What Are Super-Lice?

Lice isn’t just a start of a school year problem like buying school supplies; it can be a year round problem too. As if lice weren’t bad enough, a super-lice epidemic is now on the radar in North America. Just what is super-lice and how do we fight it off?

Lice are parasitic wingless insects that feed on the host’s skin, blood, or oil. Most of us think of lice on children’s scalps when we hear about lice. Lice are, however, extremely diverse, and have evolved in very specialized ways. There are lice that latch on to dogs, cats, and birds, and they can only survive on their specific host. This means that you can’t transfer human lice to your pets, and vice versa. Of lice that infect humans, there are head lice, body lice, and pubic lice. The most common of these is the head lice, an insect that spans about 3 mm.

Lice have long been frustrating humans, but with the prevalence of insecticide treatments, they have become relatively easy to treat and little more than a temporary nuisance. Unfortunately, lice have evolved in response to the selection pressures that were put on them by insecticides. Now, there are super-lice—bugs which have grown resistant to pyrethroids, insecticides which have been used successfully for decades. Similar to the evolution of antibiotic resistant bacteria, the lice that had a mutation that made them resistant to commonly used insecticides were the ones left surviving and replicating. The artificial evolutionary pressure brought on by insecticides have unfortunately made many lice resistant to that particular treatment.

According to a study in 2013 published by the Journal of Medical Entomology, lice have been undergoing a mutation that makes them resistant to permethrin, a commonly used insecticide in North America to treat lice infestations. The study found that 99.6% of U.S. lice samples contained this TI mutation in 2009, up from 84.4% in 1999. In Canada, 97.1% had the mutation in 2008. Effectively, most of North American head lice can be thought to contain this mutation that makes them more resistant to common insecticides. Some parents will be fighting these insecticide resistant lice off of their children’s head this year.

Are superlice dangerous?

The good news is that while the super-lice are more resistant to traditional insecticides, they are not a vector for disease transmission. While it can be frustrating to combat, head lice are not a serious medical concern so there is no reason to panic. An alternate treatment mechanism may be necessary to effectively treat these resistant lice, which your doctor will be prepared for.

How do I prevent it?

Unfortunately, lice infestations are very common in environments like schools where a large group of children congregate, and there really is no perfect solution. Lice is not a reflection of poor hygiene. Having shorter hair may help reduce the chance of getting lice, but it certainly does not guarantee that your child will not get lice.

What should I do if my son or daughter gets head lice?

Over the counter treatments are plentiful and lice combs are usually sold at drugstores. Generally, these are effective solutions, but this year, it may be best to consult a doctor to ensure that you are treating it correctly and effectively.

How do I keep the rest of my family safe if my child has lice?

Lice spreads mainly from head to head contact. This is why infestations are most common in young school children, as the school provides an environment where this commonly occurs. Clothes that come into contact with the child such as hats, coats, towels and bed linen need to be washed in hot water and dried.