Aphids belong to a class of tiny animals of the arthropods of the genus Arachnida. The body size is generally around 0.5 mm, some as small as 0.1 mm, and most species are less than 1 mm.

The locusts and spiders belong to the arachnid. The adults have 4 pairs of feet, a pair of tentacles, no wings and tentacles. The body does not divide the head, chest and abdomen, but merges into a saclike body, which is different from insects. The worm body is divided into a corpus callosum and a body. The corpus callosum is composed of a mouthpart and a scorpion, and the body is divided into a foot and a body. There are many hairs on the body and feet, and some hairs are very long. The front end has a mouthpart and is edible.

The world has found more than 50,000 aphids, second only to insects. Many types are related to medicine. In recent years, it has been found that aphids have a very close relationship with human health. For example, leather mites, mites, mites, worms, white mites, dust mites, and pampas grass can suck blood and invade the skin, causing "rosting nose" or worms. Symptoms, allergies, urinary tract snoring, pulmonary sputum, intestinal cramps and hemorrhoids, seriously endangering human health.

In the broad sense, cockroaches can be said to be ubiquitous. They spread rapidly, in large quantities, and in many species, such as spider mites (also known as spider mites) and white mites, which can harm crops, in the ground, underground, mountains, water, and inside and outside the body. Fruit trees; mites, hair follicle mites and lung mites are parasitic in humans and animals, spreading a variety of diseases. The dust mites in our homes, floors and carpets can cause many allergic diseases (asthma).

The aphids parasitic in the human body are mainly divided into two types, one is the hair follicle scorpion, also called the demodex, and the other is called the sebaceous gland, which is parasitic in the sebaceous glands of the human face, and is generally referred to as aphids.

It is a permanent parasitic genus. It is a genus of Salucoptidae. Parasitic in the epidermal layer of the skin of humans and mammals, causing a violent itching of refractory skin diseases, namely scabies.

Morphology: The worm body is nearly round or elliptical, with a back bulge, milky white or light yellow. The size of the female is 0.3 to 0.5 x 0.25 to 0.4 mm; the male is 0.2 to 0.3 x 0.15 to 0.2 mm. The carcass is short and is located at the front end. The cheeks are pincer-like and have small teeth at the tip that are suitable for biting the stratum corneum of the host's skin. The limbs are divided into three sections. No eyes and valves. The back of the body has horizontal wavy stripes and rows of scaly skin spines, and the rear half of the body has several pairs of rod-shaped bristles and long scorpions. The ventral surface is smooth with only a few bristles and 4 pairs of feet. The foot is short and thick, divided into 5 sections and is conical. The distance between the first two pairs of feet and the latter two pairs of feet is large, and the base of the foot has horny internal processes. The male and female anterior pairs have a long-handled claw pad at the end of the foot, called the ambulacra, which is a sensitive part; the rear 2 pairs of feet have different male and female ends, and the females are long bristles, while the males The fourth pair has a suction pad at the end of the foot. The spawning hole of the female is located in the center of the back 2 pairs of feet, showing a transverse crack. The male external genitalia is located slightly behind the fourth pair of feet. Both anus are located in the middle of the back of the body

Life history:

The history of life is divided into five stages: egg, larva, pre-nymph, post-nymph and adult. The mistletoe is in the stratum corneum of the human skin and bites the keratinous tissue. The cheeks and the claws at the ends of the ankles are used to puncture a tunnel that is parallel to the surface and twisted. The females lay eggs in the tunnel. (Figure 32).

The eggs are round or elliptical, pale yellow, thin in shell, about 80 × 180 μm in size, and hatched into larvae after 3 to 5 days of production. The larvae have 3 pairs of feet, 2 pairs in the front of the body, and 1 pair of the proximal end of the body. The larvae still live in the original tunnel, or another tunnel, and the nymph is the former nymph after 3 to 4 days. The nymphs are like adults, and there are 4 pairs of feet. The nymphs of the former nymphs have not yet appeared. After about 2 days, the nymphs become worms. After the female nymphs, the ovimatomas have not yet fully developed, but the vaginal pores have formed and mating is feasible. After the nymphs are worms for 3 to 4 days, they become adults. It takes 8 to 17 days to complete a generation of life history.

