Bed bugs have been associated with humans and lived in our homes for thousands of years. This small hemipteran insect is a reddish-brown ectoparasite about 5 mm in length that feeds on human blood and other animals such as poultry, bats or rodents. They are commonly known as bed bugs, and there are two species that affect humans: Bug, more cosmopolitan, and C. hemipterus more common in the tropics and subtropics.

These insects were a public health problem around the world, being almost eradicated in the 1940s and 1950s with the widespread use of insecticides such as DDT. In recent years, they have seen a dramatic resurgence that can be attributed to new aspects of pest biology and human behavior, such as the emergence of new resistance to insecticides or the increase in global travel.

What do their bites produce?

Bed bugs feed on blood and inject saliva while biting to prevent it from clotting. Some people have no reaction to stings, while others experience allergic reactions that can sometimes be serious. It can be difficult to distinguish bed bug bites from other insect bites or rashes.

The most common lesions include the development of papules (hives), often larger than 1 cm, accompanied by pruritus (itching) and inflammation that often have a darker red spot in the center. They are usually multiple and appear in groups or arranged in a line, mainly on the face, neck, arms and hands.

Wounds caused by scratching can become superinfected, causing more serious and difficult to treat conditions. They are not known to transmit any human pathogens, but they can cause emotional distress to those affected, manifested by anxiety and insomnia.

How do we verify their presence?

It is important to know that the skin lesions and accompanying symptoms can appear up to 9 days after the bites have been suffered and that they usually take several days for their complete resolution.

If we suspect that we have been bitten by bed bugs, we should look for evidence in the allegedly infested residence that demonstrates the presence of the insect. Let’s take a close look at the place, especially the cracks in the walls, mattresses, and furniture.

As indirect or presumptive evidence, the following must be taken into account:

• The presence of dark spots (droppings) around their hiding places.
• The observation of rusty reddish-brown stains (traces of blood) on mattresses and sheets.
• The bad smell, fetid and sweetish, that the secretions give off, which is appreciated when the bed bugs are numerous.

The definitive or certain diagnosis of an infestation is based on the following evidence:

• Observing adult or nymphal insects (preferably at night, when bed bugs are active).
• The presence of pale yellow exuviae (remains of empty exoskeletons after molting).
• The finding of hatched or unhatched eggs.

What should we do if we have bites?

A topical treatment to mitigate itching and good hygiene to prevent secondary infections are usually sufficient for most cases, although in any situation it is advisable to consult a specialist who will monitor and evolve. For more severe cases, corticosteroids, antihistamines, or systemic antibiotics may be necessary.

Where do bed bugs come from?

Currently, an increasing number of infestations are reported worldwide, making control difficult. Homes, bird nests, and bat caves are the most suitable habitats for bed bugs because they provide warm shelter and hosts to feed on.

In homes, they hide in cracks or crevices in walls, furniture, behind wallpaper, wood paneling or pictures, and under rugs, mattresses, or bedding. They have nocturnal habits, so they tend to hide during the day and be more active at night, when people sleep.

The risk of finding bed bugs increases if we spend time in places with high volumes of overnight guests, such as hotels, country houses, hospitals, or homeless shelters.

Why is it so difficult to get rid of them?

Bed bugs can live up to 6 months without food and survive up to 12 months without feeding on humans, attacking birds and rodents. Factors associated with some modern homes, such as increased humidity, lack of air circulation, poor cleaning and neglected furnishings, also play a role, providing refuge areas for bed bugs.

In addition, the social stigma associated with bed bug infestations in homes can force people not to turn to pest control professionals, contributing to resurgence and resistance.

How can we prevent and control them?

Avoiding their entry is the best way to prevent them. Good sanitation is the first step in controlling a bed bug infestation. However, recently they are being detected in nursing homes, hospitals, cruise ships, cinemas, the subway and even airplanes, suggesting that good hygiene is not enough to prevent them.

For its control, the first thing to do is confirm that we are in the presence of bed bugs. It is recommended not to use household insecticides, because they could worsen the situation and disperse the insects, also putting them on alert and forcing them to seek new spaces inside the house. In many cases, eradication requires more than one visit from a pest management professional.

Among the pesticides available on the market, the most used for their safety and efficacy are pyrethrins and pyrethroids, desiccants (boric acid), biochemical substances (neem oil), pyrroles, neonicoticonoids (synthetic forms of nicotine) and insect growth regulators.

To minimize the use of pesticides, control should focus on mechanical methods, such as vacuuming and removing or sealing cracks in furniture and walls. Bedding should be washed at least 60 ℃. For severe infestations, pesticides can be used, although care must be taken to allow bedding, mattresses, upholstery, and furniture to dry completely before use.

Once eliminated, special care must be taken to avoid a new infestation, especially with the introduction of furniture (particularly second-hand) and items such as clothes, backpacks, luggage or bedding, where insects can travel by “hitchhiking” , dispersing and repopulating new territories.

_{Lucrecia Acosta Soto, Professor of Parasitology, Miguel Hernández University and Fernando Jorge Bornay Llinares, Professor of Parasitology, Miguel Hernández University}

_{This article was originally published on The Conversation. Read the original.}