Medicine

Introduction in hygiene and ecology

Introduction in hygiene and ecology. Basic laws of hygiene. Bases of preventive and current sanitary supervision. Principles of the hygienical setting of norms. Cosmosphere, sun radiation and health. Hygienical value of sun radiation, physical properties and chemical composition of air environment. Hygienical value of constituents of biosphere (atmosphere, hydrosphere, litosphere).

 

1. HYGIENE AS SCIENSE

Health - is defined as a state of complete physical, mental and social well-being and not merely absence of disease or infirmity.  

Health is the functional and/or metabolic efficiency of an organism, at any moment in time, at both the cellular and global levels. All individual organisms, from the simplest to the most complex, vary between optimum health and zero health (dead).

In the medical field, health is commonly defined as an organism's ability to efficiently respond to challenges (stressors) and effectively restore and sustain a "state of balance," known as homeostasis.

Another widely accepted definition of health is that of the World Health Organization "WHO". It states that "health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity"[1]. In more recent years, this statement has been modified to include the ability to lead a "socially and economically productive life." The WHO definition is not without criticism, as some argue that health cannot be defined as a state at all, but must be seen as a process of continuous adjustment to the changing demands of living and of the changing meanings we give to life. The WHO definition is therefore considered by many as an idealistic goal rather than a realistic proposition.

The LaLonde report suggested that there are four general determinants of health which he called "human biology", "environment", "lifestyle", and "healthcare organization". Thus, health is maintained through the science and practice of medicine, but can also be improved by individual effort. Physical fitness, weight loss, a healthy diet, stress management training and stopping smoking and other substance abuse are examples of steps to improve one's health. Workplace programs are recognized by an increasingly large number of companies for their value in improving health and well-being of their employees, and increasing morale, loyalty and productivity at work. A company may provide a gym with exercise equipment, start smoking cessation programs, provide nutrition, weight or stress management training. Other programs may include health risk assessments, health screenings and body mass index monitoring.

An increasing measure of the health of populations is height, which is strongly regulated by nutrition and health care, among other standard of living and quality of life matters. The study of human growth, its regulators and its implications is known as auxology.  Wellness is a term sometimes used to describe the psychological state of being healthy, but is most often used in the field of alternative medicine to describe one's state of being.

Perfect health is an abstraction, which may not be attainable but is essential for an individual or a family or a group or a community's strivings. Optimum Health is the highest level of health attainable by an individual in his/her ecological settings. Positive health means striving for preservation and improve­ment of health. Negative health means scientific ef­forts for prevention and cure of diseases. To promote and maintain a state of positive health an individual needs the following prerequisites:

·        Supply of fresh air and sunlight

·        Safe and potable water supply

·        Balanced diet

·        Healthful shelter

·        Adequate clothing hygienic environmental sanitation

·        Protection from communicable and other avoidable afflictions

·        Complete sense of protection and security both socially and economically

·        A congenial social and cultural atmosphere.

·        In addition an individual should have a regulated way of life with proper rest and relaxation and good and simple habits.

All these factors help to maintain a normal balance of body and mind, which is must for positive health. The study of all these factors constitutes a branch of medicine designated as preventive and social medicine. Any imbalance or deviation in the above factors is likely to cause a state of illness, when curative aspect of medicine comes into picture.

A healthy diet contains a balance of food groups and all the nutrients necessary to promote good health. Human nutrition is enormously complex and a healthy diet may vary widely according to an individual's genetic makeup, environment, and health.

Healthy eating is the practice of making choices about what and/or how much one eats with the intention of improving or maintaining good health. Typically, this means following recommendations for a healthy diet.

The concept of healthy eating is primarily a problem in rich countries where the lifestyle includes a modicum of outdoor physical activities, high but not always high-quality food consumption, and a trend towards industrially-produced foods instead of locally-sourced, locally-prepared meals. The article below discusses the recommendations for most citizens of such countries, written from an admittedly developed world point of view. Unfortunately, the main food problems for most of the people in the planet are lack there of or malnutrition.

