Establishment of occupational hygiene as an independent discipline

The scientific approach to occupational health was formed during the second half of the 19th century and first quarter of the 20th century. According to F.F. Erisman (1842–1915), professor, teacher and one of the founders of hygiene as a science in Russia, public health as an independent field of research can yield long-term results [1]. Professor Erisman has also made a huge contribution to the development of preventive measures in epidemiology.

His legacy includes "School Hygiene", an extensive written work that was the first dedicated school hygiene guidebook in Russia and basis for the prevention activities measures adopted throughout educational institutions [2].

The works of F.F. Erisman and M.D. Sokolov, his friend and associate, have basically laid the foundation for anti-epidemic measures that, as implemented by epidemiologists, are aimed directly at the source and the mechanism of transmission of infection, with prevention of infection of people inside the epidemic focus being another aspect based on the same foundation.
F.F. Erisman spearheaded the study of health of industrial workers. There were identified some labor-related factors that affected the subject negatively, and the gravest of those factors was overtime work. It was only later, already in the USSR, that hygienists, therapists and occupational pathologists presented an integrated approach to creation of the optimal working conditions at plants and factories [3].

The relevance of hygiene in the USSR

G.A. Lang (1875–1948), professor at the 1st Leningrad Medical Institute, was a scholar advancing cardiology and hematology. He developed the doctrine of hypertension (including a number of preventive aspects), founded a school of thought, was a member of the Academy of Medical Sciences and winner of the State Prize of the USSR [4].

N.D. Strazhesko (1876-1952) was a professor at the Kyiv University, academician with the USSR Academy of Sciences, Hero of Socialist Labor. He studied the pathologies of blood circulation, digestion, rheumatism, worked on the problems of septicemia, fatigue, longevity.

V.N. Vinogradov (1882–1964), professor at the 1st Moscow Medical Institute, attached great importance to patient care; he developed the routines of treatment of patients with myocardial infarction.

During the time of the Soviet Union, a number of scientists, including G.V. Khlopin, F.G. Krotkov, A.N. Sysin, A.A. Minkh, G.I. Sidorenko and many others, have contributed significantly to the development of everyday hygiene and recommendations for mitigation of the hygiene standards violations, be they related to daily life or work.

The list of the most important achievements of G.V. Khlopin (1863–1929) includes numerous manuals covering general hygiene and sanitary methods, as well as the works by his students. He initiated examination and analysis of the fabrics used to make protective and everyday uniforms, sanitary routines adopted by the Red Army and the Navy. His works on the hygiene of mental and physical labor, food hygiene considered from a variety of angles (e.g., food hygiene for children or military personnel), remain relevant to this day. The algorithms of testing of food and beverages developed by G.V. Khlopin are still being actively used. He also investigated how bacteriological contamination of drinking water affects health and how it can be disinfected [5, 6].

F.G. Krotkov (1896–1983), chief hygienist of the Red Army, lead the team of authors that published over 50 hygiene and sanitation guidelines during the war. Inter alia, he wrote and compiled the "Beriberi Prevention Instructions for Doctors", "Frostbite Treatment Guidelines", various recommendations on creation of adequate sanitary and hygienic background for the troops in the Great Patriotic War of 1941–1945 [7]. In peacetime, professor F.G. Krotkov, Academician of the Academy of Medical Sciences of the USSR, Major General of the Medical Service, Hero of Socialist Labor and winner of the State Prize of the USSR, managed the Advanced Medical Training Department he established at the Central Institute until his dying day; one of the main subjects of research at the department was radiation hygiene.

A.N. Sysin (1879–1956), a hygiene scholar, is one of the founders of practical and theoretical epidemiology, general and community hygiene, disinfection and occupational medicine. He authored over 250 research papers, described the problems of epidemics and occupational toxicology, aspects of occupational health, adoption of protective equipment at production facilities and other measures of sanitary and recreational nature [8, 9].

Professor A.A. Minkh (1904–1984), corresponding member of the USSR Academy of Medical Sciences, published numerous works, but the particularly valuable among the best known of them are the monographs "Methods of Hygienic Research" and "Air Ionization and its Hygienic Significance". He has also authored "General Hygiene", the first textbook for dental students covering the subject, and a number of other textbooks [10–12].

G.I. Sidorenko (1926–1999), a world-renowned scientist and hygienist and author of over 300 scientific papers, developed the new theoretical and practical concept that describes a unified approach to the content of chemical substances in various environments through the lens of hygiene and enables forecasting their toxicity. He laid the foundation of research uniting the concepts of ecology and hygiene. In the 1980s, as part of the international cooperation with the United States, G.I. Sidorenko dedicated his time not only to the problems of hygiene but also prevention and treatment of cardiovascular and oncological diseases [13].

