2017-01-02
Abstract
The issue of such parasitic disease as toxoplasmosis is presented in this paper. This disease is caused by the pathogen Toxoplasma gondii. The cases of toxoplasmosis are more prevalent in African countries and countries of Latin and South America. The toxoplasmosis usually has final and intermediary owners: domestic animals (primarily cats) are the intermediary owners and they can infect human. There are different forms of the toxoplasmosis. The adult organism with the strong immune system may not even notice that he is sick. At the same time, the common symptoms of the toxoplasmosis are similar to the acute respiratory viral infection. The toxoplasmosis can infect the human only once in a lifetime, because after disease the immunity to pathogens is formed. The toxoplasmosis can be easily prevented through the good personal hygiene and eating only washed fruits, vegetables and thermally processed meat. At the same time, the toxoplasmosis as a prior disease is quite dangerous for the pregnant women, as it can be transferred to the fetus and causes the serious disorders. In this case, each pregnant woman should pass prenatal diagnostic for TORCH infections, including toxoplasmosis, and receive special treatment if it needs.
Key words: toxoplasmosis, Toxoplasma gondii, congenital toxoplasmosis, feline family
Introduction
This paper is devoted to the issue of such disease as toxoplasmosis. The prevalence of toxoplasmosis in the world is incredibly high, mainly due to African countries as well as countries of Latin and South America, where the infection rate of the population reaches the 90%. Indicators in Europe and North America are lower: from 25% to 50% of the population have been sick with toxoplasmosis.
The causative agent of toxoplasmosis is a simple intracellular parasite, Toxoplasma (Toxoplasma gondii), the main source of which is domestic animals (primarily, cats). In general, Toxoplasma has ever infected from 50% to 80% of the adult population worldwide.
There are different forms of toxoplasmosis. The majority of people may not even notice that they are sick because the symptoms of this disease are so minor for adults. At the same time, the form of the congenital toxoplasmosis can negatively impact on the newborns and their central nervous system.
Discussion
Toxoplasmosis is one of the TORCH-infections. Such infections are associated with a single feature: their pathogens can be transmitted in utero from mother to child. These infections are often the cause of problems with child bearing and perpetrators of congenital malformations in the baby.
The causative agent of toxoplasmosis, Toxoplasma gondii, is a type of protozoa (Protozoa), class Sporozoa (Sporozoa), a detachment of coccidia (Coccidia). Toxoplasma is mobile and has an arc or arch shape or even resembles a slice of orange. There are also oval and round shapes of the pathogens. The type of movement of Toxoplasma gondii is sliding (Davis, 2011).
The life cycle of Toxoplasma passes with the participation of final and intermediate hosts or owners. The final owner of Toxoplasma is members of the feline family, and the intermediate owners are the majority of types of mammals and birds. Toxoplasma can be not only in organs and tissues of cats (which is characteristic of diseased animals and human), but also in the intestine of cats. Thus, the sick cat can pollute the soil, lawns, fields and vegetable gardens by its excrements. Toxoplasma is derived from feces in the environment, where retains their viability in the form of cysts over a year and more and may cause the disease, if it gets inside the human body. Farm animals and birds become infected by eating grass, in which Toxoplasma cysts live (Drisdelle, 2010).
Thus, there are two main ways of human infection with Toxoplasma gondii:
through the eating of poorly cooked or roasted meat of animals and birds, unwashed vegetables, fruits, herbs, which are Toxoplasma-infected;
directly from the infected cats, but only if the pathogen together with saliva, lacrimal fluid or cat’s urine penetrates into the human body through the damaged skin and mucous membranes.
At the same time, a sick person does not spread the pathogen in the environment; therefore, he is not dangerous for others. Also, the toxoplasmosis is not transmitted sexually. In addition, not every human, which body is infected with Toxoplasma, should be treated. If the immune system of the infected person is strong and can defend him, he is almost healthy. Transmission of the pathogen from human to human is possible only with organ transplantation from a donor with a primary or congenital toxoplasmosis infection (Hökelek, 2016).
It is quite difficult not to meet with Toxoplasma during the life due to the ease of infection (there are many infected cats, and unwashed fruits and vegetables in our life). At the same time, there are not many people with the severe form of toxoplasmosis. It turns out that in fact toxoplasmosis is not so serious as it might seem at first glance.
As it is mentioned above, in most cases, Toxoplasma penetration into the human body does not cause a serious disease (or clinical disease). The risk of disease depends on the virulence of the pathogen, the quantity of Toxoplasma, which penetrates into the body and the state of the protective forces of the human body (Hökelek, 2016).
It should be noted if the disease progresses, its symptoms are not serious. It is very often that such disease passes unnoticed. As a result, human will know about his disease only through the conclusion of the serological analysis. At the same time, the severe form of toxoplasmosis is disguised as acute respiratory virus infection: the patient’s temperature rises, sometimes up to 38 degrees and above, the neck and occipital lymph nodes are increased, a headache and muscle aches, sweating and overall weakness appear. As a rule, these symptoms disappear a week later (John P. Cunha, 2016).
