Picking your nose could spread pneumonia, research has warned.
The bacteria which cause the deadly infection can also be spread by people poking, or rubbing their nose with their hands, if they have the bacteria on them.
Experts say while it would be unrealistic to stop children touching their noses, it could help stop transmission to elderly relatives who are more likely to get sick.
The disease kills millions of people around the world every year and is dangerous for the very young and old, and those with weakened immune systems.
The bacteria which cause pneumonia could enter the body through the nostrils if they come into contact with someone’s hands and they pick or rub their nose, researchers led by the Liverpool School of Tropical Medicine found
Researchers led by the Liverpool School of Tropical Medicine carried out the study to find out how well pneumonia bacteria can spread on skin.
The bacteria are normally spread as droplets in coughs and sneezes.
Four groups of 10 adults were tested in different ways and had either wet or dry bacteria put on their hand and had to either poke a finger up their nose or sniff their hand.
The ‘wet poke’ and ‘wet sniff’ groups had the most total bacteria transmitted, but experts found people are just as likely to spread the bacteria on their hands whether they’re wet or dry.
Scientists say the results could be used to advise parents to clean children’s hands and toys if they’re meeting relatives who are elderly or weaker, such as cancer patients.
Lead researcher Dr Victoria Connor said: ‘It might not be realistic to get children to stop picking, poking and rubbing their noses.
WHY YOU SHOULD PICK YOUR NOSE AND EAT IT
Eating what comes out of your nose could reduce your chance of getting various infections, a study found last year.
Austrian lung specialist, Professor Friedrich Bischinger said: ‘Eating the dry remains of what you pull out is a great way of strengthening the body’s immune system.
‘In terms of the immune system, the nose is a filter in which a great deal of bacteria are collected, and when this mixture arrives in the intestines it works just like a medicine.’
Scientists found that nasal mucus’s rich reservoir of ‘good’ bacteria prevents cavity-causing bacteria from sticking to teeth.
Published in the American Society for Microbiology, their findings also suggest snot could defend against respiratory infections, stomach ulcers and even HIV.
This builds on previous research which suggests an obsession with hygiene has led to an increase in allergies and autoimmune disorders, such as arthritis.
‘From an evolutionary perspective, we evolved under very dirty conditions and maybe this desire to keep our environment and our behaviours sterile isn’t actually working to our advantage,’ said Dr Scott Napper from the University of Saskatchewan in Canada.
‘And the presence of the bacteria can sometimes boost the immune system of children and can reduce their chances of carrying it again later in life, so it is unclear if completely reducing the spread of pneumococcus in children is the best thing.
‘But for parents, as this research shows that hands are likely to spread pneumococcus, this may be important when children are in contact with elderly relatives or relatives with reduced immune systems.
‘In these situations, ensuring good hand hygiene and cleaning of toys or surfaces would likely reduce transmission, and reduce the risk of developing pneumococcal infection such as pneumonia.’
The new study, published in the European Respiratory Journal, is the first to demonstrate that pneumonia bacteria can spread between the hand and nose.
While most people’s immune systems destroy the bacteria successfully, some people can become infected.
A pneumonia infection causes swelling in the lungs and the organs’ tiny sacs of air can become filled with fluid, reducing the amount of oxygen the body and brain get.
Researchers found that bacteria can spread at the same rate whether they are dry or wet, and whether a person picks, pokes or rubs their nose.
Dr Connor added: ‘Pneumococcal infection is a major cause of death around the world, and it is estimated that it is responsible for 1.3 million deaths in children under five years annually.
‘The elderly and people with other causes of impaired immunity, such as chronic illness, are also at an increased risk of pneumococcal infections.
‘Our current understanding of the transmission of pneumococcus is poor, so we wanted to look at how it may be spread in the community.
‘Having a clearer understanding of how the bacteria is spread will allow for better advice on how transmission can be reduced, so that there is greater prevention of pneumococcal infections.’
The researchers said using real people meant they could test how well the bacteria would survive in real situations.
Professor Tobias Welte, president of the European Respiratory Society said: ‘The findings reinforce the message that we must promote rigorous hand hygiene and basic infection control measures such as avoidance of sharing food, drink and mobile phones, in order to potentially reduce the transmission of respiratory bacterial pathogens such as pneumococcus.’