The Paris City Hall spoke of a "major upsurge" in bedbugs in Paris and the French government is preparing a specific plan of action with transport companies. In light of these recent decisions and panicked public reactions to stories of bedbugs infestation on social media, Le Monde has asked Jean-Michel Bérenger, an entomologist at the IHU (medical research center connected to hospitals) in Marseille, to answer reader questions on the issue.
Hello Sylvie,
The whole country could be affected, and bedbugs can be found wherever people go. To put it simply, we have a Paris-Lyon-Marseille axis and a Toulouse-Bordeaux one. Big cities that local populations and tourists move through are "favored," that's for sure.
We're basing our analysis on growth in the activity of pest control and dog detection companies, and indeed, their business has been increasing over the last two years.
The spread has been going on for years now. There was a lull with the lockdown due to the Covid-19 pandemic, then an upturn over the last two years with tourism back in full swing as people want to enjoy themselves.
Focus on mechanical and physical pest control, using vacuum cleaners, steam or diatomaceous earth in aerosol sprays. No supermarket-bought chemicals, however!
They can survive for several months, or even a year, without feeding.
It's true that bedbugs are currently "infesting" social networks and the media. What promotes their spread is our lifestyles, as well as mismanagement of infestations and impoverishment, which means that many people don't have the resources to fight this problem.
It's not too bad in and of itself, because you can get rid of them easily if they are caught in time. It's mainly the psychological aspect that is important: having insects in your bed that suck your blood is frightening. But beyond that, bedbugs don't transmit pathogens.
The after-effects of a bite depend on the individual, as reactions to bedbugs' saliva can be very strong, especially the first time. You can either become immune to it, and the reactions subside over time, as in my case; or, if you don't, your condition can worsen, as happened to one of our students who wanted to try the experience.
They walk, they don't fly, they don't jump, but they move with us, in our suitcases or second-hand objects, for example. They can also come from your neighbor's home.
Anyone can get them, but if you take preventative measures and act quickly, you can get rid of them. There's no need to panic. Let's not forget that it's one of our human species' parasites, along with lice and scabies, and we don't have many of them!
Choose a seat without fabric on the metro or bus, if there is one; and protect your belongings, because that's often where they'll end up. And then there's repellent or a plastic bag to protect yourself.
Sleeping areas should be inspected by turning them upside down and dismantling beds, armchairs or even sofas, in search of these little insects or their droppings, which are very clear signs. It can be very useful to use a lamp.
In the 1950s, we had a very powerful insecticide named DDT. It worked well, was persistent and inexpensive, but toxic (carcinogenic), therefore it was banned. The world's population then was 2.5 billion. It is now close to 8 billion.
The campaigns you mention would cost a fortune! The best thing to do would be to implement a new lockdown, to stop tourism, international trade and all movement of people, etc. Impossible. In reality, the best solution would be to support those associations that are active in the spread zones of big cities and also to provide better training for pest control companies, some of whom are taking advantage of this situation.
Soon after its introduction, we already found DDT-resistant insect populations. It has the same mode of operation as pyrethroids, so over time we'll see resistance to those too.
Chemical treatment requires preparation and expertise, which most companies have, to be effective. Cryonics generates pressure from the device's outlet, which can throw bedbugs far away while not killing them. What's more, it's CO2, so there's a risk to the operator if they are working in a closed room. As for steam, it's effective and safe!
Older apartments with floorboards and wood paneling are often problematic. Also, beware of BA13 (plasterboard or drywall) partitions, where bedbugs can take refuge, and false ceiling panels, since their reflex response to any treatment (chemical, thermal...) is to climb up, hence the importance of preparing the house before treating the infestation.
Yes, anything's possible, you do have to be aware of any insect that wanders onto your desk without getting too anxious. Also, don't forget that insects other than bedbugs do exist. To the best of my knowledge, there are no campaigns to raise awareness of the subject in offices, but I have performed some awareness training for social housing managers, journeymen builders, social workers and nurses.
No, they can't be hosts but can occasionally be victims if their owners are away. Bedbugs don't like fur and, given the choice, will prefer humans.
No, because they live in human homes and go wherever we go. However, high temperatures accelerate their development.
It's hard to estimate. The factor it can detect from the furthest distance away is the release of CO2 when we breathe, so it's only a distance of a few meters.
In the case of bites, when there are three or four in a line, or maybe clustered together. Welts can appear on areas of uncovered skin. As for their droppings, these are small black dots of digested blood that bed bugs leave around their hiding places.
The traps work as long as your bed is an "island": no contact with the walls, no sheets or other items touching the floor. In fact, there's a risk of bringing some back to the office if you have some in your bag. You can treat your bed with any spray-on-fabric mosquito repellent that's stronger than those intended for use on skin, or put it in a plastic bag or a large Tupperware-style plastic container.
The bed is the place where you're at your most vulnerable and need to feel safe. For many people, knowing that there are insects there to suck your blood is unbearable. What's more, we live in an increasingly "sterile" world, and any insect or animal that disturbs that concept provokes disproportionate reactions.
There are five stages between the egg and the adult bedbug. In optimal humidity and temperature conditions, this cycle lasts forty-five days. As for fertilization, the female bedbug lays three to five eggs a day.