It is an infectious disease caused by a protozoan called Toxoplasma gondii. This protozoan is easily found in nature and can cause infection in large numbers of mammals and birds worldwide.
Infection in humans is asymptomatic in 80 to 90% of cases, ie it causes no symptoms, and may go unnoticed in those patients whose immunity is normal. The normal person's immune defenses can leave this parasite "inert" in the body (without causing any damage) indefinitely.
However, when this person becomes immunosuppressed (with diminished immune defenses) for any reason (AIDS, secondary to drugs used for transplantation or even after a very debilitating disease) the symptoms and toxoplasmosis disease may manifest.
Another particularly risky period for acquiring the infection is during intrauterine life, from pregnant woman to fetus (vertical transmission). The fetus may have affected its formation when contaminated.
How do you get the disease?
In four ways:
- By ingestion of cysts present in contaminated animal manure, particularly cats, which may be present in any soil where the animal moves. Most common in our midst.
- By eating meat from infected animals (raw or undercooked), most common in Asia.
- By intrauterine transmission of the contaminated pregnant woman to the fetus (vertical).
- A fourth form of transmission can occur through contaminated organs that, when transplanted into people who will have to use immunity-lowering medications (to combat rejection to the received organ), cause the disease.
What do you feel?
Here we need to distinguish between:
- “immunocompetent” people (with normal immunity), and
- immunocompromised people (with decreased immunity).
In those who have preserved immunity, symptoms occur only in 10% of cases. In these cases the main manifestation is the presence of enlarged lymph nodes or lymph nodes: these are the called languages, which can occur anywhere in the body where there are ganglia (inguinal, axillary, neck, etc.), but most often affect the neck. The ganglia are noticeable upon simple visualization or palpation and are painless. Manifestations may be restricted to this and are self-limiting, that is, they disappear spontaneously.
However, some patients may have fever, muscle and joint pain, tiredness, headaches, and visual changes when retinal involvement occurs (the lining of the inner and posterior surface of the eye that is rich in light-sensitive nerve endings), sore throat, the appearance of diffuse reddish spots all over the body - such as an allergy, hives and enlargement of the liver and spleen; less commonly occurs inflammation of the heart muscle. Abdominal pain may occur when there is involvement of the ganglia of the posterior abdomen. Although most of the time these ganglia disappear spontaneously, in some cases it may take months, as well as tiredness and fatigue.
A less benign form of involvement of patients with normal immunity is the aforementioned retinal inflammation (chorioretinitis).
It most often occurs as a result of contamination in fetal life, manifesting in adolescence or as a young adult, rarely after the age of forty, but can - much less often - occur in acute infection.
People with these conditions have blurred vision and blind spots in the visual field that may remain or even lead to compromised eye blindness if not properly treated.
After an acute phase of infection, whether with minimal manifestations (lingual) or not, the disease is latent, as if “asleep” thus remaining forever or may spontaneously recur later or as a result of a drop in immunity level .
The presentation of this disease in those with diminished immunity, as one might imagine, is much more aggressive. Particularly more common in this group are patients infected with the HIV-1 virus (virus that causes acquired immunodeficiency syndrome, AIDS).
In general it also occurs by reactivation of latent infection.
Symptoms in these cases are manifestations of impairment of the brain, lungs, eyes and heart.
The most common presentation is due to brain impairment manifested by headaches, fever, drowsiness, decreased generalized or part body strength (right or left half) and progressively decreases lucidity to coma.
If left untreated, these cases progress to rapid progression and death.
How is the diagnosis made?
Because it is a disease with very nonspecific symptoms common to many others, the diagnosis is usually made by physicians with experience in the field. Confirmation of the diagnosis is made by several blood tests. The most common are those that detect the presence of antibodies in the blood against the Toxoplasma gondii.
The need and duration of treatment will be determined by the manifestations, places of involvement and especially the immune status of the person who is ill.
There are three situations:
Immunocompetent with acute infection
- Ganglion involvement only: usually requires no treatment.
- Infections acquired from transfusion with contaminated blood or accidents with contaminated materials are usually severe and should be treated.
- Retinal infection (chorioretinitis): should be treated.
Acute infections in pregnant women:
- They should be treated as there is evidence that this reduces the chance of fetal contamination.
- With evidence of fetal contamination: needs treatment and treatment regimen can be harmful to the fetus, so special vigilance should be maintained in this regard.
- These people should always be treated and some groups, such as those infected with the HIV-1 virus, should remain on a slightly lower dose of the medication they used to treat the disease indefinitely. In the latter case, we discuss the possibility of interrupting this maintenance of treatment in those who achieve immune recovery with the so-called AIDS cocktails.
How to prevent?
As the main form of contamination is oral, prevention should generally be done:
- By not eating raw or undercooked meat.
- Eat only vegetables and fruits well washed under running water.
- Avoid contact with cat feces.
Pregnant women, in addition to avoiding contact with cats, should undergo appropriate medical (prenatal) monitoring. Some countries have been successful in preventing intrauterine contamination by performing laboratory tests on all pregnant women.
In people with immune deficiency prevention may be necessary with the use of medication depending on an individual analysis of each case.