Causes of Toxoplasmosis

The causes of toxoplasmosis are those factors that lead to the development of this infection in the human body. The causative agent of toxoplasmosis is the simplest microorganism of the class Sporoviki - Toxoplasma gondii. Most likely is infection through dirty hands, dishes, water, pathogens can be found in raw meat, which is not washed enough and thermally processed.

Susceptibility to toxoplasmosis in humans is high. There are entire regions in the world in which the infection rate of the population exceeds 80%.

Causative agent of the disease

Toxoplasma gondii causes a chronic protozoal infection in the human body that affects the nervous system, spleen, liver, skeletal muscle, and myocardium.
The primary owners of toxoplasma are representatives of the cat family. Man, as well as many wild animals, are intermediate hosts of pathology that can become ill on their own and be carriers of the infection in question.

Ways of infection

From person to person

Toxoplasmosis can be transmitted from person to person only if a donor organ transplant or a blood transfusion is performed. Since a person is not the final owner of toxoplasma, contact with the patient does not pose any danger to other people. Thus, the disease is not transmitted either by contact-household, or sexually, or by airborne droplets between people. The only donor route of transmission of the disease is also very low in the modern world.

But the most difficult and dangerous way of transmitting toxoplasmosis is intrauterine infection of the fetus from a sick mother. Such infection is possible only with a woman's primary infection during pregnancy, which previously was not a carrier of the pathogen microorganism. In this case, toxoplasma easily overcomes the placental barrier, infecting the fetus. The consequence of such an infection can be catastrophic pathologies in the health of the newborn, premature birth, stillbirth, miscarriage. Therefore, when revealing the primary toxoplasmosis of pregnant women, urgent treatment and monitoring of the fetus is mandatory.

From animals to humans

Since the main owner of toxoplasma is a cat, that is, an animal, it is precisely its body that acts as the main source of the spread of the infection in the environment. It is easiest to catch toxoplasmosis by touching cat feces, and bacteria can be in the environment for a very long time and be active, contaminating the land on which people and other animals are located. Therefore, it is important to be very careful not only in direct contact with cat feces, but also when working in the garden, playing in the sand with children and other conditions.

Toxoplasmosis earth can also infect fruits and vegetables, so if they are poorly washed or do not have the necessary heat treatment, it is very easy to become infected with a pathology, the source of which in this case is still an animal. According to research, a cat that is sick for 15-20 days, during this time manages to allocate up to 2 billion invasive cysts to the outside world that retain infectivity for up to 2 years.

Also, animals that have become intermediate hosts of toxoplasma are able to infect humans. For example, if a cow eats grass that grows in the place where the feces of an infected cat are located, and then a person comes into contact with the meat of such a cow without observing hygiene rules, or if she eats insufficiently processed meat, the risk of infection is very high. However, animals, which are intermediate hosts of toxoplasmas, do not secrete them into the external environment, like cats, and therefore, simple contact with such animals cannot harm a person.

Oocysts can also be found in eggs, so it is also very important to process them well and not to drink raw.

Is it possible to get infected through a scratch

In the presence of small scratches, cuts and other injuries on human skin, the risk of infection with toxoplasmosis may exist if such a wound comes in direct contact with infected excrement, the ground in which such feces were found, or with raw meat of an infected animal. The risk of infection in this case is very small, but still possible. Therefore, in the presence of any skin lesions, you should always use protective gloves if you need to work in the garden, clean up after a pet or cut meat when cooking.

Infection during pregnancy

Pregnant toxoplasmosis is the above-described pathology that a woman encounters in the process of bearing a child. Most often, the disease does not have pronounced symptoms, but sometimes it can manifest itself with signs that are very similar to the symptoms of ordinary flu.

The causative agent during pregnancy of this pathology, as well as in any other case, will be the microorganism Toxoplasma gondii - an obligate intracellular parasite of 4-8 micrometers in size. The environment determines one of the possible forms of toxoplasma - an oocyst, tissue cyst, or tachyzoite. The oocyst and tissue cyst for the pregnant woman are invasive; they can infect the patient through contact with infected products, agricultural work, and insufficient hygiene of fruits and vegetables. Such toxoplasmas are viable in humid and warm conditions for 2 years, which increases the risk of their transmission to people many times. When invasive parasites enter the body of a pregnant woman, they are transformed into a type of tachyzoitis, causing clinical manifestations of pathology and infecting the human fetus in utero.

Thus, the main ways of infecting a person with toxoplasmosis are eating raw meat, insufficient washing of fruit crops and hands after contact with them, contact with the ground and sand, which may contain sources of infection, congenital transmission of the disease from mother to child and transplantation of an infected organ to a person during surgery. About 65% of pregnant women become infected with contaminated food and water, which causes the primary disease. The most dangerous contacts with animals are those that concern homeless cats or cats that regularly eat raw meat.

The author of the article:
Furmanova Elena Alexandrovna

Specialty: doctor pediatrician, infectious disease specialist, allergist-immunologist.

Total experience: 7 years.

Education: 2010, Siberian State Medical University, pediatric, pediatrics.

Experience as an infectious disease specialist for more than 3 years.

He has a patent on the subject "A method for predicting a high risk of the formation of a chronic pathology of the adeno-tonsillar system in frequently ill children." As well as the author of publications in the journals of the Higher Attestation Commission.

Other articles by the author

Watch the video: Live imaging of Toxoplasma parasites invading human cells (February 2020).