Generally, a healthy diet will include:

1.     Sufficient calories to maintain a person's metabolic and activity needs, but not so excessive as to result in fat storage greater than roughly 12% of body mass[1];

2.     Sufficient fat, consisting mostly of mono- and polyunsaturated fats (avoiding saturated and "trans" fats) and with a balance of omega-6 and long-chain omega-3 lipids;

3.     Sufficient essential amino acids ("complete protein") to provide cellular replenishment and transport proteins;

4.     Essential micronutrients such as vitamins and certain minerals.

5.     Avoiding directly poisonous (e.g. heavy metals) and carcinogenic (e.g. benzene) substances;

6.     Avoiding foods contaminated by human pathogens (e.g. e. coli, tapeworm eggs).

7.     Avoiding chronic high doses of certain foods that are benign or beneficial in small or occasional doses, such as

·                 foods or substances with directly toxic properties if chronically ingested at high doses (e.g. chickpeas, ethyl alcohol, Vitamin A);

·                 foods that may interfere at high doses with other body processes (e.g. table salt);

·                 foods that may burden or exhaust normal functions (especially refined carbohydrates eaten without adequate dietary fiber).

In specific individuals, ingesting foods containing natural allergens (e.g. peanuts, shellfood) or drug-induced allergens (e.g. tyramine for a person taking an MAO inhibitor) may be life-threatening.

Hygiene -  is a basic preventive science in medicine. It generalizes all dates of theoretical and clinical disciplines in the field of prophylaxis, integrates knowledge’s about complex influence of an environment for health of the man, work out principles and systems of preventive measures.

 The word Hygiene is derived from the Greek word (Hygeia) Hygieia — the goddess of health.

In Greek mythology, Hygieia (Roman equivalent: Salus) was a daughter of Asclepius. She was the goddess of health, cleanliness and sanitation (and later: the moon), and played an important part in her father's cult (see also: asklepieion). While her father was more directly associated with healing, she was associated with the prevention of sickness and the continuation of good health.

Though Hygieia had been the subject of a local cult since at least the 7th century BC, she did not begin to spread out until the Oracle at Delphi recognized her, and after the devastating Athens plague in 429 and 427 BC and in Rome in 293 BC. Her primary temples were in Epidaurus, Corinth, Cos and Pergamon.

Pausanias remarked that, at the asclepieion of Titane in Sicyon (founded by Alexanor, Asclepius' grandson), statues of Hygieia were covered by women's hair and pieces of Babylonian clothes. According to inscriptions, the same sacrifices were offered at Paros.

Ariphron, a Sicyonian artist from the 4th century BC wrote a well-known hymn celebrating her. Statues of Hygieia were created by Scopas, Bryaxis and Timotheus, among others.

She was often depicted as a young woman feeding a large snake that was wrapped around her body. Sometimes the snake would be drinking from a jar that she carried. These attributes were later adopted by the Gallo-Roman healing goddess, Sirona.

Hygiene is defined as the science and art of preserving and improving health. Hygiene deals both with an individual and a community as a whole. Personal Hygiene is the term used for improvement of hygiene of an individual or a person. Social Hygiene is usually the term used for dealing with problems of sex especially for control of venereal diseases. Similarly other terms like mess hygiene, milk hygiene, hygiene of feeding, hygiene of clothes, hygiene of infant feeding etc., are self-explanatory

Hygiene and Good Habits are commonly understood as preventing infection through cleanliness. In broader call, scientific terms hygiene is the maintenance of health and healthy living. Hygiene ranges from personal hygiene, through domestic up to occupational hygiene and public health; and involves healthy diet, cleanliness, and mental health.

Etymology

The term hygiene originates as a reference to Hygieia, who was a daughter of Asclepius and the goddess of health, cleanliness and sanitation. Hygiene is also a scientific study: The science that deals with the promotion and preservation of health. Also called hygienics.

History

Elaborate codes of hygeine can be found in several Hindu texts such as the Manusmriti and the Vishnu Purana.[1] Bathing is one of the five Nitya karmas (daily duties) in Hinduism, not performing which leads to sin according to some scriptures. According to historian William Dalrymple, many early Christians considered one bath to be sufficient for purification for one lifetime, and considered regular bathing a heretical pagan ritual. [1] According to him, the Europeans seem to have learned the habit of taking regular baths in the seventeenth century upon their colonization of India. [2]

In Islam, Ghusl (taking a bath) on Friday is compulsory for every Muslim reaching the age of puberty.