All the above mentioned studies by Soviet scientists and their associates were designed to solve the main problem, that of organization and large scale implementation of preventive measures to lower the incidence and preserve health of people.

The current stage of development of hygiene

The task of hygiene as a science is to mitigate the negative factors and increase the impact of positive factors through hygienic measures. For example, it has been established that fluorine in drinking water has a certain positive effect on the development and formation of teeth.

In the 20th century, the investments into health care were mainly used to solve the already actual problems and not to prevent such. Therapy, not prevention and health strengthening, was the common solution in case of any condition that caused deterioration of health. However, currently, prevention as an area of medicine receives much attention.

It is known that environmental factors affect the course of development of various pathologies, and disregarding such factors degrades the effectiveness of treatment. For example, it was established and proven that occupational risks influence development of diseases of the oral cavity. Exposure to certain chemicals can boost a pathological process there, like caries and other diseases. There is a significant number of diseases known to have associations with the factors of the environment. Living conditions, mineral composition of the commonly consumed water affect the course of a number of diseases. Occupational factors, like conditions a person works in, can contribute to the development of certain diseases, exacerbate cardiovascular or respiratory pathologies [14].

A doctor must know of the influence of certain factors, such as nutrition, natural conditions and quality and composition of water, on the body. Drug prescriptions should factor in dietary habits of the patients, since nutrition can weaken or enhance the effect of the drug, same as drinking water.

Currently, hygiene develops in two directions. On the one hand, it undergoes differentiation, with a number of branches stemming out of the common body of hygiene as a science, including social hygiene, public hygiene, food hygiene, labor protection, children's and adolescent hygiene, radiation hygiene, military hygiene, hygiene of polymeric materials and toxicology, hygiene of space flights and aviation hygiene. On the other hand, there is an integration process underway that merges hygiene with clinical areas of medicine, therapeutics, pediatrics, obstetrics and gynecology etc. [15].

This relationship is also seen in occupational health, which affects the performance of health care professionals. Different professions have different requirements for those practicing them. For physicians with a therapeutic profile, patience and attentiveness are important. District doctors, or neighborhood physicians, work under a rather tangible physical load and in conditions constantly causing nervous and emotional stress associated with a lack of time needed to properly diagnose and prescribe treatment. The specifics of work or peculiarities of the patients may be the reasons behind trauma suffered by psychiatrists in hospitals and clinics, STD and skin doctors, paramedics involved in transportation.

Doctors have to work under a high neuropsychic load in outpatient clinics and inpatient hospitals, feel negative emotions associated with difficulties in treating and caring for patients, visiting them at home or contacting their relatives. Studies investigating nervous system functions in doctors and hospital therapists have revealed that some indicators of attention (in particular, stability of attention, speed of sensorimotor reactions to light and sound stimuli) progressively deteriorate by the end of a shift.

During the coronavirus pandemic, which gave rise to a new round of hygiene and prevention improvements throughout the world, many medical researchers took it as their professional duty to delve deeply into the theoretical and practical issues of mutual support between hygiene and prevention.

Tens of thousands of articles have been written; to a greater or lesser extent, they address the issues of health education, compliance with hygiene and sanitation standards, prevention of infectious diseases, innovative methods of treatment relying on telemedicine and remote monitoring of chronic patients, and AI-enabled diagnosing. All of these are breakthroughs in the field of occupational health, which can quickly improve the quality and efficiency of work of health care professionals while protecting their lives and health. The challenges of the pandemic have unexpectedly brought together doctors of two specialties, therapists and hygienists, who join forces in an integrated approach to pathology elimination.

More and more often, there appear articles, research and development efforts dedicated to the problems of improvement of epidemiologically safe scenarios of interaction between doctors and patients under the multifactorial impact of COVID-19 [16, 17].

It can be stated that, in actuality, the third period in the history of hygiene has began. In addition to sanitary rules, pharmacological and therapeutic treatments, it sees hygiene and therapy discovering a previously unknown channel of interaction. The two specialties have connected on the basis of a fundamentally new format through digital technologies such as artificial intelligence, remote monitoring of and care for infected patients, including online consultations when the patients stay at home (telemedicine), as well as various smart medical devices for personal use and direct communication with attending physicians.

