Epidemiology of tuberculosis

Epidemiology of tuberculosis is a section of phthisiology examining sources of tuberculosis infection, transmission routes of infection, the prevalence of tuberculosis as an infectious disease among the population, unfavorable exo- and endogenous factors affecting the epidemic process, and the most endangered people with tuberculosis.

Epidemic - a massive spread of human infectious disease in any area, significantly exceeding the usual incidence rate (5-6 times). The rate of increase in the incidence of disease distinguishes explosive epidemics and long-term epidemic processes with a slow (for many years) rise and slow decline. The latter include tuberculosis.

[1], [2], [3], [4], [5],

Ways of spreading tuberculosis

Inherent parts of the epidemic process are the reservoir of tuberculosis infection, its source, the susceptible population and the transmission routes of infection.

A reservoir of tuberculosis infection is made up of people infected with mycobacteria of tuberculosis, some of which become ill during their lifetime. Some animals are also referred to the tub of the tuberculosis. The reservoir consists of two parts: potential (infected, but not sick people) and active (identified and undiagnosed patients with active tuberculosis).

The source of tuberculosis is people with tuberculosis and animals. Isolating mycobacterium tuberculosis in the external environment.

Susceptible population - people infected with mycobacterium tuberculosis who are susceptible to tuberculosis.

Since mycobacterium tuberculosis is resistant to many environmental factors and persists for a long time in various substances (liquid and dry sputum, other discharge of patients, food, etc.), tuberculosis infection occurs in various ways.

• Air-drop is the main way of infection. In this case, the smallest droplets of phlegm, containing mycobacterium tuberculosis, enter the alveoli. The most dangerous are patients with massive bacterial excretion, which even during a normal conversation disperse infected sputum droplets. Spread of aerosol also occurs with a strong cough, sneezing, loud conversation. Sprayed aerosol (the smallest infected sputum droplets up to 5 microns in size) is stored in the air of a closed room for up to 60 minutes, and then settles on furniture, floor. Walls, clothing, linen, food, etc. The best conditions for infection are poorly ventilated closed rooms where the coughing patient is.
• Infection by airborne dust occurs when breathing dust particles with mycobacteria included in them, for example when shaking clothes. Linen and bedding bacteriostatic indoors.
• Alimentary route of infection is possible when eating food contaminated with mycobacteria products. Among animals, more than 50 species of mammals and the same number of bird species that are susceptible to tuberculosis are known. Among these animals, cows and goats can be involved in human infection. In this case, infection occurs when bovine mycobacteria are transmitted through milk and dairy products, much less often when consumed in meat or when in direct contact with animals. Tuberculosis of dogs, cats, sheep, pigs has no serious epidemiological significance.
• Contact path of infection through the skin and mucous membranes can be observed in persons directly working with the culture of mycobacterium tuberculosis or infectious material (for example, pathologists, laboratory workers). The same way can catch workers of animal industries at contact with a sick animal.
• Intrauterine route of infection (extremely rare) is possible if the placental barrier is broken or as a result of swallowing amniotic fluid containing mycobacteria. At present, there is no serious epidemiological significance for this route of transmission.

Infection and tuberculosis

Tuberculosis is an infectious disease with a long period between infection (infection) and the development of the disease. After human contact with a bacteriostatic or infected material, there is a possibility of infection of a healthy person, which depends on the properties of the pathogen, as well as on the susceptibility of the human body. One bacterial excretor per year can infect an average of about 10 people. The likelihood of infection increases in the following situations:

• when in contact with a sick tuberculosis with a massive bacterial release;
• with prolonged contact with a bacteriovirus (residence in a family, being in a closed institution, professional contact, etc.);
• at close contact with bakteriovydelitelem (being with the patient in the same room, in a closed collective).

After infection with mycobacteria, the development of a clinically pronounced disease is possible. The probability of a disease in a healthy infected person throughout life is about 10%. Development of tuberculosis primarily depends on the state of the human immune system (endogenous factors), as well as from repeated contact with mycobacteria tuberculosis (exogenous superinfection). The likelihood of the disease increases in the following situations:

• in the first years after infection:
• during puberty;
• with repeated infection with mycobacteria tuberculosis:
• in the presence of HIV infection (the probability increases to 8-10% per year);
• in the presence of concomitant diseases (diabetes mellitus, etc.):
• during the therapy with glucocorticoids and immunosuppressants.

Tuberculosis is not only a medical-biological, but also a social problem. Great importance in the development of the disease has psychological comfort, socio-political stability, material standard of living, sanitary literacy. General population culture, housing conditions, availability of qualified medical care, etc.

