Waterborne infections. Water-borne diseases identified by WHO experts

Water is of great importance in epidemic the spread of infectious diseases - the second place after the air route. But there is also a peculiarity: if the air route operates with mass gatherings of people, then the water route also covers sparsely populated settlements. According to WHO, 80% of infectious diseases are associated with the poor quality of drinking water. Every year, up to 2 billion people suffer from water-related diseases. Bacterial intestinal infections are transmitted through water - cholera, typhoid fever, dysentery and viral diseases - hepatitis A (Botkin's disease), poliomyelitis, as well as leptospirosis (water fever - from mice), tularemia. Helminthiases spread through the aquatic environment: through fish and molluscs - opisthorchiasis (the liver is affected), diphyllobothriasis (a 10-meter wide tapeworm affects the small intestine), schistomatosis (larvae pierce the skin of the legs, enter the bloodstream and affect the bladder and large intestine - get sick up to 200 million people in hot climates). In water basins, mosquitoes multiply, carrying pathogens of malaria (up to 800 million people are ill) and filariasis.
Conditions and terms of survival of pathogenic microorganisms in water

Almost all microbes and viruses in water survive rainy days, waiting to enter a sensitive organism. The duration of survival depends on 1) the residence time of microorganisms in the water; 2) water pollution with faecal water, 3) water temperature and 4) the origin of water - sea, river or boiled, i.e. from water chemistry; in boiled water they live several times longer. The more fecal matter in the water and the cooler the water, the longer they remain viable: in river water: E. coli 21-183 days, typhoid bacillus 4-183, dysentery 12-92 and cholera vibrio - 1-92 days. The exception is Vibrio cholerae: at a water temperature of 28 ° C and above, it begins to actively multiply in protein residues in water and in silt, the contents of the intestines of crustaceans and small fish, and within a few days in hot weather it can spread up to a thousand km upstream the Volga river , Nile, Ganges, causing massive cholera. To get sick with a certain infection, you must swallow the appropriate number of bacteria: dysentery or cholera - from 100 thousand to 1 million, typhoid fever - up to 10 thousand.
Features of water epidemics

In order for waterborne diseases to arise - dysentery, typhoid fever or cholera, the law of hygiene must be in force - a disease can occur under the action of three conditions (3 links): 1) the presence of a source of harmfulness - a sufficient number of pathogens must enter the water, 2) the factor and transmission mechanism must work - the pathogen must remain viable in water or multiply, and 3) get into a susceptible organism.
Ways of pollution of water sources are divided into local (getting into the wells, ditches, ponds of the contents of garbage pits, toilets) and centralized (getting untreated water from rivers and lakes into the water pipes, breaking water pipes and sucking sewer water., Discharging fecal water into a drinking reservoir , mass bathing in contaminated reservoirs).
Main signs of water epidemics:

1) sudden simultaneous appearance of a large number of patients (from several tens to several thousand);
2) use of one source of water supply or bathing;
3) the predominance of adult patients at the beginning of the epidemic;
4) after the elimination of the accident and the introduction of effective water disinfection - a sharp break in the number of cases;
5) the presence of an "epidemic tail" - diseases continue for a long time due to single isolated diseases, mainly among children - maintenance due to the action of food and contact-household transmission routes;
6) polyetiology - other diseases associated with water (typhoid fever + dysentery; cholera + dysentery; dysentery + typhoid fever + hepatitis A) are partially mixed with the main diseases.

30The concept of the term "soil", soil as an element of the biosphere
Soil is the surface layer of the Earth's crust, which is of great importance in human life. Soil is the surface part of the lithosphere, formed after the appearance of life on Earth under the influence of climate, plant and soil organisms. Soil is an integral part of the circulation of substances in nature - an element of its biosphere.

28. Hygienic requirements for the quality of drinking water. Bacteriological indicators of water quality.

Water used by the population for household purposes must meet the following hygienic requirements:
1) have good organoleptic properties and refreshing temperature, be transparent, colorless, without unpleasant taste or smell;
2) be harmless in chemical composition;
3) do not contain pathogenic microbes and other pathogens, i.e. do not serve as a source of infections.
These requirements are reflected in the current standard in our country for the quality of drinking water supplied to the population by water pipelines (GOST 2874-73). Compliance of drinking water quality with the standards established by the standard is determined by sanitary chemical and bacteriological analysis of water from the water supply network. Water must meet the following requirements.

