Photo by Guillaume Piron

Climate change: Why the amount of hair lice increases everyday?

Climate change and the misuse of treatments to combat them have helped these insects to become increasingly larger and more resistant in children’s heads.


he city of Barcelona fights against an authentic plague of hair lice. A subject that goes beyond the school’ doors, since it is affecting all the residents in Barcelona, whether they have children of school age or not. Therefore, the City Council has taken the initiative by issuing a statement to inform the population and clarify how to act to combat them.

While some wonder how it is possible that there are so many lice at this moment, when their normal period of appearance is at the end of summer and autumn, others wonder why this invasion is occurring and those who suffer it directly, also want to know how you can get, totally, rid of them.

There are many studies that suggest that the increase of temperature directly affects the number of insect pests that we will face

One of the factors that undoubtedly helped to magnify this problem is climate change. In addition to what we already know, such as the alteration of the seasons or the extreme atmospheric phenomena, there are many other fields that are affected by this increase of planet’s temperature.

There are many studies that suggest that the increase of temperature directly affects the number of insect pests that we will face. The extent of lice in some crops, such as wheat or rice, has already been estimated by 20% for each degree of increase in thermometers, as recently was published by the journal Science.

The reason why these changes affect the number of insects is very simple. With more heat, these invertebrates reproduce more quickly while changing also their metabolism, which makes them hungrier and willing to devour more vegetables. It also changes their lives’ cycles, something that explains why it is becoming more common to see flies in winter, for example. But crops will not be the only victims because of this increase in the number of insects.

A little over a year ago, the price of salmon skyrocketed due to an epidemic of sea lice. The warming of oceans caused a change in cycle’s life of these insects that due to their fast reproduction generated a great concentration of them to which many salmon could not survive.

Vegetables, animals and even humans. And so we return to the louse that live in the heads not only of children, but also of many adults. Insects that do not usually exceed the size of two millimeters, that live in the scalp and that feed on blood. Their number has increased alarmingly and not only in our country, with the increasingly hot weather. Now they are reaching latitudes where before it was very rare to find them, such as the Nordic countries.

In general, they aren’t a serious health’s risk. They do not transmit diseases, but the discomfort they cause is high. Young children, exposed to their constant bites on the head and the itch they produce, can easily provoke wounds on the scalp when scratching, which in many cases, become infected. There have even been cases of mild anemia due to lice.

The current problem does not lie only in the highest number of hair lice. The issue is aggravated by knowing that they are becoming larger, which force them to eat more and also affects directly to their blood needs. Nevertheless, what it is really worrying is they are no longer resistant to the usual treatments.

For years, products intended to eliminate hair lice have been used without following the recommended guidelines. In many cases, before the school informed of a plague, the shampoo or lotion was used for the time considered appropriate, without verifying if its application was really necessary. Error.

Just as the misuse of antibiotics has caused bacteria to mutate and become more resistant, something very similar has happened to lice. Treatments based on permethrin and pyrethrins no longer work. Several studies suggest that, in the last 20 years, there have been more than 100 mutations of hair lice, which allows them to resist the most common products.

Experts recommend passing the nursery to the children once a week

If we take as a reference that with a specific shampoo to combat pediculosis, a term used to describe the infestation of the skin by lice that causes skin irritation, we only end up with 60 or 70 percentage of the unwanted tenants in a child’s head. The only way to get rid of them is by a pure mechanical work. So, patience and constant work are the solution.

The nit comb created to find and eradicate head lice and their eggs, with tines very closed one to another, must become our best ally. It is necessary to pass it slowly, separating carefully all the strands to not leave even one lock of infected hair. A very useful advice is to put a towel or white cloth underneath so that, if a louse falls, it can be easily seen.

Once the head is clean, do not think all is done. Experts recommend the using of the nit comb in children once a week. This should become another attitude, a new cleaning habit in all homes with small children.

The Phthiraptera (latin name for lice) usually live between 16 and 30 days, time in which they can reproduce up to 300 nits – as their eggs are known-. These bright white balls incubate for about a week. There is no need to use a calculator to say that if a child catches a louse and is not treated, in a month he may have his head completely infested by them.

The most vulnerable ages are from 3 to 8 years old. The only reason is that the form of contagion is as simple as the contact between two heads, something that happens easily at these ages. Head lice do not jump or fly, and they need body heat and moisture to survive. That is why contagion is always direct and, in rare cases, by exchange of an infected object such as a hat or a pillow.

Head lice like warm heads and they do not care if they are clean or dirty, have long or short hair, or even if they are collected in a pigtail or a braid. The idea that lice are a sign of lack of hygiene is almost banished, but not entirely. For this reason, many parents still prefer not to tell anyone and act as if nothing happened, thus causing the plague to keep growing and more difficult to eradicate.