head lice
Scientists have discovered head lice in the United States that have developed a high resistance to common types of treatments. A minimum of half of the U.S. states contain the mutated bugs, which are unaffected by various over-the-counter (OTC) medicines that doctors and schools often recommended.
Dr. Kyong Yoon of Southern Illinois University said his research team's study was the first to collect many head lice populations across the entire U.S. They will present their findings at an American Chemical Society (ACS) event.
The scientists discovered that 104 out of 109 lice populations had high levels of genetic mutations that are linked to pyrethroid-resistance, according to Mirror. Those are chemical insecticides used indoors and outdoors to kill insects such as mosquitoes.
The ingredient contains permethrin. That is an active ingredient in some common OTC lice treatments. Yoon explained that the first reported case of pyrethroid-resistant lice was in the late 1990s, and it has become more common since then.
The head lice samples tested positive for knock-down resistance (kdr), which make them less sensitive to pyrethroids, according to Science Times. Kdr was first discovered in house flies during the late 1970s.
Yoon recently discovered that kdr lice live in 25 states, including California, Texas, and Florida. In addition, four states' lice contained two or three mutations.
Only Michigan's lice are still greatly vulnerable to pyrethroids. Scientists are uncertain why they have not produced a resistance yet.
Yoon recommends not using OTC lice treatments to control lice, as the bugs can develop a resistance. The good news is that lice do not transmit diseases.
This video explains what head lice are:
