toxoplasmosis

Toxoplasmosis is a little known disease. It is benign, but it can have serious consequences for pregnant women and immunosuppressed people, who belong to the risk group and must take measures to prevent the disease. Toxoplasma gondii
is the parasite that causes toxoplasmosis, it can infect humans as well as other animals, but it needs felines like cats to complete its life cycle and be transmitted to the environment like soil.

Toxoplasmosis is generally a benign disease, except in pregnant women (because they can transmit the disease to the fetus through the placenta) and in immunosuppressed people (with a deficiency in the immune system). Many people around the world are infected by this disease, but usually do not develop symptoms. The severe form of the disease develops in the fetus and in people with a deficiency in the immune system (AIDS and people with grafts).

Transmission can be done through direct contact with soil or objects contaminated by excrement of infected cats, eating food infected by toxoplasma such as raw or undercooked vegetables and meat, drinking contaminated water, blood transfusion or organ transplants and from mother to child during the pregnancy.

The most common symptoms, when they appear, are: adenopathy (increase in the volume of the lymph nodes), fever, chills, malaise and headache. Much like the symptoms of mononucleosis.

Among the complications we have complication in childbirth, abortion, transmission to the fetus, retinochorioditis, problems in the brain, heart, liver and other organs.

Diagnosis is usually done through blood antibody research, there are other alternative ways.

In healthy people, treatment is generally not necessary, but in cases of complications, immunosuppressed, pregnant women and newborns, treatment is based on antibiotics.

Definition

Toxoplasmosis is an infection generated by a unicellular parasite, a protozoan – Toxoplasma gondii.

This parasite can infect people and all animals, especially cats, but it needs to infect felines to carry out their sexual cycle. In cities, the main disseminators of this disease are cats, but other animals such as cows, pigs and chickens can also transmit the disease through eating raw or undercooked meat.

The parasite is usually acquired during childhood and adolescence. In the United States, about 11% of the population between 6 and 49 years old are seropositive for T. gondii, which means that these people have already been infected by this parasite at least once in their lives. In developing countries, the number of HIV positive people is higher, usually between 40 and 80% of the population.

Toxoplasmosis is generally a benign disease, except in pregnant women (because they can transmit the disease to the fetus through the placenta) and in immunosuppressed people (with a deficiency in the immune system). Many people around the world are infected by this disease, but usually do not develop symptoms. The severe form of the disease develops in the fetus and in people with a deficiency in the immune system (AIDS and people with grafts).

Approximately 85% of cases of toxoplasmosis in healthy people are asymptomatic, when symptoms are present the most common are: adenopathy, headache, fever, chills, among others.

Therefore, not everyone needs toxoplasmosis treatment. On the other hand, pregnant women who contracted the disease during pregnancy and immunosuppressed people should treat the disease to avoid serious consequences.

When the parasite infects a person, it remains latent in neural and muscle tissues, never being eliminated. But most people are able to control the parasite, not spreading the parasite and remaining asymptomatic for life.

The complication that most frequently leaves sequelae is inflammation of the retina and choroid (retinochoroiditis), which in the United States and Europe occur in approximately 1% of cases. In Brazil, the prevalence of retinochoroiditis caused by toxoplasmosis is much higher, and in some regions it reaches 20% of the population. In Latin America, toxoplasmosis is one of the main causes of blindness, unlike Europe and the United States.

Some studies published mainly in mid-2010 have shown that people carrying (without symptoms) of Toxoplasma gondii are associated with a greater risk of suffering from schizophrenia or committing suicide.

Epidemiology

According to a study published on July 14, 2016 in the specialized journal Scientific Reports , Toxoplasma gondii infects the brain and eyes of about 2 billion people worldwide. The vast majority of infected people do not require special treatment, as the infection is said to be asymptomatic (without symptoms).

– In some countries, such as Brazil, 60 to 70% of people are infected with Toxoplasma gondii1.

Causes

As we saw in the “Definition of toxoplasmosis” section, this disease is a consequence of the infestation of a parasite, Toxoplasma gondii. This parasite was discovered in 1908 by two French scientists, Nicolle and Manceaux, in a rat species typical of Africa.

Despite infesting countless animals, in addition to people, their eggs (called oocysts) are produced only in the intestines of cats, and spread on the ground through the animal’s excrement. The different ways to contract the disease are:

– touch soil soiled with excrement from cats carrying protozoan eggs, and take this dirt into your mouth (eg gardening, children playing,…).

– eating food infected by toxoplasma (eg vegetables that grew in infected soil, undercooked meat from infested animals, such as beef, pork or lamb).

– transplacental transmission from mother to foetus. Contamination can only occur if the mother contracts the disease during pregnancy. We then found that a woman who contracted toxoplasmosis before pregnancy will not infect her child.

– transmission through blood transfusion or organ transplants, practically only in immunosuppressed people.

– blood transfusion.

Groups of risk

As we saw in the “Definition of toxoplasmosis” section, this disease is generally benign in healthy people. Despite being infected by the disease, people usually remain asymptomatic.

