Toxoplasmosis

Introduction to Toxoplasmosis Toxoplasmosis, also known as toxoplasmosis, is a zoonotic disease caused by Toxophas magondii. Most of the human body is a hidden infection. The clinical manifestations of the patients are complicated, and their symptoms and signs are lack of specificity, which may cause misdiagnosis, mainly invading the eyes, brain, heart, liver and lymph nodes. After the pregnant woman is infected, the pathogen can infect the fetus through the placenta, directly affecting the development of the fetus, and the teratogenicity is serious. The risk is 10 times larger than that of the uninfected pregnant woman, affecting eugenics and becoming one of the most serious diseases in human congenital infection. Widely attached, the relationship between this disease and AIDS is also close. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: 1, mother-to-child transmission 2, blood transmission 3, respiratory tract transmission Complications: pneumonia myocarditis orchitis meningitis

Cause of toxoplasmosis

Infection factor (55%)

The only infectious factor of this disease is toxoplasma infection. The toxoplasma invades the body and locally invades and invades the local lymph nodes, and then invades other organs or tissues with the blood or lymphatic circulation. The pathogen proliferates in nucleated cells until the cells rupture, and the oozing worms invade adjacent other cells, resulting in tissue necrosis, an acute inflammatory reaction that forms small necrotic foci and surrounding tissues, and the latter manifests as edema, monocytes, and A small number of multinucleated cells infiltrate.

Dietary factors (35%)

The usual route of infection for pathogens may be due to the consumption of food or water sources that have not been warmed and disinfected by pathogens. Causes pathogens to attach and survive in the human body.

Placental infection factor (10%)

After the pregnant woman is infected, the pathogen can infect the fetus through the placenta, which directly affects fetal development and is teratogenic .

Toxoplasmosis prevention

(1) Controlling the source of infection

Control of sick cats, pregnant women should be serological examination, the initial infection of the disease should be artificial abortion, middle and late infection should be treated, for vascular serological examination of Toxoplasma antibody positive should not supply blood, organ transplant serum Those who are positive for antibodies should also not be used.

(two) cut off the route of infection

Do not keep close contact with cats and dogs, prevent cat feces from contaminating food, drinking water and feed, not eating raw or unripe meat and raw milk, laying eggs, etc., strengthen health education, and do a good job in environmental hygiene and personal hygiene.

Toxoplasmosis complications Complications pneumonia myocarditis orchitis meningitis

Toxoplasma infection can increase pregnancy complications, such as pregnancy toxemia accounted for 8.7% to 9.6%, their positive rate of Toxoplasma skin test is 56% to 67.4%, higher than the general population. You Chuanxin et al (1988) detected 610 pregnant women, the infection rate of hypotension, hepatitis, nephritis, anemia, etc. was 14.3% (2/14), and those without comorbidities were 7.0% (3/42). It was also reported that the incidence of uterine contractions, postpartum hemorrhage, uterine insufficiency, micro-heat, endometritis, and early water-breaking were higher than normal. The insect also affects endocrine by damaging the placenta and ovaries.

Concurrent pneumonia, myocarditis, orchitis, meningitis.

Symptoms of Toxoplasmosis Common symptoms Abdominal pain Hepatosplenomegaly High fever Unconsciousness Visual impairment Lymph node enlargement Sore throat Coma Meningitis Stimulus Pleural effusion

Most of them are asymptomatic worms. Only a few people have morbidity and clinical manifestations are complicated. Acquired toxoplasmosis is more complicated than congenital toxoplasmosis. The severity of the disease is related to the health of the body.

1. Acquired toxoplasmosis in normal immune function: Most patients are asymptomatic, and symptoms are about 10%-20%. The main clinical manifestations are fever, general malaise, night sweating, muscle pain, sore throat, rash, Liver, splenomegaly, systemic lymphadenopathy, etc., lymph node enlargement is more prominent, in addition to superficial lymph node enlargement, mediastinum, mesenteric, retroperitoneal and other deep lymph nodes can also be swollen, abdominal lymph nodes can be accompanied by abdominal pain. Swelling lymph nodes are hard, may be accompanied by tenderness but not purulent. Symptoms and signs usually disappear for 1-3 weeks. A few cases can reach 1 year. Individual patients may have persistent high fever, single case retinal choroiditis, transient Pneumonia, pleural effusion, hepatitis, pericarditis, myocarditis, Guillain-Barre syndrome, intracranial space-occupying lesions and meningoencephalitis.

2. Acquired toxoplasmosis in patients with immunodeficiency: the risk of infection with Toxoplasma gondii in patients with congenital and acquired immunodeficiency is extremely high, especially the recurrence of latent infections, in which case acquired toxoplasmosis Lymph node lesions may not be obvious, there may be widespread dissemination and rapid fatal infections, manifested as hyperthermia, pneumonia, rash, hepatosplenomegaly, myocarditis, myositis, pill inflammation, and even brain toxoplasmosis, typical brain arch The disease begins in a subacute manner, with headache, hemiplegia, seizures, visual impairment, confusion, and even coma. Fever and meningeal irritation are rare. Cerebrospinal fluid examination shows a small number of red blood cells, mononuclear cells are slightly increased, and protein Slightly higher, the sugar can be completely normal, occasionally reduced, CT examination shows encephalitis changes, can also present single or multiple contrast-enhanced space-occupying lesions, less than 2cm in diameter, mostly in the basal ganglia, after ringing or Nodular enhancement.

