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Updated: 16 hours 59 min ago

Bedbugs thought to 'hitchhike' on dirty holiday laundry

Fri, 09/29/2017 - 18:00

"Dirty laundry a powerful magnet for bedbugs, study finds," is The Guardian's headline, with The Times and The Daily Telegraph also covering this creepy-crawly story.

Bedbugs are small blood-sucking insects that live in cracks and crevices in and around beds. They crawl out at night and bite exposed skin to feed on blood.

The number of bedbugs has soared across the globe recently, with cheap air flights believed to play a role in their spread. But until now, it hasn't been clear how or why these tiny wingless bugs manage to travel great distances.

The authors of this latest study now think they have the answer: dirty laundry left lying around in hotel rooms, regardless of the presence of a human host.

In experiments done on identical rooms, researchers found bedbugs were most likely to collect in bags containing dirty clothes than in bags of clean laundry. The researchers propose that traces of body odour on dirty laundry are enough to attract the critters – the presence of humans isn't necessary.

Once in the laundry bag, the insects can travel in a person's luggage back home and then hide under mattresses, in headboards, or along carpet edges.

The researchers suggest a simple way of protecting yourself against the unwelcome hitchhikers: keep dirty laundry in sealed bags.

This was a small experimental study with limitations. But as bedbug infestations are so tricky to treat, prevention is key – and it makes sense to try this simple measure the next time you're travelling.


Where did the story come from?

The study was carried out by researchers from the University of Sheffield and was funded by the university's Department of Animal & Plant Sciences.

The study was published in the peer-reviewed journal Scientific Reports and is free to read online.

The Telegraph headline, that "Keeping dirty laundry in the bedroom allows bed bugs to thrive," may be slightly misleading: bedbugs have to be present in the first place, so the average home is unlikely to be at risk. It is travel that's likely to pose more of a risk, which the article doesn't mention until later on.


What kind of research was this?

This was an experimental study, carried out by researchers who wanted to understand how and why bedbugs travel so easily in suitcases and clothes, given that they like to hide in crevices in and around beds and are thought to like being near sleeping people.

The researchers of this study wanted to look into how odours may attract bed bugs while also investigating other potential reasons, such as carbon dioxide levels, which have previously been shown to influence mosquitoes.

Experimental studies like this are useful early stage research – however, especially in a study such as this one, there could be other factors at play that can't be necessarily be accounted for in a controlled environment.


What did the research involve?

Clothes were taken from four volunteers, which had been worn for 3 hours during normal daily activity. Clean clothes were also used as a comparison. Both sets of clothes were placed into clean, cotton tote bags.

Two temperature-controlled (22C) experimental rooms were used. One of the rooms received an increase in carbon dioxide (CO2) to imitate a human breathing in the room; the other room had normal levels of carbon dioxide.

A sealed container with bed bugs in was placed in each room for 48 hours. Four clothing bags were then introduced into each room – two containing soiled laundry and the other two containing clean laundry, placed in such a way to alternate between clean and dirty.

After 24 hours, the lid of the container was removed, allowing the bugs to roam free. After a further 96 hours, the number of bedbugs and their locations were noted.

Location was categorised into three groups:

  • remaining in the original space
  • within/on clothing bag
  • on the floor of the arena (room)

The experiment was repeated six times and the rooms were cleaned with bleach between each run. Findings were compared between the two rooms.


What were the basic results?

This study found the following:

  • Bedbugs were more likely to be on or within the bags containing soiled clothes than the ones containing clean laundry. Levels of carbon dioxide had no effect on this.
  • Higher CO2 levels did, however, affect the behaviour of bedbugs within the room: more bedbugs left the container in the high-CO2 room compared with the control room.


How did the researchers interpret the results?

The researchers concluded: "Our results show that over a period of several days bedbugs are attracted to, and remain on, soiled clothing: this provides a biologically realistic mechanism that underpins passive, long-range dispersal in bed bugs."

They added: "Careful management of holiday clothing may be an important strategy in the prevention of bringing home bedbugs."



This experimental study suggests a likely way that bedbugs get into luggage and travel long distances to spread between countries.

It found that bed bugs are more attracted to dirty laundry than clean laundry, highlighting that it is probably human body odour – regardless of whether a human is present or not – that is the magnet for bed bugs.

The researchers suggest that worn clothing left out in the open – even just in an open suitcase – is likely to attract any bedbugs that may be present in a hotel room or hostel, and be transported back home by holidaymakers.

But don't worry: a laundry bag in the average home probably isn't a cause for concern, where bed bugs are thankfully quite rare.

