Bedbugs reappear after 30 years, say scientists


Booking.com	Published Tuesday, February 25, 2020 Bedbugs reappear after 30 years, say scientists By the A.M. Costa Rica staff and wire services Four scientists from the University of Costa Rica reported the reappearance of bedbugs, Cimex lectularius, 30 years since they had been detected in the country. Scientists Juan Carlos Cambronero-Heinrichs, Ólger Calderón-Arguedas and Adriana Troyo-Rodríguez of the School of Microbiology, together with Laura Sofía Sánchez-Portilla from the School of Biology published their findings in Journal of Medical Entomology. Bed bugs, characterized by being dark or light brown, can measure up to seven millimeters and feed on blood. Since the 1980s, there had been no reports of any species of Cimex in Costa Rica, said the scientists. The bugs were identified with tests at the molecular level that showed the presence of C. lectularius throughout Central America. “We realized the reappearance of bed bugs in Costa Rica thanks to the first report that I received in 2017,” said biologist Sánchez. “A family that lived in an apartment located in the Province of Heredia reported the problem. For a personal interest I introduced myself, collected some insects and then realized that, due to the morphology of the animals, it could be C. lectularius. Afterwards the Faculty of Microbiology made the final confirmation at the molecular level.” Bedbugs are insects considered as ecto-parasites. That means, they do not live inside the host and are only located in the skin. In this case, they do it for short times and only to feed on blood. But its most outstanding ability is survival, which is accompanied by fast reproduction, the scientists said. According to Cambronero, one female can lay about 50 eggs in a month (up to 540 eggs in the total life span that is two years maximum). In three months, there could be hundreds of bedbugs. About 150 days later, the home infestation will be difficult to control. “The form of reproduction of the bugs is very particular because it is given by traumatic insemination,” said Troyo. “To deposit his sperm, the male breaks through the wall of the female's abdomen with his spine. After that process, the female heals the wound and can continue laying eggs for a month without re-copulating. So, with just one-bed bug that has already copulated, it is enough to start a plague.” Sánchez said that a sample of 25 bedbugs was used to identify the arthropod. The finding of the entire scientific team represents an alert call, because in more than 30 years in Costa Rica there were no reports. “In 2010 there was a resurgence of this insect as a pest in many parts of the world, and it has the potential to be a public health problem,” said Sanchez. “We should not be alarmed, because this insect does not transmit any disease. C. lectularius has a lot of history and has accompanied humans for thousands of years, even Socrates mentions it in some of his texts. However, care should be taken because the bed bug causes bites and pula (hives with infection). If there is an infestation, anxiety problems such as insomnia, phobias or poor sleep can be increased.” According to scientists, one of the main possibilities of the bedbugs reappeared is the high number of international trips, so that the main cause of dispersion is a consequence of human beings themselves. By the end of the 20th century, bedbugs of the species C. hemipterus had been reported in the country. Therefore, the C. lectularius represents a new species that arrived in the country, due to its enormous capacity to move from one continent to another through furniture, suitcases and clothing. The scientific community even considers them cosmopolitan insects. “We don't know where they came from,” said Cambronero. “Bedbugs are transported primarily by passenger luggage. For example, when the person is asleep in a hotel or house , bedbugs at night come out and then they can hide between the briefcase or the suitcase with clothes. Smaller bedbugs can be difficult to detect and, if it were a female, there could even lay eggs that are even harder to see. People don't realize it and take them home. This ends up generating the infestation.” For bedbugs to become a plague, they must complete their life cycle. First, they must leave the egg that measures almost a millimeter, and then successfully overcome five stages of metamorphosis, known as the nymph states. They all sting to feed on blood. When insects arrive at a home, the first one continue this process successfully to reproduce. “Bedbugs can be found hidden in wooden furniture, cracks in the walls, floors inside holes. Their favorite places are those that are hidden from the light, narrow and near where they are feeding during the night. The bugs are flattened, which also allows them to be in hard-to-reach places such as slits, between the joints of the boards or the screw holes of a bed, ” said Troyo. The other two components that have to do with their reappearance are resistance to insecticides and inadequate pest control, according tot he scientists. “One of the main problems is the control method used by fumigators, usually for other pests. These methods are not completely effective for bugs, because many times the fumigation does not penetrate those holes where the insects are, ” said Cambronero. Currently, the fumigation treatment that is applied is usually the traditional one through pyrethroids (molecules with insecticidal activity). However, many of the populations of C. lectularius have developed resistance, as a result of repeated use of these molecules and others such as pyrethrins and deltamethrins, he added. “Around the world, many of the bed bugs are highly resistant to pyrethroids. Recent studies have revealed that this phenomenon is linked to mutations. Resistance is something very gradual. It does not occur from one moment to another. In other words, it is not that the infested house treated it with a pyrethroid and in a week it will have resistant populations. It's something that takes a more long time, ” said Cambronero. For readers who think you may have these bugs in the home, scientists recommend: - Make sure they are bedbugs. To be sure, you can ask the Cimex C.R. at the cell phone (506) 8591 4502. Also, you can contact the Medical Entomology section of the Faculty of Microbiology of the university at (506) 2511 5430. In case of a positive result, if the creatures are bedbugs, those affected should start the pest control immediately. The scientists recommend hiring a pest control agency with proven experience in this type of bug. The company must select the chemical that is going to help eliminate the problem. An experienced agency must apply complementary strategies beyond the chemical, such as aspiration or the application of heat so that the bugs leave where they are hidden. The scientists recommend not spraying without the help of pest control professionals because there is a risk that the insects will not be eliminated. Despite the resistance, in the last 10 years, insecticides have been the quintessential treatment to fight bedbugs, they said. However, a truly effective approach requires integrated control, they added. “In the United States, the use of insecticides is reported with another compound called piperonyl butoxide, an inhibitor of one of the enzymes that make the parasite more resistant to the insecticide. So, we inhibit that enzyme that allows bugs to eliminate toxic substances and thus the insect becomes more sensitive to pyrethroid treatment,” said Cambronero. But the right treatment is not enough just to apply insecticides, the scientists warn. It is also necessary to vacuum the insects, use alternative measures and apply the chemicals several times, as some of the eggs can survive and hatch. This would generate the infestation again. “Not all infestations have the same conditions and people should not be guided by advice on the internet. Some source says you have to burn the furniture when this is dangerous and can be treated more effectively and safely. People should not be afraid to talk about the problem and be aware that the correct approach is taken from various angles to achieve the desired result, not to generate resistance and to protect health and the ecosystem, ” said Sanchez. If you believe you have this parasite in your home, you can take a photo of the insect and contact the scientists at the Cimex C.R. telephone (506) 8591 4502, or, you can contact the Entomology section of the UCR School of Microbiology at telephone (506) 2511 5430. ------------------------ Have you heard of bedbugs in your home country? We would like to know your thoughts on this story. Send your comments to news@amcostarica.com