Bacteriological indicators of water quality. From an epidemiological point of view, pathogenic microorganisms play an important role in the hygienic assessment of water.
However, the study of water for their presence is a complex and lengthy process. In this regard, indirect bacteriological indicators are used. The application of these indicators is based on the observation that the less water is contaminated with saprophytic (non-pathogenic) microbes (including E. coli), the less epidemiologically dangerous it is. Since E. coli is excreted in the faeces of humans and animals, its presence signals fecal contamination of water and, therefore, the possible presence of pathogenic microorganisms in it.
When examining water for Escherichia coli, the results of the analysis are expressed by the value of the coli-titer or coli-index. Coli titer is the smallest amount of water in which one Escherichia coli is found. The lower the coli-titer, the stronger the fecal contamination of the water. Coli index - the number of Escherichia coli in 1 liter of water.
Experimental studies have shown that if, after disinfection of water, the coli index decreased to 3 (and the coli titer became above 300), then there is a full guarantee that pathogenic microbes of the typhoid paratyphoid group, leptospira and tularemia pathogens died.
Based on the above data, the requirements of the standard for the quality of tap water in relation to its bacterial composition were drawn up. The number of saprophytic bacteria in 1 ml of tap water (microbial number) should not exceed 100; if the titer should be at least 300 or if the index should be no more than 3.
When evaluating water in mine wells, which is not covered by this standard, the following requirements must be followed: transparency must be at least 30 cm, color - no more than 40 °, taste and smell - no higher than 2-3 points, hardness - no more than 7 mmol / l, if the index is not more than 10.
Along with this, when assessing the quality of water in wells, usually used for drinking without any treatment, the so-called chemical indicators of water source pollution by organic substances and their decay products (ammonium salts, nitrites, nitrates) can be used. The presence of these compounds may indicate contamination of the soil through which the water that feeds the source flows, and that along with these substances, pathogenic microorganisms could enter the water.
In some cases, each of the indicators may have a different nature. For example, the organic matter may be of plant origin. As a result, a water source can be considered contaminated if the water contains not one, but several chemical indicators of pollution, if bacterial indicators of pollution, such as E. coli, are simultaneously detected in the water, and if the possibility of pollution is confirmed by a sanitary examination of the water source.
The content of organic substances in water is judged by the oxidizability, expressed in milligrams of oxygen, which is spent on the oxidation of organic substances contained in 1 liter of water. Artesian waters have the least oxidizability - usually up to 2 mg of oxygen per 1 liter. In the water of mine wells, oxidizability can reach 3-4 mg of oxygen per 1 liter. An increase in water acidity beyond these levels often indicates contamination of the water source.
The main source of ammonium nitrogen and nitrites in water is the decomposition of protein residues, animal carcasses, urine and feces. With fresh pollution with waste in water that did not contain ammonium salts before, their amount exceeds 0.1-0.2 mg/l. Being a product of further biochemical oxidation of ammonium salts, nitrites in an amount exceeding 0.002-0.005 mg/l are also an important indicator of water source pollution. Nitrates are the end product of the oxidation of ammonium salts. The presence of nitrates in water in the absence of ammonium salts and nitrites indicates a relatively long time ago that nitrogen-containing substances entered the water, which had already been mineralized. In recent years, due to the abundant use of nitrogen-containing fertilizers, high concentrations of nitrates in well waters are often observed.
With an increased content of nitrates in water (more than 40 mg / l, or 10 mg / l, counting on N), diseases of infants fed with nutrient mixtures prepared on this water can be observed. The disease is caused by a significant increase in the content of methemoglobin in the blood, which disrupts the transfer of oxygen from the lungs to the tissues of the body. With water-nitrate methemoglobinemia in infants, dyspeptic symptoms, shortness of breath, blueness of the skin and mucous membranes (cyanosis) are observed, in severe cases, convulsions and death.
When assessing the water wells are guided by the following considerations. If the sanitary conditions in which the source of water is located, and the results of the study of water are favorable, then the water can be used raw, that is, without any treatment. If the quality of the water does not meet hygienic requirements, and the sanitary examination and analysis showed that contamination of the well is not excluded, then it is allowed to use it only if the water is disinfected by chlorination or boiling and after the improvement of the sanitary condition of the well.

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Water can have an adverse effect on a person if it:
1) contains pathogens of infectious diseases and helminthic invasions;
2) its chemical composition contains harmful substances;
3) has an unpleasant taste, color or smell.

The role of water in the spread of infectious diseases was established much earlier than pathogenic microorganisms were found in it.

Subsequently, this was confirmed by numerous microbiological and epidemiological studies. The causative agents of many infectious diseases can be transmitted through water.

The most characteristic water epidemics are those of cholera, typhoid, paratyphoid, and dysentery.

In the past, these contagious diseases were widespread, but at the present time, thanks to the vigorous implementation of sanitary and anti-epidemic measures, they are rare. Water infections include leptospirosis and tularemia, which are caused by contamination of natural water sources with rodent secretions or decay products of their corpses.

Viruses of infectious hepatitis, poliomyelitis, brucellosis can be transmitted through water, but for the causative agents of these diseases, the water route of infection is not the main one.

The water factor plays an important role in the transmission of geohelminths, the larvae of which enter water sources with domestic wastewater (roundworm, whipworm, etc.).

From an epidemiological point of view, untreated or insufficiently treated faecal and household wastewater and drinking water, which, in turn, are not subjected to sufficient disinfection, are of great danger.