Benefits

Outward signs of good hygiene include the absence of visible dirt (including dust and stains on clothing) or of bad odor/smells. Since the development of the germ theory of disease, hygiene has come to mean any practice leading to the absence of harmful levels of bacteria.

Good hygiene is an aid to health, beauty, comfort, and social interactions. It directly aids in disease prevention and/or disease isolation. (That is, good hygiene will help keep one healthy and thus avoid illness. If one is ill, good hygiene can reduce one's contagiousness to others.)

Washing (with water) is the most common example of hygienic behavior. Washing is often done with soap or detergent which helps to remove oils and to break up dirt particles so they may be washed away. Frequent hand washing is among the most common hygienic advice.

Hygienic practices—such as frequent hand washing or the use of autoclaved (and thus sterilized) water in surgery/medical operations—have a profound impact on reducing the spread of disease. This is because they kill or remove disease-causing microbes (germs) in the immediate surroundings. For instance, washing one's hands after using the toilet and before handling food reduces the chance of spreading E. coli bacteria and Hepatitis A, both of which are spread from fecal contamination of food. Adequate hygiene requires an adequate and convenient supply of clean water.

Hygienic practices

Personal hygiene

·                 Daily washing of the body and hair.

·                 More frequent washing of hands and/or face.

·                 Oral hygieneDaily brushing and flossing teeth.

·                 Cleaning of the clothes and living area.

·                 General avoidance of bodily fluids such as feces, urine, vomit.

·                 Not touching animals before eating.

·                 Avoidance of direct or indirect contact with unhygienic people.

·                 Holding a tissue over the mouth or using the upper arm/elbow region when coughing or sneezing, not a bare hand. Alternatively, washing hands afterwards.

·                 Suppression of habits such as nose-picking, touching the face etc.

·                 Not licking fingers before picking up sheets of paper.

·                 Not biting nails

Food safety

·                 Maintain good food and cooking hygiene to prevent food poisoning

·                 Cleaning of food preparation areas and equipment for example using designated cutting boards for preparing raw meats and vegetables.

·                 Thorough cooking of meats

·                 Institutional dish sanitizing.

·                 Washing of hands after touching uncooked food when preparing meals.

·                 Not using the same utensils to prepare different foods.

·                 Non-sharing of cutlery when eating.

·                 Not licking fingers or hands while or after eating.

·                 Proper storage of food so as to prevent contamination by vermin.

·                 Refrigeration of foods (and avoidance of certain foods in environments where refrigeration is or was not feasible).

·                 Labeling food to indicate when it was produced (or, as food manufacturers prefer, to indicate its best before date).

·                 Disposal of uneaten food and packaging.

Medicine

·                 Use of bandaging and dressing of wounds.

·                 Use of protective clothing such as masks, gowns, caps, eyewear and gloves.

·                 Sterilization of instruments used in surgical procedures.

·                 Safe disposal of medical waste.

Personal services

·                 Sterilization of instruments used by hairdressers.

·                 Sterilization by autoclave of instruments used in body piercing and tattoo marking.

Grooming

The related term personal grooming/grooming means to enhance one's physical appearance or appeal for others, by removing obvious imperfections in one's appearance or improving one's hygiene.

Grooming in humans typically includes bathroom activities such as primping: washing and cleansing the hair, combing it to extract tangles and snarls, and styling. It can also include cosmetic care of the body, such as shaving and other forms of depilation.

In India and other countries, the terms Hygiene and Public Health have been replaced by Preventive and Social Medicine. In fact the term incorporates all the con­cepts discussed under Hygiene, Public Health, Preventive Medicine and Social Medicine. In Hygiene and Public Health, there was more em­phasis on classical public health. In Preventive and Social Medicine, the emphasis is more on total health care programmes for individuals, families, groups as well as communities through integration of medical, public health and social welfare services.

