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Lice used to be a regular in human life, but today, their appearance has become extremely rare.
This phenomenon raises the question: why do lice seem to have become the dust of history in modern society?
01
The name lice is likely to make most people uncomfortable, yet their existence has crept through the long history of humans and even many animals.
These tiny creatures, with their parasitic lifestyles, evolved almost in sync with our ancestors.
Lice were recorded in Egypt as early as 5000 BC, and they still play a non-negligible role in human society today.
Lice are not monogeneous, they have a diverse family of members, each adapted to a different host environment.
Lice are everywhere, from the hair on the top of the head to the crevices of the clothes and even the hidden places of the body.
Their lifespan is generally between 20 and 30 days, but in this short life, lice are able to complete their life cycle and continue to reproduce.
Head lice on the human scalp are often prevalent enemies among children.
They multiply in clumps of hair, suck blood, cause unbearable itching and redness of the skin.
The spread of body lice is often closely related to the hygiene of the living environment, and they can spread indiscriminately in densely populated areas with poor cleaning conditions, posing a threat to human health.
Lice are not only in the company of humans, domestic animal lice choose domestic animals such as pigs and dogs as their hosts, and their presence not only makes animals uncomfortable, but can also become vectors for disease transmission.
Birds are not spared, as bird lice likewise nest in their feathers, posing pain and potential health risks.
In these lice families, there is also a special existence - pubic lice, which inhabit the intimate parts of humans quietly, and their Xi life is difficult to talk about, but the discomfort and social impact they cause cannot be ignored.
But don't rush to have a negative impression of lice, although they do cause a lot of problems, in the big arena of biological evolution, the existence of lice may also have other meanings.
Their life cycle and reproductive Xi provide scientists with valuable research material in parasitic biology.
Moreover, they have a long history and have developed almost simultaneously with the trajectory of human civilization, which also provides historians with clues about the human living environment and health conditions.
02
Lice are a direct attack on human skin, and the skin reaction to a lice bite is usually intense itching, which can cause people to scratch involuntarily, triggering a chain reaction.
Frequent scratching can not only lead to skin injury, but can also further develop into dermatitis and even ulcers in some severe cases.
Behind these symptoms, there is a kind of physical and psychological suffering, which can range from subtle to significant.
The effects of lice extend far beyond the surface of the skin, these seemingly inconspicuous parasites are actually transmitters of some serious diseases.
Their harm can be silently transferred from one host to another, transmitting diseases including typhus and Japanese encephalitis to humans.
This seemingly simple bite can actually be a vector for the spread of deadly diseases.
More far-reaching, the presence of lice poses a serious threat to people's quality of life.
Imagine the impact on your mental health when you have to constantly cope with itching on your skin?
This constant discomfort, caused by a creature that is barely visible, can become an invisible killer that affects the well-being of life.
03
Among them, lice and bed bugs are two completely different creatures, not only in terms of morphology, but also in their survival strategies and impact on humans.
Lice specialize in sucking the blood of humans, but they do not feed on the blood of other mammals, in contrast to bed bugs.
But even so, lice do not transmit disease, which is considered a "mild" trait among parasites.
When lice problems surface, people often use sulfur soap to clean them.
Sulfur soap is known as an effective weapon against lice.
The principle is simple and crude – the sulfur component has a lethal effect on lice.
However, while sulfur soap is indeed effective, caution should be taken when using it to avoid irritation to the skin.
Another extreme method of lice removal is the use of dichlorvos, a powerful pesticide that kills lice quickly, and there are huge risks associated with this method.
Dichlorvos is a highly toxic chemical that is also extremely toxic to humans.
Therefore, although it can relieve a thousand sorrows in one drop, it must be solemnly warned against this cruel method: dichlorvos should not be used on the human body.
They are transmitters of diseases, and many conditions such as relapsing fever, leprosy, and plague have been associated with the name of bed bugs.
The severity of these diseases makes bed bugs a problem that cannot be ignored in the field of public health.
Bed bugs are amazing in their ability to survive without food for up to a year, a trait that makes them highly adaptable in nature.
Bed bugs also use the "play dead" strategy, where they hide in beds, carpets, or furniture, and when the host passes by, they creep onto their skin to suck blood.
In movies and TV series, lice and bed bugs are often confused, but in real life, we can't take it lightly.
04
However, in the changes of modern society, those small creatures that were once troublesome have gradually faded out of life.
Because in the era of underdeveloped technology in the past, in the densely populated and intimate environment such as rural areas and even collective dormitories, the existence of head lice was almost unavoidable on a daily basis.
Outdoor activities such as working in the fields and community gatherings form an important part of daily life, and these activities not only provide opportunities to get close to nature, but also increase the risk of head lice transmission.
With the acceleration of urbanization, people's living environment has begun to change significantly.
The increasing privacy of personal spaces and the reduction of close contact between people in living conditions have undoubtedly constituted an obstacle to the spread of lice.
Offices have replaced fields, conference rooms have replaced meeting places, and more and more time has been occupied by indoor activities, a shift in lifestyle that seems to have invisibly put an end to the spread of head lice.
However, this is only the appearance.
Improvements in hygiene Xi, especially hair cleansing and care, have added a solid line of defense to our health moat.
The use of personal care products such as shampoos and conditioners effectively reduces the likelihood of head lice breeding.
Before the 80s of the 20th century, most of the shampoos, laundry detergents and other personal care products that were commonly used were based on soap, and some of the raw materials of these soaps came from pig skin.
This detail is crucial, as pork rinds are not adequately treated during the soap-making process and are prone to parasites and bacteria.
Lice are a parasite, and their presence is directly linked to this mode of production.
However, with the advancement of science and the spread of hygiene knowledge, the toiletry industry changed dramatically in the late 20th century.
Modern toiletries are becoming more widely made from chemical or plant-based raw materials, both of which have nothing to do with animal fats.
These new detergents are not only effective at cleaning, but they also provide better antimicrobial benefits.
Of course, this change is not achieved overnight, but gradually takes shape with the progress of society and the improvement of people's awareness of hygiene.
The more critical change is the rapid development of medical conditions and sanitation.
In the past, due to the scarcity of medical resources in rural areas, people lacked knowledge about the prevention and control of head lice, which gave head lice an opportunity to take advantage of.
Today, even though cases of head lice are still occasional, advances in modern medicine have been able to provide patients with timely and effective treatment options.
People are no longer helpless against head lice, but can quickly control and eliminate the problem.
Although there has been a significant decrease in the occurrence of head lice in modern society, it does not mean that we can completely let our guard down.
Personal hygiene is still the key to preventing lice, and we need to continue to maintain good personal hygiene Xi, such as: wash your hair regularly, use shampoo and conditioner, and change personal items in a timely manner.
In addition, in schools, kindergartens and other congregate living places, it is still necessary to strengthen hygiene inspections and regular cleaning to reduce the risk of head lice transmission.