Toxoplasma is a zoonotic infectious disease caused by Toxoplasma gondii, which has a wide range of natural epidemics and can be found in many mammals and birds. Toxoplasma gondii invasion of the human body can lead to Toxoplasma infection and toxoplasmosis, the latter specifically referring to pathological changes in clinical manifestations and active infections. Toxoplasma infection is mostly a latent infection, but when the resistance is low, serious clinical symptoms can occur. Congenital infections often cause fetal malformations, stillbirths and miscarriages. Commercial Pizza Oven,Pizza Oven,Electric Pizza Oven,Conveyor Pizza Oven Guangzhou New Power Catering Equipment Manufacturing Co.,Ltd , https://www.gznewpower.com
[Etiology] Toxoplasma life history includes two stages of sexual reproduction and asexual reproduction. The whole process requires two kinds of hosts - the terminal host (cat and feline) and the intermediate host (other animals or human body). There are five different forms in the development of Toxoplasma: trophozoites, cysts, schizonts, gametophytes and oocysts.
After the cat eats the toxoplasma oocysts or cysts, sporozoites and trophozoites are released in the intestinal lumen, and the small intestinal epithelial cells are invaded to proliferate. Some merozoites develop into male and female gametophytes, and the two combine to form zygotes. It is an oocyst that is excreted with cat feces.
After eating human toxoplasma oocysts or swallowing cysts, sporozoites, tachyzoites or tachyzoites escape in the intestines, and then invade the intestinal wall through the blood or lymph into the mononuclear phagocyte system and spread to various organs of the body. The parenchymal cells of the tissue multiply, causing the cells to rupture, causing various acute conditions. In a body with normal immune function, after some tachyzoites invade the host cells, especially the brain, eye, and skeletal muscles slow down and form cysts, which can survive for several months and years in the host. Even life is not equal. When the body's immune function is low or long-term use of immunosuppressive drugs, the cysts in the tissue can rupture, release the euphraticia, enter the bloodstream and other new tissue cells to continue to develop.
The tachyzoite stage is the main pathogenic stage of Toxoplasma gondii, and its host cell is destroyed by its invasiveness to host cells and proliferation by unique internal budding in nucleated cells. After the worms escape, they re-invade the new cells, stimulating the infiltration of lymphocytes and macrophages, leading to acute inflammation and necrosis of the tissues.
Prolongation in the capsule is the main form of chronic infection. The cyst is enlarged due to the proliferation of the tachyzoites, and the organs are squeezed to make the function impaired. The cyst is increased to a certain extent and can be broken by a variety of factors. Free worms can stimulate the body to produce delayed allergic reactions and form granulomatous lesions. Later fibrous calcifications are more common in the brain and eyes. After the host is infected with Toxoplasma gondii, under normal circumstances, it can produce effective protective immunity, most of which have no obvious symptoms. When the host has immunodeficiency or low immune function, it causes toxoplasmosis, even in latent infection, it can cause recurrence. Or lethal disseminated infection; in recent years it has been reported that AIDS patients die from Toxoplasma encephalitis.
[laboratory diagnosis]
Specific examination (1) smear examination.
(2) Animal inoculation separation method.
(3) Serological examination.
(4) Molecular biological diagnosis.
[Result analysis and judgment]
1. The smear examination takes the body fluid, cerebrospinal fluid, blood, bone marrow, amniotic fluid, pleural effusion of the acute phase patient after centrifugation, the sediment is used as a smear, or a biopsy smear is used. After staining with Giemsa, the bow is examined under the microscope. The trophozoite can be diagnosed. This method is simple, but the positive rate is not high and it is easy to miss. In addition, the immunological enzyme or fluorescent staining method can be used to observe the specific reaction, and the detection rate of the worm can be improved.
2. Animal inoculation isolation method Animal inoculation isolation method or cell culture method to find trophozoites. The sensitive experimental animal mice were used, and the samples were inoculated into the abdominal cavity. After 1 week, the peritoneal fluid microscopy was performed, and the negative cells were blindly passaged at least 3 times. The samples were also inoculated into single-layer nucleated cells cultured in vitro. Animal inoculation and cell culture are currently commonly used pathogens.
3. Serological examination Serological examination has become a widely used diagnostic tool due to the lack of toxoplasmosis. There are many types of methods, mainly the following four.
(1) Staining test: It is a classical specific serological method. The living trophozoite is combined with the specific antibody in the sample with the participation of the active factor, so that the damage of the surface of the worm is not stained by the coloring agent. Microscopic examination showed that the worm body was not positive by blue dye, and most of the worm body was negative by blue dye.
(2) IHA: This method is specific, sensitive and simple, and is suitable for epidemiological investigation and screening antibody detection, and is widely used.
(3) Indirect immunofluorescent antibody test: The whole antibody is detected by using the fluorescently labeled second antibody with the whole insect as an antigen. This method can measure both isotype and subtype antibodies, and the detection of IgM is suitable for early clinical diagnosis.
(4) ELISA: used to detect specific circulating antibodies or antigens in the host. A variety of improved methods have been widely used for the diagnosis of early acute infection and congenital toxoplasmosis. The sensitivity of this method can be detected as 0. .5ug/L
4. Molecular biological diagnosis In recent years, PCR and DNA probe technology have been applied to the detection of Toxoplasma gondii infection, which is more sensitive, specific, and early diagnosis. It has begun to be used in clinical practice.
The clinical manifestations of toxoplasmosis are diverse and easily confused with many diseases, and differential diagnosis is critical. Congenital Toxoplasma infection must be distinguished from rubella, cytomegalovirus infection, and herpes simplex virus. Shanghai Yuanye Biotechnology Co., Ltd.: