Toxoplasma | As IgM | Laboratory research

Toxoplasmosis Is a parasitic disease (parasitosis) caused by an intracellular single-celled parasite, Toxoplasma gondii-With. 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 transmission of the parasite. 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 look for specific antibodies against the pathogen. Based on serological tests IgM and IgG antibodies To reveal.

In the acute period of infection, in the first week, IgM antibodies Appears and reaches a peak in about 30 days, then gradually decreases in 3-6 months, but may persist for a low titer for about two years. Demonstration of IgM antibodies is useful in diagnosing recent infection.

In some patients, IgM antibodies may disappear within 3 weeks of the onset of the disease. Therefore, detection of IgM may not be a reliable criterion for diagnosing acute primary infection or reactivation of the infectious process. The diagnostics of primary infection can be made in the presence of IgM antibodies, in the presence of low-grade IgG, and in increased dynamics of IgG antibody concentrations (increased 4-fold at 10-14 day intervals).

Detection of IgM during pregnancy in early seronegative women may indicate a recent infection that may lead to congenital toxoplasmosis. False positive reactions to various IgM and IgG antibodies are often observed during pregnancy. In such cases, studies are performed to determine the dynamics of IgG at intervals of 10-14 days.

The results should be interpreted with caution in patients with impaired immune status as they are characterized by low IgG titers and IgM antibodies may not be detected at all.

When should I get tested for Toxoplasma IgM?

• Diagnosis of toxoplasmosis (in the presence of clinical manifestations: lymphadenopathy, hepatosplenomegaly, fever of unknown nature);
• Planning and screening for current pregnancies;
• Signs of intrauterine infection;
• Immunodeficiency conditions;
• Suspicion of congenital 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:

• Acute infection;
• Persistence of IgM antibodies, with unspecified time of infection;
• Reactivation of infection;
• Congenital toxoplasmosis.

Negative result:

• No infection is noted;
• Early or late phase of infection;
• Absence of congenital toxoplasmosis (study conducted in the first weeks of life)

Resources

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

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