In rural areas, the most common way for the spread of water epidemics are ponds and other slow-flowing water bodies with weak self-purification processes.

A serious condition for the emergence of a water epidemic is the preservation of the viability of pathogens of infectious diseases in water.

The terms of their survival in water are presented in Table 8.

WHO experts have found that 80% of all diseases in the world are associated with the poor quality of drinking water and violations of the sanitary and hygienic standards of water supply.

Human diseases that are associated with water are divided into four types:

diseases caused by water contaminated with pathogens (typhoid, cholera, dysentery, poliomyelitis, gastroenteritis, VIRUS hepatitis A);
diseases of the skin and mucous membranes that occur when using contaminated water for washing (from trachoma to leprosy);
diseases caused by mollusks living in water (schistosomiasis and guinea worm);
diseases caused by insects living and breeding in water - carriers of infection (malaria, yellow fever, etc.);

For the occurrence of these diseases are favorable:

unorganized water consumption;
insufficient amount of water;
appropriate natural conditions for the spread and survival of an infectious agent in environmental objects;
technical violations at water intake, water treatment facilities and water pipelines;
accidents at sewerage and treatment facilities;
discharge of untreated wastewater into water bodies;
non-observance of elementary norms of personal hygiene.

Cholera is traditionally considered the most dangerous intestinal disease of water origin. This disease covers vast areas, affecting the population of entire countries and continents.

Due to the severity of the clinical course and the trend towards pandemic spread, cholera is a particularly dangerous infection.

Since 1961, there has been an increase in the epidemic process of cholera.

Large waterborne outbreaks of cholera were in St. Petersburg in 1908-1909 and in 1918, when polluted water from the Neva got into the water supply network and water chlorination was disrupted.

In recent years, only isolated "imported" cases of cholera have been noted in Russia.

High morbidity and mortality are also typhoid fever and paratyphoid A and B. The causative agents of these diseases are microbes of the genus Salmonella of the family of intestinal bacteria, which are very resistant to external influences. The death of microorganisms accelerates with increasing ambient temperature.

So, in cold clean water, typhoid pathogens persist for up to 1.5 years, withstand freezing for several months and can overwinter in ice. .

In tap water, they are viable for up to 3 months, and in the water of open reservoirs - up to 12 days.

In Russia, epidemics of typhoid fever in different years also covered a significant part of the population. . The sad championship in this respect belonged to St. Petersburg, where, at the beginning of the 20th century, about 1,000 people died every year when using contaminated water due to violations of the water supply network. However, even in modern conditions, there are separate outbreaks of typhoid fever.

In some cases drinking water is involved in the transmission of colienteritis- diseases caused by enteropathogenic Escherichia coli.

Outbreaks of these diseases are typical for young children who are in closed communities (children's homes, nurseries, kindergartens), where elementary rules of personal hygiene are not observed.

Many viral diseases are spread by water. These are infectious hepatitis (Botkin's disease), poliomyelitis, adenovirus and enterovirus infections. The hepatitis virus is more resistant to environmental factors than pathogens of bacterial intestinal infections.

The virus remains pathogenic after freezing for 2 years, is resistant to most disinfectants and dies only after 30-60 minutes when boiled.

In this regard, standard methods of water purification and disinfection are not always effective enough against the hepatitis virus, and colibacterial indicators may not reflect the actual contamination with viruses. The cause of outbreaks of epidemics can be accidents at sewage and treatment facilities.

Outbreaks of epidemic hepatitis are more likely to occur in those settlements where small surface sources are used for household purposes, and water disinfection is not given due attention.

The most massive entry of tuberculous bacteria into water bodies is associated with the discharge of untreated wastewater from tuberculosis hospitals.

The water way of transmission of such a dangerous disease as polio. Water outbreaks of poliomyelitis have been noted in many countries of the world. It should also be borne in mind that enteroviruses and adenoviruses can spread by water, causing severe damage to the intestines, central nervous system, skin and mucous membranes in humans.

Prevention of viral diseases is complicated by the lack of sufficiently reliable methods for isolating viruses from various environments of the biosphere.

In countries with a hot climate, there are diseases related to kleptospirosis.

These are Weil-Vasiliev's disease (ictero-hemorrhagic leptospirosis) and water fever (anicteric leptospirosis). Carriers of the infection are most often rodents, sometimes cattle, pigs. A person becomes infected through the water of stagnant reservoirs (lakes, ponds, swamps) and ground wells; contaminated with animal excreta.

Infectious agents enter the body through the gastrointestinal tract, as well as when bathing through the mucous membranes of the lips, mouth, nose and damaged skin.

Some types of bacterial zoonotic infections have a waterway of distribution.

Sources of pathogens can be rodents (tularemia) or cattle (brucellosis, anthrax). The pathogen can enter the body both through the gastrointestinal tract and through the skin. According to a number of authors, transmission of tuberculosis pathogens through water is possible, although the water route of infection is not considered the main one for this infection.

