The return of bed bugs: a forgotten enemy
Technical note on the return of bed bugs: a forgotten enemy, with a focus on diagnosis, prevention and criteria applicable to professional pest management.
Recent years have seen increasing reports of bed bug infestations, a blood-sucking insect that has become a public health problem in many parts of the world. Bed bug infestations have spread in Europe, Asia, Australia and North America, where reports are growing at alarming levels. Recently, cases of bed bugs have been reported in Brazil, Argentina, Colombia, Venezuela and Peru, although in these countries infestations have not reached epidemic levels.
Several factors have contributed to the resurgence and spread of bed bugs, including the growth of the global economy, the ease of travel today, and the increasing presence of insecticide-resistant bed bug populations. History tells that bed bugs were present in Europe in the times of the Greeks and Romans, in northern Europe during the 11th century, while in North America they were present in the mid-17th century thanks to the first navigators and colonizers.
The escalation of bed bug infestations in Europe and the United States coincides with the increase in the use of central heating during the early 20th century. Bed bugs were very common in the United States during the 1930s and 1940s, particularly in poorer, more crowded places. During this time, various control methods were used without much success to eliminate these insects. The turning point in the history of bed bug control occurred in the mid-1940s with the arrival of synthetic insecticides such as DDT, and subsequently organophosphates and carbamates. Since then, bed bugs have practically disappeared, particularly in developed countries, with only sporadic presence of infestations in places with high movement of people and questionable sanitary conditions.
The resurgence
In the early 2000s, bed bugs began to make a surprising resurgence in modern society. Bed bugs have shown that age, race, sex, country of origin, type of residence and socioeconomic status are not a problem for using human blood as a food source.
Today, as you read this article, hundreds of bed bugs live in many parts of the world in beds of all shapes, sizes and brands in family homes, hotels, hospitals, in used furniture, used clothing, books in libraries, laundromats, seats in theaters and in mass transportation vehicles.
Description of the pest
The adult bed bug is a wide, flat, oval, tan-brown insect that measures approximately 6 millimeters. There are 5 immature or nymph stages and each stage needs to consume blood before moving to the next stage. Unfed nymphs are light yellow and turn dark red after a blood meal.
The first nymphal instar is as small as the head of a pin, about 1 millimeter, while the fifth nymphal instar is slightly smaller than the adults. The small and flat size of bed bugs allows them to fit into slots and crevices of any item present in a room. There the bed bugs aggregate, mate, digest blood, molt and the females lay their eggs. Each female can lay 200 or more eggs in her entire life, which are stuck to surfaces.
Although bed bugs prefer to feed on humans, these insects can also feed on birds, cats, dogs, and rodents. The average lifespan of bed bugs is six months, but they can survive a year or more, depending on temperature and humidity conditions. Therefore, it is of little use to vacate a bed bug infested site in the hopes of eliminating the infestation through starvation. Bed bugs can spread from an infested site to an adjacent non-infested site when people, the bed bugs' food source, leave infested homes.
Habits of bed bugs
Bed bugs typically feed at night and find their hosts through human body odors, carbon dioxide expelled in respiration, and/or body heat. The insects sting the host's skin several times before feeding, a process that takes 5 to 10 minutes to complete.
Because bed bugs come out of their shelters and feed at night, many victims are likely unaware of the insects' presence. However, bed bugs tend to leave evidence of their presence, such as black spots on walls, bedding, pillows, and mattresses. These points correspond to the fecal matter of the insects. Insect eggs and molts also serve as evidence of a bed bug infestation.
Although bed bugs tend to stay in the bed, close to where the victim is, some bed bugs can wander on the walls, ceiling or hiding behind electrical outlets and switches. Some individuals may also be found between the hollow areas of common walls that separate residences, facilitating the movement of bed bugs from one residence to another. Bed bugs can also hide in closets and the items present there, coats, clothing, footwear and others, and this could explain the rare circumstance of finding bed bugs in theaters, vehicles or places where used clothing is collected or sold.
The ability of these insects to hide in many places requires Pest Management Professionals to do a thorough inspection when a bed bug infestation is suspected.
Impact of bed bugs on human health
Currently, there is no scientific evidence that bed bugs transmit diseases to humans through their bites. The importance of bed bugs in public health is associated with the allergic reaction caused by the bite. These reactions vary considerably between people. It is estimated that about 40 percent of people bitten do not show skin reactions.