While bedbugs aren't dangerous and don't spread disease, some people can experience a reaction to the bites.

Signs of an infestation can include:

  • small bugs or tiny white eggs in the crevices and joints of your mattress and furniture
  • bites on your skin
  • tiny black spots on your mattress or blood spots on your sheets
  • mottled bedbug shells

Keeping your laundry sealed in a bag the next time you're travelling is a simple measure that may reduce your chance of bringing home the unwelcome hitchhikers.

Read more about bedbugs and how you can keep your home bug-free.

Links To The Headlines

Dirty laundry a powerful magnet for bedbugs, study finds. The Guardian, September 28 2017

Keeping dirty laundry in the bedroom allows bed bugs to thrive, say scientists. The Daily Telegraph, September 28 2017

Bed bug pandemic is linked to dirty laundry. The Times, September 29 2017 (subscription required)

Links To Science

Hentley WT, Webster B, Evison SEF, Siva-Jothy MT. Bed bug aggregation on dirty laundry: a mechanism for passive dispersal. Scientific Reports. Published online September 28 2017

Any type of physical exercise is good for the heart

Fri, 09/22/2017 - 01:00

"Vacuuming and scrubbing the floor are enough exercise to protect the heart and extend life," reports The Telegraph, with other media sources reporting a similar finding – that physical activity in our everyday lives is just as good as going to the gym.

This follows a large international study published in The Lancet that included more than 130,000 people from 17 countries.

The researchers wanted to compare physical activity and heart disease levels in countries ranging from low income to high income.

There's firm evidence that regular physical activity reduces the risk of cardiovascular disease (CVD) and other long-term diseases. However, most evidence has come from high-income countries where people often exercise for leisure – for example, going to the gym or playing sport.

In lower-income countries, it's possible people are generally less likely to do recreational exercise but more likely to have physically active lifestyles involving manual work. The aim was to see if this sort of day-to-day activity could be just as beneficial as any other type of exercise.

The main finding was that it made no difference. Physical activity of any type – whether it was walking or doing household chores – was clearly linked with a lower risk of death or heart disease and stroke.

The study supports current government recommendations to do at least 150 minutes of moderate activity a week. People who achieved this had about a 20-30% reduced risk of death, heart disease or stroke compared to those who didn't.

Where did the story come from?

The study was carried out by researchers from Simon Fraser University and Hamilton Health Sciences & McMaster University, both in Canada, and from the University of Edinburgh, among other international institutions.

Funding was provided by a number of organisations including the Population Health Research Institute, and the Canadian Institutes of Health Research, Heart and Stroke Foundation of Ontario, as well as pharmaceutical companies AstraZeneca, Sanofi-Aventis, Boehringer Ingelheim, Servier, GSK, Novartis and King Pharma.

The study was published in the peer-reviewed medical journal The Lancet, and is free to read online.

Generally, the media accurately reported the finding that the more exercise you do – regardless of the type – the better. However, headlines tended to emphasize household and other daily chores rather than recreational activities, which was slightly misleading. Housework wasn't found to be any better than other forms of activity recorded.

What kind of research was this?

This was an international prospective cohort study that looked at the relationship between physical activity and cardiovascular disease and mortality.

The Prospective Urban Rural Epidemiologic (PURE) study included 17 countries around the world with different income levels to see if the benefits of exercise on the heart depended on the type of physical activity done.

What did the research involve?

The PURE study included three high-income countries (Canada, Sweden and the United Arab Emirates), seven upper-middle-income countries (Argentina, Brazil, Chile, Poland, Turkey, Malaysia and South Africa), three lower-middle-income countries (China, Colombia and Iran), and four low income countries (Bangladesh, India, Pakistan and Zimbabwe).

Within the countries, different urban and rural communities were selected to represent geographical diversity. Adults aged 35 to 70 from selected households were invited to take part, mostly between 2005 and 2010.

Participants answered questions on sociodemographics, medical health and lifestyle. They also completed the International Physical Activity Questionnaire (IPAQ), which asked them to record any activity they did – whether non-recreational (occupational, transportation, housework) or recreational.

Total physical activity was categorised as:

  • Low physical activity – less than 600 metabolic equivalents (MET) x minutes per week, which equates to less than 150 minutes of moderate physical activity a week.
  • Moderate physical activity – 600-3,000 MET × minutes per week, which equals 150-750 minutes of moderate activity a week.
  • High physical activity – more than 3,000 MET × minutes per week, equal to more than 750 minutes of moderate activity per week.