The most massive entry of tuberculous bacteria into water bodies is associated with the discharge of untreated wastewater from tuberculosis hospitals.

Protozoan invasions, i.e. diseases caused by protozoa are found mainly in the hot climates of Asia and Africa.

Expressed forms of diseases are relatively rare, although the carriage, depending on sanitary well-being, can exceed 15%. These are amoebiasis or amoebic dysentery caused by Eniamoeba hislolytica, balantidiasis caused by the ciliate Balantidium coli, and giardiasis caused by the flagellate Lamblia intestinalis.

Amebiasis and balantidiasis develop as acute diseases that turn into a chronic form, accompanied by diarrhea, when protozoa enter with drinking water and penetrate into the mucous membrane of the colon. Sometimes diseases become protracted, recurrent. Giardia does not cause disorders of the intestinal mucosa, so the disease does not have a clear clinical picture. There are pains in the abdomen and dyspeptic disorders, but more often giardiasis remains asymptomatic.

Carriage of lamblia among the population is very high and averages about 15%, and in children's groups with unfavorable hygienic conditions it exceeds 30-40%.

Another group of widespread diseases, transmitted through water are helminthic infestations.

All helminthic diseases can be divided into geohelminthiases and biohelminthiases. The causative agents of geo-helminthiases develop and spread without the participation of intermediate hosts. Transmission factors are water, soil, various objects contaminated with eggs or helminth larvae. The most famous representatives of this group are roundworms. Although water is not the leading route for the spread of ascariasis, the development of the disease is possible when drinking water containing helminth eggs.

With a similar migration path, strongyloid larvae are located both in the upper sections of the small intestine and in the bile and pancreatic ducts.

The main host in which schistosomes of this species reach sexual maturity are domestic and wild ducks. The intermediate host is a freshwater mollusk. Schistosoma larvae, released from the mollusk, penetrate into the human epidermis when bathing, causing severe itching, swelling and rashes.

Repeated cases of infection are especially difficult due to severe sensitization of the body. However, the helminth does not go through the full cycle of development in the human body and dies, so the duration of the disease ranges from several hours to 2 weeks.

Documentary about catastrophic environmental pollution

A documentary film about catastrophic environmental pollution, about how people, domestic animals, birds cause diseases such as typhus, smallpox, AIDS, hepatitis with their feces.

Outside the cities, where there are no sewage treatment plants, sewage gets into the ground - drinking water is contaminated even in deep wells, in which there are viruses, bacteria and heavy metals. The famous actress, businessman, living in the suburbs, consume poisons and microbes through the water.

Water is similar to chemical warfare agents. Mankind consumes tons of medicines, which again enter the person through feces and water. Female hormones, through hormonal drugs in drinking water, are one of the reasons why men change their sexual orientation, the desire for a woman that mother nature laid down disappears. Children in the sandbox can easily become infected.

It is necessary to increase the immunity of the body, natural means of NSP.

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The role of water in the transmission of infectious diseases (typhoid fever, dysentery, cholera). Fecal domestic wastewater as the main sources of pathogenic microorganisms. Purification and disinfection of tap water. The influence of bacillus carriers on the body.

Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.

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The role of water in the transmission of infectious diseases

In the context of the rapid growth of cities, the rapid development of industry and agriculture, the construction of treatment facilities is sometimes delayed, as a result of which reservoirs become recipients of poorly treated wastewater. Water is polluted, and the processes of its self-purification from extraneous microflora, including pathogens, proceed much more slowly, because the extensive construction of hydroelectric stations, reservoirs, canals changes the hydrological regime of rivers, the biological and chemical composition of water.

This means that the microbes that enter the reservoir now retain their pathogenic properties for a longer time.

bacillus carrier water infection pathogenic

The causative agents of diseases, getting into the human intestine, find favorable conditions for reproduction there, as a result of which an acute intestinal disease occurs. Since a large number of people usually use one source of water supply, the way the disease spreads through water is the most massive, and therefore the most dangerous.

Human faeces and fecal sewage are the main sources of water-borne pathogens.

Fecal contamination of water worsens its quality, and pathogenic microorganisms that enter the water with the secretions of warm-blooded animals can cause an increase in the incidence of intestinal infections. Pathogenic microbes can get into open water bodies when sewage is discharged from ships, when coasts are polluted, when crossings are built, when cattle are watered, when washing clothes, bathing, when sewage is washed off the soil surface by atmospheric precipitation, etc.

Wherever organic waste accumulates (soil, open reservoirs, groundwater), conditions are created for maintaining the life of bacteria, and sometimes for their rapid development.

Many of these microorganisms are harmless, but some of them have the ability to cause certain contagious diseases. Even in the presence of well-arranged and equipped filtration stations, equipped with the most advanced equipment and devices, with their impeccable operation, outbreaks and epidemics of intestinal diseases of water origin periodically occur in different countries.

