Bed bugs may cause more than just itchy welts, as researchers warn the blood-sucking pests can harbour and transmit a deadly strain of antibiotic-resistant bacteria.
A resurfaced study by researchers at the University of South Dakota revealed that bed bugs can acquire Methicillin-resistant Staphylococcus aureus, commonly known as MRSA, from a single feeding on contaminated skin and pass it to other humans during subsequent feeds.
While MRSA is generally harmless when restricted to the surface of the skin, causing only red and swollen boils, it can cause multiorgan failure and kill about one in five patients if it enters the bloodstream through an open wound. Because MRSA does not respond to common antibiotics such as methicillin and penicillin, treatment is limited to alternative drugs that carry higher side effect risks and take longer to clear the infection.
Jose Pietri, author of the 2023 study who is now at Purdue University, emphasized that more research is needed to confirm if bed bugs can truly spread MRSA to humans, but noted "it changes the perspective of what bed bugs do, in terms of public health."
Bed bugs, which are roughly the size of an apple seed, hide between mattress seams and inside cracks of wooden bed frames during the day before emerging to feed on the blood of sleeping humans at night. When the bugs pierce the skin, they leave behind itchy red welts that can trigger allergic reactions.
Experts believe bed bugs originated over 245,000 years ago in caves, living on bat blood before eventually shifting to humans. Ancient records documented their presence in Egypt and Greece, while European settlers brought them across the Atlantic to American colonies in the 17th and 18th centuries.
Surging infestations across major American cities
The findings on MRSA come as bed bug infestations surge across the United States, with all 50 states reporting their presence in hotels and apartments with high tourism and foot traffic. Experts estimate that the bed bug population in the country has increased fivefold over the past decade, with major metropolitan areas bearing the brunt of the increase.
Recent data from pest control company Orkin shows Chicago is America's most bed bug-infested city for the fifth year in a row. Experts attribute Chicago's top ranking to its dense population, heavy tourist traffic, and abundance of multi-unit buildings. Los Angeles, Detroit, Cleveland, and Indianapolis rounded out the top five most infested cities.
"Bed bugs are resilient pests that can be difficult to control once introduced into a home or hotel room, and they are skilled at hiding in cracks, crevices and personal belongings," said Dr Shannon Sked, Orkin entomologist and national technical director. "A quick inspection of hotels or short-term rentals while traveling, or belongings before unpacking at home, can help travelers reduce the chance of bringing bed bugs home."
Though the findings regarding MRSA have sparked concern, experts note there is not yet clear evidence that bed bugs can spread other diseases from person to person, owing to their unique anatomy and digestion.
Spotting signs and treating bed bug outbreaks
Because bed bugs are so tiny, detecting an early infestation can be difficult. Subtle clues include small blood stains on pillowcases and sheets, tiny black dots of fecal matter, a lingering musty odor, and small pale yellow or pearly-white oval eggs that measure about one millimeter.
To prevent bringing pests home, experts urge travellers to check suitcases for signs of bed bugs when returning from hotels and to avoid placing luggage directly on or near beds. Laundry should also be washed immediately after returning home.
For active infestations, Pietri suggests hiring professional exterminators who can spray insecticides, though treatment can cost hundreds to thousands of dollars. Homeowners can also use silica dust, a microscopic crystal spray that kills bed bugs by absorbing moisture directly from their bodies.
