"Parasitology" Trichomonas vaginalis

<h1 id="hi-170964" > trichomoniasis vaginalis</h1>

Trichomonas vaginalis Donne 1837 is a flagella parasitic in the human vagina and urinary tract, mainly causing trichomoniasis vaginitis, is a sexually transmitted infectious disease, global distribution, population infection is more common.

morphology

The life history of this insect consists only of the trophozoite phase and the non-enveloping phase. The trophozoite is pear-shaped or oval, 10 to 15 μm wide, up to 30 μm long, colorless and transparent, with folding light, with 4 anterior flagella and 1 posterior flagella, the posterior flagella stretches backwards to connect with the outer edge of the worm body fluctuation membrane, the wave membrane is located in front of the worm body 1/2, for the insect body for rotational movement of the organ. The nucleus is located at 1/3 of the anterior end and is an oval vesicle-like nucleus with 5 cup-shaped matrices arranged at the upper edge of the nucleus, from which flagella is emitted. The axial column is slender and transparent, runs through the worm body, protrudes from the posterior end to make the worm body pear-shaped, and because it is sticky, it is often visible with epithelial cells or debris. The cytoplasm contains deeply stained particles, arranged in parallel along the axis column, and has been shown to be hydrogenosome, an enzyme system unique to the worm. The insect body is soft and changeable, and the mobility is strong.

life history

The life history of Trichomoniasis vaginalis is simple, with only the trophoblast phase. The worm body reproduces by longitudinal dichotomy to devour and swallow food. The insect body has a strong ability to live in the external environment and has a certain ability to resist the bad environment. The trophozoite is the period of infection of the worm and is transmitted through direct or indirect contact. It is mainly parasitic in the female vagina, with the posterior vaginal vault being more common and can also be found in the urethra; male infected people generally parasitize the urethra, prostate, or parasitize in the testicles, epididymis, or under the foreskin.

Pathogenic

The pathogenicity of Trichomoniasis vaginalis varies with the strain and host physiological state. Under normal circumstances, the vaginal environment of healthy women remains acidic due to the action of lactobacilli (pH between 3.8 and 4.4), which can inhibit the growth and reproduction of insects or other bacteria, which is called the self-purification effect of the vagina. If the genitourinary system is dysfunctional, such as pregnancy and menstruation, the pH in the vagina is close to neutral, which is conducive to trichomoniasis and bacterial growth. When trichomoniasis parasitizes the vagina, it consumes glycogen, hinders the fermentation of lactobacillus, affects the concentration of lactic acid, so that the pH of the vagina changes to neutral or alkaline, and the trichomoniasis can multiply in large quantities, which promotes secondary bacterial infection and aggravates the inflammatory response.

Most insect strains are less pathogenic, many women have vaginal trichomonas infection, but no clinical symptoms or symptoms are not obvious; other insect strains can cause significant vaginitis, the patient's vaginal wall can see mucosal hyperemia, edema, epithelial cell degeneration and shedding, white blood cell infiltration and other lesions, mild vaginal mucosa no abnormal findings. The patient complains of itching of the genitals and increased vaginal discharge. In severe cases, the vulva feels burning and tingling, painful intercourse, and even affects work or sleep. Increased vaginal discharge on negative examination, grayish yellow, vesicular, accompanied by odor, and milky white discharge, with pus-like or pink discharge when accompanied by bacterial infection. Trichomoniasis may present with symptoms of urinary frequency, urgency, and dysuria when trichomoniasis invades the urethra, and sometimes hematuria may be seen. Male infected people are generally asymptomatic and worm-carrying, which can lead to continuous re-infection of the spouse. Sometimes it also causes urethral prostatitis, increased nocturia, local tenderness. It has been reported that the discovery of trichomonas vaginal trichomoniasis in nascent respiratory tracts and conjunctiva of respiratory tract infections may have acquired infections while passing through the birth canal. Some scholars believe that trichomonas vaginalis can devour sperm, and secretions hinder sperm survival, so it may cause infertility. It is also thought that cervical cancer is associated with vaginal trichomoniasis infection.

diagnosis

Diagnosis is based on the presence of trophozoites in secretions, urine precipitates, or prostatic fluid taken from the posterior vaginal vault. Commonly used methods are: saline direct smear method or smear staining method (Reye's or Ji's liquid staining), microscopic examination of trophozoites. It can also be used by culture method to add secretions to liver immersion medium and incubate in a 37 °C incubator for 48 hours for post-microscopic examination, which has a high detection rate and can be used as the basis for the diagnosis and efficacy evaluation of difficult cases.

popular

Trichomonas vaginalis is distributed worldwide, with infection rates varying from place to place, with the highest infection rate in the 20-40 age group of women, with an average infection rate of 28%. The causes that constitute the epidemic are related to the following factors:

Source of infection: patients with trichomoniasis vaginitis and asymptomatic carriers or male infected people.

Route of infection: direct transmission, mainly through sexual intercourse. In sexually open countries, both men and women can be infected, and prostitution has a high rate of infection; indirect transmission, mainly through public baths, baths, public swimwear and pants, sitting toilets, especially in units with poor sanitation facilities, often through bath toilets caused by epidemics. The trophozoite has great resistance in the external environment, and the trophozoite adhering to the toilet board can survive for 30 minutes, can survive for 23 hours in damp towels and pants, can live for 102 hours in 40 ° C water, can live for 65 hours in 2 ~ 3 ° C water, and 45 to 150 minutes in ordinary soap water, so it is easy to infect each other in a society that ignores hygiene and is less civilized.

prevention and cure

Asymptomatic carriers and patients should be diagnosed and treated in time to reduce and control the source of infection, especially if both couples must use drugs at the same time to cure them. The commonly used oral drug is metronidazole (metronidazole), which can be used topically with dovitin. The vagina is more effective in maintaining an acidic environment, and the vagina can be flushed with 1:5000 potassium permynic acid solution. Improve public facilities, purify public baths and toilets, such as changing baths to showers, toilets to squatting toilets, paying attention to personal hygiene and menstrual hygiene.