The main outcomes the researchers looked at were death from cardiovascular disease and having a heart attack, stroke or heart failure. In high-income countries, this information was taken from registries, but in middle- and low-income countries researchers sometimes had to rely on family or friends of participants to provide information on probable cause of illness or death.

The analyses included 130,843 people who completed the IPAQ. Anyone who had CVD at the start of the study was excluded. Researchers looked at the relationship between activity and cardiovascular disease or heart-related deaths, adjusting the data to take into account factors that may have influenced results, such as age, sex, BMI and waist-hip ratio, smoking, high blood pressure, and diabetes. The participants were followed up over an average period of 6.9 years.

What were the basic results?

Overall, the total amount of physical activity and recreational activity decreased from high-income to low-income countries. Levels of non-recreational activity were similar across all countries.

Rates of deaths, heart attacks and stroke also significantly decreased with increasing levels of physical activity. The overall rates of mortality or major cardiovascular disease events (stroke, heart attack or heart failure) were 9.46 per 1,000 people per year in the low-activity group, which reduced to 7.14 in the moderate-activity group, and to 6.60 per 1,000 per year in the high physical activity group.

People who met current physical activity recommendations – at least 150 minutes of moderate activity each week (the moderate to high activity groups) – had a 22% lower risk of death or risk of a major cardiovascular event compared with those who with low physical activity levels (hazard ratio [HR] 0.78, 95% confidence interval [CI] 0.74 to 0.83). Risk of death was 28% reduced (HR 0.72, 95% CI 0.67 to 0.77) and risk of heart attacks or strokes was 20% reduced (HR 0.80, 95% CI 0.74 to 0.86).

The beneficial effect of exercise (and the increased risk of heart-related deaths from lower levels of physical activity) was seen across all countries.

How did the researchers interpret the results?

The researchers concluded: "Higher recreational and non-recreational physical activity was associated with a lower risk of mortality and CVD events in individuals from low-income, middle-income, and high-income countries. Increasing physical activity is a simple, widely applicable, low cost global strategy that could reduce deaths and CVD in middle age."


This study shows that all physical activity, in any form, is good for us. This includes both recreational and non-recreational activities.

Don't be misled by some of the media: non-recreational activities like housework are not "better" than recreational activities like playing sports or going to the gym.

The fact that reduced risk was seen with non-recreational activity across all countries, but only seen with recreational activity in high-income countries was probably just because fewer people in lower-income countries play sports or go to the gym.

The researchers estimate that 8% of all deaths and 4.6% of all cardiovascular disease events in the population could be prevented if everyone met the current physical activity recommendations: doing at least 150 minutes of moderate activity each week.

The study had a few important limitations:

  • Participants may have inaccurately reported the amount and type of activity.
  • Disease outcomes and cause of death may be inaccurate – particularly in lower-income countries where this information could not be collected as reliably through registries and medical records. And people with pre-existing disease may not have been reliably excluded.
  • The researchers tried to adjust for confounding factors that may influence the results, but weren't able to cover them all – notably, they failed to adjust for diet.
  • Participants were from a range of countries worldwide, but this may not have been entirely representative. For example, in some lower-income countries it may have been harder to contact households. Also, the main age group represented was middle-aged adults.

These limitations mean the study results are only estimates and cannot be taken as hard figures. Nevertheless, this is a large, good-quality study published in a highly respected medical journal, and the findings reinforce current government recommendations for physical activity.

You should aim to do at least 150 minutes of moderate exercise per week, such as brisk walking or cycling and strength exercises on two or more days a week.

However, if you feel this advice might be unachievable to start with, aiming for 10 minutes moderate exercise a day, such as brisk walking, is a good start. Any type of exercise is likely to be good and a gym membership isn't necessary.

Read more about how to get and stay fit.

Links To The Headlines

Get up, stand up: including exercise in everyday life healthier than gym, says study. The Guardian, September 21 2017

Vacuuming and scrubbing the floor are enough exercise to protect heart and extend life, study finds. The Daily Telegraph, September 21 2017

Thirty minutes of exercise is the secret to living longer. Daily Express, September 22 2017

Household chores could save your life: The tiny amounts of physical activity from cleaning the floor and tidying up cut your risk of death by 28%, study finds. Mail Online, September 22 2017


Links To Science

Lear SA, Hu W, Rangarajan S, et al. The effect of physical activity on mortality and cardiovascular disease in 130 000 people from 17 high-income, middle-income, and low-income countries: the PURE study. The Lancet. Published online September 21 2017