The role of primary infection, endogenous reactivation and exogenous superinfection

Primary tuberculosis infection occurs during primary infection of a person. As a rule, this causes adequate specific immunity and does not lead to the development of the disease.

With exogenous superinfection, repeated penetration of mycobacteria of tuberculosis into the body and their multiplication are possible.

With close and prolonged contact with the bacteriovirus, the mycobacterium tuberculosis is repeatedly and in large quantities enters the body. In the absence of specific immunity, early massive superinfection (or constant re-infection) often causes the development of acute progressive generalized tuberculosis.

Even in the presence of specific immunity, developed after the previous primary infection, late superinfection can also contribute to the development of the disease. In addition, exogenous superinfection can exacerbate and progress the process in a patient with tuberculosis.

Endogenous reactivation of tuberculosis arises from retained activity or aggravated primary or secondary foci in organs. Possible causes - a decrease in immunity due to the presence of background or exacerbation of concomitant diseases. HIV-infection, stressful situations, malnutrition, changes in living conditions, etc. Endogenous reactivation is possible in persons of the following categories:

• an infected person who has never had any signs of active tuberculosis:
• in a person who has transferred active tuberculosis and a clinically cured person (once infected, a person retains mycobacterium tuberculosis for life in the body, that is, a biological cure is impossible);
• in a patient with a diminishing activity of the tuberculosis process.

The likelihood of endogenous reactivation in infected individuals allows tuberculosis to maintain a reservoir of infection even in the clinical cure of all contagious and non-contagious patients.

Control of the tuberculosis epidemic process

The presence of tuberculosis patients with bacterial excretion (identified and not identified) allows to preserve the reproduction of new cases of the disease. Even in case of curing of bacterial invaders, the reservoir of tuberculosis infection will persist, as long as there is a significant number of infected people among the population who have the opportunity to develop tuberculosis due to endogenous reactivation. Therefore, talk about the victory over tuberculosis will be possible only if a new uninfected generation of people grows up. In this regard, health-improving prevention activities among the whole population are particularly important, with an emphasis on risk groups.

The goal of tuberculosis work is to establish control over the tuberculosis epidemic process, which will entail a decrease in the true incidence. Mortality and prevalence of tuberculosis. For this, a set of measures is necessary. Aimed at reducing the number of sources of infection, blocking transmission routes, reducing the reservoir and increasing the population's immunity to infection.

[6], [7], [8], [9], [10],

Measures to reduce the number of sources of tuberculosis

• Identification of patients with tuberculosis by all available methods - with the help of mass preventive examinations of the population, as well as examination when referring to a doctor of any specialty of patients with symptoms suspicious of tuberculosis. Increasing the coverage and quality of preventive examinations, as a rule, leads to a short-term increase in the incidence rate.
• Clinical cure of the vast majority of tuberculosis patients (newly diagnosed persons and patients from contingents of anti-tuberculosis facilities). This is possible only with the use of an integrated approach to treatment (controlled chemotherapy, pathogenetic therapy, collapse therapy, according to indications - surgical treatment, sanatorium treatment, etc.), and establishing an adequate sanitary and hygienic regime.

Measures to prevent transmission of tuberculosis

• Hospitalization of bacterioviruses in an anti-tuberculosis hospital until the cessation of massive bacterial excretion.
• Carry out measures to limit the spread of infection in anti-tuberculosis institutions (administrative measures, environmental monitoring, use of personal protective equipment).
• Carrying out anti-epidemic measures (current and final disinfection, chemoprophylaxis of contact persons, etc.) in the foci of tuberculosis infection (in patients' places of stay, in any medical institutions where a tuberculosis patient is identified in the institutions of TB service).

Measures to reduce the reservoir of tuberculosis and increase the immunity of the population to the disease

Are directed to work with the infected and uninfected population.

• Prevention of recurrent cases of tuberculosis among the cured persons due to the implementation of a set of preventive measures (health-improving procedures, sanatorium treatment, anti-relapse therapy courses).
• Conducting preventive antituberculous immunization of the population.
• Raising the standard of living of the population, improving living conditions, improving sanitary literacy, general culture, etc.

Indicators characterizing the epidemic process

The main task of the analysis of the epidemic process is to clarify the nature and intensity of the spread of tuberculosis infection, identify sources of infection, ways of transmission of the pathogen and identify priority areas of the antiepidemic measures.

Analysis of the epidemic situation is carried out according to intensive indicators describing the spread of the phenomenon. The main intensive indicators characterizing the tuberculosis epidemic process are mortality, morbidity, morbidity (prevalence) and infection.

Extensive indicators are used to characterize the structure of the phenomenon (for example, the specific weight of this clinical form of tuberculosis among all forms).

