Latin: Phthirus pubis
In the group of blood-sucking parasites is crab louse found, which also goes by the Latin name Phthirus pubis. Crab louse has a mixed reputation as not only a pests but also a parasites that feed on human blood.
Appearance
The small louse is perfectly adapted to its peculiar way of life and therefore has no wings. Its head is designed for its blood-sucking purpose, which is why the mouthparts are built to stick and suck with, while the eyes are quite reduced. Also, the body bears the imprint of this purpose, and its hind legs end in a kind of claw or powerful claws that help the louse to be able to grip the hairs of its host.
The crab lice have a grayish color and an almost leathery skin. The hind body can be enlarged in great style when it must make room for the blood it fills with. Its hind body is short but rather wide. The crab lice themselves become about 1.5 millimeters long, while the eggs are somewhat smaller.
Biology and behavior
Crab lice are designed to live in areas with scattered hair, where they can grab powerful strands of hair with their claws. Therefore, they especially seek out areas on the body such as in the pubic hair or in the hairs in the armpit or on the chest. They can in rare cases also appear in beards, along the hairline in the neck, in temples or in the hair itself of thin-haired men. In children in particular, flat lice can also be found in eyebrows or eyelashes, where they can appear in as many as 100 lice in the eyelashes.
A crab louse feeds on blood. Once at ease with its host, it grabs the strands of hair with its claw scissors. It then drills its mouthparts into the skin of the host. The flat lice can then sit and suck blood for several hours, which are only interrupted by a few short breaks. If the lice are removed from its host, it dies within a day when it can no longer suck blood.
The crab louse female mates only once in her life, after which she lays three eggs a day or about 25 in total. Her eggs are placed in the hair individually, where they are glued. This means that they are something near impossible to remove. After a period of 7 to 8 days, the eggs hatch and the small larvae must then undergo 3 larval stages before they reach sexual maturity. That process lasts between 13 and 17 days.
The total development from egg to adult louse lasts about 20 to 25 days. But after that, the life cycle is not long. A crab lice only live for about a month.
Damage
Although crab lice are highly disparaged, they do not pose a great danger as such. They cannot transmit diseases. But in return, their bite can be a major nuisance as it itches and can cause skin irritations. The bites leave the skin with small red spots that can become bluish after a few hours.
Prevention and pest control
The crab louse can only live on humans and does not leave its host with its good will. But they can “infect” or spread when they jump from one host to another. This happens mainly through intercourse. But “homeless” crab louse that have been scratched by other people can also crawl from one host to another. This can happen, for instance, if they are sitting on a toilet seat or in bedding. Crab lice are controlled just like ordinary head and body lice with shampoo or lotion, both of which are sold at the pharmacy. Crab lice in the eyelashes or eyebrows, on the other hand, are treated with an eye lotion. Since crab lice are most often transmitted through sexual intercourse, any sexual partners should be notified if you are exposed to a crab louse infestation so that they can be examined and treated.
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"Food Pests"
"Husets dyreliv" (Insects Around the House - Only danish)
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