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Toxoplasmosis, popularly known as cat disease, is an infectious disease caused by the protozoan Toxoplasma gondii (T. gondii), which has cats as its definitive host and people as intermediaries. Most of the time, the infection does not cause symptoms, however if the person has a compromised immune system, it is possible that the signs and symptoms of the infection are present and there is a greater risk of developing more severe forms of the disease.
The disease is transmitted mainly by eating food contaminated by the parasite's cysts or through contact with the feces of infected cats. In addition, toxoplasmosis can be transmitted from mother to child, however this only happens when the disease is not diagnosed during pregnancy or the treatment is not done correctly.
Although it does not cause symptoms, it is important that toxoplasmosis is identified and treated correctly according to the doctor's guidance to prevent complications, such as blindness, seizures and death, for example.
How the transmission happens
Toxoplasmosis can be transmitted through the consumption of raw and poorly sanitized foods, such as raw or undercooked meat, that are contaminated with feces from infected cats or consumption of water contaminated by parasite cysts.
Contact with infected cats is not sufficient for transmission of the Toxoplasma gondii, it is necessary that the person has contact with the feces of these cats for the contamination to happen, because the contamination can happen through inhalation or ingestion of the infective form of the parasite. Thus, when cleaning the cat's litter box without protective measures, it is possible that there is contact with the infective form of the parasite.
Due to the fact that the infective form of T. gondii being able to remain infectious in the soil for long periods, some animals such as sheep, oxen and pigs, for example, can also be infected by the parasite, which enters the intestinal cells of these animals. Thus, when consuming undercooked meat, the person can also be contaminated by Toxoplasma gondii. In addition to the consumption of raw meat, the consumption of smoked meat or sausages that have not been processed according to adequate hygiene conditions, or contaminated water can also be considered ways of transmitting the parasite.
The transmission of toxoplasmosis can also happen during pregnancy through the passage of the parasite through the placenta. However, transmission depends on the pregnant woman's immune status and stage of pregnancy: when the woman is in the first trimester of pregnancy and has a compromised immune system, there is a greater chance of transmitting the disease to the baby, however the consequences are considered milder . See more about toxoplasmosis in pregnancy.
Life cycle Toxoplasma gondii
In people the T. gondii it has two evolutionary stages, which are called tachyzoites and bradyzoites, which is the evolutionary form that is found in the raw meat of animals. People can acquire the infection by contacting the cysts of the parasite present in cat feces or by eating raw or undercooked meat containing bradyzoites.
Both cysts and bradyzoites release sporozoites that penetrate the intestinal cells and undergo a differentiation process into tachyzoites. These tachyzoites reproduce and disrupt cells, and can spread throughout the body and invade other tissues, forming cysts that contain several tachyzoites. In pregnant women, after disruption of cells, tachyzoites can cross the placenta and reach the baby, resulting in infection.
Main symptoms
In most cases, toxoplasmosis does not cause symptoms, however when the person's immunity is low it is possible that symptoms similar to those of other infectious diseases, such as flu and dengue, for example, may be the main ones:
- Body language, mainly in the neck region;
- Fever;
- Muscle and joint pain;
- Tiredness;
- Headache and throat;
- Red spots on the body;
- Difficulty seeing.
Symptoms appear more often in people who have a weakened immune system, such as those who have chemotherapy for cancer, who have recently undergone transplants, are carriers of the HIV virus, or in women who contract the infection during pregnancy.
In more severe cases, toxoplasmosis can impair the functioning of organs such as the lungs, heart, liver and brain, and symptoms of the severe form are usually severe tiredness, drowsiness, delusions and decreased strength and body movements. Know how to identify the symptoms of toxoplasmosis.
Types of toxoplasmosis
O Toxoplasma gondii it can spread through the bloodstream, especially when the person has a weakened immune system or when treatment for the infection is not started or done correctly. Thus, the parasite can reach one or more organs, giving rise to some complications and consequences of infection, such as:
1. Ocular toxoplasmosis
Ocular toxoplasmosis occurs when the parasite reaches the eye and affects the retina, causing an inflammation that can lead to blindness if not treated in time. This disease can affect both eyes, and vision impairment can be different for each eye, with decreased vision, redness and pain in the eye.
This complication is more common to occur as a result of infection during pregnancy, however it can also happen in people with the most compromised immune system, although it is uncommon.
2. Congenital toxoplasmosis
Toxoplasmosis in pregnancy causes congenital toxoplasmosis, which is when the baby is infected with this disease while still in the mother's womb. Toxoplasmosis in pregnancy can lead to serious consequences, such as malformations of the fetus, low birth weight, premature birth, abortion or death of the baby at birth.
The consequences for the baby vary according to the gestational age at which the infection occurred, with a greater risk of complications when the infection occurs closer to the end of pregnancy, with a greater risk of eye inflammation, severe jaundice, enlarged liver, anemia, cardiac changes, convulsions and respiratory changes. In addition, there may be neurological changes, mental retardation, deafness, micro or macrocephaly, for example.
3. Cerebrospinal or meningoencephalic toxoplasmosis
This type of toxoplasmosis is more common in people diagnosed with AIDS and is usually related to the reactivation of T. gondii in people who have latent infection, that is, who have been diagnosed and treated, but the parasite has not been eliminated from the body, allowing it to travel to the nervous system.
The main symptoms of this type of toxoplasmosis are headache, fever, loss of muscle coordination, mental confusion, convulsions and excessive tiredness. If the infection is not identified and treated, it can lead to coma and death.
How the treatment is done
The treatment of toxoplasmosis is only done when the person has symptoms of the disease, since the drugs indicated can be toxic when used frequently. Thus, treatment is only recommended in symptomatic cases and in pregnant women diagnosed with the disease.
The treatment of toxoplasmosis should be started as soon as the disease is identified, the diagnosis being made through a blood test that identifies the existence of IgG and IgM antibodies in the body, which are produced to fight the protozoan that causes the disease.
Prevention of toxoplasmosis
To prevent toxoplasmosis, it is important to take some precautions, such as:
- Consume drinking, filtered or mineral water;
- Cook meats well and avoid eating rare meat in restaurants;
- Avoid contact with unknown cats and wash your hands well if you touch animals you don't know;
- Wear a glove when cleaning the litter box and collecting cat feces.
People who have pets should take them to the veterinarian to have tests done to identify the toxoplasmosis parasite and deworming the animal, avoiding the possible transmission of toxoplasmosis and other diseases.