There is no animal scarier than a cat
The growth of schizophrenia in Moscow was associated with feline parasites
Ivan Ortega, "The Attic"
Russian researchers compared the prevalence of latent toxoplasmosis among ordinary people and patients with schizophrenia. It was found that people suffering from the latter disease show signs of toxoplasmosis twice as often as healthy people. This correlation was especially strong among women.
Toxoplasma gondii, the protozoan that causes toxoplasmosis in cats (they are the ultimate hosts of this parasite), has long been considered safe for humans. The acute phase of MI disease in almost everyone (except embryos) does not last long and, at first glance, without noticeable consequences. However, in recent decades, evidence has begun to appear that in reality, even after the formation of an immune response and the disappearance of an acute picture of the disease, a person may experience some not completely clear negative consequences from toxoplasmosis - part of Toxoplasma gondii still remains in his brain and, apparently, affects his behavior. For example, among Russian drivers who get into an accident, toxoplasmosis occurs almost twice as often as among those who, through their own fault, do not get into an accident. Also, the percentage of "toxplasmosis" among those who attempt suicide is higher.
This is somewhat similar to the behavior that toxoplasmosis causes in cats and mice. Rats and mice with toxoplasmosis begin to ignore the risks, including the smell of cats. As a result, infected rodents are more easily killed by cats, and the parasite is transmitted along with the meat. Increasing the riskiness of human behavior does not make biological sense for the Toxoplasma gondii affecting it, since cats rarely eat raw human meat and the chances of getting into a cat after the death of an intermediate human host are few for the parasite. Despite this, the modification of human behavior by toxoplasmosis really looks like a rather serious threat. The fact is that this is a fairly massive disease: in Moscow, for example, latent toxoplasmosis is observed in a quarter of the population, that is, millions of people. Naturally, the high frequency of accidents and suicides for people infected with toxoplasma can be a serious problem for society as a whole.
In such conditions, it is important to understand whether toxoplasmosis can be dangerous for people with anything other than a reduced ability to drive safely or an increased frequency of suicides. The authors of a new paper published in the journal PLOS ONE (Stepanova et al., Toxoplasmosis and mental disorders in the Russian Federation (with special reference to schizophrenia)) tried to clarify the issue by comparing the frequency of latent toxoplasmosis in two groups. In the first group there were 155 people with a confirmed diagnosis of schizophrenia, and in the second, control group – 152 people without it.
To find out exactly who is the carrier of latent toxoplasmosis and who is not, they took blood plasma and looked for two types of antibodies to Toxoplasma gondii – IgG and IgM. The first are typical for an established immune response, when the immune system already controls the pathogen with which this type of antibody works. IgMs are a sign of a primary immune response when the attacked pathogen is "unusual" for the immune system and the disease is acute. If there is a noticeable amount of IgG-type antibodies in a person's blood serum, but there are no IgM-type antibodies, then his toxoplasmosis is latent. All the examined showed only latent toxoplasmosis (other variants of it are rare in humans).
Out of 155 examined Muscovites with schizophrenia, 40% were carriers of latent toxoplasmosis. Among healthy Muscovites, there were 25% of them.
This is approximately the average occurrence of toxoplasmosis among today's residents of the capital, the authors note. Thus, the presence of toxoplasmosis in a person shows a clear correlation with the presence of schizophrenia. This correlation is weaker in men: 39% of sick men had latent toxoplasmosis, among healthy men there were 27%. But in women it was stronger: 41% of women with schizophrenia showed latent toxoplasmosis, and among healthy ones there were only 24%.
The authors of the work pay special attention to the fact that similar studies in the USSR were conducted back in the 1960s and 1980s, but then the proportion of the population with latent toxoplasmosis was significantly less than in today's Moscow. According to past studies, among ordinary citizens infected with toxoplasma there were no more than 13%, and among schizophrenics this proportion reached 32.1%. This means that the incidence of toxoplasmosis has increased in Russia over the past decades – at least in the capital.
Therefore, the authors write, hypothetically new data can be interpreted as a link between the spread of toxoplasmosis among residents of the Russian Federation and the parallel increase in the frequency of mental disorders, especially schizophrenia, observed in recent years. Apparently, the researchers believe, the process began under the USSR: in 1965-1987, the diagnosis of "schizophrenia" began to be made 4.7 times more often. Today, there are 0.55 million such patients in Russia – this is more than one per 300 inhabitants, and probably not all patients with schizophrenia have been identified in practice.
The physiological mechanism behind the correlation between toxoplasmosis and schizophrenia may be the ability of Toxoplasma gondii to survive for many years in the nerve cells of the human brain, while affecting its work in some way that has not yet been fully elucidated.
The authors note that ignoring the role of toxoplasmosis in the increase in the risk of schizophrenia for many years was based on the assumption that people with schizophrenia simply do not follow their diet and hygiene well (the main source of the causative agent of the disease is insufficiently roasted meat of some animals). In such a picture, toxoplasmosis is not so much a cause as a consequence of schizophrenia. However, the researchers note, new works refute this point of view and show that toxoplasmosis may be the cause, not the consequence of schizophrenia. A new study shows that this would quite organically explain the explosion in the incidence of schizophrenia, which has been observed in Russia in recent decades.
Unfortunately, latent toxoplasmosis itself is treated poorly enough, there are no truly effective remedies against it. Nevertheless, by observing general hygiene and watching your diet, you can reduce the chances of infection with the causative agent of this disease.
Portal "Eternal youth" http://vechnayamolodost.ru