An international team of scientists led by Vegard Eldholm of the Norwegian Institute of Public Health found that the cause of the spread of tuberculosis may lie in armed conflicts. So, in one of the specialized scientific publications, an article was published, the authors of which suggested that the disease could appear on the territory of Europe in 1979-1989, during the participation of Soviet troops in the Afghan war.
Researchers have reconstructed the evolution of the so-called "Beijing" strain of Koch's bacillus, notorious for its resistance to various antibiotics. It is generally accepted that the bacteria of this strain are susceptible to mutations to a much greater extent than other types of microbacteria. Such mutations lead to the emergence of new genes that contribute to the emergence of microbial resistance to drugs, even the most modern and most powerful.
For the first time, this bacterial strain was identified in histological samples of lung tissue from patients living in the suburbs of Beijing. Currently, Bactria of this family are found in the states of South Africa, Asia, as well as in the United States and the Caribbean. Scientists believe that the spread of the bacillus was made possible by low levels of health care and large flows of migrants.
It was previously believed that the tuberculosis bacillus originally appeared on the Somali peninsula in Africa. According to experts, the common ancestor of all types of bacteria appeared about 40-70 thousand years ago. At a time when the settlers left the Black Continent in order to develop new territories, tuberculosis began to spread with them around the world.
Today, seven types of bacteria are known, which differ in genetic sequences. You can meet them all over the planet, but at the same time, some types have evolved in different regions. So, according to the results of phylogeographic analysis, the "Peking" strain appeared on the territory of Southeast Asia about 30 thousand years ago. In the Neolithic era, it penetrated into North China. Another study suggests that this strain was formed only six thousand years ago.
As part of the new study, experts have compared the DNA of different types of "Beijing" strain, which are characteristic of South and Central Asia, as well as Europe. As a result, it was found that their development and spread across the territory of European states was closely associated with certain historical events. In particular, it turned out that the countries of the former Soviet Union were breeding grounds for the strains of tuberculosis most resistant to various drugs. In addition, scientists have found that the tuberculosis bacillus even earlier penetrated the territory of Afghanistan, then spreading throughout Europe.
The researchers analyzed the genomes of the "Beijing" strain in the inhabitants of Denmark, Norway, Moldova, Germany and some other countries, and also decoded the DNA. Thus, sets of DNA sequence differences were identified, the so-called single nucleotide polymorphisms. Scientists have established that they all belong to the so-called "Afghan" strain, which also includes clade A, a group of organisms characteristic of Russia. This group of bacteria is found in large numbers in those territories located east of the Volga River. Having compared the known and putative mutations that lead to the formation of resistance, experts have established that bacteria that are found in Central Asia, in the former Soviet republics, have a large number of genes that contribute to the formation of resistance. Besides,it was found that most of these mutations were formed after the collapse of the USSR. Misregulated drug distribution and the collapse of public health may have contributed to the development of drug resistance.
Scientists managed to establish that the types of the "Peking" strain characteristic of the USSR penetrated the territory of Afghanistan during the participation of Soviet troops in hostilities on the territory of this country in 1979-1989. Subsequently, refugees brought the bacterium into many European countries, which caused separate outbreaks of tuberculosis.
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It is well known that improper treatment methods and unsanitary conditions provoke the formation of new strains of infections that are refractory to treatment. In particular, one of the main sources of the emergence of antibiotic-resistant tuberculosis is medical facilities, where conditions of detention leave much to be desired, and prisons. In addition, in the countries of the former Soviet Union in the mid-90s of the last century, the centralized supply of free anti-tuberculosis drugs stopped. Ultimately, inadequate therapy led to the emergence of a strain of tuberculosis resistant to most drugs.
According to scientists, the results of the studies prove that armed conflicts and political instability contribute to the spread of various kinds of infections and the formation of bacteria that have increased resistance to drugs.