Toxoplasmosis (synonyms: toxoplasma infection; toxoplasma gondii infection; toxoplasma; toxoplasmosis; ICD-10 B58.-: Toxoplasmosis) is an infectious disease caused by Toxoplasma gondii, a protozoan (single-celled organism). Due to a two-host development cycle, a distinction is made between intermediate hosts and a final host. Intermediate hosts are mouse, pig, sheep, cattle, poultry and humans. Final hosts are Felidae, such as cats. They excrete a feces containing oocysts that is infectious in the environment for a long time. Occurrence: The infection occurs worldwide. Transmission of the pathogen (route of infection) can occur through undercooked meat, especially lamb and pork (tachy- and bradyzoites; about 20% of pork is infected) or direct handling of infected cats. Another source of human T. gondii infection is insufficiently washed fruit and vegetables contaminated with oocystsFurthermore, infection occurs via soil, for example during gardening, via contaminated surface water, or diaplacentally, i.e., from the mother to the unborn child. In addition, there is a small risk of becoming infected with the pathogen during blood transfusions and organ transplants. The incubation period (time from infection to onset of the disease) is usually 14-21 days. Three different forms of toxoplasmosis can be distinguished, depending on the clinical symptoms:
- Postnatal infection in immunocompetent individuals – infection after birth in individuals with competent immune defenses.
- Postnatal infection in immunocompromised individuals (reactive toxoplasmosis) – in individuals with asymptomatic Toxoplasma infection can occur due to a weakening of the immune system (especially in AIDS), reactivation of Toxoplasma infection, usually severe.
- Prenatal (connatal) infection – infection of the unborn child by the mother during pregnancy; in this case, the risk of transmission to the child increases with the duration of pregnancy, but the severity of infection decreases.
In Germany, the contamination with the pathogen in the elderly is up to 70%, that is, more than 70% of the population over 50 years have antibodies to Toxoplasma gondii. Pregnant women do not show immunity in up to 75% of cases.Once you are infected, you remain infected for life, so reactivation is also possible. Toxoplasmosis is dangerous in pregnancy if it is a first infection of the mother, because then there are no antibodies to protect the fetus in utero (unborn child in the womb). If infection with the pathogen occurs during pregnancy, the fetus may experience the following symptoms/diseases.
In the first trimester (third trimester of pregnancy).
- Abortion (miscarriage)
In the second and third trimesters
- Abortion (miscarriage)
- Chorioretinitis – inflammation of the choroid (choroid) with retinal (retina) involvement.
- Hydrocephalus (hydrocephalus) – pathological expansion of the liquid-filled fluid spaces (brain ventricles) of the brain.
- Intracranial calcifications – calcifications in the brain.
- Epilepsy
- Cerebral atrophy – decrease in the mass of the cerebrum.
- Microcephaly – abnormal smallness of the head due to a developmental disorder of the brain.
- Strabismus (strabismus)
- Mental retardation
- Optic atrophy – reduction of vision due to degeneration of the optic nerve.
- Iritis – inflammation of the iris in the eye.
- Cataract – clouding of the lens of the eye.
- Premature birth
- Pneumonia (pneumonia)
- Myocarditis (inflammation of the heart muscle)
- Nephritis (inflammation of the kidneys)
- Hepatitis (liver inflammation)
- Gastroenteritis (gastrointestinal inflammation)
If the mother becomes infected shortly before the end of pregnancy, the child is usually born asymptomatic (85% of cases), but later develops symptoms (chorioretinitis, iritis, deafness, encephalitis, microcephaly, epilepsy, psychomotor retardation) of Toxoplasma infection without adequate therapy. For this reason, existing immunity should be clarified in pregnant women with testing of antibody status.
Laboratory Diagnostics
Toxoplasmosis testing is required in the following cases:
- Before a planned pregnancy, the following women should be tested:
- With infertility and desire to have children
- With a stressed pregnancy or birth history
- Without known immune status
- During pregnancy, the following women should be screened:
- Without known immune status
- After infertility treatment or with a strained pregnancy or birth history.
- Without immunity after infertility treatment or with strained pregnancy or birth anamnesis.
- Regardless, screening should be sought in pregnant women with unknown immune status or lack of immunity.
Laboratory parameters 1st order – mandatory laboratory tests.
- Direct microscopic detection of the pathogen in the blood.
- Toxoplasma gondii antibody detection (IgM/IgG detection in immunofluorescence).
Pregnant women should be retested serologically (from blood) 14 days after a positive IgM test. In pregnant women without immunity, repeated tests should be performed preferably at intervals of eight weeks, but at least not greater than twelve weeks until the end of pregnancy. Second-order laboratory parameters-depending on the results of the history, physical examination, etc.-for differential diagnostic workup
- Toxoplasma gondii DNA detection (genetic detection of Toxoplasma gondii infection).
Interpretation
| Toxoplasma gondii IgG | Toxoplasma gondii-IgM | Results, usually indicate the following infection status. |
| Low | Low | Not relevant, inactive infection |
| High | Low | Decaying infection |
| High | High | Recent infection |
| Low | High | Acute infection |