PREVENTIVE MEDICINE

Prevention is better than cure is an old saying. Preventive medicine deals with the measures to protect the individuals from the diseases, and to keep them in a state of positive health. For this we have to ensure all the above-mentioned prerequisites required for the maintenance of positive health. The environments must be hygienic, with supply of fresh air, safe potable water and balanced diet. This aspect of preventive medicine started gaining more importance from 18th century onwards with the discovery of various vaccines and sera for the protection against various diseases like small pox, cholera, plague, whooping cough, tetanus, tuberculosis, poliomyelitis etc

Ecology is constituted by the total environment of man. The environment of modern man is partly natural and partly man-made. It consists of physical, mental and social factors, which are dynamic and interacting both within themselves and with the life process in the internal environment of men. The im­portant physical factors are air, water, food, build­ings, their contents and multiple devices produced by man to adjust the physical environment around him. The important biological factors are pathogens, other microorganisms as well as living beings, vec­tors, plants, etc., which have implications on health and disease. The important social factors are cus­toms, beliefs, laws, peculiarities and modes of living of human beings with their implications on health and disease.

What is pollution.htm

Environmental Sanitation

The word Sanitation -  is derived from the Latin word Sanitas which means a state of health. Environ­mental Sanitation means the control of all those fac­tors in man's surroundings, which cause or may cause adverse effects on his health. The sanitarian directs his efforts towards hygiene of water and food supply, hygienic disposal of human wastes, hygiene of hous­ing and control of vectors and rodents etc.

The following definition now is accepted: «Hygiene is a science, which investigates regularities of influence of the environment on the organism of the man and public health with the purpose of the substantiation of the hygienic norms, sanitarian rules and measures, realization of which will ensure optimum conditions for vital activity, improving of health and preventing of diseases ».

The principal topics of the subject are:

 Hygiene of atmospheric air

Water supply hygiene

               Hygiene of nutrition

Occupational hygiene

              Radiological hygiene

Hygiene of children and teenagers

              Hospital hygiene

Hygiene of extraordinary situation

             Tropical hygiene

 

Hygiene is a science of preserving and promoting the health of both the individual and the community.

          It has many aspects:

Ø     personal hygiene (proper living habits, cleanliness of body and clothing, healthful diet, a balanced regimen of rest and exercise);

Ø      domestic hygiene (sanitary preparation of food, cleanliness, and ventilation of the home);

Ø     public hygiene (supervision of water and food supply, containment of communicable disease, disposal of garbage and sewage, control of air and water pollution);

Ø      industrial hygiene (measures that minimize occupational disease and accident);

Ø     mental hygiene (recognition of mental and emotional factors in healthful living) and so on.

2. THE AIM AND TASKS OF HYGIENE

Basic aim of hygiene

Preservation and improving the health of the man is a basic aim of hygiene.

In this occasion the English scientist E.Parce has told, that the hygiene has a great and generous purpose: «...To make development of the man most perfect, life most intense, wasting least fast, and death most remote».

The tasks of a hygienic science:

          1. Study of the natural and anthropogenesis factors of the environment and social conditions which influence on health of the man.

          2. Study regularities of influence the factors and conditions of an environment on an organism of the man or population.

          3. Scientific substantiation and working out of the hygienic norms, rules and measures, which help use maximum positively influencing on an organism of the man the factors of an environment and elimination or restriction up to safe levels unfavourable operating ones.

          4. Introduction in practice of public health services and national economy developed hygienic recommendations, rules and norms check of their effectiveness and perfecting.

          5. Prediction of the sanitarian situation for the nearest and remote perspective in view of plans of development of the national economy. Definition of appropriate hygienic problems, which implying from prognostic situation and scientific working out these problems.

3. BASIC METHODS OF HYGIENIC RESEARCHES

          During the development the hygiene used many methods of study an environment and its influence on the health of the population.

Methods of hygiene

1. Methods of environment studying.

2. Methods of studying of environmental influence on human organism and health

 1. Methods of environment studying

Methods of sanitary examination with further sanitary description

 Speaking about methods of the research the exterior factors, first of all it is necessary point at method sanitarian description, which for a long time being almost only. It did not lost the value and now.

