"Oh, hush—and quit clawing at yourself," said my wife, who was consulting The AMA Home Medical Encyclopedia. "'Children,'" she read aloud, "'are most affected, women occasionally, and ...' —it figures—'men rarely.'"
The head louse, Pediculus humanus capitis, is a cousin of the body and pubic lice that truly are indicative of trash. The former live in filthy clothing, and the latter are the result of reading Kahlil Gibran by lava lamp and cavorting on a waterbed. But the head louse is different. The American Academy of Pediatrics, The Merck Manual of Diagnosis and Therapy, the New England Journal of Medicine, and the Harvard School of Public Health say, respectively, "All socioeconomic groups are affected"; "It is common among school children, without regard to social status"; "[It] affects persons of all ... socio-economic backgrounds"; and "Head lice ... do not respect socio-economic class distinctions." One need not scratch one's head about the repeated mentions of status. The New England Journal of Medicine notes, "Most children get them at some point, including doctors' children."
The adult head louse is usually described as being the size of a sesame seed. But a sesame seed stuck between teeth is visible at ten yards, whereas to my bifocaled eyes lice are ...
"I think I have lice all over my shoes."
"Those are the holes in your wing-tips," my wife said.
The female louse lays one to six nits a day, according to the NEJM. She lays ten nits a day, according to the American Academy of Pediatrics. The nits hatch in three to fourteen days, claims The Merck Manual; in ten to fourteen days, maintains the Academy of Pediatrics; in about a week, declares the Centers for Disease Control. The CDC states that the louse nymphs (a Nabokovian, and not very proper, image) mature in about another week. The Harvard School of Public Health avers maturation in nine to twelve days. A louse that's been separated from its host dies in a day or so, says Harvard; within forty-eight hours, asserts the CDC; in fifty-five hours, opines the NEJM. That journal postulates head-lice-infestation rates of one to three percent in industrialized countries. This would give the United States 2.8 to 8.4 million cases a year. The CDC estimates only 6 to 12 million cases worldwide. The AAP thinks there are that many cases among three-to-twelve-year-olds in the United States alone.
Medical researchers don't know much about head lice because they don't much care. The reason that they don't much care is, paradoxically, that they know a lot. That is, they know one important thing: there is no evidence that head lice transmit disease. Body lice can carry deadly typhus, and pubic lice breed fatal excuses. All that head lice cause is a vibrant pizzicato on the skull and an occasional secondary infection from fingernail raking. The Merck Manual, however, does say, "Moderate discrete posterior cervical adenopathy is frequent." I was halfway through calling an ambulance for the girls when my wife slammed my hand with the Merriam-Webster. That means "swollen glands."