Absolute values should be taken into account when planning the volume of anti-tuberculosis measures (the burden on physicians, the calculation of the need for preparations, the planning of the number and profile of beds, etc.).

The indicators of visibility reflect the changes in the epidemiological situation. The indicator of the initial (or base) year is taken as 100%, and the indicators of subsequent years are calculated in relation to them.

It is important to understand that only interaction between indicators can more likely characterize one or another epidemic situation in the region and be an indirect reflection of the level of organization of anti-tuberculosis care to the population.

Mortality from tuberculosis is a statistical indicator expressed by the ratio of the number of deaths from tuberculosis to the average annual population in a particular administrative territory over a certain period of time (for example, during the reporting year).

Analyzing the death rate from tuberculosis, it is important to determine the proportion of patients diagnosed posthumously, and the proportion of patients who died in the first year of follow-up. The increase in the death rate from tuberculosis is the most objective criterion for the ill-health of the epidemic process.

The indicator of tuberculosis incidence, or detectability, is the number of tuberculosis patients newly detected and registered in a specific administrative territory over a certain period of time (for example, during the reporting year). The incidence rate also includes the number of people diagnosed with tuberculosis who have been posthumously diagnosed.

It is necessary to distinguish the incidence rate of tuberculosis and the true incidence in the administrative territory.

The incidence rate reflects only the cases of the disease that are detected and taken into account by official registration and directly depends on the following factors:

• coverage and quality of conducting preventive examinations of the population for tuberculosis;
• organization and quality of examination of the patient when referring to a doctor with symptoms that are suspicious of tuberculosis;
• the level of registration of identified cases;
• the level of true incidence of tuberculosis.

In practical work, the phthisiatrician-organizer of health care has to evaluate the quality of the work of the general medical network for identifying patients with tuberculosis. If in the administrative territory the coverage of the population by preventive examinations is low, it is possible to approximately calculate the number of undiagnosed patients in the previous year. To do this, it is necessary to know the number of people whose disease was detected extremely late, to which, as a rule, the following cases:

• the newly diagnosed patients with fibrous-cavernous tuberculosis;
• persons identified posthumously;
• persons who died of tuberculosis in the first year after detection.

When calculating the death rate from tuberculosis in the Russian Federation, mortality from the consequences of tuberculosis is also taken into account. However, the total number of such persons is small and does not significantly affect the death rate.

The calculation of the incidence rate in the Russian Federation is different from that of WHO. WHO for all countries calculates the incidence rate, which includes the number of newly diagnosed patients and relapse of tuberculosis. The WHO European Office also includes a group of patients with an unknown history in the incidence rate.

Soreness (prevalence, contingents of patients) is a statistical indicator reflecting the relative number of patients with active tuberculosis (newly diagnosed, relapses, after early termination of chemotherapy, after ineffective chemotherapy, chronic patients, etc.). Registered at the I and II GDU at the end of the reporting year in the administrative territory.

Infection of the population with Mycobacterium tuberculosis is determined by the percentage of the number of persons with a positive Mantoux test with 2 TE (with the exception of persons with postvaccinal allergy) among those surveyed.

In conditions of continuous vaccination of newborns and revaccination (given the difficulties in differential diagnosis between infectious and postvaccinal allergies), the use of infection rates can be hindered. Therefore, an indicator is used that characterizes the annual risk of infection-the percentage of people who have undergone primary infection with tuberculosis mycobacteria.

To assess the epidemic situation of tuberculosis, the indicators characterizing the level of organization of anti-tuberculosis care for the population are also used. The main ones are coverage of the population with preventive examinations for tuberculosis, the effectiveness of treatment of patients, as well as indicators characterizing the effectiveness of preventive measures in the focus of infection.

The list of listed individuals and the approach to calculating the indicator are not final and indisputable. For example, patients with cirrhotic tuberculosis are also referred to late-identified patients. In addition, some of the patients who died in the first year of follow-up and found posthumously may die not from late detection of advanced tuberculosis, but from acute progression of the process. Nevertheless, information about the persons listed in the text is available, they are annually calculated and monitored, and they can be obtained from approved forms of statistical reporting.

Factors of increased risk of tuberculosis

The phenomenon of "selectivity" of the tuberculosis disease infected by mycobacterium tuberculosis of persons has long been of interest to researchers and encourages them to look for causes that contribute to the development of the disease. A retrospective analysis of the spread of tuberculosis infection inevitably leads to the conclusion that migration, demographic and social factors are the most "early" in origin and the most significant in terms of impact. This can be proved by:

• epidemic character of the spread of tuberculosis during the development of urbanization processes (from the Middle Ages in Europe);
• the prevalence of tuberculosis among the poorest layers of the urban population living in crowded and unsanitary conditions;
• the increase in the prevalence of tuberculosis in times of war, socio-economic and demographic shocks.

