Don’t let the bed bugs – or the dust mites – bite

Ah, bed. A place of rest and refuge… But not always just for you, as you might have to share it with some small, scaly and successful insects.

Some of these “guests” can destroy your sleeping and waking life – like bed bugs – or they can be so innocuous and secret that you might never know they’re there unless they give you an allergic reaction or asthma – that’d be the dust mites.

Let’s start with bed bugs.

Bed bug nymph, Cimex lectularius, sucking blood from the arm of a “voluntary” human host (Photo by Piotr Naskrecki, via Wikimedia Commons)

These little bloodsuckers are on the rise. In the past, they used to be a nasty problem in high density living – imagine if you will what it was like in the Middle Ages.

They greatly declined in numbers in the 20 century, but now they’re on the rise again as they hitchhike on global travellers. They can sneak into your bags and clothes and get a lift to the next spot.

In New York, the Statue of Liberty bears the inscription: “Give me your tired, your poor/Your huddled masses yearning to breathe free.” Unfortunately, those “huddled masses” now includes bed bugs.

To battle this crisis, the city has a management plan which states:

Bed bugs have become a serious issue for many New Yorkers, especially those least equipped to deal with them. The spread of bed bug infestations is a burden on the resources of New York City residents, property owners and health and social services providers in both the public and private sector. Bed bugs are not known to transmit disease through their blood-feeding activity; however, it is the Advisory Board’s position that bed bugs are a pest of public health importance due to the emotional and psychological impact that they can have on those affected (Reinhardt and Siva-Jothy, 2007; Hwang et al., 2005; Kussman, 2008; Doggett and Russell, 2009; Potter et al., 201)

Australia’s not immune either – according to the Department of Medical Entomology at Westmead Hospital, we’ve had a 5000% increase in bed bug infestations since 1999.

But what exactly are bed bugs? Well, they’re actually a type of wingless insect. They are only 5-6 mm long and are a rusty brown colour – although they change to a deeper red after they have had a meal of blood. They are quite flat and this lets them sneak into cracks and crannies.

Their life cycle starts with 5 juvenile stages, all known as nymphs, which are pale and only 1-4 mm long. In each of these stages the bed bug needs a blood meal. It takes them only 5-10 minutes to get full of your blood and then they drop off and back to bed.

It takes the bed bug 6-8 weeks to grow up and then adults can live for 6 months (although they can actually live for longer than that if it’s cold). Females lay 2-3 eggs a day in their lives and these will hatch in around 10 days.

The two main species that bite humans include the common bed bug, Cimex lectularius, and the tropical bed bug, Cimex hemipteus.

They don’t really live on humans, they just jump on for a feed and they like to feed at night. They cluster together in dark secret spots, like under mattresses and behind wallpaper, and can emit a sweet, buggy smell. Blood spots on the bedclothes are also a sign – if the red itchy welts are not a big enough indicator themselves.

People can get a skin reaction to them because they inject a little bit of saliva into you when they bite (like mosquitoes). Your body reacts to this saliva and causes a little welt that can be itchy and inflamed. These red spots can last a couple of days. And it has been recorded that if you get bitten enough you can get iron deficiencies!

But it could even be that the psychological impacts are the most sinister: the thought of little creatures feeding on your blood that might leave a red welt, not to mention the sleeplessness that might accompany being fed on.

Getting rid of them can be tricky as they can hide in small places. You can wash everything in hot water or freeze it – if it will fit in the freezer. But if they are in the house, they will hide everywhere, so they can be hard to wash or freeze away.

Alternatively, you can use a pesticide like synthetic pyrethroid (a pyrethroid is a chemical produced by the flowers of pyrethrums, such as chrysanthemums). These chemicals cause paralysis in the insect. The chemical breaks down in sunlight and will be broken down in a day or two.

If all this hasn’t quite got your skin crawling, here’s a nice video to make you squirm.

Now onto dust mites, as these little critters can also live in your bed.

House dust mite, Dermatophagoides pteronyssinus (Image from US Food and Drug Administration, via Wikimedia Commons)

These are not too noxious, as they don’t feed on your blood but on the dead skin cells that have fallen off you, as well as other small bits of organic matter. They can however cause allergic reaction and asthma.

Dust mites are not insects, they’re mites, from the class Arachnida (along with spiders). They are really small – only about half a millimetre or smaller – and can only just be seen by humans in the right light.

They live in the layer of very fine dust that settles around the house. People are allergic to their bodies and to their poo. In a 10 week life, a dust mite can produce 2000 very small poos and many more dust particles that are covered in digestive enzymes. Oh, and they like their food to be a little decomposed from fungi.

Apparently sunlight will kill dust mites if you leave your bed clothes out in the sun for a couple of hours. You can also wash your bedclothes in warm water and even put them in a dryer for 10 minutes, and they all will be killed.

You can also vacuum a lot and cover all your mattresses and furniture in plastic that you can wipe down, but it’s pretty impossible to remove dust mites from a house. But, like many unwanted house guests, you might not be able to get rid of them, but you don’t have to share your bed.