Specific hygienic method is method of sanitary examination and describing which is used for studying the environment.

           Sanitary examination and describing is carried out according to special programs (schemes), which contain questions. Answers to these questions characterize the object, which is being examined hygienically. As a rule it is usually supplemented by laboratory analyses (chemical, physical, microbiological and other), which allows characterizing environment from the qualitative side.

Instrumental and laboratory methods With the help of physical methods we can study microclimatic conditions, electrical conditions of air, all aspects of radiant energy, mechanical and electromagnetic oscillation, carry out the spectroscopic analysis and much other.

          By chemical methods we can determine peculiarities of a natural structure of all elements of an environment, the quantitative and qualitative indexes of it contamination, enable to make conclusion about sanitarian troubles of the investigated object.

           The biological methods, first of all bacteriological researches, for example, definition of a credit of the Esherichia colli, have much value for conclusion about epidemiological safety of the potable water.

Sanitation

Sanitation is the hygienic disposal or recycling of waste, as well as the policy and practice of protecting health through hygienic measures. [1] The term sanitation is sometimes understood in a narrow sense as the collection and treatment of wastewater. In a somewhat broader sense the term also includes on-site sanitation, for example through septic tanks and latrines. In the broadest sense of the term, sanitation also includes the collection and disposal of municipal solid waste (see below). In addition, the term sanitation is also used in the food industry as the adequate treatment of food-surface areas (see below).

 Hygienic standardization:

Environmental standards are definite ranges of environmental factors, which are optimal, or the least dangerous for human life and health. In Ukraine basic objects of hygienic standardization are:

§        MAC – maximum admissible concentration (for chemical admixtures, dust and other hazards)

§        MAL – maximum admissible level (for physical factors)

§        LD – dose limit (for ionizing radiation)

§        Optimum and admissible parameters of microclimate, lighting, solar radiation, atmospheric pressure and other natural environmental factors.

§        Optimum and admissible daily requirements in food and water.

 

Let's study the methodical scheme of hygienic norms of substantiation using, the example of MAC for some toxic substance. The first stage is stud physical and chemical properties of the substance, elaboration of methods of quantitative determination of this substance in different subjects, determination of its regimen of action on the human (duration, interruption, changes of intensity), ways of getting into the organism, study migration in different elements of the surrounding, mathematical prediction of duration of existence in different surroundings.

The second stage is study direct influence on the organism. It is started from 'sharp' experiments the main goal of which is getting initial toxicometric data about the substance (determination of LD50, or LC50 threshold of strong action (LIMac) and other. With the knowledge of physical and chemical properties of t he substance, its initial toxicological characteristics and approximate level of MAC can be calculated. The third stage - is conduction of 'subsharp' experiment during l-2 months for determination of cumulating coefficient and the most vulnerable physiologic systems and organs specification of mechanisms of action and metabolism.

The fourth (basic) stage is carrying out chronic experiment which lasts 4-6 months in the case of modeling of working conditions, 8-12 - communal conditions, 24-36 - in study processes of aging or induction of tumours.

During the experiment integral parameters are studied. They reflect condition of animals, degree of strain of regulative systems, functions and structure of organs which take part in processes of metabolism (activity of enzymes), influence of functional loadings.

Numbers of MACs of toxic chemical substances in the Ukraine are various: for the air of working: zone - more than 800, water- 700, atmosphere air- 200, food-stuffs - more than 200, soil - more than 30.

Basic objects, which are under the hygienic norms setting, can be divided into two groups.

          The first group contains factors of anthropogenous origin, which are unfavorable for human being, and are not necessary for the normal life activity (dust, noise, vibration, ionizing radiation, etc.). MAC, MAL and LD are those parameters, which are set for this group of factors.

          The second group contains factors of natural surrounding which are necessary (in certain amount) for normal life activity (food-stuffs, solar radiation, microclimatic factors and others). For this group the following parameters must be set: optimum, minimum and maximum admissible parameters.

