Where do bed bugs come from?

Almost everyone who finds bed bugs asks the same thing first: how did they get here? The honest answer is that it is usually impossible to say for certain. What is certain is where they did not come from. They do not appear out of damp, rubbish or a dirty house. They are carried in.

They travel with people’s belongings

Bed bugs cannot fly or jump. They are flat, about the size of a lentil, and very good at squeezing into seams, folds and joints. That makes them ideal stowaways. The University of Kentucky’s entomology department, one of the most cited sources on the subject, lists the usual ways in as luggage, clothing, beds, furniture and other belongings.

In practice, most London infestations trace back to one of these:

• A trip away. A hotel, hostel, holiday let or a friend’s spare room. Bugs climb into a suitcase left on the bed or the floor and come home with you.
• Second-hand furniture. Mattresses, bed frames, sofas and upholstered chairs, whether from a market, an online listing or left out on the pavement. The NHS specifically warns against bringing second-hand furniture indoors without checking it carefully.
• Visitors and new flatmates. Someone staying over, or moving into a shared house, can bring them in their bags without knowing.
• Moving home. Removal vans, storage units and the previous occupant’s leftovers.

Being clean makes no difference. Bed bugs feed only on blood, so a spotless flat suits them as well as a cluttered one. Clutter does make them harder to find and treat, which is why specialists ask you to clear it before a visit.

In flats, they also come from next door

This is the part that matters most in London, where so many people live in flats, conversions and shared houses. Once bed bugs are in a building, they spread. The University of Kentucky notes they move between rooms, floors and flats through cracks and openings.

In a London block or a converted terrace, those openings are everywhere: the gaps where heating pipes pass through a floor, cable runs in shared risers, gaps behind skirting boards, and the spaces under old floorboards. If a neighbour’s flat is being treated, bugs can also be pushed into yours.

Signs that bed bugs may have come from a neighbour:

• You have not travelled or bought second-hand furniture recently.
• The first bites or spots appeared in a room that shares a wall with another flat.
• A neighbour, a building manager or a letting agent has mentioned bed bugs.

If that sounds familiar, tell your landlord or managing agent as well as the specialist. Treating one flat in a building where the next one is still infested is how people end up paying twice.

What about the Tube and buses?

In the autumn of 2023, after reports of bed bugs on public transport in Paris, videos claiming to show bed bugs on London trains spread widely on social media. The Mayor said at the time that there was no sign of an infestation on the Underground, and that cleaning was being stepped up as a precaution.

Could a bed bug hitch a ride on a commuter’s coat? It is possible, as it is on any seat where people sit for a while. But the realistic risk is small compared with the routes above. A bug needs to get from a seat onto you, stay on you, and then get off in your home. Beds, sofas and suitcases are far more likely carriers than a 20-minute journey.

How to stop them coming home with you

The British Pest Control Association suggests a few simple habits:

When you travel

• Before you unpack, check the mattress seams, headboard and the edges of the bed in a hotel or holiday let. Look for small dark spots, blood smears and the bugs themselves.
• Keep your suitcase off the bed and the floor. A luggage rack or the bath is better.
• When you get home, unpack straight into the washing machine. The NHS advises a 60°C wash and a hot tumble dry for at least 30 minutes for anything that might be affected.

With second-hand furniture

• Check every seam, joint and fold with a torch before it comes through the door.
• Be most wary of mattresses, bed frames and upholstered sofas. Hard furniture is easier to inspect.
• Never pick up a mattress left on the street. In London, a dumped mattress outside a block is sometimes there because of bed bugs.

In a block of flats

• Report bites or signs early. A building problem caught in one flat is much cheaper to deal with than one in six.
• Do not move your mattress or bedding through shared corridors or stairs until you have spoken to a specialist.
• Ask whoever treats the building whether neighbouring flats should be checked.

Can bed bugs come from nowhere?

No. A home that has no bed bugs today and no new belongings, visitors or connections to an infested flat will not develop them. When people say they “just appeared”, the most common explanations are that they arrived weeks earlier and the numbers have only now grown large enough to notice, or that they came from a neighbouring flat.

Bed bugs can also survive a long time without feeding. University of Kentucky entomologists put it at one to four months in a warm building, and much longer somewhere cold. That is why an empty flat can still have them when a new tenant moves in.

What to do if you think they have arrived

If you have bites, spots on the sheets or have seen a bug, the next step is to confirm it. Look along the seams of the mattress and the joints of the bed frame. Our guide to the signs of bed bugs shows where to look.

Do not spray shop-bought insecticides or set off a fogger. They tend to scatter bed bugs into other rooms and make the job harder. The NHS advises contacting your council or a pest control service, because getting rid of them yourself is very difficult.

If you want a specialist to check, we can find one who covers your borough. An inspection usually costs £60 to £150 in London, and many firms take it off the price if you book the treatment.