A common mechanism for the rapid spread of tuberculosis in these settings can be considered an increase in the number of close contacts of healthy individuals with tuberculosis patients (ie, with sources of tuberculosis infection). An important factor is the decrease in the general resistance of the body to the majority of people who are under conditions of prolonged stress, malnutrition and unfavorable living conditions. At the same time, even in extremely unfavorable living conditions and in the presence of close contact with patients who isolated mycobacterium tuberculosis, tuberculosis did not develop for a long time in a certain category of people. This indicates a different degree of genetically determined individual resistance to tuberculosis. It should be recognized that the currently available factual material does not allow the formation of risk groups for tuberculosis disease on the basis of studying the genetic characteristics of different individuals.

A huge number of studies (most of them conducted in the second half of the 20th century) are devoted to the analysis of endogenous and exogenous factors or their combinations that increase the risk of tuberculosis. The methodology and ideology of these studies are so dissimilar, and the results are so contradictory (and sometimes diametrically opposed). That now with a sufficient degree of certainty it is possible to speak only about presence of three basic groups of the factors defining the raised risk of disease by a tuberculosis:

• close contact with patients with tuberculosis (domestic and industrial);
• various diseases and conditions that reduce the resistance of the organism and create conditions for the development of tuberculosis;
• socio-economic, domestic, environmental, production and other factors.

These factors can affect both the different phases of the epidemiological process and the pathogenesis of the development of clinical forms of tuberculosis in an individual, micro-, macrosocium or population (society).

This influence is carried out in a certain sequence:

• infection;
• latent (subclinical) infection;
• clinically manifested form of the disease:
• cure, death, or a chronically current form of the disease.

In general, studies on the allocation of risk groups for tuberculosis were based on a retrospective study of cases. There was no trace of the probability of an individual with one or more risk factors throughout life. The role of a particular risk group in the total incidence of tuberculosis has not been sufficiently assessed. In some cases, it is not so significant. For example, persons from contact with tuberculosis patients in 2005 accounted for only 2.8% of all newly diagnosed tuberculosis patients. In addition, various combinations of several risk factors are possible, which is extremely difficult to take into account in statistical studies. The same disease has a different effect on the overall resistance of the organism not only in different people, but also in one individual, depending on the presence and combination of many endogenous and exogenous factors.

In Russia, groups of increased risk of tuberculosis are identified based on medical and social characteristics, which is reflected in the current regulatory and instructive documents. However, the combination of these factors and the significance of each of them are very dynamic and unequal even in conditions of stable territorial formations. Taking into account the social, ethnic and demographic diversity of Russia, the definition of the general characteristics of the "risk groups" of tuberculosis is a serious scientific, organizational and practical problem. Experience of work in individual territories shows that when forming "risk groups" taking into account regional specifics, it is possible to significantly increase the effectiveness of the survey and the effectiveness of tuberculosis prevention among these populations. So, carried out in the Tula region in the 90 years of the XX century. The study allowed to develop and implement a differentiated scheme for examining population groups with varying degrees of risk of tuberculosis. As a result, it became possible to detect 87.9% of tuberculosis patients with a decrease in the volume of fluorographic examinations to 58.7%. The results of other studies indicate that. That an increase in coverage by preventive examinations of risk groups by 10% makes it possible to identify among them 1.6 times more patients. Therefore, in modern conditions, preventive examinations for tuberculosis should be not so much massive as group and differentiated, depending on the risk of disease or the epidemic danger of each group.

Also, there is no doubt that the inclusion in the high-risk group of tuberculosis patients of homeless people, immigrants and refugees. Obtaining reliable information on the incidence of these contingents is hampered by the complexity of their registration, registration and conduct of preventive examinations. Therefore, along with the allocation of this risk group, it is also necessary to develop interdepartmental measures (involving the general medical network, the Ministry of Internal Affairs and other departments) to involve it in the survey.

For several decades, various pathological conditions, acute and chronic infectious and somatic diseases are considered factors of increased risk of tuberculosis. The structure and number of data of "risk groups" in some regions can differ significantly, which is due both to real regional characteristics and the quality of the work of medical institutions in identifying people with various diseases, their examination, treatment and dispensary observation. A common trend in recent years is a significant increase in the number of people with HIV infection; these contingents are the group of the highest risk of tuberculosis. The methodology for monitoring, detecting and preventing tuberculosis among HIV-infected individuals is very time-consuming and in many respects differs from activities conducted in other risk groups.