          In those cases when factors influence on the human not only directly (physiologically) but also indirectly (through the environment) all types of possible influence must be examined at hygienic norms setting. For example setting of hygienic norms for toxic substance in the water of natural reservoirs determination of maximum concentrations must be based on worsening of organoleptic properties of the water (organoleptic sign), toxic influence (sanitary - toxicological sign) and disturbance of processes of self-clearing of reservoirs (general sanitary sign). In this case MAC are set according that harmful parameter which is characterized by the lowest level of concentration Such parameter is called limiting.

History of Hygiene

Beginnings in antiquity

          Most of the world's primitive people have practiced cleanliness and personal hygiene, often for religious reasons, including, apparently, a wish to be pure in the eyes of their gods.

          For thousands of years primitive societies looked upon epidemics as divine judgments on the wickedness of mankind. The idea that pestilence is due to natural causes, such as climate and physical environment, however, gradually developed.  

This great advance in thought took place in Greece during the 5th and 4th centuries bc and represented the first attempt at a rational, scientific theory of disease causation. The association between malaria and swamps, for example, was established very early (503-403 bc). In the book Airs, Waters, and Places, thought to have been written by Hippo crates in the 5th or 4th century bc, the first systematic attempt was made to set forth a causal relationship between human diseases and the environment. Until the new sciences of bacteriology and immunology emerged well into the 19th century, this book provided a theoretical basis for the comprehension of endemic disease (that persisting in a particular locality) and epidemic disease (that affecting a number of people within a relatively short period).

The middle ages

In terms of disease, the middle Ages can be regarded as beginning with the plague of 542 and ending with the Black Death (bubonic plague) of 1348.

          The isolation of persons with communicable diseases first arose in response to the spread of leprosy. This disease became a serious problem in the Middle Ages and particularly in the 13th and 14th centuries.

The Black Death reached the shores of southern Europe from the Middle East in 1348 and in three years swept throughout Europe. The chief method of combating plague was to isolate known or suspected cases as well as persons who had been in contact with them. The period of isolation at first was about 14 days and gradually was increased to 40 days. Stirred by the Black Death, public officials created a system of sanitary control to combat contagious diseases, using observation stations, isolation hospitals, and disinfections procedures. Major efforts to improve sanitation included the development of pure water supplies, garbage and sewage disposal, and food inspection. These efforts were especially important in the cities, where people lived in crowded conditions in a rural manner with many animals around their homes.

During the Middle Ages a number of first steps in public health were made: attempts to cope with the unsanitary conditions of the cities and, by means of quarantine, to limit the spread of disease; the establishment of hospitals; and provision of medical care and social assistance.

 

The Renaissance

Centuries of technological advance culminated in the 16th and 17th centuries in a number of scientific accomplishments. Educated leaders of the time recognized that the political and economic strength of the state required that the population maintain good health.

          Scientific advances of the 16th and 17th centuries laid the foundations of anatomy and physiology. Observation and classification made possible the more precise recognition of diseases. The idea that microscopic organisms might cause communicable diseases had begun to take shape.

National developments in the 18th and 19th centuries

From about 1750 the population of Europe increased rapidly, and with this increase came a heightened awareness of the large numbers of infant deaths and of the unsavory conditions in prisons and in mental institutions.

          This period also witnessed the beginning and the rapid growth of hospitals. This era was also characterized by efforts to educate people in health matters.

           

In 1852 Sir John Pringle published a book that discussed ventilation in barracks and the provision of latrines. Two years earlier he had written about jail fever (now thought to be typhus), and again he emphasized the same needs as well as personal hygiene. In 1754 James Lind published a treatise on scurvy, a disease caused by a lack of vitamin C.

  As the Industrial Revolution developed, the health and welfare of the workers deteriorated. In England, where the Industrial Revolution and its bad effects on health were first experienced, there arose in the 19th century a movement toward sanitary reform that finally led to the establishment of public health institutions.

            Around the beginning of the 19th century humanitarians and philanthropists in all countries worked to educate the population and the government on problems associated with population growth, poverty, and epidemics.