Not everywhere the purification and disinfection of tap water is properly established.

In some cases, good quality water enters the distribution network, which is then subjected to secondary bacterial contamination due to the significant deterioration of water pipes. In some settlements, part of the inhabitants use water from open reservoirs or technical water pipes for household and drinking purposes.

Causes of waterborne infectious diseases can be poor control of water treatment, pollution of the water collection system, pollution of the distribution system (tanks, pipes), consumption of surface water without treatment.

Well water is polluted when the contents of latrines, garbage pits and other sewage pits seep through the soil, contaminated water flows from the soil surface.

Tap water can be polluted in case of accidents at head structures, sewage breakthroughs, groundwater suction, water flowing from the soil surface into manholes. Water pollution is possible during storage and transportation.

Water is one of the specific factors in the transmission of intestinal infections and, first of all, typhoid and paratyphoid diseases.

Sanitary and epidemiological observations show that epidemic outbreaks occur not only with the direct use of contaminated water for drinking, but also with its indirect participation, i.

e. when washing dishes, equipment and hands with it, when using contaminated water for the preparation of certain dishes. Violations in the centralized water supply system represent the greatest epidemiological danger. The use of water from technical water pipes for drinking and household purposes leads to serious consequences.

Unsatisfactory sanitary condition of the water supply network, errors in its design and installation, improper operation can lead to contamination of water with pathogenic microbes.

The causes of dysentery can be the use of water from open reservoirs, as well as the poor sanitary condition of wells and violation of the rules for using them.

Water-borne diseases cause ill health, disability and death in large numbers of people, especially children, predominantly in less developed countries where poor personal and communal hygiene is common.

Many of these diseases, including typhoid fever, dysentery, cholera, schistosomiasis and hookworm, are transmitted to humans as a result of environmental pollution from human excreta. In most cases, the main carrier of the infectious principle is water. Success in the fight against these diseases or the achievement of their complete elimination depends on how the system for removing all metabolic products excreted from the human body is organized, how the matter of purifying water and protecting it from pollution is organized.

So, the water factor becomes important in the occurrence of infectious diseases under the following conditions:

1) pathogens with secretions of patients and bacillus carriers (both people and animals) enter the water;

2) pathogens retain their viability and ability to cause disease in water;

3) infected water enters the human body (through the digestive tract, external mucous membranes, microdamaged skin).

Infectious patients, as a rule, are hospitalized in infectious disease hospitals, where conditions are created for the disinfection of their secretions, as a result of which they should not be sources of infectious diseases during this period.

They can infect the environment, including water, in the last days of the incubation period, when there are no manifestations of the disease yet, but the microbes in the body multiply intensively and are released.

Bacillus carriers who have had an infection are of particular danger.

So, after suffering from typhoid fever, the ill person continues to excrete pathogens of this disease with feces and urine. In the first weeks after recovery, the release of typhoid microbes is observed in almost every second of those who have been ill (acute carriage). Over time, the number of carriers decreases and after three months it is reduced to 3-3.5% of the number of those who have been ill.

However, some people who have had typhoid fever may remain carriers for many months or even years (chronic carriers).

Chronic carriers of typhoid fever have often been the source of major outbreaks of this disease. Acute and chronic carriage is observed in dysentery and other waterborne infections.

Chronic bacillus carriers are epidemiologically very dangerous for others because very often the carriage of the name of even virulent (resistant, with an increased ability to infect) pathogens does not affect their condition (i.e.

e. occurs imperceptibly) and can only be established by repeated bacteriological studies.

There are also so-called healthy bacillus carriers. They are more often observed among persons who are in close contact with patients.

Such bacillary carriage, as a rule, is short-lived, but it poses a great danger to others with its secretions. Therefore, the sanitary-epidemiological stations take into account all those who have recovered from infectious diseases, especially intestinal ones, and periodically check them for the carriage of bacteria.

Persons who have had intestinal infections are not allowed to work in canteens, kitchens, food warehouses, in the water supply system until complete recovery.

The World Health Organization (WHO) estimates that 80% of all diseases on earth are caused by contaminated water or lack of basic hygiene.

Waterborne diseases

Many infectious diseases are transmitted through water: typhoid fever, dysentery, cholera, etc.

An infection is the interaction of pathogenic microorganisms with other organisms under certain environmental conditions, which may result in an infectious disease.

Pathogenicity is the potential ability of certain types of microorganisms to cause an infectious process. Pathogenic microbes are characterized by specificity, i.e. each microbe is capable of causing a specific infectious process. However, the possibility of occurrence and the nature of the development of the process, its severity, duration, outcome largely depend not so much on the microbe as on the degree of reactivity and resistance of the human or animal organism.

Pathogenic microbes can be in the body of a healthy person without causing the development of the disease.

