Why have bed bugs become a nightmare for Paris?

In France, the development of pesticide resistance and the spread of bed bugs through tourism have made them a difficult problem for Parisian authorities to completely eradicate.

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

Videos of bed bugs crawling all over Paris, from subway seats to cinema recliners, are flooding social media and news outlets. The insects are causing concern throughout Paris and the world due to the large number of tourists who visit the city and may return home with blood-sucking bugs. "No one is safe," the deputy mayor of Paris stressed on Twitter during Paris Fashion Week.

Although bed bugs can be a pest, they don't spread disease and usually cause itching and discomfort rather than posing a serious health threat. Bed bugs were virtually absent from the 1940s to the late 1990s due to the use of pesticides, but they have reappeared in recent years, outbreaks in almost 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-standing problem and an example of the bed bug's effective survival skills, according to National Geographic .

Anyone who has ever encountered bed bugs in their home knows that their bites can cause uncomfortable itching and swelling. Eradicating bed bugs is also incredibly difficult because they nest inside the fabrics and upholstery of furniture. A single bed bug typically only lives for a few months or a year in some cases. But that's enough time for a population to explode, according to Zachary DeVries, an urban entomologist at the University of Kentucky. "You can release a female bed bug out of your house. It 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 family Aphididae, which includes about 100 species of small, parasitic insects that feed on 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, wingless, and only about 0.6 cm long, roughly the size of an apple seed. They are often mistaken for other blood-sucking insects like fleas, but can be distinguished by their flattened, oval-shaped bodies.

Bed bugs have been a problem since human history began to record them, DeVries says. Traces of them have been found in Egyptian tombs dating back more than 3,500 years. But where did they first come from? Scientists aren't sure about the oldest known ancestor of bed bugs, but a leading theory about the emergence of modern bed bugs is that they evolved alongside bats. "About 200,000 years ago, when humans lived in caves with bats, a species of bed bug attached itself to them," says Coby Schal, an entomologist at the University of North Carolina. "When humans left the caves, that species of bed bug went with them."

After bed bugs find their target, they insert a needle-like tube attached to their tip into the skin to suck warm blood. They also inject a series of proteins at the bite site, including anesthetics and anticoagulants. While not disease-carrying, bed bug saliva can cause an allergic reaction in some people, leaving large, itchy bumps. Others may not even realize they are living with bed bugs because their skin doesn't react, according to Schal.

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

Over time, female bed bugs evolve a specialized organ in their abdomen called the spermalegid, which contains immune cells that help prevent infection at the wound site. After aggressive mating, female bed bugs typically lay 1-7 eggs per day, and the eggs hatch into pupae. The pupae go through five developmental stages before reaching adulthood, although they must feed on blood to complete each molt.

Throughout history, humans have attempted countless ways to control bed bug outbreaks. One of the most successful efforts occurred during World War II, when the now-banned insecticide DDT was widely distributed to kill bed bugs. The chemical was initially very effective in controlling them. However, in the 1990s, a new population of bed bugs immune to the effects of DDT began to spread.

The problem is exacerbated by the growth of global tourism in recent decades, allowing these blood-sucking insects to spread throughout the world and seek new hosts every day. As a result, bed bug populations thrive, and many individuals develop resistance to commercially available pesticides. Extermination experts often rely on heat treatment, as bed bugs will die if exposed to temperatures of 43.3 degrees Celsius for at least 90 minutes.

An Khang (According to National Geographic )

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