Toxoplasmosis check

(1) Pathogen examination

1. Direct microscopic examination: take the patient's blood, bone marrow or cerebrospinal fluid, chest and ascites, sputum, bronchoalveolar lavage fluid, aqueous humor, amniotic fluid, etc. for smear, or lymph nodes, muscle, liver, placenta and other biopsies. Swine or Ji's staining microscopy can find trophozoites or cysts, but the positive rate is not high, and can also be used for direct immunofluorescence to examine Toxoplasma gondii in tissues.

2. Animal inoculation or tissue culture: take the body fluid or tissue suspension to be inoculated, inoculate the abdominal cavity of the mouse, which can produce infection and find the pathogen. When the first generation is negative, it should be blindly passaged 3 times, or as tissue (monkey kidney or Porcine kidney cells were cultured to isolate and identify Toxoplasma gondii.

3. DNA hybridization technology: For the first time, domestic researchers applied 32P-labeled probes containing specific DNA sequences of Toxoplasma gondii to molecular hybridization with cells or tissue DNA in peripheral blood of patients, showing that specific hybridization bands or spots were positive, specificity and The sensitivity is high. In addition, the polymerase chain reaction has been established in China to diagnose the disease, and hybridization with the probe, animal vaccination and immunological examination methods show that the spring is highly specific, sensitive and rapid.

(two) immunological examination

1. Detection of antibodies: The antigens used mainly include tachyzoite soluble antigen (cytoplasmic antigen) and membrane antigen. The former antibody appeared earlier (using staining test, indirect immunofluorescence assay), while the latter antibody appeared later ( Detection by indirect hemagglutination test, etc., and simultaneous detection by multiple methods can increase the detection rate. Since Toxoplasma gondii can exist for a long time in human cells, it is generally difficult to detect antibodies or previous infections. According to the level of antibody titer and its dynamic changes, commonly used detection methods are:

(1) staining test (Sabin-Feldman DT): detection of IgG antibody, positive 1 to 2 weeks after infection, antibody titer reached a peak at 3 to 5 weeks, then gradually decreased, can be maintained for many years, antibody titer 1: positive suggestion is hidden Sexual infection; 1:256 is an active infection 1:1024 is an acute infection, which has the disadvantage of requiring live insects to operate.

(2) Indirect fluorescent antibody test (IFAT): detection of IgM and IgG antibodies, sensitive, specific, rapid, reproducible, etc., consistent with DT, but if rheumatoid factor, anti-nuclear antibody positive, can cause false positive Response, serum antibody titer 1:64 for previous infection, the same as DT.

(3) Indirect hemagglutination test (IHA): The test method is simple and has a high coincidence rate with DT results, but it is generally positive one month after the disease. The result is judged to be the same as IFAT, poor repeatability and sensitized red blood cell instability and its shortcomings.

(4) Enzyme-linked immunosorbent assay (ELISA): It can detect IgM and IgG antibodies, and has the advantages of high intensity per degree and specificity. It can also be used for antigen identification. In recent years, it has been created on the basis of ELISA. New assays such as Golden Grape Protein A (SPA)-ELISA; Horseradish Peroxidase Labeled SPA Substituted Enzyme Standard Secondary Antibody for ELISA (PPA-ELISA); Avidin-Biotin (ABG) ELISA Gel-diffusion (DIG)-ELISA; spot (DDT)-ELISA and monoclonal antibody (McAb)-ELISA are more sensitive and more specific methods.

(5) Radioimmunoassay (RIA): highly sensitive and specific.

2. Detection of antigen

Immunological methods for detecting pathogens (tachyzoites or cysts) in host cells, metabolism or cleavage products (circulating antigens) in serum and body fluids, are reliable methods for early diagnosis and diagnosis, and domestic and foreign scholars have established McAb - ELISA and sandwich ELISA of McAb and polyclonal antibody to detect circulating antigen in acute patients with a sensitivity of 0.4 g/ml of antigen in serum.

(3) Intradermal test

With the peritoneal fluid or chicken embryo fluid of the infected mice as the antigen, there is often a delay, tuberculin reaction, which can be used as an epidemiological investigation, and there are not many applications at present.

Diagnosis and diagnosis of toxoplasmosis

The clinical manifestations of this disease are complex and difficult to diagnose. In case of certain clinical manifestations, such as chorioretinitis, hydrocephalus, microcephaly, brain calcification, etc., the disease may be considered.

Congenital toxoplasmosis should be differentiated from other diseases in TORCH syndrome (rubella, cytomegalovirus infection, herpes simplex and toxoplasmosis), in addition to syphilis, Listeria or other bacterial and infectious encephalopathy , fetal polycythemia, sepsis, infectious mononucleosis, lymph node tuberculosis, etc., mainly rely on pathogens and immunological examination.

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