How do lice come about and how harmful are they?

When it comes to parasites such as lice, everyone probably feels disgusted. The most critical cause of lice is poor personal hygiene. What kind of harm can lice cause to humans? In addition to human infection, what should we do if lice grow outside the human body?

When lice bite the human body, the saliva they secrete enters the skin and makes it itchy. Scratching with hands can damage the skin, leading to secondary infection and the formation of abscesses. Lice can also spread a variety of diseases when sucking blood. Body lice and head lice are considered to be the main vectors of epidemic typhus and lice-borne relapsing fever. Body lice can also spread trench fever. When war or natural disasters occur, the level of hygiene declines and people become relatively concentrated, making it more conducive for lice to spread diseases. In addition, lice-borne diseases are more common in winter, which is related to personal hygiene.

Both nymphs and male and female adults are fond of sucking human blood. Adult worms need to suck blood several times, often defecating while sucking blood. Lice are extremely sensitive to temperature and humidity, and are afraid of both heat and humidity as well as cold. Since the temperature and humidity of a normal human body surface are exactly the optimal temperature and humidity for lice, lice generally do not leave the human body. When the host's body temperature rises due to illness or strenuous exercise, and the clothes are soaked with sweat, or when the body becomes cold after death, the lice will crawl away from the original host. The above habits play an important role in the spread of lice and the transmission of diseases. The spread of human lice is caused by direct and indirect contact between people. Pubic lice are mainly spread through sexual intercourse. There are three types of lice that parasitize on the human body: body lice, head lice and pubic lice.

method:

You can add 4 ml of 50% DDT emulsion to 500 ml of water and then spray it on the surface. You can also use a brush dipped in 4 ml of 50% DDT emulsion and draw vertical and horizontal lines on the clothes and bedding infested with lice, with a distance of 10 cm (3 inches) between the lines. Then roll up or fold the clothes and bedding and leave them for 2 hours to kill the lice inside.