Everything you need to know about bedbugs, if they have still reappeared among us. Biology teacher: “The main cause is the acquisition of resistance to insecticides”

Everything you need to know about bedbugs, if they have still reappeared among us.  Biology teacher: “The main cause is the acquisition of resistance to insecticides”

A professor from the Faculty of Biology at the University of Bucharest answers nine questions about bedbugs, after the reappearance of these annoying insects in big cities, especially in Europe.

The bedbug crisis. Stuff left to dry in a building in MarseillePhoto: Shutterstock Editorial / Profimedia Images

Over the past two years, bed bugs have made a comeback in most major cities. These insects have created problems in France, especially because the 2024 Olympic Games will be held in Paris. Britain and the United States have also announced they are facing multiple outbreaks, and South Korea recently established a special disinfestation unit to combat the numerous infestations in Seoul.

Even Romania has not escaped the bedbug invasion. On Facebook, the group “Bedbugs – the nuisance of every night” appeared, where hundreds of people share their experiences and exchange advice on the best solutions to get rid of them.

The National Library in Bucharest was closed in August due to the bedbug infestation, and the following month many of the CFR’s sleeping cars were found to be infested.

In the context where this topic is debated on the Internet, we wanted to know more from the experts and asked several questions to Ms. Andrea Cristina Staicu, university professor. Dr. at the Department of Biochemistry and Molecular Biology of the Faculty of Biology of the University of Bucharest.

Where do bedbugs come from and what living conditions do they need?

“The bed bug, Cimex lectularius L (Hemiptera: Cimicidae), has been a constant pest to humans throughout history. They may have evolved from ectoparasites of cave mammals (particularly bats). mouse). When people moved from caves to tents and then to houses, the virus followed.

The species has been mentioned in the literature and folk medicine of many cultures, starting with ancient Greece,” explains Andrea Cristina Staicu.

As characteristics, to make them easier to identify, we find that adults measure 6-7 mm, have an oval, flattened, reddish-brown body, with beak-shaped mouthparts composed of three segments, antennae with four segments and reduced wings. Short, golden hairs are visible on the surface of the body.

The tip of the abdomen is generally pointed in males and more rounded in females. A life cycle lasts five weeks at temperatures of 28 to 32°C. They remain active up to temperatures of 7°C and die at 45°C.

Each female can lay between 200 and 500 eggs during her lifetime, which can last two years or more.

“They have a distinctive, sweet, musty odor, which contains aldehydes produced by scent glands. They consume the blood of their hosts, mammals and birds, and tend to deposit parts of their previously unavailable food into their burrows. digested as rust spots. They are nocturnal insects, but they also feed during the day when they are hungry. Bed bugs can be found almost anywhere people have built homes and towns. They thrive under the temperature and humidity conditions agreed by humans,” adds Ms. Staicu.

Why are we having real invasions lately?

Bed bugs became very rare in many industrialized countries shortly after World War II due to the widespread use of synthetic insecticides. Until 1997, they were rarely reported in the United States and Britain.

Since 1998, a resurgence of the insects has been reported in the United States, Canada, some European countries, Australia, and parts of Africa.

Among the causes mentioned in the specialist literature are the low level of public awareness, the exchange of second-hand objects, particularly furniture, the increase in local and international traffic, and changes in the management of invasions.

The main cause is the acquisition of resistance to insecticides. First there was resistance to DDT, previously used to control insect populations. This has contributed to the current increase in resistance to pyrethroid and neonicotinoid insecticides.

Mutations at target sites resulted in a lack of sensitivity to insecticides (e.g., kdr mutations).

Changes in the insect’s cuticle (not the outer layer) may explain pyrethroid resistance. Therefore, combinations of insecticides began to be used to control resistant populations. (Neonicotinoids in combination with pyrethroids).

What are the potential consequences on human health of a bedbug infestation?

Although 28 natural human pathogens have been identified in common bed bugs, none have ever been shown to be biologically or mechanically transmitted.

