Children are more attractive victims for head lice because they have much more physical contact with each other, especially in kindergartens and schools. In these places, it is quite common, for example, for kids to share caps, combs, brushes, pillows… As among adults this contact between several people is less, insects do not spread so easily. Therefore, this plague, which is usually a huge problem during childhood, almost always disappears from the lives of those who are getting older. “In addition, children are generally less sensitive and do not realize that they are being bitten, which facilitates infestation and delays treatment”, says biologist Carlos Fernando Andrade, from the State University of Campinas (Unicamp). There are still scientists who are speculating on another theory, that the children’s heads would be more appetizing for these insects, which feed on blood. Some experts believe that children can exude certain hormones, called kairomones, that make them more attractive to head lice. But this is not yet proven. According to biologist and head lice specialist Pedro Marcos Linardi, from the Federal University of Minas Gerais (UFMG), the main periods of transmission and infestation of this plague occur during the back-to-school periods, both in the beginning and in the middle of the year. A universal insect, the louse (Pediculus capitis) is found in any climatic region of the world and infests people of all social classes.
Lice live for a month and can lay up to a hundred eggs in that period.
IT’S THE BEGINNING OF THE PICK
The louse’s food is our blood, which it gets by biting the scalp. In this attack, the louse uses a proboscis-like sucking organ. He still injects a kind of saliva into the site, which has substances that prevent blood clotting, ensuring a richer food.
WOUND BARK BIRTH
The number of lice varies. In an average infestation, about 50 insects feast on the victim’s head. Already in a large infestation, there is even twice as much – in these cases, the person can even become anemic from blood loss. Another problem is the reactions to the bites, which, in some cases, can generate wounds on the scalp, leading to infections.
AT THE BASIS OF THE ITCH
The life cycle of a louse is about a month. During this period, the female is able to lay more than a hundred eggs. These nits are fixed at the base of the hair strand, next to the scalp, thanks to a substance released by the “mothers” that works like a cement. The nape of the neck and ears are the preferred places for laying eggs.
EGG WITH EXPIRY
Whitish, the nits are about 0.8 mm long and have a shell that is highly resistant to penetration by insecticides. As they take about seven days to become nymphs — when lice become vulnerable to drugs — the treatment to eliminate this plague needs to be repeated after a week.
ATTACK OF NYMPHETS
There are three main phases in the life of this insect: the nit phase (the egg of the louse), the nymph phase (when it leaves the shell and begins to develop) and the adult louse phase. A nymph measures around 1.5 mm, takes two weeks to reach adulthood and sheds its skin three times in that period.
THE INSECTICIDE COUNTS AGAINST
The best way to get rid of the pest is using lotions and shampoos based on insecticides — with substances such as pyrethroid. These products penetrate the lice’s body and cause neurotoxic reactions that kill the insects. In addition to medication, it is essential to use a fine-toothed comb, to clean (louse by louse) and to clean the infested person’s bed linen and towels.
THE THING OF THE MEADA
About 2.5 mm long, adult lice have three pairs of legs and a claw at the end of each leg, which allows them to attach themselves to hair shafts. They go down to the scalp just to feed. Unlike fleas, lice do not jump and only move from one head to the other if the hairs on both have some contact.
Two other species of the “family” attack humans
Pubic Lice (Pthirus Pubis)
Also known as a bore, it infests the hairs in the genital area.
Body Lice (Pediculus Humanus)
It lives in clothes and bedding and infests the hairs scattered around the person’s body.
The three types of lice live in different places because of the characteristics of the body regions, which may or may not be favorable to the fixation of each species. Head lice, for example, need sheltered territories to live and, therefore, do not attack the hairs scattered around the body, which are more exposed. The boring one, on the other hand, loves very stuffy places, so he prefers to stay under his underwear.