Thus, there are quite a number of factors (social, industrial, somatic, etc.), the adverse effect of which increases the risk of tuberculosis disease for individuals and groups of people (often too many). The degree of negative impact of each of these factors varies from region to region and changes dynamically over time. This circumstance makes it important to analyze and monitor the incidence of tuberculosis in various population groups, with the identification of risk factors that are specific for a specific region in a certain period of time.

At the moment, Resolution of the Government of the Russian Federation No. 892 of 25.12.2001 "On the Implementation of the Federal Law on the Prevention of the Spread of Tuberculosis in the Russian Federation" identifies groups of the population that are subject to additional examination and surveillance in order to detect tuberculosis, including people at risk for tuberculosis or its relapse, as well as those who have tuberculosis disease can lead to massive contact with infection of a large group of people, including particularly susceptible to tuberculosis (neonates, children, etc.) It should be noted that the allocation and examination of risk groups does not mean the cessation of mass preventive examinations of the population - it is another matter that a survey of risk groups should be close to 100% with full compliance with the frequency of the survey, which, unfortunately, is not always carried out.

At the present time, it is also not determined in which epidemic situation it is necessary to survey the whole population, and in which - mostly at risk. In those subjects of the Russian Federation, where the incidence rate of tuberculosis has exceeded 100 per 100,000 population over the past few years, and coverage by preventive examinations of the population is below 50%, where the death rate from tuberculosis also increases, it is necessary to address the question of a preventive survey of the entire population with a multiplicity of not less than 1 time per year.

In more favorable epidemiological conditions with constant good coverage of the population by preventive examinations, decreasing death rates from tuberculosis, where the incidence rate also tends to decrease. A transition to a preventive examination of the predominantly at-risk groups for tuberculosis is possible.

[11], [12], [13], [14],

World Tuberculosis Epidemic

Tuberculosis is the oldest of infectious diseases known to mankind. With a high degree of probability it can be argued. That mycobacterium tuberculosis as a biological species is much older than the species Homo sapiens. Most likely, originally mycobacterium tuberculosis was predominantly prevalent in southern Europe, Asia and northern Africa.

The discovery by Europeans of America, Australia, their advance into the interior of Africa, the expansion of contacts with Europeans in Japan led to the widespread spread of mycobacteria of tuberculosis and, as a result, to the massive tuberculosis of the indigenous population of these territories. Retrospective analysis allows us to state that ethnoses that have had a long-term interaction with mycobacteria of tuberculosis, gradually increase the number of people who are stable (or relatively resistant) to tuberculosis in their population. That is why, for a significant part of the representatives of the European superethnosis, which has a centuries-old history of fighting tuberculosis, mycobacteria of tuberculosis are currently weakly pathogenic, as no more than 10% of all infected become ill. At the same time, among ethnoses whose contact with mycobacteria of tuberculosis began after a relatively recent meeting with Europeans, the incidence of tuberculosis is extremely high and still represents not only a social but also a biological problem. An example of this is the extremely high prevalence of tuberculosis among American Indians. In Latin America, among the indigenous population of Australia and Oceania.

To judge the true prevalence of tuberculosis is quite difficult not only because of the disparity (and at times - the incompatibility and unreliability) of statistical data. So far, different countries have different approaches to diagnosing tuberculosis and verifying the diagnosis, determining the case, registering it, etc. In connection with the foregoing, many researchers, in a retrospective analysis of the dynamics of the epidemic situation of tuberculosis, give preference to the death rate, quite justifying its informativeness and objectivity in comparison with other indicators.

The first statistical data on mortality from tuberculosis belong to the end of the XVII century. And by the first half of the 18th century. At that time they concerned only certain European cities. This is quite natural for at least two reasons. At first. The problem of mass spread of tuberculosis has become one of the priorities for humanity precisely because of the development of cities in which close contact (and, consequently, infection) of a healthy population with tuberculosis patients has occurred. Secondly, it was in the cities that the level of development of medicine made it possible to organize such studies and document their results.

These data indicate that in the XVII, XVIII and the first half of the XIX century. Tuberculosis was a pervasive and progressively spreading epidemic that claimed a large number of human lives. At the same time, do not forget that during this period, the population of Europe also suffered severely from other infectious diseases: smallpox, typhus and typhoid, syphilis, diphtheria, scarlet fever etc. The more significant is the "contribution" of tuberculosis as the cause of mortality of the population. So. In London in 1669, the extensive death rate from tuberculosis was 16%, in 1741 - 19%, in 1799 - 26.3%, and in 1808 - 28%. Close to these indicators was the proportion of tuberculosis among the causes of death in Plymouth (23%). And in Breslau, even 40%. In Vienna in 1648-1669 years. Tuberculosis accounted for 31% of the deaths of the local Jewish population.

