What's one word that strikes both fear and nausea in even the strongest-willed parent or teacher?
And for decades, treating the nasty critters has been an arduous, toxic task. But the days of chemical-laden shampoos and tiny combs may soon be over.
Four years ago, the prototype for the LouseBuster, made headlines when research showed the chemical-free, warm-air device wiped out head lice on children.
And a new study reveals that a revamped, government-cleared model of the lice-killing device is just as effective.
The LouseBuster works by blasting warm air at the patient's scalp, where the lice take refuge, a little like a hairdryer.
"For a louse, it's like sticking your head out a window at 100 miles an hour; they're going to get dried out," says University of Utah biology Professor Dale Clayton, senior author of the study and a founder of Larada Sciences, a university spinoff company that sells or leases the LouseBuster to schools, camps, medical clinics and delousing businesses.
While the older version of the LouseBuster proved effective in a study published in November 2006 in the journal Pediatrics, it wasn't perfect.
It was noisy, it wouldn't plug into home electrical outlets and it got tangled in curly hair. It looked like a cumbersome canister vacuum with a hose on it, and blew warm air through a comb-like applicator.
The new LouseBuster is less noisy, can be plugged into a standard electrical outlet and sports an applicator with 28 cone-shaped tips that doesn't get tangled in hair.
The improved LouseBuster more user-friendly, but still just as effective.
The new study compared the number of live and dead lice and nits (eggs) before and after treatment on the 56 louse-infested children and adults. Lice and nits were collected from half of each patient's head at the start of the experiment.
Then, the whole head was treated with the LouseBuster. Lice were collected from the other side of the head. The researchers checked how many lice were alive and how many of the nits would hatch.
Most of the lice and nits collected at the start of the experiment were alive. After treatment by experienced LouseBuster operators, 88.2 percent of hatched lice were dead and 99.2 percent of nits failed to hatch, for an overall mortality of 94.8 percent.
Lice not killed immediately apparently were sterilized by the LouseBuster or died later. Any eggs that might have been missed by combing or other methods did not hatch because the LouseBuster treatment killed them.
That means the LouseBuster can be an important tool for schools that abandon the "no nit" policy, as was recommended recently by the American Academy of Pediatrics. If the eggs have been killed, then removing all of them is not essential and kids may not have to miss school.
After the first study, thousands of people with louse-infested children contacted Clayton and the University of Utah seeking the device, even though it was only a research prototype and was meant for eventual use by school nurses and other delousing professionals, not private individuals.
The revamped LouseBuster to hit the market after gaining U.S. Food and Drug Administration clearance as a medical device. It was patented in September 2010.
"We've moved from clinical trials to having the machine available so infested people can get treated by this device. It's not a prototype anymore," says the study's first author, Sarah Bush, an assistant professor of biology at the University of Utah.
Larada Sciences sells the LouseBuster for $2,000 to $2,500 to nonprofit organizations such as schools and medical clinics.
The company also has various sale or lease arrangements with trained and certified LouseBuster operators who provide treatments in salons or clients' homes for $125 to $275 per person.
So why all the hubbub over this machine?
Lice are evolving resistance to insecticides, and many people find the old treatments, such as shampoos and other chemical treatments, ineffective. As a result, louse infestations are on the rise.
Even when the shampoos work, they kill only hatched lice, not nits. Infested people must shampoo again after the nits have hatched, and if they get the timing wrong -- waiting until the newly-hatched lice have laid eggs of their own -- treatment must begin again.
Also, many parents are reluctant to use chemical treatments on their children.
Combs to remove lice and nits also are popular, but combing out the critters is tedious and can take hours, particularly in long hair, because every nit must be removed.
People also use various other products and home remedies to combat lice, but most alternative treatments are untested or ineffective.
The LouseBuster, however, is easy to use, safe, and effective.
"This thing is incredibly innocuous," with no ill effects reported, said Clayton.
The LouseBuster's also effective in any type of climate and on any type of hair.
Tests were conducted in Florida and Tennessee, which have humid climates, and Utah, which has a dry climate. The researchers also categorized each subject's hair as long or short, thick or thin, and curly or straight. Climate and hair type made very little difference in the LouseBuster's ability to kill lice and nits.
The device's patent holds out the possibility that people may not be the only customers for the LouseBuster.
In the future, a similar device may be developed for use on louse-infested sheep and other livestock.
The new LouseBuster study will be published in the January 2011 issue of the Journal of Medical Entomology.
Bush and Clayton ran the study with Alex Rock, Sherri Jones and Jael Malenke, research technicians from Larada Sciences in Salt Lake City. The study was funded by the National Science Foundation, Utah Centers of Excellence program and Larada Sciences. Clayton and some other authors have a financial interest in the company.