It has been proven that malnutrition, exposure to cold, alcohol, physical overwork, etc. contribute to the development of an infectious disease. Many pathogenic microorganisms produce enzymes that can destroy tissues and cells in the body. As a result, the permeability of microorganisms to the attacked organism increases.

The most important feature of pathogenic microbes is their toxicity. Distinguish between exotoxins and endotoxins.

Exotoxins are poisons that readily diffuse into the environment. Endotoxins are firmly bound to the body of the microbial cell and are released only after it dies. The action of exotoxins is specific, i.e. they affect certain organs and tissues. For example, tetanus exotoxin causes damage to the nervous system, as a result of which the patient experiences muscle spasm; diphtheria affects the cardiovascular system, adrenal glands.

If microbial exotoxins, being very strong poisons, have a detrimental effect on the body already in very small doses, then endotoxins are less toxic, do not have strict specificity, and cause general signs of poisoning in the body: headache, weakness, shortness of breath.

Endotoxins are composed of polysaccharides and lipoproteins, and exotoxins are of a protein nature.

Infectious diseases differ from non-infectious diseases not only in their origin, but also in their course and clinical signs.

There are the following periods of the course of the infectious process: incubation (hidden); period of precursors (prodromal); the period of the highest development of the disease (acme period); The outcome of the disease is recovery, transition to a chronic state, death.

An epidemic (a mass disease of people) occurs when there is an epidemic chain consisting of three links: the source of the infection, the ways of transmission of the infection, and the susceptibility of the population to this disease.

The source of infection can be a sick person, animal or bacillus carriers. A bacillus carrier is a healthy organism, to which microbes do not cause harm, but, developing in it, are released into the external environment.

Infectious diseases are transmitted in different ways: through food, air, insects, contact with the patient, including through water. This happens when drinking, bathing, washing dishes, vegetables, fruits, etc. The development of the epidemic depends on the susceptibility of the population and animals to this type of disease.

Improving the living conditions of people, their accuracy, the implementation of preventive measures, the identification of bacillus carriers - all this limits the possibility of spreading diseases.

A wide variety of microbes can accidentally appear in water, but they can live in it for a long time, as numerous studies by scientists have shown, only causing cholera, typhoid fever, dysentery and other gastrointestinal diseases.

The duration of their preservation in water is different. Cholera pathogens can survive in water from several days to several months. Dysentery sticks can stay in tap water for up to 27 days. The causative agents of typhoid fever remain viable in water for up to three months. Especially often the transmission of acute intestinal infections is observed when drinking contaminated water, but infection is also possible when using water for household needs.

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A living organism cannot exist without water and food. This fact is known to all. But what to do when life itself is threatened by drinking or bathing in dirty water?

Doctors try to answer this question with recommendations on how to protect themselves from infection through water. But the possibility of infection depends not only on the person, but also on the communications through which water is transported to apartments and houses. Water often enters homes with a predetermined set of unwanted micro-organisms. Reservoirs in which you have to swim in the summer are not always cleared of dirt. Naturally, you can become infected not only while drinking water, but also when processing vegetables or fruits, while washing your hands. Possible places of infection are a pool, a lake, a river, even the sea, an apartment, a summer house and a house. What diseases transmitted through water threaten to worsen well-being and health, up to death, read in this article.

Methods of infection from water

The quality of water supplied to apartments and houses depends on special services that purify and filter drinking water, as well as on services that control the presence of pathogenic organisms in water. In addition, when purified water moves through old pipes, through the thin walls of which sewage with a huge amount of microbes can seep, this can also lead to poisoning and infection.

In the summer, recreation near water bodies is popular, especially urban ones - rivers, lakes, reservoirs. In them, water almost does not circulate and stagnates, which further worsens the pollution situation. If you swallow this water, you can easily pick up a sore. Water-borne infectious diseases are very difficult to cure, some of them are so severe that they lead to death.

According to statistics, four diseases out of five are partially or completely associated with water, drinking or bathing. Diarrhea is the leading cause of death.

It is appalling that more than 1.1 billion people simply do not have access to clean drinking water. They have no choice but to use for all needs and drink ordinary water from the reservoir, without purification and disinfection. Every year, more than 2 billion people die worldwide from waterborne infections.

Among other things, even in the pool you can catch many ailments, feeling not only all the benefits of swimming, but also adding health problems. That is why people do not want to take risks and do not go to the pool for swimming, so as not to undermine their health even more.

Waterborne diseases

The list of diseases that are transmitted through water is huge. We provide data only for those diseases that are the most common.

Waterborne diseases:

ascariasis;
botulism;
anemia;
cholera;
diarrhea;
campylobacteriosis;
dengue fever;
fluorosis;
cyanobacterial toxin;
hepatitis E and A (Botkin's disease);
malaria;
Japanese encephalitis;
legionellosis;
trachoma;
lead poisoning;
giardiasis;
schistosomiasis.

