allergies, dandelion

Lice-Free Living May Cause Asthma and Allergies, Study Finds

April 24, 2009 07:20 AM
by Haley A. Lovett
Mice infested with lice had less sensitive immune systems than those without parasites; scientists think our hyper-clean style of living may cause the increase in human allergies.

Lice and Worms May Be Key to Controlling Allergies

Long have theories existed that say the human immune system needs to exposed to a certain amount of infection to prevent it from being oversensitive to relatively harmless stimuli. New Scientist explains this “hygiene hypothesis,” saying that our immune system evolved to cope with constant infestation with intestinal parasites, and that now that people live without infestation, our immune system has become hyper-sensitive and our digestive track is prone to becoming irritated and inflamed.

According to Reuters, researchers have also suspected that some other sort of infection or infestation might help children develop less sensitive immune systems. But scientists are unsure exactly what people needed to be exposed to in order to lose the sensitivities associated with asthmas and allergies.

Studies conducted on the immune system of mammals have largely been carried out in sterile lab environments in the past, and the “hygiene hypothesis” was only known to apply to intestinal worms, until now.

Researchers at the University of Nottingham decided to try a study on field mice captured from the wild in order to study the effects of natural parasites on the immune systems of the mice.

What they found was that the more lice and worm parasites a mouse was infested with, the less sensitive its immune system was. Jan Bradley, one of the researchers, told New Scientist that this means that infestation with lice might also play a part in desensitizing the immune system of humans.

Background: Super clean living and bugs' resistance to treatment

The United States uses more than 50 million pounds of antibiotics each year. This prevalence of antimicrobial chemicals is causing an increase in strains of bugs resistant to the low-level antibiotics.

Recently, the Environmental Protection Agency held a summit to address what is known to be the worst outbreak of bedbugs since WWII. It’s believed that the increase in bedbug infestations is caused by a decrease in the use of pesticides like DDT in the United States, alongside the development of pesticide-resistant bedbugs due to the continued use of pesticides in other countries.

Head lice are also evolving into “Super Lice” strains resistant to the pesticide shampoos normally used to kill them. Since the shampoos have been around for decades, the lice have had plenty of time to develop a resistance; some estimate that the shampoos used are only effective in half of lice cases.

Bedbugs and lice are relatively harmless bugs, as neither are known to pass infectious diseases to humans. However, more harmful bacteria are becoming resistant to cleaners and antimicrobials, leading to serious illness and death. The occurrence of MRSA (an antibiotic-resistant strain of the staph bacterium) is becoming common in hospitals and elsewhere, MRSA is known to be deadly.

Reference: Lice in humans


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