It is usually mated on the surface of the skin at night, and it is mated by male nymphs after female adult and female. Most males die shortly after mating; female nymphs are drilled into the host skin within 20 to 30 minutes after mating, and the molting is female, and the eggs are laid in the tunnel 2 to 3 days later. It can produce 2 to 4 eggs per day, and can lay 40 to 50 eggs in a lifetime. The life expectancy of females is about 5 to 6 weeks.

Ecology:

Parasitic parts often parasitize the softer and thinner skin.

Activities and excavation tunnels The mistletoe is deep in the stratum corneum of the host epidermis, feeds on keratinous tissue and lymph, and excavates with cheeks and anterior jaws, gradually forming a tunnel parallel to the skin. The tunnel can be up to 10~15mm long. The tunnel dug by the female is the longest, and there is a small longitudinal passage to the epidermis at intervals. The male and the rear nymphs can also be excavated separately, but they are extremely short. The former nymphs and larvae cannot dig tunnels and only live in tunnels dug by females. Females can dig 0.5 to 5 mm per day, generally not deep into the stratum corneum.

Females after mating and fertilization are the most active, crawling 2.5 cm per minute, which is also the most susceptible to new host.

Effects of Temperature and Humidity The activity, life and infection of female adults after leaving the host are related to the temperature and relative humidity of the environment. The temperature is lower, the life is longer when the humidity is larger, and the high temperature and low humidity are unfavorable for its survival. The optimum temperature for females to spread is 15 to 31 ° C, and the effective diffusion time is 1 to 6.95 days. During this time, the activity is normal and infectious.

Pathogenicity and diagnosis: The lesions in the mistletoe are small papules, vesicles and tunnels, mostly symmetrically distributed. The acne papules are reddish, the needle size is sparsely distributed, and the middle skin is normal; it can also be densely integrated, but not integrated. The blind end of the tunnel is often hidden by the worm body, which is a gray point with a needle tip size. Severe itching is the most prominent symptom of acne. The cause of itching is caused by the mechanical stimulation of the female excavation tunnel and the action of excretion and secretion produced in life. Itching is lighter during the day, and the night is aggravated, even worse after sleep. Due to itching and scratching, it can cause secondary infections, abscesses, folliculitis or bloating.

Based on the history of exposure and clinical symptoms, it is not difficult to make a diagnosis. If you can find 疥螨, you can confirm the diagnosis. In the past, the method of detecting cockroaches used to sterilize the needle tip to break the end of the tunnel, and remove the cockroaches; or use the disinfected mineral oil to drip on the affected part of the skin, and then scrape the part with a razor blade to take the scraping object for microscopic examination. Recently, domestic scholars used a anatomical mirror to directly examine the lesion site, and found that there is a tunnel and its blind end of the sacral contour, that is, the apex of the scalpel is used to pick out the sacral end, and the diagnosis can be confirmed, and the positive rate can reach 97.5%.

Many mammalian baboons can occasionally infect humans, but the symptoms are mild.

Treatment: Commonly used drugs for treating acne include: 10% sulfur ointment, 10% benzyl benzoate tanning agent, 1% DDT cream, 1% C 666 cream, compound trichlorfon cream, 10% excellent cream And ivermectin and the like. Before treatment, the affected part should be washed with hot water. After being dried, it should be applied with sputum, once a night, the effect is better. After treatment for about 1 week, if no new skin lesions appear, you can think of recovery.

[Diagnosis of human Demodex]

First, self-diagnosis method

The mites are contacted and cross-infected. When the mites are infected, the parasites are easily accessible. The temperature and humidity are suitable for growth and reproduction, and the sebaceous glands are richer, such as the nose, forehead, and face. When a few people sweat when they are infected, they will feel a slight itching feeling on their nose and face when they sleep at night. After a while, blackheads (the secretions of aphids excretion, clogged pores and air-hardening) will appear. As the pores begin to thicken gradually, the skin begins to change from neutral to mixed, and then becomes oily. If it is not treated promptly and effectively, it will cause skin inflammation. This is what we call "acne." , hemorrhoids, rosacea."

Second, the microscope test

It is to take a little oil secretion from the nose or the oily part, and observe it under the microscope. Because the microscope observation is scientific and intuitive, it has certain limitations. It may be impossible to see the aphids in a single test. It is necessary to repeat the test several times.

Aphid is a kind of parasite that is not a bacterium. Therefore, when the operator who requires the test uses the microscope, the objective lens is 10 times and the eyepiece is 10 times. It is not necessary to use a high power microscope. The drops can be made from ordinary vegetable oil or peanut oil.