Water becomes contaminated after sewage enters reservoirs with purified water. This can happen due to a system malfunction or after a flood, when the water level rises strongly, sweeping away everything in its path. It also happens that the infection comes from a source of drinking water and retains its viability even after passing through filters and cleaning procedures. The resistance of pathogenic microorganisms is increasing every day, so today doctors recommend purifying and filtering water from the tap so as not to get infected.

In addition to direct infection through water after drinking, you can become infected by washing fruits or vegetables with dirty water or not thoroughly washing your hands after hygiene procedures, for example.

How to protect yourself from infection through water

To protect yourself from infection and prevent the spread of diseases from water, you must:

perform all water procedures correctly,
be sure to wash your hands with soap,
wash vegetables and fruits thoroughly with running water to wash off all the dust,
use only purified water;
keep dishes and all kitchen utensils clean;
do not use the same water for washing hands, dishes and food.

Diseases transmitted through water cause significant damage to health, so you should be careful about water procedures, do not visit polluted water bodies, and protect children from swimming in dirty water. The children's body is especially sensitive to infections and poisonings of various kinds, it is difficult to tolerate such diseases and it takes a long time to rehabilitate after that.

For a person, water is an obligatory component of the body, of which it consists of 65-70%. When the body is dehydrated, the state of health worsens + the processes of tissue protein decay increase + the water-salt balance is disturbed + the working capacity, the activity of the nervous and cardiovascular systems decrease. With the loss of 10% of water, there is a sharp anxiety, weakness, trembling of the limbs. At 20-22% death occurs. Depending on the ambient temperature, a person can live without water for 4-6 days (there is no longer any hope of finding survivors in the rubble of houses). It is necessary to consume at least 1.5-2 liters of liquid per day. Unfortunately, most people do not use this rate, which causes chronic constipation, headaches, yellow skin, and premature aging.

Water is indispensable for recreational activities: when bathing, the body hardens and trains muscles.

For your information: on average, the human body contains up to 50 liters of water. The distribution of water in individual tissues: in bones - 30%, cartilage - 60%, liver - 70%, muscles - 75%, brain - 79%, kidneys - 83%. The richer the organ in water, the more intense the metabolism in it. The least water-poor skull. The eye is almost entirely water. With age, the amount of water in the body decreases: at the 3rd month of uterine life - 94%, at birth - 69%, at 20 years old - 62%, old age - 58%. A dry Egyptian mummy weighs about 8 kg.

Water is also the main element in food products: in bread - up to 40%, eggs - up to 65%, meat - 75%, fish - 80%, milk - 87% and vegetables - 90%.

WHO experts have found that 80% of all diseases in the world are associated with the poor quality of drinking water and violations of the sanitary and hygienic standards of water supply.

Human diseases that are associated with water are divided into four types:

diseases caused by water contaminated with pathogens (typhoid, cholera, dysentery, poliomyelitis, gastroenteritis, VIRUS hepatitis A);
diseases of the skin and mucous membranes that occur when using contaminated water for washing (from trachoma to leprosy);
diseases caused by mollusks living in water (schistosomiasis and guinea worm);
diseases caused by insects living and breeding in water - carriers of infection (malaria, yellow fever, etc.).

For the occurrence of these diseases are favorable:

unorganized water consumption;
appropriate natural conditions for the spread and survival of an infectious agent in environmental objects;
technical violations at water intake, water treatment facilities and water pipelines;
accidents at sewerage and treatment facilities;
discharge of untreated wastewater into water bodies;
non-observance of elementary norms of personal hygiene.

Cholera is traditionally considered the most dangerous intestinal disease of water origin. This disease covers vast areas, affecting the population of entire countries and continents. Due to the severity of the clinical course and the trend towards pandemic spread, cholera is a particularly dangerous infection.

In some cases, drinking water is involved in the transmission of colienteritis, diseases caused by enteropathogenic Escherichia coli. Outbreaks of these diseases are typical for young children who are in closed communities (children's homes, nurseries, kindergartens), where elementary rules of personal hygiene are not observed.

Many viral diseases are spread by water. These are infectious hepatitis A (Botkin's disease), poliomyelitis, adenovirus and enterovirus infections. Hepatitis A virus is more resistant to environmental factors than pathogens of bacterial intestinal infections. The virus remains pathogenic after freezing for 2 years, is resistant to most disinfectants, and dies only after 30-60 minutes when boiled. In this regard, standard methods of water purification and disinfection are not always sufficiently effective against the hepatitis A virus, and colibacterial indicators may not reflect real contamination with viruses.

The cause of outbreaks of epidemics can be accidents at sewage and treatment facilities.

Outbreaks of epidemic hepatitis A often occur in those settlements where small surface sources are used for domestic purposes, and water disinfection is not given due attention.

