What are bedbugs and why are they making a comeback?

Night night, sleep tight...
13 October 2023

Interview with 

James Logan, London School of Hygiene and Tropical Medicine


A bed bug nymph (Cimex lectularius) as it was in the process of ingesting a blood meal from the arm of a “voluntary” human host


“Night night. Sleep tight. Don’t let the bedbugs bite!” will be a familiar bedtime rhyme for many across the world. But it’s fast becoming one that you may need to take more seriously, because these critters are back with a vengeance and causing very real problems in some major cities…and there are also fears they are on the move. To separate the fact from the fiction, Professor James Logan is a bedbug expert at the London School of Hygiene and Tropical Medicine…

James - bed bugs are really quite fascinating insects in their own right. A lot of people get them mixed up with house dust mites. So when you think about bed bugs in your home, you think about something microscopic that's crawling around on your bed, but those tend to be dust mites. bed bugs, when they're adults, are actually pretty big about the size of an apple pip. When they're younger, they can be a bit smaller than that and sort of translucent. They need blood to produce eggs and to survive. Although one of the incredible things about them is that they can survive for up to a year without feeding on any blood, which makes them really formidable insects to control.

Chris - How do they find us and why do they go for us?

James - Well, they will feed on pretty much any animal. So if you've got a pet at home, they might feed on that pet as well, although they tend to prefer to feed on us. And like most insects, they use their sense of smell. So they're attracted to chemicals that are given off in our body odour and in our breath. So let's set the scene. Imagine you've come back from holiday and you've been staying in a hotel with bed bugs. When you get back home, the bed bug comes out of your suitcase. The first thing it will do is run off and it will hide somewhere. It will get into a little tight space until it feels safe. Then when the lights go off and it can smell a human, it will come out and it'll follow that trail of odour and heat to find you where it'll then feed and then as soon as it's done that it goes all the way back to its safe refuge.

Chris - And how do you know you've fallen victim to a bed bug and not say a mosquito or a flea?

James - It can be quite difficult to determine the difference between bites. Reactions vary and so it's difficult to kind of pinpoint it. But with a mosquito, you tend to just get one bite, maybe two. With a bed bug, you often get a cluster of bites. Sometimes they're in a line as well. So if you imagine you're lying on your bed and your arm is sort of outside of the sheet, a bed bug might crawl onto the bed onto the mattress and it will feed and it will probably sort of move along the arm. It'll take multiple bites along the arm. So you might get a line of bites if you're staying somewhere where there's a really bad infestation. You know, it's quite rare, but it does happen if there's a bad infestation. People report having hundreds and hundreds of bites, which can be really quite debilitating.

Chris - And how do the bed bugs themselves reproduce?

James - The male essentially penetrates through the cuticle of the female and inserts sperm into the female, which is quite traumatic for the female as you can imagine. But that's quite an unusual way of mating. But once that's happened, then after a few weeks the female will lay eggs and she can lay hundreds of eggs. And if you've got an infestation, you can often see those eggs either sort of in a crack in furniture or along the mattress. And they're tiny. They're really, really small. Sort of white, sort of transparency, white sort of colour as well. Once they hatch out, it takes a couple of weeks for them to then become adults themselves. All the time they require blood, so they'll be feeding every few days until the point at which they then begin to lay eggs, once they've mated as well. So an infestation can go from one pregnant bed bug laying eggs to thousands of bed bugs within a matter of weeks.

Chris - And is this why we keep seeing these reports of cities in America, cities in Europe, like Paris and now people are saying London might be at risk as well? Is that what's going on?

James - We're certainly seeing a trend for bed bug infestations increasing across the world. We've seen reports in France and the UK, New York. But really bed bugs are a global issue. They can be found pretty much anywhere in tropical regions. There's a slightly different species. So for example, the ones that we encounter are Cimex lectularius and the ones that you find in more tropical regions are Cimex hemipterus. Now we're seeing a rise in the number of bed bugs because of a few different factors. One is that bed bugs have become resistant to insecticides and that's causing a big problem. So the toxic chemicals we normally use to kill them are no longer as effective for many populations around the world. The second thing is that as humans, we like to travel and travel over the years has increased substantially. And now we're sort of beginning to get back to the sort of pre pandemic levels of travel. And so that helps to spread bed bugs. And then there's other things as well, like people like to upcycle second hand furniture, which can contain bed bugs if you're not careful. So it's always worth checking that. And then there's climate change to consider as well. Now we don't really know what's happening with climate change and bed bugs. However, as a general trend, we know that warmer temperatures, when there's more months of the year that are warmer, there's more chance of insects surviving better for longer and breeding quicker.

Chris - And so if one does fall victim to an infestation, how do you rid yourself of the pest?

James - You want to pray that you don't. The way to get rid of it essentially is to call a pest controller. Now you can try and tackle it yourself, but the chances are you won't be successful. And there are some products out there that you can use. There are insecticides that you can put down. But as I said, you know, insecticides may no longer work on the bed bugs that might be in your home. What you can do is use some of those products to maybe just sort of control it to a certain extent, but it probably won't get rid of the problem. So unfortunately the best thing you can do is call a pest controller and that's going to cost a bit of money.

Chris - Prevention's always better than cure. What steps can we take to keep ourselves from being infested?

James - So the good news is that there are things that you can do to minimise the risk of bringing home bed bugs. So the first thing I would do is I would check the reviews before you go or before you book a hotel, check the reviews and just check that there aren't reports of bed bugs being there. And if there are reports the hotel may have got rid of the bed bugs and they should say that if they have. Once you're there, and if you think there are bed bugs because you see them or you feel you're being bitten a lot in the room, then ask to move rooms. Or if it's really bad, move hotels. The telltale signs of bed bugs are a) the bites b) looking out for little brown spots on the bed sheets, which are little droplets of poo from the bed bugs. That can be a telltale sign or if indeed you see them. Now if there are bed bugs there, and in fact even if there aren't bed bugs wherever you are, whether it's a five star hotel or it's a youth hostel, it doesn't matter. Keep your luggage off the floor. So use the luggage racks, keep your luggage zipped up. Any clothes that you unpack. Make sure you hang them up in the wardrobe. I wouldn't put them in drawers just in case because that's a likely place with bed bugs possibly to be hiding. Hang them up, don't leave them on the floor. When you then go home, before you go, check your clothes along the seams, just make sure there are no bed bugs hiding in there. Check inside your luggage. When you get back, if you know you've stayed somewhere where there were bed bugs or likely to be bed bugs, unpack your bag in the garden. Bed bugs won't survive outside. So that's a good place to do that. And then if you're really worried, what you can do is you can bag up your clothing and stick it in the freezer for a couple of days, which should kill anything that's there. The other thing you can do is wash your clothing at 60 degrees and that would kill any bug that is there as well.


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