Via TH: Drug-resistant Head Lice

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‘Super lice’ leave parents scratching their heads

Stubborn parasites outsmart drugs — and mortify moms

By JoNel Aleccia

Health writer

MSNBC

updated 5:31 a.m. PT, Wed., Sept. 10, 2008
JoNel Aleccia

Health writer

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Three weeks into Maddie Ratcliff’s first year of school, the South Carolina kindergartner is already the subject of an unwelcome science experiment: What’s the best way to get rid of head lice?

It’s a question that has stumped her mother, Brittany Ratcliff, 28, of Charleston, who was horrified to find tiny parasites in her 5-year-old’s hair this week — and even more upset to discover that over-the-counter medications wouldn’t kill them because the bugs have grown resistant to the poison.

“I’m a little traumatized,” said Ratcliff, an office administrator. “I was very grossed out by it.”

As school begins, health officials and parents across the country are bracing for this year’s bout of what some call “super lice,” drug-resistant critters that fend off nearly all pesticides, even as experts say better treatments for the ancient, annoying condition may be waiting in the wings.

Researchers have been warning for years that head lice in the U.S. and around the world are developing immunity to the strong insecticides used in over-the-counter and prescription shampoos. It takes just three to five years for the bugs to adapt to a new product, despite claims to the contrary by the manufacturers, noted Shirley C. Gordon, an associate professor at Florida Atlantic University who studies persistent head lice.

Health officials have continued to recommend the products, however, because over-the-counter medications like the permethrin in Nix, the pyrethrin s in RID, the lindane in Kwell and the prescription malathion in Ovide still work in some people, some of the time.

But the nation’s school nurses, often the first defense against the scourge, say it’s clear to them that families confronted with the critters are increasingly frustrated by the product failures.

“I had a mom drag her child into my office on the first day of school,” said Jill Burgin, a registered nurse at Stiles Point Elementary in Charleston. “She had been battling it throughout the summer and wanted advice on where to go from there.”

Burgin and other nurses are hoping that potential new solutions — from faster-acting, more effective insecticides to gels that smother the lice to hot air treatments that desiccate them — will come to the rescue.

Itchy condition most common in schoolkids
Infestations of head lice — or pediculosis — long have been common in day care centers and elementary schools, mostly because the close contact among young children is suited to spreading the tiny insects, about the size of a sesame seed, that crawl from head to head and latch onto hair follicles so they can feed on tiny droplets of blood.

NBC VIDEO

Super head lice?
June 14, 2007: British researchers find that common head lice has become more resistant to antibiotics. ITN's Elaine Willcox reports.

MSNBC

Adult lice can live for up to a month on a person’s head, but they need to feed several times a day. Without nutrition, lice will die within one to two days of leaving the host.

Exactly how common the critters have become is a subject of much debate. The federal Centers for Disease Control and Prevention estimates that between 6 million and 12 million children aged 3 to 11 are infested each year. In a letter in this month’s edition of the Journal of Emerging Infectious Diseases, researchers in Greece summarized studies on the prevalence of head lice around the world, reporting that it ranged from 1.6 percent in schoolchildren in the United States to 30 percent of kids in Turkey and nearly 60 percent among those in Egypt.

However, those figures are questionable at best, said Richard J. Pollack, a public health entomologist at the Harvard School of Public Health who has studied lice for decades. Underdiagnosis of head lice is very common among parents and health workers who miss the signs of the tan-colored lice and their tiny, opalescent eggs, called nits. But over-diagnosis is also a problem when it contributes to hysteria that keeps perfectly healthy children out of school. Pollack said he once pursued reports of lice outbreaks the way some weather-watchers chase tornadoes, but stopped when many proved to be parental worry run amok.

"Real as well as imagined infestations are over-treated, often multiple times," Pollack said.

By his calculations, about 1 percent of kids actually are infested at any single moment in time, which would amount to about 400,000 cases in the U.S. each year.

Head lice aren’t dangerous and don’t spread disease, said Pollack, who scoffs at the notion of "super" lice and considers the bugs more a nuisance than a public health menace. But that argument is a hard sell among parents who encounter the crawly creatures on a child’s head.

“I have literally had parents scream on the other end of the phone,” said Burgin, the South Carolina school nurse.