XX century. Was characterized by the most rapid dynamics of the prevalence of tuberculosis. This is due to the fact that it was at the turn of the XIX-XX centuries. For the first time mankind had "tools" of active influence on tuberculosis. The discovery of mycobacterium tuberculosis by R. Koch allowed to study the characteristics of the causative agent of the disease, which was used initially to develop bacteriological diagnostic methods and tuberculin diagnostics, and then - to create a specific vaccine. Using the discovery of V.K. Roentgen and the massive introduction of radiation research methods into practice was the second revolutionary contribution to the development of phthisiology. Thanks to the X-ray method of research, clinicians significantly expanded their understanding of the nature and characteristics of the course of the tuberculosis process and. Which is especially important, for the first time it was possible to diagnose the disease before the onset of its clinical manifestations.

The progressive development of medicine, biological sciences and a number of related specialties, the integration of specialties and the use of advances in scientific and technological progress made the solution of the problem, seemingly unsolvable to many generations of doctors and patients, the development and introduction of specific antituberculous drugs. Do not underestimate the contribution of surgical methods of treatment, the development and use of which in the XX century. Saved the lives of hundreds of thousands of tuberculosis patients. Their contribution to the fight against tuberculosis was made by epidemiology, development and implementation of a system of organizational measures, the creation of a methodology for accounting, statistics, and then - and monitoring of tuberculosis.

The presence of sufficiently reliable factual data makes it possible to conduct a retrospective analysis of the patterns and dynamics of the epidemic of tuberculosis in the 20th century. To the beginning of XX century. Tuberculosis remained a widespread disease. In 1900 in Paris, for example, 473 people per 100 thousand people died, in Vienna -379, in Stockholm-311, etc. Against the backdrop of economic growth before the First World War, in some countries there was a decrease in mortality from tuberculosis (England, Germany, Denmark, Netherlands, USA) or stabilization of this indicator (Austria, Norway, Finland, France).

The economic and social upheavals associated with the First World War caused a significant increase in the death rate from tuberculosis in all European countries. Its rise was noted by the end of the first year of the war, and later this indicator had a distinct tendency to grow in England, Austria, Germany, Italy and Czechoslovakia. In Austria, in 1918, the death rate from tuberculosis exceeded the pre-war level by 56%. And in Germany - by 62%. The mortality rate among the population of large cities increased rapidly (London, Berlin, Vienna). In Warsaw, by 1916, mortality increased almost 3-fold.

During the First World War, certain features of tuberculosis among various age groups of the population were noted. The least affected were young children, the largest - older children and a young population (15 to 30 years). In most countries, differences in the mortality rate among men and women are characteristic of peacetime. So, its higher figures among men in England were observed throughout the war. The reverse ratio, which took place in Switzerland and the Netherlands in peacetime, did not change in 1915-1917. At the end of the First World War, against the backdrop of economic recovery and the stabilization of the social sphere, the mortality rate from tuberculosis to some extent decreased in most countries of Europe, in Australia. New Zealand and the USA.

During World War II, mortality in the German-occupied countries once again increased, in Germany and Japan itself. The mortality from tuberculosis in many countries and in large cities has steadily increased as the hostilities continue. In 1941-1945 years. It surpassed the pre-war level among the inhabitants of Amsterdam. Brussels, Vienna. Rome, Budapest 2-2.5 times, and in Berlin and Warsaw - 3-4 times.

At the same time, it should be taken into account that the given data only concerned the civilian population; they did not include a huge number of deaths from tuberculosis in the army, captivity and concentration camps. Meanwhile,. Among prisoners of war liberated from concentration camps and sent to Sweden, there were 40 to 50% of tuberculosis patients. At the same time, in most countries that did not participate in the Second World War (for example, in Sweden and Switzerland), the death rate continued to decline. Stable was the figure in Canada and the United States, which did not take an active part in the fighting. Thus, the sanitary effects of the Second World War on tuberculosis were not the same in different countries. To a large extent, this depended on the degree of destruction of the material and technical base and economic ties, the crowding of the majority of the population, the high intensity and partial uncontrollability of migration processes, mass violations of sanitary norms, disorganization of the medical and sanitary service and anti-tuberculosis care for the population.

At all times it was very difficult to speak about the true prevalence of tuberculosis because of the unequal nature of statistical data coming from different countries. However, at the end of the XX century. The work carried out by WHO and the health authorities of different countries made it possible to draw up a general picture of the main epidemiological indicators for tuberculosis in different regions of our planet. Since 1997, WHO has issued an annual report on the situation of tuberculosis in the world. In 2003, the report provided information on 210 countries.

