Bed bugs: what their bites do and do not do, why they came back and what getting rid of them involves

Qantas took a Boeing 787 out of service in Rome this month after bed bugs were found in economy seats on a flight from Perth, the Guardian reported on October 13. The return flight was canceled while the cabin was cleaned. The paper described the culprits in a sentence. Bedbugs are small, difficult-to-eradicate insects that feed on the blood of some mammals, including humans.

Both parts of that description hold up in the research. Bed bugs bite, and they are hard to remove. What the research does not support is the fear that tends to follow a story like this one, that they spread disease. Decades of study have found germs inside bed bugs and no case of the insects passing one to a person. Their documented harms are itchy skin, lost sleep, distress, cost and, in a growing number of poison center reports, exposure to the chemicals people use against them.

What bed bugs are

Bed bugs are insects of the genus Cimex, and two species feed on people. A genus is a group of closely related species. The common bed bug lives mainly in temperate regions and the tropical bed bug in warmer ones.

The Centers for Disease Control and Prevention (CDC) gives the basics. Bed bugs are reddish-brown in color, are wingless, and range from 1mm to 7mm in size. They are flat, which lets them slip into seams and cracks. They feed at night on the blood of sleeping people and animals and hide by day in mattress seams, bed frames, headboards and nearby furniture.

They are patient. They can live several months without a blood meal. And they stay close to their food. According to the CDC, bed bugs can travel over 100 feet in a night but tend to live within 8 feet of where people sleep.

Because they cannot fly, they spread by being carried. The CDC says they move by getting into the seams and folds of luggage, overnight bags, folded clothes, bedding, furniture and other hiding places. Michelle Power, a parasitologist at Macquarie University, told the Guardian how the Qantas insects probably boarded. “They’re associated with travel. People may go to a hotel that’s infested and because they like dark spaces and are attracted to the smell of human clothes, they make their way into someone’s luggage,” Power said.

Hygiene has little to do with it. How clean a place is does not determine whether bed bugs are present, the CDC says, noting that they turn up in five-star hotels.

What bed bug bites do

A bed bug’s saliva contains substances that numb the skin and keep blood flowing, so the bite is not felt at the time. What follows depends on the person. The CDC lists the range as no physical signs, small bite marks or, rarely, serious allergic reactions. It says the marks look similar to mosquito or flea bites.

Timing varies as much as appearance. Most people do not notice the bite marks until they appear from one to several days after the initial bite. For some the delay is longer. The agency notes that these bite marks may take as long as 14 days to develop in some people.

The standard medical description comes from a 2012 review in the journal Clinical Microbiology Reviews. Skin reactions, it says, can start out as small macular lesions that can develop into distinctive wheals of around 5 cm in diameter, with intense itching. Macular means flat and discolored. A wheal is a raised, swollen patch of skin. Five centimeters is about two inches. The review adds a pattern that many people recognize. Often, bites occur in lines along the limbs.

A 2026 systematic review gathered every published case report it could find to see where on the body bites fall. Eighty-four patients were included. The arms and legs, which are often uncovered in bed, were bitten most. In that review, arms were reported in 71.4% of cases, legs in 59.5% and trunk in 34.5%.

The same review cautions that bites are easy to misread. It found variable dermatologic patterns that can be confused with other arthropod bites. Dermatologic means relating to the skin, and arthropods are the group that includes insects, mites and spiders. A bite mark alone does not prove bed bugs. That is why the CDC points to other evidence of an infestation, such as shed skins, live insects in the folds of mattresses, rust-colored blood spots on mattresses or furniture and a sweet, musty smell.

Doctors treat bites simply, and the treatments are largely untested. The CDC says bites usually do not require medical treatment, and mentions antiseptic creams and antihistamines for itching. A systematic review in JAMA, a leading medical journal, looked for trials and found none for bites. Its authors concluded that treatment options for cutaneous and systemic reactions from bed bug bites have not been evaluated in clinical trials. Cutaneous means of the skin, and systemic means affecting the whole body.

Do bed bugs spread disease?

This is the question with the most reassuring answer.

Bed bugs drink blood, as mosquitoes and ticks do, so it is reasonable to ask whether they carry infections from one person to the next. Researchers have looked inside them and found plenty. The 2012 review put the tally in a sentence. Over 40 pathogens have been detected in bed bugs, but there is no definitive evidence that they transmit any disease-causing organisms to humans. A pathogen is a germ that can cause disease.

A systematic review four years later asked the question directly. It searched for clinical and laboratory studies from 1990 to 2016 that tested bed bugs as vectors, which means carriers that pass an infection on. The authors wrote that upwards of 45 disease pathogens have been reported in bed bugs. Their conclusion was unambiguous. To date, no published study has demonstrated a causal relationship between bed bugs and infectious disease transmission in humans.

The review does not close the matter entirely. Laboratory experiments have shown that some organisms, including the parasite that causes Chagas disease, can survive inside bed bugs. The authors call those results worrisome and add a caveat about them. In their words, pathogens may behave very differently in laboratory conditions than in real life. They also note that studies have reported bed bugs unable to transmit hepatitis B virus and HIV.

The earlier JAMA review reached the same place. Evidence for disease transmission by bed bugs is lacking. The CDC’s current summary is that bed bugs are not known to spread diseases to people.

Other health effects of bed bugs

The absence of infection does not make bed bugs harmless.

