Toxoplasma | As IgG | Laboratory research

Toxoplasmosis Is a parasitic disease (parasitosis) caused by an intracellular single-celled parasite, Toxoplasma gondiiBy. In the life cycle of a parasite, humans are the intermediate hosts and members of the cat family are the ultimate hosts. The life cycle includes various forms: trophozoite - invasive form (acute manifestation); Cyst - responsible for persistent and latent infection; Oocyst - is found only in cats and plays an important role in the parasite transmission process. In the latter hosts the parasite multiplies and is excreted (in the form of oocysts) during the acute course of feces.

Cats are the main reservoir of the disease. The parasite is ubiquitous. It is found in soil contaminated with the feces of infected animals (cats). Humans become infected by eating raw or undercooked meat that contains parasite cysts or by the water and food in which oocysts are found. Vertical transmission (fetal transplants) from the mother who developed the disease during pregnancy is important.

Infection develops when parasitic forms first enter the digestive system, where they multiply in intestinal cells. They reach the lymph nodes through the lymphatic system, from where they enter the bloodstream and reach distant organs. The parasite mainly affects the nervous system, eyes, skeletal muscles and heart. Cysts can form in these organs - during latent and chronic infection. The immune system is important for disease progression.

There is no specific symptom characteristic of toxoplasmosis. In immunocompetent people it either occurs asymptomatically or with nonspecific symptoms - fatigue, fever, and enlarged lymph nodes (most often the neck lymph nodes).

In people with impaired immunity treated with cancer, HIV, and immunosuppressants or corticosteroids, the parasite can cause serious harm. Active toxoplasmosis can cause encephalitis, myocarditis, pneumonia, chorioretinitis, or a widespread infection. The suppressed immune system promotes the activation of latent toxoplasmosis.

Acute toxoplasmosis is asymptomatic in most pregnant women. Injury to the fetus occurs during transplacental transmission from a mother who became infected during pregnancy. Toxoplasmosis in the first trimester of pregnancy is associated with an increased risk of preterm birth and miscarriage. The fetus has chorioretinitis (damage to the eyes), diffuse intracranial (intracranial) calcifications, hydrocephalus (larger head circumference, increased volume of fluid in the skull).

Toxoplasmosis manifests itself in the second or third trimester in a subclinical or mild form. Toxoplasmosis is involved in TORCH syndrome.

5 forms of toxoplasmosis are described:

• Acquired toxoplasmosis in an immunocompetent state;
• Acquired or reactivated toxoplasmosis in immunosuppression;
• Eye shape - manifests itself in the form of acute chorioretinitis, characterized by severe inflammation and necrosis;
• Toxoplasmosis in pregnant women;
• Congenital toxoplasmosis;

For the diagnostics of toxoplasmosis, imaging tests, serological tests, and tests for parasitic DNA are performed by molecular biological methods.

Serological tests Seeks out specific antibodies against the pathogen. Based on serological tests IgM and IgG antibodies To reveal.

IgG antibodies It occurs a few weeks after the initial infection by the body and can persist in the blood for a long time. IgG levels increase with the progression of the infection. The test can be used as an adjunct to the IgM test to confirm the presence of acute or past infection with Toxoplasma gondii. Increasing the titer 4 or more times will confirm the presence of an acute infection.

To avoid complications during pregnancy, it is recommended to assess the immune status before giving birth. Seropositive women before pregnancy are protected from future fetal infection, while seronegative women are at risk of infection during pregnancy.

When should we take the test?

• Screening examination before and during pregnancy;
• Immunodeficiency conditions;
• Clinical signs of toxoplasmosis infection;
• Repeat examination if a pregnant woman receives a suspicious result during the initial examination;
• Evaluation of the strength of immunity to toxoplasmosis.

How to prepare for the test?

No special preparation is required for the test.

Research material

Venous blood

Possible interpretation of the results

Positive result:

• Current or previous infection;
• Activation of the infectious process (4-fold increase in the level of antibodies in the paired serum during the study at intervals of 10-14 days indicates the activation of the infectious process).

Negative result:

• No infection is noted;
• Early stage of infection;
• The level of antibodies in the blood is less than the sensitivity threshold of the analyzer.

Resources

https://spravochnik.synevo.ua/ru/torch-infekcii/toxoplasmosis.html

https://www.synevo.bg/toksoplazmoza-serologiya/