At present, it should be recognized that tuberculosis is prevalent in all countries of the world. The highest incidence of tuberculosis is found in Africa, especially in countries with high HIV prevalence. It accounts for about 1/4 of all newly diagnosed tuberculosis patients. Half of all newly diagnosed patients in the world are in 6 Asian countries: India. China. Bangladesh, Indonesia. Pakistan. Philippines.

It should be said that if in 1970 the incidence of tuberculosis in the world was about 70 per 100 thousand, then at the beginning of the XXI century. It reaches the level of 130 per 100 thousand.

According to WHO, the current increase in the incidence rate is due primarily to the rapid spread of undiagnosed HIV infection in the African continent, which led to a sharp increase in the incidence of tuberculosis.

In the 90s of XX century. The highest death rate from tuberculosis in the world was registered. In 1995, according to the WHO. 3 million patients died of tuberculosis every year. In 2003, 1.7 million people died. For the period 2002-2003. The death rate among all tuberculosis patients decreased by 2.3%, and among HIV-negative tuberculosis patients - by 3.5%, nevertheless, nowadays, around 5000 patients die every day around the world. About 98% of deaths occur in a young, workable population. In Africa, tuberculosis is the leading cause of death for young women.

In 2003, 8.8 million tuberculosis patients were diagnosed in the world, of which 3,9 million were defined as sputum smear microscopy. In all, there were 15.4 million tuberculosis patients, of whom 6.9 million were sputum smear microscopy. According to the WHO, currently the rate of increase in the incidence rate in the world is increasing by 1% annually, mainly due to the increase in the incidence in Africa. Among the population of Africa with a high prevalence of HIV infection, the incidence of tuberculosis reaches 400 per 100,000.

The incidence rate varies very sharply in different countries and regions. It largely depends on socio-economic development, the level of organization of medical care and, as a consequence, methods for identifying patients, the quality of population survey using these methods, completeness of registration. For example. The detection of patients in the United States is mainly performed due to tuberculin diagnostics of persons who were in contact with a sick tuberculosis. In the case when it is known that the person from the contact previously had tuberculosis, radiation methods of diagnostics are used, and in the presence of sputum, its investigation by various methods. In Russia and a number of former USSR countries, the detection of patients with pulmonary tuberculosis is based on mass fluorographic examinations of the adult population, tuberculodiagnosis in children and adolescents, and microscopic examination of sputum in coughing patients. In India, African countries and a number of other countries where there is no developed system of medical care for the population, the detection of tuberculosis is mainly due to microscopic examination of sputum in coughing patients. Unfortunately, WHO experts in the annual reports do not give an analysis of the incidence rate in the regions and countries of the world in terms of methods of detecting and the presence or absence of screening of the population. Therefore, the information provided in the annual reports can not be considered completely reliable. Nevertheless, WHO divided the globe into six regions with different incidence rates (the Americas, Europe, the Eastern Mediterranean, the Western Pacific, Southeast Asia and Africa).

But even in one region in different countries, these indicators vary significantly. If the average incidence in the Americas was 27 per 100 thousand population, then its dispersion in the American continent ranged from 5 to 135. Thus. For example, in 2002 in the USA and Canada the incidence was 5 per 100 thousand people, Cuba 8, Mexico 17, Chile 35, Panama 37, Argentina 54, Haiti 98, Peru - 135.

In Central European countries, incidence rates were also different: in Cyprus, Iceland - 3 per 100,000, in Sweden - 4, Malta - 6, in Italy - 7, in Germany and Israel - 8, in Austria - 11, in 12 in Anglin, 14 in Portugal, 44 in Portugal. In Eastern Europe, the incidence of tuberculosis was slightly higher: in Turkey and Poland 26, in Hungary 27, in Bosnia and Herzegovina 41, in Bulgaria 42, in Estonia - 46, in Armenia - 47, in Belarus -52, in Azerbaijan - 62, in Tajikistan - 65, in Lithuania - 70, in Turkmenistan and Latvia - 77, in Uzbekistan - 80, in Ukraine - 82, in Georgia - 87, in Moldavia - 88, in Kyrgyzstan -131, in Romania -133, in Kazakhstan -178. In total in the countries of Western and Eastern Europe the average incidence rate was 43 per 100 thousand.

In this case, according to WHO. In the countries of the European Region in 2002 there were registered 373497 newly diagnosed tuberculosis patients, with relapses of tuberculosis and other patients. The WHO European Office identified 18 countries with relatively high incidence rates for the European Region, accounting for 295,240 patients. These are the countries of the former USSR, as well as Romania and Turkey, which were declared by the WHO European Bureau as priority for TB work in the "Stop TB in the European Region" plan for 2007-2015.

