In fact, I realized, I’d personally helped our household’s lice inch toward Darwinian success. By spreading the limited quantity of malathion lotion I was able to procure over five heads (in all this time, my husband never once found a louse) rather than the three heads for which it was prescribed, I probably enabled some of the hardier, more malathion-resistant lice to survive their bath in isopropanol and to pass their malathion-resistant genes on to future generations. Because a 2-ounce bottle of the stuff runs about $65—and because some pediatric nurses, including ours, won’t prescribe malathion to children under 6, whether or not your 5-year-old outweighs your 6-year-old—plenty of parents find themselves stretching a malathion supply well beyond its intended use.
But overcaution and frugality aren’t the only malathion application problems. Assuming nonresistant lice and flawless application, three researchers from Mount Sinai, writing in the Journal of Pediatrics, note that even “a perfectly ovicidal and pediculicidal agent” (one that kills both lice and eggs) requires two treatments at least seven days apart, because some eggs are too undeveloped to be affected at the time of the first treatment. Every source I consulted agreed that more than one treatment is necessary. Every source, that is, except the one that mattered: the instructions on malathion, which say that “normally, only one treatment is needed.”
In truth, most of the lice treatments on the U.S. market, malathion lotion included, are relying on the efficacy of an external ingredient: you. Over the course of the year it became very clear what a “good parent” in this circumstance is supposed to do: comb. There are a finite number of lice and nits on your child’s head. With proper dedication, (examining each and every one of those hairs nightly for two weeks after the last live louse is found, in case anything new has hatched) you should be able to remove them even without any other treatment.
So here’s the final flaw in the battle against our superlouse: I’m not naturally picky. I tried to comb away the bugs and nits, but I blew it. And when I admitted it, everyone from my fellow parents to the people at my kids’ schools and at the pediatrician’s office treated me like the—yes—lousy parent I’d proven myself to be. The researchers I spoke to were far more realistic, however, and in the case of one British expert, highly dismissive of this very modern-day American hover-parent approach. “Combing,” Ian Burgess, director of the Medical Entomology Center in London, said, “is just not a practical proposition.” Even in the U.K., where malathion resistance is rampant, combing alone fell so far short of malathion as an effective treatment in trials that researchers there dubbed it flat-out “inappropriate” as a recommendation.
Fortunately, given that “superlice” aren’t always up against superparents, new treatments are starting to come out. Had we known better, we could have tried nonprescription LiceMD, a version of the most popular treatment in the U.K. (it kills lice Goldfinger-style by coating them in a silicone oil, which doesn’t “suffocate” them—remember, that doesn’t work—but instead prevents them from extruding bodily fluids), or Natroba, a new prescription insecticide derived from a bacteria found only on the ground of an abandoned rum distillery in the Caribbean.
We didn’t know about these new options, so in the end it was more skilled combing and the Lindane that allowed us to bag our last louse. Lindane has four strikes against it: It’s a neurotoxin for people as well as lice, it’s illegal in California (outlawed on the grounds that it gets into the water supply), and, once again, many lice are resistant. It’s still unlikely a louse will be resistant to both malathion lotion and Lindane, though, which explains our success.
The fourth strike? “It’s awful stuff,” one expert told me. I started to agree, but she wasn’t done. “I just hate to see them suffer. Lindane takes forever to kill a louse, and it’s a terrible death.”
Fortunately, my sympathy for the louse with the disrupted nervous system is limited.