If the immune system of the human is weak, the probability of disease increases. In this case, Toxoplasma can fall from the gastrointestinal tract of human into the lymph and blood, and spread throughout the whole body, affecting various organs and tissues, especially the brain, eyes, heart, muscles.
The most severe form of the disease may cause encephalitis or meningoencephalitis, which are usually accompanied by a sharp headache, attacks of convulsions, loss of consciousness. At the same time, such cases happen very rarely. It can be explained by the following facts. The healthy body of adult or child fairly easy copes with Toxoplasma. After penetration of the parasite in the gastrointestinal tract, the complicated response arises. The result of it is almost always predetermined and assumes the formation of antibodies, which neutralize Toxoplasma, and the formation of a stable immunity for a lifetime (John P. Cunha, 2016). Thus, one can say that toxoplasmosis is not an essential problem for human if he has a strong immune system.
The diagnosis of toxoplasmosis is based on the complex indices that include clinical data and results of laboratory confirmation. The epidemiological preconditions, such as contact with cats, features of the dietary habits (eating raw, half-baked meat, testing a raw meat, unwashed vegetables, fruits), personal hygiene habits, profession and others have a relative value.
It should be noted that the extreme diversity of clinical manifestations, lack of symptoms, which are unique to the toxoplasmosis, complicates the clinical diagnosis and allows only assuming the diagnosis, which is formed during the complete differential diagnosis and analysis of the results of the laboratory research.
The methods of laboratory diagnosis of toxoplasmosis are divided into two groups: parasitological and immunological ones. One more feature of the toxoplasmosis is that the proof lifelong immunity is formed after the disease. The immunoglobulin of the class G remains for the whole life as evidence that there is no Toxoplasma in the body. Fluctuations in the level of immunoglobulin, especially taken separately, do not matter.
Another situation is characteristic of the pregnant women. The toxoplasmosis as a primary infection is quite dangerous for the pregnant women as it can negatively impact on the fetus and cause irreversible consequences and abnormal disorders. According to statistics, about 1% of women are infected with Toxoplasma during pregnancy. One third of cases of primary infection during the pregnancy are accompanied by the infection of the fetus. The risk of fetal infection increases from trimester to trimester. At the same time, the infection is not dangerous to the fetus, if:
the infection of woman was more than three months before pregnancy;
the first child was born with congenital toxoplasmosis;
the expectant mother has the immunity to Toxoplasma.
If the special treatment of the pregnant woman is started timely, the risk of a baby’s infection and probability of congenital toxoplasmosis reduces to only 1-5% (John P. Cunha, 2016).
Anyway, the pregnant woman should perform the following actions in order to prevent the emergence and development of congenital toxoplasmosis:
At the same time, toxoplasmosis is not so dangerous for men and nonpregnant women. In general, the toxoplasmosis is one of those diseases, which are very easy to prevent, following the basic rules of hygiene:
In this case, children (for example) in schools should be educated the above mentioned rules of hygiene and care rules of pets (cats) in order to prevent disease infection. It can be seminars, testing or even games, which can help children to understand the danger of disease.
Another priority group is pregnant women and those, who plan a pregnancy. This group should be educated more thoroughly as the effects of the disease during the pregnancy can be quite dangerous for the fetus. Education, including rules of hygiene, behavior with cats and necessary of repeated tests must be conducted for women in hospitals and special courses for pregnant women.
Conclusion
In the end one can say that toxoplasmosis is a widespread disease of humans and animals. Around 70% of the population may be infected with Toxoplasma worldwide, mostly in such regions and Africa, Latin and South America. More than 90% of infected people have never experienced serious symptoms of this disease.
An interesting fact is that even the very first infection of human, accompanied by the fairly substantial reaction of his immune system, as a rule, does not cause any symptoms: the person feels completely healthy. Sometimes, the infected person can notice the symptoms, which are similar to the acute respiratory virus infection.
Thus, the toxoplasmosis is one of those diseases that can infect the person once in a lifetime, and so easily, that it cannot even be noticed. After this illness, the strong immunity remains for a lifetime. As a result, the secondary infection cannot be.
At the same time, the toxoplasmosis is quite dangerous primary infection for the pregnant women. If the woman is pregnant, she should be tested for toxoplasmosis in the antenatal clinic. If the clinical manifestations of toxoplasmosis as well as antibodies to Toxoplasma class IgM are detected, it should decide about the treatment or even abortion in early pregnancy.
References
Davis, R. (2011). Animals, Diseases, and Human Health: Shaping Our Lives Now and in the Future (1st ed.). Santa Barbara, Calif.: Praeger.
Drisdelle, R. (2010). Parasites: Tales of Humanity's Most Unwelcome Guests (1st ed.). Berkeley: University of California Press.
Hökelek, M. (2016). Toxoplasmosis: Background, Etiology and Pathophysiology, Epidemiology. Emedicine.medscape.com. Retrieved 27 December 2016, from http://emedicine.medscape.com/article/229969-overview
John P. Cunha, F. (2016). Toxoplasmosis: Learn About Symptoms and Treatment. MedicineNet. Retrieved 27 December 2016, from http://www.medicinenet.com/toxoplasmosis/article.htm