On the other hand, the severe form of the disease can develop in:

– fetuses (spontaneous abortion, birth of a stillborn fetus, birth of a child with congenital toxoplasmosis, with possible brain, eye or liver anomalies).

– immunodeficient people, such as AIDS patients, people who make chronic use of corticoids, people with cancer, among others (in which the parasite can reach the brain and cause inflammation: meningitis ).

Symptoms

People affected by toxoplasmosis are usually asymptomatic or develop a benign form of the disease. Healthy people are protected by their immune system, which manufactures antibodies against the protozoan (Toxoplasma gondii). The possible symptoms are similar to those of mononucleosis :

– fever

– adenopathy (enlarged lymph nodes)

– feeling unwell

– chills

-headache

However, for those belonging to the risk group – fetuses, immunosuppressed people – toxoplasmosis can be very serious.

The disease can reach the brain and cause paralysis, epileptic seizures or even pulmonary complications, if it is disseminated to other parts of the body.

Diagnosis

To diagnose toxoplasmosis, the doctor will perform a blood test, which should identify the antibodies produced by the body, with the aim of eradicating the parasite responsible for the disease, Toxoplasma gondii.

In pregnant women with suspected toxoplasmosis, a test for these antibodies will be carried out by puncture of the amniotic fluid or fetal blood.

There are other possible diagnoses, such as research for the presence of the parasite in the blood, tomodensitometry (scanner) and MRI (Magnetic Resonance Images) of the brain.

The doctor may also take a biopsy of the infected tissue (more rare).

Blood tests such as cell counts may indicate a Toxoplasma gondii infection when you have lymphocytosis and less than 10% total white blood cell count. Some liver enzymes may also be altered.

Complications

In general, toxoplasmosis is a benign disease triggered by the parasite Toxoplasma gondii. The immune system is normally strong enough to get rid of the parasite.

On the other hand, in pregnant women, the parasite can pass to the fetus through the placenta and trigger serious complications such as:

– a miscarriage

– abnormalities in the liver, brain or eye region. Such as intracranial calcifications, hydro or microcephaly, bilateral retinochoroiditis, mental retardation, acute myocarditis, pneumonitis, hepatitis, strabismus, microphthalmia.

It is necessary to be very cautious during the first trimester of pregnancy, because in this period the risks are greater. See the section “Tips for preventing toxoplasmosis”.

We emphasize that if the mother contracted toxoplasmosis before becoming pregnant, there is no risk for the fetus. The danger is imminent when the mother contracts the disease during pregnancy, so it is important to be extra careful if she has not had the primo-infection (first infection).

The risk to the fetus depends very much on the woman’s gestational age when she first contracts the disease:

In immunosuppressed people, depending on where the parasite reaches in the body, this can have serious consequences:

– In the brain region, abscesses can occur that can trigger epileptic seizures, paralysis or speech disorders.

– If the parasite is disseminated, respiratory disorders may occur, such as pneumonitis, asthenia or skin rashes, cardiomyopathies, hepatitis, retinochoroiditis.

Psychiatric Risks:
Numerous studies have shown a correlation between people suffering from schizophrenia and the presence of the parasite Toxoplasma gondii . This means that more people with schizophrenia have Toxoplasma gondii in their brains than those without schizophrenia. We can cite a study carried out with American soldiers published in 2008 in the American Journal of Psychiatry (DOI :  10.1176/appi.ajp.2007.06081254 ). Toxoplasma gondii may also increase the risk of suicide, according to a 2018 South Korean study (DOI:  10.9758/cpn.2018.16.1.95 ).

Treatments

In healthy people, toxoplasmosis is cured spontaneously and generally goes unnoticed.

Incidentally, it is not appropriate to treat young girls and women who are not pregnant. On the contrary, in case of infection, it is important that these people develop the necessary antibodies to protect them, and subsequently protect their fetus, in case of a future pregnancy.

As for the pregnant woman who has not previously had an infection, there may be complications for the fetus, so the doctor will prescribe an antibiotic , usually spiramycin.

Antibiotics and corticosteroids may also be given to children born with severe symptoms, and to immunosuppressed people.

There is no vaccine against toxoplasmosis.

It is important to know that there are treatments (antibiotics) only for the acute phase of the disease, there is no treatment when the parasite is latent in the brain in asymptomatic carriers, despite the possible psychiatric risks. (read under Complications above).

Tips & Prevention

Toxoplasmosis is usually treated only in people who belong to the risk group, so we have some tips to prevent the disease.

These tips are useful for both pregnant women and immunosuppressed people:

– Avoid eating raw meat and raw foods (leave these foods to eat at home, where we know how they are washed)

– Wash fruits and vegetables well

– When cleaning the cat’s feces box, use gloves. If you come into contact with the animal’s excrement, wash your hands immediately afterwards.

– Wear gloves and wash your hands immediately after gardening, and never bring dirt-soaked hands to your mouth.

– Wash your hands frequently, especially before preparing meals and before sitting down to the table.

Jeanne Kenney
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I’m a stylist trainer, a content creator, and an entrepreneur passion. Virgo sign and Pisces ascendant, I move easily between my dreams, the crazy world I want, and my feet on the ground to carry out my projects.

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