A louse about to suck, stations itself with the body perpendicular to the skin. A short tube appears from the mouth. It has many small and sharp chitin teeth in the front of the tube. They act as barbs when the louse head is anchored to the skin. Then three long, elastic rods are shot through the tube and into the skin. The rods form a triangular channel leading saliva to the location, the rods hit. The louse sucks the blood using a muscle pump in the throat.
Lice suck blood at least twice a day and preferably five times. At room temperature, the lice can only survive for two days without getting any blood. The greediest lice, the females, consume up to 1 mg blood each meal. This means that the host’s blood loss is very low – even when there are many lice. The blood is digested in the gut. The undigested leftover blood comes out as excrement – small, dry and dark clumps that stick together in short chains. When heavily infected people wear white clothes, lice excrement can be seen as fine black grains on the neck and shoulders.
Lice bite effects. The bite produces a small red spot that does not itch. It disappears after a few hours. After a large number of bites – more than 10,000 – it really begins to itch. It’s not just the new bites that itch but also the old ones, which were initially not noticed. Along with the itching, redness of the skin and blisters may occur – a kind of hives.
After about a year, untreated louse infestations lead to some non-specific, secondary symptoms: Body aches, fatigue, tiredness, lack of concentration, etc. The English have a special term for it: “to feel lousy.” Today, the term mostly used humorously, for example about a person’s condition the day after a drinking binge or a fight but it actually refers to how uncomfortable you feel when you’ve had lice for a long time.
Distribution. There is nothing, which suggests that head lice can transmit infectious agents from one person to another. Louse gut contents are sterile and the infections you get from scratching, is not primarily caused by the lice.
"Pests in House and Home"
"Bed Bugs - Bites, Stings and Itches"
"Food Pests"
"Husets dyreliv" (Insects Around the House - Only danish)
"Skadedyr i træ" (Timber Pests - Only danish)
"Stuefluen" (Common Housefly - Only danish)