Sleep and mental health. The CDC lists insomnia and anxiety among the effects of bites. Few studies have measured exposure in a general population. One comes from Montreal, where researchers analyzed a housing survey of 5,000 adult tenants. Four percent of tenants reported being exposed to bed bugs in the year preceding the survey. Those tenants had about 1.7 times the odds of reporting anxiety or depression, after taking sociodemographic factors and housing conditions into account. When the figures were weighted to represent the city’s tenants as a whole, the gap narrowed. The weighted estimate for the same outcome was about 1.5 times the odds, with a range from slightly lower odds to 2.5 times, which is no clear difference.

The survey was a snapshot. It cannot show whether bed bugs came before the anxiety. Its authors nonetheless argue that the biggest health impacts of bed bugs appear to be psychological. They also describe who is exposed. Infestations, they write, are more prevalent in high-density multi-unit housing environments, and disproportionately affect people in vulnerable situations.

Power made the same point to the Guardian. People already facing health inequities, they said, may not be able to afford pesticides or the hot water needed to kill the insects.

Blood loss. In heavy, long-running infestations the feeding itself can matter. The 2012 review warns that anemia may result when bed bugs are numerous, and their allergens can trigger asthmatic reactions. Anemia is a shortage of red blood cells. The 2026 review of case reports found such problems confined to severe infestations in neglected patients. Its summary of the wider picture was that psychological manifestations were reported in a small subset of cases, while systemic complications were rare.

Poisoning from treatments. The 2012 review foresaw a harm that comes from people and not from the insects. The misuse of chemicals and other technologies for controlling bed bugs has the potential to have a deleterious impact on human health. Deleterious means harmful.

French data bear that out. The French Poison Control Centers recorded 1056 cases of exposure to bed bug insecticide products between 1999 and 2021, with a marked rise from 2016. Of the patients whose age was known, 16% were under 18. The reports showed repeated misuse of insecticides, including substances banned or not approved for this use. About three in four patients had symptoms, nearly all of them mild, and one case was fatal.

Why bed bugs came back

For a few decades bed bugs were rare in wealthy countries. Then they returned. The 2012 review dates the change. Since the late 1990s, bed bugs of the species Cimex lectularius and Cimex hemipterus have undergone a worldwide resurgence.

A 2022 review in the Annual Review of Entomology, co-written by the lead author of the 2012 paper, gives the leading explanation. The resurgence is believed to be primarily due to the development of insecticide resistance, along with global travel and poor pest management. Insecticide resistance means that the insects have evolved to survive chemicals that once killed them.

The practical result is that sprays alone often fail. The JAMA review said in 2009 that control was challenging due to insecticide resistance, lack of effective products, and health concerns about spraying mattresses with pesticides.

What getting rid of bed bugs involves

US agencies describe a slow process that uses several methods at once. The Environmental Protection Agency (EPA), which regulates pesticides, sets expectations at the top of its guidance. Treating bed bugs is complex and can take weeks to months, depending on the extent of the infestation. Success, it says, depends on how many insects there are, how much clutter gives them cover, whether neighbors have them and whether everyone in the building takes part.

The EPA’s guidance covers the following methods.

• Heat. For fabrics, the agency says a person can use a clothes dryer on high heat. It says steam cleaners can treat carpets, baseboards and bed frames if the steam reaches at least 130 degrees Fahrenheit. It warns against trying to heat a home with a thermostat, space heater or fireplace, which it calls ineffective and dangerous.
• Cold. Freezing works only at 0 degrees Fahrenheit for three days, and the EPA notes that many home refrigerator freezers are not cold enough to kill bed bugs.
• Barriers and traps. The guidance includes sealing cracks and crevices with caulk to remove hiding places. Sealing covers for mattresses and box springs trap insects inside. The agency adds that bed bug interceptor traps can be placed under the legs of furniture to catch bed bugs as they climb.
• Pesticides. The EPA points to products registered with it that list bed bugs on the label. It is cautious about foggers, also called bug bombs. The spray will not reach the cracks and crevices where bed bugs hide. It describes desiccants, powders that kill by drying the insect out, as a class the bugs cannot become resistant to, though they can take months to work.
• Things that do not work. Under treatments to avoid, the EPA lists rubbing alcohol, kerosene and gasoline, which it says can harm people and easily ignite. It says sticky traps are not meant for bed bugs.

The agency’s guidance says checking continues for at least a year after treatment ends. The CDC, for its part, points people who suspect an infestation toward a professional pest control company.

Entomologists call this layered approach integrated pest management. The 2012 review described it as nonchemical means of control combined with the judicious use of insecticides. How well any one method works is less certain than the lists suggest. The JAMA review’s search turned up few controlled tests. Only 2 clinical trials concerning bed bugs were identified, both of pest control methods, and the reviewers found no evidence-based way to eradicate the insects or prevent bites.

What the bed bug evidence cannot show

That transmission is impossible. No study has shown bed bugs infecting people. That is an absence of evidence after a long search. Some viruses have never been specifically tested.

How common bed bugs are. Good counts are scarce. The Montreal figure of 4% covers tenants in one city in 2017 and relies on people’s own reports.

Whether bed bugs cause anxiety. The survey measures both at a single moment, and people in poor housing face many other strains.

What bites typically do. The 2026 review drew on 84 published cases, and doctors write up unusual cases more often than ordinary ones.

Which control methods work best. The 2009 search found only two trials, and the 2022 review calls for better insecticide test protocols and management strategies.

Age of the main review. The main clinical review dates from 2012. Its description of bites has held up, while the control picture has moved on.

Whether a skin reaction in a particular person needs treatment is assessed by their doctor.

Bed bugs remain a pest of skin, sleep and peace of mind, and the evidence so far has not shown them passing disease to people.