Why have bedbugs become a nightmare in Paris?

FRANCE Pesticide resistance and spread through travel make bedbugs a difficult problem for Paris authorities to completely solve.

Bed bugs nest in fabrics and upholstery of furniture. Photo: Guardian

Videos are flooding social media and news accounts of bedbugs crawling around every corner in Paris, from subway seats to recliners at movie theaters. These insects are causing concern throughout Paris and the world in general due to the number of visitors to the city who may return home with blood-sucking bedbugs. "No one is safe," the deputy mayor of Paris emphasized on Twitter during Paris Fashion Week.

Although bed bugs can be pests, they do not spread disease and often cause uncomfortable itching rather than being a serious health threat. Bed bugs were virtually absent from the 1940s to the late 1990s due to pesticide use, but they have reappeared in recent years, breaking out in nearly every major city, including New York and Hong Kong. . The situation in Paris may not be an outbreak, but it is evidence of a long-term problem and an example of bed bugs' ability to survive effectively, according to National Geographic .

Anyone who has ever encountered bedbugs in their own home knows that bites from them can cause itching, swelling and discomfort. Getting rid of bed bugs is also extremely difficult because they nest inside the fabric and cushioning of furniture. A bed bug usually only lives a few months or a year in some cases. But that's enough time for populations to explode, said Zachary DeVries, an urban entomologist at the University of Kentucky. "You can release a female bed bug out of your house. She will mate and quickly start a population that grows out of control in just a few weeks or months," DeVries says.

Bed bugs belong to the Aphid family, which includes about 100 species of small parasitic insects that suck the blood of warm-blooded animals. Only three of these species commonly bite humans, the most common being Cimex lectularius. Adult bed bugs are reddish brown in color, have no wings, and are only about 0.6 cm long, about the size of an apple seed. They are often confused with other blood-suckers such as fleas but can be distinguished by their flat, oval-shaped bodies.

Bed bugs have been a problem since recorded human history, DeVries said. Their remains were discovered in Egyptian tombs dating back more than 3,500 years. But where do they come from in the first place? Scientists aren't sure about bed bugs' oldest ancestors, but a leading theory about the emergence of modern bed bugs is that they evolved with bats. "200,000 years ago, when humans lived in caves with bats, a species of bedbugs attached to them," said Coby Schal, an entomologist at the University of North Carolina. "When humans left the cave, the same bedbugs followed."

Once bed bugs find their target, they insert a needle-like tube that attaches its tip to the skin to suck out warm blood. They also inject a series of proteins at the bite site, including anesthetics and anticoagulants. Although they do not carry disease, bed bug saliva can cause allergic reactions in some people, leaving large itchy bumps. Others may not even realize they're living with bedbugs because their skin doesn't react, according to Schal.

Through a strategy called traumatic insemination, adult male bed bugs insert their sickle-shaped penis into the female's abdomen and inject sperm directly into her body. Sperm travels through the female bed bug's circulatory system to the uterus and fertilizes the eggs. According to William Hentley, an ecologist at the University of Sheffield in the UK, how they evolved this reproductive mechanism is still a mystery.

Over time, female bed bugs evolve a specialized organ in their abdomen called a spermalege that contains immune cells that help prevent infection at the wound site. After rough mating, female bedbugs usually lay 1 - 7 eggs/day and the eggs hatch into pupae. Pupae go through five stages of development before becoming adults, although they must suck blood to complete each molt.

Throughout history, people have tried countless times to control bed bug outbreaks. One of the most successful efforts took place during World War II, when the now-banned pesticide DDT was widely distributed to kill bedbugs. This chemical is initially very effective in controlling them. In the 1990s, a new population of bedbugs immune to the effects of DDT began to spread.

The problem has worsened as global tourism has grown in recent decades, allowing these bloodsuckers to spread around the world and find new hosts every day. As a result, bed bug populations thrive and many individuals are resistant to pesticides on the market. Extermination experts often rely on heat measures because bed bugs will die if exposed to temperatures of 43.3 degrees Celsius for at least 90 minutes.