Bedbugs produce clinical, psychological and economic effects. Although their feeding on the host’s body goes unnoticed, their saliva contains biologically active proteins, which can cause progressive allergies, symptomatic skin reactions visible after repeated bites.

Typical symptoms include an enlarged, inflamed area next to each sting, erythema, edema, eczematous lesions, generalized lesions, secondary infections, intense itching for several days.

After a sting, immediate reactions occur 1 to 24 hours and last 1 to 2 days. Delayed reactions usually appear after 1 to 3 days (or more) and can last 2 to 5 days.

What are the obvious signs of a bedbug infestation that we should pay attention to?

They have to worry about the presence of eggs, larval stages, the remains of the exoskeleton, which are periodically eliminated by molting, the remains of undigested food, which appear as spots inside the bed frame, the smell emanating from these insects. .

What effective bed bug prevention methods are recommended?

Bed bugs are often difficult to control because they are nocturnal, seek cryptic shelters, are very small, and can detect and avoid many chemicals, including cleaning agents. They are easy to carry or in luggage, furniture, boxes and clothing.

Because they are very thin, they can fit or hide in very narrow crevices. Adults can live for several months (some more than a full year) and nymphs can survive three months or more without feeding. Complete elimination is almost impossible to achieve after a single disinfestation.

The conditions under which bed bugs thrive include a sufficient number of available hosts, an abundance of crevices or shelters approximately 1.5 m from the host, and ambient temperatures between 28 and 32ºC.

Cluttered, currently occupied rooms with little air movement are ideal. While sanitation alone will not eliminate an infestation, decluttering, removing accumulated dirt and debris, and sealing cracks and crevices reduces available shelter, making it easier to detect remaining insect populations and increase the chances of treatment success.

In addition to chemical treatments, it is recommended to empty the location of textile objects, eliminate adult insects with a vacuum cleaner, remove the vacuum cleaner bags into airtight plastic bags, and wash the textiles.

Given their sensitivity to temperature, it is recommended to heat contaminated surfaces to 60 ºC, steam treatment or, conversely, low temperature treatment for two hours.

Other more difficult methods are presented in the literature: treatment with pheromones, combined with insecticides and entomopathogens, ozone treatment, traps with adhesive substances, use of electromagnetic or ultrasonic waves.

How do chemical treatments differ from natural treatments?

Chemical treatments have lost their effectiveness due to the acquisition of resistance and the high level of adaptation of these organisms. It has become necessary to administer mixtures of insecticides, to apply chemical treatments repeatedly, to use high concentrations (sometimes 2000 times higher!) to satisfactorily control the bedbug population.

Chemical treatments sooner or later produce the appearance of resistance in insects to chemical compounds and pose a risk of poisoning to people, pets and the environment, if applied incorrectly.

For population control, the use of predatory or parasitic insects has been proposed: arachnids, Serratia bacteria, fungi (Aspergillus flavus). But treatments using parasites and predators are thought to be far from widespread, requiring higher costs, trained personnel and slower results.

Losing control of the organisms used to fight bedbugs, predators, bacteria, fungi, would in turn be dangerous. These methods have the advantage of protecting habitats against chemical pollution.

What preventative measures are recommended for people who travel frequently and are at risk of bringing bed bugs home?

It is recommended to carefully inspect suitcases and bags before bringing them home. Application of steam treatment. Wash all clothing and apply heat treatment. Periodic inspection of vulnerable areas of the house, which constitute preferred refuges for bedbugs.

Are there ways to prevent bed bugs from returning after successful treatment?

Periodic inspection of spaces previously occupied by bedbugs, timely repairs to seal cracks and cracks in masonry, frequent ventilation, sanitation of spaces, by painting.

What should hotel or accommodation owners do who want to prevent and manage infestations in their establishments?

Monitoring the quality of furniture, its periodic replacement, washing and heat treatment of textile objects, periodic repairs to seal cracks and cracks in the masonry, frequent ventilation, disinfection of surfaces by painting, the application of heat treatments to textile articles.



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