In countries with a hot climate, there are diseases related to leptospirosis. These are Weil-Vasiliev disease (icterohemorrhagic leptospirosis) and water fever (anicteric leptospirosis). Carriers of the infection are most often rodents, sometimes cattle, pigs. A person becomes infected through the water of stagnant reservoirs (lakes, ponds, swamps) and ground wells; contaminated with animal excreta. Infectious agents enter the body through the gastrointestinal tract, as well as when bathing through the mucous membranes of the lips, mouth, nose and damaged skin.

Some types of bacterial zoonotic infections have a waterway of distribution. Sources of pathogens can be rodents (tularemia) or cattle (brucellosis, anthrax). The pathogen can enter the body both through the gastrointestinal tract and through the skin.

Schistosomiasis dermatitis (bather's itch) is ubiquitous. Recently, in connection with bathing in stagnant and low-flowing water bodies contaminated with feces, cases of such dermatitis have been noted in Russian cities, especially in children. The main host in which schistosomes of this species reach sexual maturity are domestic and wild ducks. The intermediate host is a freshwater mollusk. Schistosoma larvae, released from the mollusk, penetrate into the human epidermis when bathing, causing severe itching, swelling and rashes. Repeated cases of infection are especially difficult due to severe sensitization of the body. However, the helminth does not go through the full cycle of development in the human body and dies, so the duration of the disease ranges from several hours to 2 weeks.

Reminder for the population. What infections are waterborne?

The relationship between the incidence of the population and the nature of water consumption has long been noted. The use of pure water is beneficial for the body, but can also be dangerous to humans if it contains pathogenic microorganisms that cause infectious diseases.

The following are transmitted by water: cholera, typhoid fever, paratyphoid fever, dysentery, leptospirosis, tularemia (contamination of drinking water with rodent secretions), brucellosis, salmonellosis.

Among the viral diseases transmitted by water, the predominant place is occupied by the intestinal group of viruses, including enteroviruses, hepatitis A and many others.

Water infections are characterized by:

1) Sudden rise and high incidence;

2) The rapid spread of diseases.

Measures to prevent waterborne diseases:

Wash your hands thoroughly with soap and water as often as possible.
Use only boiled or bottled water for drinking.
Observe the rules for storage and preparation of food.
Eat thermally processed foods.
Observe the rules of personal hygiene.
Process vegetables and fruits with boiled water.
Do not swim in polluted waters.
Timeliness of vaccination.

Department of Medical Prevention

In some developing countries of the world, up to 80% of all diseases, leading not only to severe symptoms and complications, but even to death of people, fall on the waterway of the spread of infections. Up to a billion people around the world are deprived of the use of normal quality drinking water. The most dangerous infection is cholera, which belongs to the group of deadly quarantine pathologies. It causes epidemics with high mortality, especially in the presence of a low sanitary culture of the population.

Poisoning caused by water

Water belongs to universal solvents, respectively, a large number of organic and inorganic compounds entering open water bodies and water intake zones can cause poisoning of people. The most dangerous is poisoning with mercury salts. According to WHO, the permissible limits for the content of this substance in drinking water should not exceed 0.01 mg per liter. The use of drinking water with a high content of mercury for several months or years leads to chronic poisoning of its salts. About 4.5 tons of mercury annually enters the atmosphere and with precipitation into soils and water, including those used for drinking. Mercury ions, penetrating into the water, form oxides or other compounds, which, accumulating in the body, lead to poisoning and disruption of enzymes.

No less dangerous in terms of poisoning is cadmium, since water can contain its toxic salts or oxides. They are also prone to accumulation in the human body and chronic intoxication. Cadmium poisoning is most dangerous for those who live in industrial cities, where water sources are contaminated with industrial waste products.

In tropical countries, the virus that causes dengue and West Nile fevers is dangerous, with severe symptoms of intoxication, fever and skin rashes, with damage to the lymph nodes, diarrhea and vomiting, the development of coma and numerous lesions of internal organs.

Waterborne bacteria

No less dangerous are bacteria that are transmitted with water. They can be found both in drinking water and in reservoirs where people swim in the warm season. The most dangerous bacteria are Vibrio cholerae, which leads to a severe and especially dangerous disease, as well as Escherichia coli, which is the cause of dysentery (shigellosis). E. coli bacteria lead to the formation of severe diarrhea with dehydration and abdominal pain, nausea and general malaise.

Bacteria such as salmonella are also dangerous, resulting in outbreaks of salmonellosis. Such an infection is especially dangerous for children, the elderly and patients with chronic pathologies, since for them it can be fatal. With water, typhoid fever bacteria, belonging to a special variety of salmonella, are also transmitted. With the development of this disease, the digestive organs and lymph nodes of the abdominal cavity are affected, prolonged diarrhea and fever, and skin rashes occur. Without proper therapy, the disease can lead to death.

To avoid the dangers associated with water, it is worth remembering that water for drinking and cooking should be taken only from centralized sources of drinking water supply, and if there are none, it should be filtered and boiled, disinfected by any possible methods. Swimming in dubious reservoirs with stagnant water should be abandoned, especially while on vacation in Asian and African countries.