Description
With coronavirus spreading all over the world at an alarming pace, one of the precautionary measures being recommended was proper sanitisation. With masks and sanitizers being regular features in daily life now, we are looking at certain other aspects of sanitisation.
According to some reports, too much cleanliness may be causing us to develop allergies, asthma, inflammatory bowel diseases, and other autoimmune disorders. The idea is that for many children in the wealthy world, a lack of exposure to bacteria, viruses, and allergens prevents the normal development of the immune system, ultimately increasing the chance of disorders within this system down the road. This is called the hygiene hypothesis, according to a report in Vox.com.
To Whom
"A child's immune system needs education, just like any other growing organ in the human body," Erika von Mutius, a pediatric allergist at the University of Munich and one of the first doctors to research the idea was quoted as saying in the Vox.com report. "The hygiene hypothesis suggests that early life exposure to microbes helps in the education of an infant's developing immune system." Without this education, your immune system may be more prone to attacking the wrong target — in the case of autoimmune diseases, yourself. Barna vikas
It's still a matter of active debate among scientists, but evidence for the idea has been slowly accumulating over time, both in humans and animal subjects. It's been cited as an explanation for why allergy and asthma rates are so much higher in wealthy countries, and most recently, a study found that babies who grow up in houses with higher levels of certain bacteria — carried on cockroach, mouse, and cat dander — are less likely to develop wheezing and asthma by the age of three.
However, it's important to note that despite the claims of some anti-vaccine activists, there's absolutely no evidence that not getting vaccinated has similar benefits. How could this kind of filth possibly make us healthier? Here's an explanation of the hygiene hypothesis.
Obviously, the basic sanitary practices we've developed as a society over the past few centuries — such as building infrastructure to remove garbage and sewage from cities — have provided all sorts of benefits. They're a huge part of the reason so few Americans get infectious diseases like cholera or typhoid nowadays, the report pointed out.
But researchers have found that a few specific autoimmune diseases — asthma, hay fever, inflammatory bowel diseases, and various allergies — have become much more common as we've become more sanitary, and are much more prevalent in the wealthy world than the developing one.
In the late 1980s, when studying childhood allergies in East and West Germany, British epidemiologist David Strachan began to suspect there was a connection. In the dirtier, more polluted, less wealthy cities of East Germany, he found, children had much lower rates of hay fever and asthma than in the cleaner, richer cities of West Germany.
To explain this, he looked at all sorts of lifestyle differences — and found that West German children were much less likely to spend time in day care centers, around other kids, than East German children. He proposed that their reduced exposure to bacteria and other antigens, normally acquired from other children, somehow affected their immune systems, leading to their increased chance of developing the autoimmune diseases.
In the decades since, all sorts of epidemiological evidence has been collected that supports Strachan's idea. He initially found that in Britain, children who grew up in larger families also had lower chances of developing asthma and hay fever, presumably because they were exposed to more bacteria from their siblings.
Other doctors have found that, on the whole, people in wealthy, more heavily sanitized nations have much higher rates of asthma and allergies than those in the developing world. This could be a function of natural variations among the populations, but more recently, doctors have found that people who move from a developing country to a wealthier one have a higher chance of developing these diseases than people who stay in their country of origin.
Even within a developing country like Ghana, wealthy urban children have higher rates of these autoimmune diseases than poorer or rural children. In the wealthy world, adults who clean their houses with antibacterial sprays have higher asthma rates, and people who are more often exposed to triclosan (the active ingredient in antibacterial soap) have higher rates of allergies and hay fever. Kids who grow up on farms or have pets, meanwhile, have lower rates of allergies and asthma.
These are all correlations — not causations — but they suggest that something about the relatively clean, modern urban environment makes these autoimmune diseases more likely to develop. And the handful of controlled studies conducted on the topic have provided further support — such as one, conducted recently in Uganda, in which babies born to mothers who were given drugs to treat parasitic worm infections during pregnancy ended up having higher rates of eczema and asthma.
Controlled studies with animals have also provided compelling evidence for the idea. "In experimental studies with germ-free mice raised in a sterile environment, researchers have found they're extremely prone to developing colitis and asthma, among many other problems," von Mutius says. But interestingly, if during childhood, these ultra-sanitized mice are inoculated with the stomach bacteria present in normal mice, they no longer have an increased autoimmune disease risk. Somehow, not being exposed to bacteria during childhood seems to increase the risk of autoimmune diseases, for both mice and humans, the Vox.com report added.