In the countries of the Eastern Mediterranean, the incidence rate on average is 37 per 100 thousand. It is the largest in Djibouti with a population of 693 thousand people - 461 per 100 thousand. The smallest - in the United Arab Emirates - 3 per 100 thousand. In Jordan, it is 6 per 100 thousand. , in Egypt - 16, in Iran - 17, in Pakistan - 35, in Iraq - 49, in Afghanistan - 60, in Sudan - 75.

In the Western Pacific, the average incidence is 47 per 100,000, in Australia 5 per 100,000, in New Zealand 9, China 36, Malaysia 60, Viet Nam 119, Mongolia, 150, in the Philippines - 151, in Cambodia - 178.

In South-East Asia, the average incidence rate is 94 per 100 thousand. The highest incidence of 374 per 100 thousand is registered in a small country East Timor with a population of 739 thousand people, the smallest - 40 per 100 thousand - in the Maldives. In India, the incidence is about 101 per 100 thousand. In Sri Lanka, the incidence rate is 47 per 100 thousand, in Bangladesh - 57, in Indonesia -71, in Thailand - 80, in Nepal - 123, in the Republic of Korea - 178.

Official morbidity rates in 2002 in some countries of the African continent are Namibia - 647 per 100 thousand, Swaziland - 631, South Africa - 481, Zimbabwe - 461, Kenya - 254, Ethiopia - 160, Nigeria - 32.

In 2002, the average incidence rate in Africa, according to WHO, was 148 per 100 thousand. Over the past decade and a half, the number of newly diagnosed patients in Africa has quadrupled. The annual death rate from tuberculosis is more than 500 thousand people. The emerging epidemic of tuberculosis on the continent has compelled African ministries of health to declare an emergency situation for tuberculosis in the region in 2005.

The greatest number of tuberculosis patients in absolute figures is annually detected in two countries - India (more than 1 million) and China (more than 1.3 million).

Among the regions of the world, the largest number of patients in 2002 was found in Southeast Asia (1,487,985 people), Africa (992,054 people) and the Western Pacific (806112 people). For comparison, only 373,497 people were found in Central and Eastern Europe, 233,648 people in the Americas and 188,458 in the Eastern Mediterranean countries.

The highest incidence is registered in the following countries: Namibia. Swaziland, South Africa, Zimbabwe. Djibouti. East Timor, Kenya. The smallest (up to 4 per 100 thousand of the population inclusive) is in Grenada, Barbados, Cyprus, Iceland, Jamaica, and Dominica. Puerto Rico, United Arab Emirates. "Zero" incidence of tuberculosis is registered in Monaco (population 34 thousand people).

Given the fact that according to the WHO recommendations, tuberculosis in most countries of the world (with the exception of the United States of Russia and the former USSR countries) is diagnosed mainly with the help of a simple bacterioscopy of sputum, the incidence figures should be considered underestimated - the true incidence in many countries of the world is undoubtedly higher .

Multidrug-resistant tuberculosis has been identified in all 109 countries where WHO or its partners maintain records. Annually around 450 thousand such new patients are found in the world. In recent years, the so-called "super-drug resistance", or XDR, has been diagnosed. It is characterized by resistance to HR, as well as to fluoroquinolones and one of the drugs of the second line for intramuscular injection (kanamycin / amikacin / capreomycin). In the US, XDR is 4% of all patients with multidrug-resistant tuberculosis. In Latvia - 19%, to South Korea - 15%.

At the end of XX century. Humanity revealed a new dangerous disease - HIV infection. With the spread of HIV infection among the population of people infected with Mycobacterium tuberculosis, there is a significant risk of the transition of the so-called latent tuberculosis infection into an active form of tuberculosis. Currently, tuberculosis has become the leading cause of death for people with HIV infection.

In 2003, 674,000 patients with a combination of tuberculosis and HIV infection were identified worldwide. In the same year, 229,000 such patients died. Currently, the increase in the incidence of tuberculosis in the world is mainly due to African countries with a high incidence of HIV infection.

Despite the increase in the incidence in the world, the prevalence and death rates from tuberculosis decreased slightly. This is due to the introduction in a number of countries of the world where previously there has not been properly provided assistance to patients with controlled chemotherapy of patients, as well as more harmonized figures from a larger number of countries reporting to WHO.

The prevalence of tuberculosis in 1990 in the world was about 309 per 100 thousand people, in 2003 - 245 per 100 thousand people. Over the period from 2002 to 2003, the rate of decline in the prevalence of tuberculosis was 5%. Infected with mycobacteria tuberculosis on the globe about 2 billion people, mainly due to the prevalence of infection in the so-called "third world". The infected population is a passive reservoir of tuberculosis infection.