All these digital tools allow separating infected patients from healthy people and doctors as much as possible, building additional barriers before a spreading epidemic disease. Such capabilities gain additional relevance since pandemics have not left us for good. According to the official data, SARS-CoV-2 claimed 5 million lives, however, some experts estimate the true toll taken by the pandemic is about 17 million people [18]. Regardless of what number is closer to reality, COVID-19 ranks first on the list of the deadliest diseases in history.

In the last thirty years, until 2020, the development of hygiene was somewhat stalling: the investments made into health care were mainly used to solve the already actual problems, i.e., to provide treatment proper, but not to prevent such problems. The focus of attention was not on health promotion and disease prevention but on therapeutic and other assistance rendered when the pathology has already developed. It is obvious that the link was broken by the degression of health education efforts aimed at the general public, shrinking of the hygiene curriculum and deterioration of its quality at medical universities, as well as general commercialization of medicine, when treating a disease is more profitable than preventing it.

The COVID-19 pandemic marked a turning point in the history of hygiene and therapy. We are seeing how the priorities are changing in real time. At the peak of the pandemic, all media explained to the general population the essence and importance of the standard hygiene recommendations by WHO, recommendations that, when followed, reduce the risk of contracting coronavirus.

Personal protective equipment (PPE) came into limelight. It became the backbone of one of the most effective safety strategies that kept both the patients and the doctors safe from transmissible pathogens.

This hygiene strategy was the top priority one when the effective treatment and prevention measures against the disease were yet to be developed.

At this stage, hygiene came to the foreground again. Modern PPE were being actively designed; their primary purpose was to protect medical workers from virulent pathogens by preventing contact with biological fluids and infection by airborne droplets. Rigid protocols were formulated, which required the use of appropriate PPE by all health care providers who contact patients with confirmed or suspected COVID-19.

The world saw improvement and large-scale production of protective suits, waterproof gowns, a variety of gloves, breathing masks, surgical masks, hair protection devices, goggles and face shields that, combined with consistent hand hygiene, could minimize exposure to airborne particles and their landing on mucous membranes. En masse, health care professionals were taught the updated hygiene rules that describe how to use the PPE properly, down to the sequence of donning and doffing them.

Largely, the convergence of hygiene and therapeutics during the 2020 crisis was enabled by the unprecedented explosive development of a range of digital technologies, including the Internet of Things (IoT) with next-generation 5G networks, artificial intelligence (AI) relying on deep learning, big data analytics, blockchain, robotic technologies and the widespread introduction of telemedicine [19].

The third stage of the hygiene evolution, the era of digital transformation of medicine, has begun during the COVID-19 pandemic. Its emergence has stimulated worldwide introduction of measures designed to curb the spread of the disease, such as social distancing, quarantine and cordon sanitaire, all of which were supported by the doctor-patient interaction opportunities opened by the digital technology.

CONCLUSION

Hygiene is a medical prevention discipline that studies the patterns of environmental factors as they act on the body with the aim of preventing diseases and improving the environment itself. Hygiene, as opposed to other disciplines, allows applying the main breakthroughs and achievements at the stage of primary prevention of the diseases, which can significantly reduce the incidence of more severe forms of the pathologies.

Rethinking the history of hygiene and therapeutics yields interesting ideas supporting formulation of unexpected innovative variants of the socio-medical paradigm of the future. The attitudes and concepts of the past years, with their understandable and clear values, help to develop the new rules of health preservation that, along with classical preventive measures, include innovative methods of protection of doctors and persons (on both occupational and individual levels) that have to constantly be among people during a pandemic.

In general, the entire history of hygiene and therapeutics, from antiquity to the present day, can be said to be the history of their deepening mutual penetration, influence and support. Both disciplines transform in line with the evolutionary changes of human society and medical science, absorbing breakthroughs and adapting them to serve the ultimate goal, which is to ensure maximum reliability in preserving human health and prolonging an active and fulfilling life.

The COVID-19 pandemic has become a separate chapter and a new phase in the world history of hygiene and prevention: it taught the current civilization the lessons of extreme reformatting under the pressure of sudden qualitative changes in the attitude towards sanitary standards during a pandemic, and initiated the development of preventive measures that utilize the new digital opportunities open to medicine.

At the stage of digitalization, hygiene and telemedicine were connected by another rigid bridge, "the use of communication and information technology to provide medical services regardless of the temporal and spatial barriers" [20].

Relying on the digital technology, epidemiologists and therapists can monitor infected patients and shield doctors from the danger of infection.

The classical algorithms of organization of health care and preventive hygiene should give way to advanced technologies. Doctors have entered the era of digital opportunities for implementation of sanitary rules known since ancient times; the new stage of digitalization of all traditional hygiene tools and the related therapies has begun.