Most patients present reactions very similar to those caused by mosquito bites. These welts usually appear days or weeks after the bite has occurred. Injuries caused by bed bug bites usually occur on exposed areas of skin, such as the face, neck, shoulders, back, and extremities. Reactions can intensify over time when people are bitten by bed bugs again.
The presence of bed bugs should be suspected if the hives appear after traveling or if the lesions appear after purchasing used furniture. However, the bites themselves are not a definitive diagnosis of bed bug infestation. Affected people should seek medical attention if the itching intensifies. Intense itching from hives can predispose to secondary skin infections with bacteria. Blood loss and iron deficiency anemia have also been reported in people who have been continually exposed to severe bed bug infestations.
The psychological effect of bed bugs should not be underestimated. The presence of bed bugs in intimate places such as beds and rooms often creates anxiety and, if the bites persist, these people can become nervous, agitated, stressed and suffer from insomnia. Bed bugs also cause an economic impact, as infestations often require constant inspections and treatments. Many times furniture infested with bed bugs must be discarded and replaced with new ones, hotel rooms must be kept unoccupied while the infestation is eliminated and this causes economic losses to the hotel industry.
Bed bug detection
There is a greater chance of eradicating infestations when bed bugs are detected early. However, detecting bed bugs is difficult when the infestation is recent, in addition to the fact that these insects have the ability to hide anywhere. Hiding sites can be so remote and inaccessible that it is common for Pest Management Professionals to miss the insects on a regular inspection visit.
Educating yourself about what bed bugs look like and identifying evidence of infestation is extremely critical to properly managing an infestation. Glue traps are not effective in detecting bed bugs. There have been many attempts to develop effective traps for detecting bed bugs using heat, carbon dioxide, and chemical baits. Although some traps may work, many have been developed based on generalizations of host chemicals detected by other blood-sucking insects and the effectiveness of some of these attractants for use in bed bug traps has not been scientifically documented.
Fighting bed bug infestations
Once a bed bug infestation is discovered, its removal is generally not easy. Knowing the biology and behavior of bed bugs is as necessary as developing a complete, patient and multiple approach to be able to effectively eradicate these insects. It is key to hire a professional company with experience in bed bug management.
Many people affected by bed bugs take action into their own hands to control infestations; However, these measures are not aggressive enough to effectively combat these insects. Generally, several treatments with insecticides are necessary because bed bugs can disperse to other places, female bed bugs hide their eggs very well and they are difficult to kill with contact insecticides. Typically, Pest Management Professionals have to treat the site several times before completely eliminating the infestation.
High temperature treatment, a technology similar to that used to eliminate termites, has become popular in several parts of the United States. Temperatures of 60°C for 2 hours, or 55°C for 3 hours, kill most bed bugs and eggs. Other measures that should be incorporated into integrated bed bug control management include the use of vaporizers and mattress covers.
Use of insecticides
Insecticides that are registered for use against bed bugs, not home remedies, are very valuable components of an integrated bed bug control management program. However, using insecticides alone will not eliminate an infestation due to the invasive and hidden behavior of bed bugs.
Pest Management Professionals who choose to use insecticides for bed bug control should consider which insecticides can be used to treat cracks and crevices, mattresses or upholstered furniture, in wall voids, or other locations in the room or home. Since bed bug infested sites may have countless places where bed bugs hide, it is necessary to use various products or formulations, including insecticidal dusts.
The most common active ingredients among registered bed bug control products are pyrethroids and the natural botanicals pyrethrins. In several countries, insecticides such as carbamates and some organophosphates are still allowed to control bed bugs. Pest Management Professionals must use the appropriate equipment for the application of the insecticidal product and also ensure that the product is applied safely and properly according to label directions. They should also review all safety precautions for application, preparation of the areas to be treated, and estimated drying time of the insecticide to also establish when residents can re-enter the treated sites.
Bed bugs have been associated with humans for thousands of years and will continue to be a pest for a long time. Although it is normal to feel anxiety and worry when the presence of bed bugs is discovered, it is important to remember that they can be controlled with diligence, cooperation, complementary treatments and with the proper use of available products. Knowledge is the most valuable tool in preventing bed bug infestations, as well as combating this insect when it has established itself.