring them back from their travels and then “re-enter” the country.
They live in houses and inhabit the crevices of the house. During the day, they hide in cracks in pillars, in furniture and furnishings, in beds, behind pictures on the wall, and in electrical appliances and books.
At night, they emerge from the crevices to feed on human blood and return to the crevices when their stomachs are full. In many cases, they are hard to find when you look for them, and by the time you find them, they have infested the entire house in large numbers.
Once even a single animal is brought into the house, they steadily increase their offspring in a comfortable, air-conditioned environment. The abundance of human blood as food and the lack of other natural enemies make it difficult to stop them from reproducing.
Many insect females can store enough sperm to lay eggs for the rest of their lives once they have mated with a male.
In other words, if even one adult female that has mated invades and lives there, she will survive by sucking blood at night and lay more than 200 eggs during her lifetime. Once the larvae grow up to one or two months and a female-male pair is formed, they will reproduce forever.”
The infestation is “super bed bugs,” which insecticides do not work on.
Most bed bug bites are on exposed hands and feet while sleeping. Some people suffer insomnia due to the intense itching.
The itching from insect bites is caused by the salivary gland component of the injected insect. The itching occurs as an allergic reaction; the first time you are bitten you have no symptoms, but if you are bitten several times, itching and redness occur the next day or two.
After several more stings, itching appears soon after the sting. Occasionally, large redness and swelling with lumps may appear.
Topical application of medication can improve symptoms within a week to 10 days, but “the difficult part is the diagnosis leading up to treatment,” says Dr. Natsuaki.
In many cases, subjective symptoms appear one or two days after being bitten, so it is difficult to know when and where the bite occurred. In addition, since the symptoms are not so different from other insect bites, there are cases in which bed bugs are diagnosed as simple insect bites and treated without being aware of the bed bugs, and then the symptoms worsen.
To confirm the diagnosis, it is necessary to find bed bugs that must be somewhere. Dr. Natsuaki recommends the “lie-down strategy” as a method of almost certain capture.
By using their nocturnal nature, bed bugs can be captured with a high probability by pretending to sleep for 20 to 30 minutes and then quickly turning on the lights to see bed bugs gathering on bedding and limbs.
The “lie-down strategy” uses you as a “decoy” to lure the bed bugs to you. The bed bugs captured by this method are brought to the doctor’s office to confirm the diagnosis. Another thing that Dr. Natsuaki finds troublesome is the difficulty of extermination.
Most of the bed bugs that are spreading around the world are insecticide-resistant bed bugs, a type of bed bug that does not respond to common insecticides,” says Dr. Natsuaki. They are also called “super bed bugs.
There are some insecticides that are effective against bed bugs, but they are often not available in drugstores. If you do use them, you must anticipate the routes and areas bed bugs will take and spray them, which can make it difficult to get rid of them yourself unless you know their biology.
If there is one bed bug, the possibility of it breeding in all rooms is great, so it is best to use a reliable pest control service.
If the infestation spreads, it can cost up to 100,000 yen to “exterminate” them!
We receive extermination consultations from people who have been told they have bed bugs because of itching after traveling abroad, or who have imported furniture from overseas and found them attached to it,” says Mr. Shogo Ishida of Sharing Technology, which operates “Pest Extermination 110.
It is not only ordinary residences that receive extermination consultations and requests. We also receive requests from facilities used by large numbers of people, which increases the scale of our extermination work.
The number of requests has not increased significantly, but we are noticing cases where they are breeding in large numbers. For example, when our staff checked a nursing home after receiving a request that it might have bed bugs, they found that the infestation had already spread to several rooms, not just one room.
Even in private homes, there are many cases where the owner thought it was only in the bedroom, but when he checked, he found bed bugs in other places such as the living room and the bathroom.
Before exterminating bed bugs, visually check the bed bug habitat. After that, we use insecticides effective against bed bugs and heat from a high-temperature steam steamer to exterminate them.
Commonly available pyrethroid insecticides are not effective against super bed bugs. Therefore, we use organophosphorous and carbamate insecticides, which are very effective. Also, given their propensity to hide in crevices and the fact that they lay eggs, it is more effective to wait a week or so before exterminating them again.
The cost of extermination will be high if the infestation is large by the time it is noticed. However, if extermination is kept to a minimum out of concern for the cost, even a single “remnant” will repeat the process of reproduction.
The average cost is about 100,000 yen. By the time the presence of bed bugs is noticed, the infestation is often so large that careful investigation and extermination are necessary, and the cost becomes prohibitive. If the scale of the infestation is large, as in the case of the nursing home mentioned earlier, the cost can run into the hundreds of thousands of yen, so there is nothing better than finding out early before the damage escalates.”
Dr. Natsuaki, mentioned above, has seen the slowly increasing number of bed bugs and is wary of a future pandemic in Japan.
He said, “Now that the new coronas have calmed down, many travelers from abroad are visiting our country. It is expected that bed bugs will continue to spread in accommodations, and it is possible that Japanese who stay in the same room may bring them back home. The more people travel domestically and internationally, the greater the possibility of a pandemic like the one in France,” said Dr. Masaru Natsuaki, Department of Dermatology, Hyogo Medical University.
When you return from your trip, you may have to bring some unexpected “souvenirs” with you. Although it is difficult to completely prevent bed bug infestation, it is advisable to see a dermatologist as soon as possible if you notice any abnormalities on your skin after your trip.
Masaru Natsuaki is a professor at Hyogo Medical University. He is a professor at the Department of Dermatology, Hyogo Medical College Hospital, where he diagnoses and treats skin diseases. Specializes in skin diseases caused by insect bites, contact dermatitis, and atopic dermatitis. He is a board-certified dermatologist by the Japanese Dermatological Association and a board-certified Kampo specialist and advisor by the Japanese Society of Oriental Medicine. He has long been studying harmful arthropods that cause skin diseases. He is the author of “Dr. Natsuaki’s Clinical Illustrated Guide to Insects and Dermatitis, Revised Second Edition” (Gakken).
Interview and text by： Yoko Nemmochi
Editor and writer, born in Yamagata Prefecture in 1983, worked for 10 years in the editorial department of a health information magazine, editing monthly magazines and web media before becoming a freelancer. Currently, she interviews, plans, and writes about doctors and specialists, focusing on healthcare and medical fields.