Developments from 1875

 

In the last decades of the 19th century the French chemist Louis Pasteur, the Germans Ferdinand Julius Cohn and Robert Koch, and others developed methods for isolating and characterizing bacteria; the English surgeon Joseph Lister developed concepts of antiseptic surgery; the English physician Ronald Ross identified the mosquito as the carrier of malaria; a French epidemiologist, Paul-Louis Simond, provided evidence that plague is primarily a disease of rats spread by rat fleas; and two Americans, Walter Reed and James Carroll, demonstrated that yellow fever is caused by a filterable virus carried by mosquitoes. Thus, modern public health and preventive medicine owe much to the early medical entomologists and bacteriologists. A further debt is owed bacteriology because of its offshoot, immunology.

In the 19th century the efforts of health departments to control contagious disease consisted in attempts to improve environmental conditions. As bacteriologists identified the microorganisms that cause specific diseases, progress was made toward the rational control of specific infectious diseases.

          While improvements in environmental sanitation during the first decade of the 20th century were valuable in dealing with some problems, they were of only limited usefulness in solving the many health problems found among the poor.

          The first half of the 20th century saw further advances in community health care, particularly in the welfare of mothers and children and the health of schoolchildren, the emergence of the public health nurse, and the development of voluntary health agencies, health education programs, and occupational health programs.

In the second half of the 19th century two significant attempts were made to provide medical care for large populations. One was by Russia, and took the form of a system of medical services in rural districts; after the Communist Revolution, this was expanded to include complete government-supported medical and public health services for everyone. Similar programs have since been adopted by a number of European and Asian countries.

          The other attempt was prepayment for medical care, a form of social insurance first adopted toward the close of the 19th century in Germany, where prepayment for medical care had long been familiar. A number of other European countries adopted similar insurance programs.

Public health interests also have turned to such disorders as cancer, cardiac disease, thrombosis, lung disease, and arthritis, among others. There is increasing evidence that several of these disorders are caused by factors in the environment; for example, the association of cigarette smoking with certain lung and cardiovascular diseases. Theoretically, they are preventable if the environment can be altered. Health education is of great importance and is a responsibility of national and local government agencies as well as voluntary bodies. Life expectancy has increased in almost every country, except where public health standards are low.

 

This subject studies the factors which influence on the human body, create the threshold values and maximum admissible concentrations, levels and doses for these factors. There are psychogenic (information) and material (chemical, physical, biological) factors. Afferent stimulation causes various emotions (grief, horror, joy etc), changes physical state of the organism. Positive emotions are realized in positive changes: better blood supply of the brain, heart, normalizing blood pressure. Distress, negative emotions can cause disease. They are risk factors for myocardium infarction, hypertension, ulcerous disease, diabetes etc. Great part of afferent loading has social nature. Chemical compounds are often necessary for vital activity and health, but they can be the cause of disease. For example: iodine deficit causes goiter and cretinism, chemical hazards (pollutants) can cause poisoning. Physical factors (microclimate, noise, ionizing radiation, vibration, air pressure) present various kinds of energies. They form an environment we live in but all these factors can be the hazards too. For example, high air temperature can cause overheating and heat stroke, intensive noise – cochlear neuritis and deafness, etc. Biological factors are microbes, viruses, fungi, and helminthes. They can cause diseases of the man and animals, spoil food products, damage sanitary-technical equipment. In real life human being is under the influence of not only one but also complex of environmental factors. They use the terminology: combined influence – influence of several factors of common origin (for example, several chemical compounds). “Common influence” means several factors of different origin are acting. Complex influence is characterized by the situation when only one factor is present but it has different routes of exposure.

Hygiene is a science of preserving and promoting the health of both the individual and the community. It has many aspects: personal hygiene (proper living habits, cleanliness of body and clothing, healthful diet, a balanced regimen of rest and exercise); domestic hygiene (sanitary preparation of food, cleanliness, and ventilation of the home); public hygiene (supervision of water and food supply, containment of communicable disease, disposal of garbage and sewage, control of air and water pollution); industrial hygiene (measures that minimize occupational disease and accident); mental hygiene (recognition of mental and emotional factors in healthful living) and so on. The World Health Organization promotes hygienic practices on an international level.