Infectious diseases transmitted by water. What waterborne diseases are dangerous to human life? Transmission routes inherent in the blood contact mechanism

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 water route of infection. 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 is one of the universal solvents, respectively. a large number of organic and inorganic compounds that enter 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.

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, polio, gastroenteritis, viral 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

relevant natural conditions for distribution and survival in objects environment infectious onset;

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-compliance with basic standards 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 last years in Russia there are only a few "imported" cases of cholera.

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 sufficiently effective against the hepatitis virus, and colibacterial indicators may not reflect the actual contamination by 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.

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.

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. Amoebiasis and balantidiasis develop as acute diseases, turning into a chronic form, accompanied by diarrhea, when protozoa are admitted with drinking water and their introduction 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 Giardia among the population is very high and averages about 15%, and in children's groups with unfavorable hygienic conditions exceeds 30-40%.

Schistosomiasis dermatitis (bather's itch) is ubiquitous. IN Lately in connection with bathing in stagnant and low-flowing reservoirs 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 mollusc. 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 treatment facilities, 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.

Biological objects in natural water can be represented by bacteria, viruses and protozoa. The fact that water can be the cause of mass ("epidemic") diseases has been known since ancient times. Historically, the role of water in the transmission and spread of infectious diseases was known to Hippocrates in the 4th century BC. BC e. The first reliable description of a water infection was made in the 19th century. English scientist Snow. It concerned the cholera epidemic in London in 1854.

The water way of spreading intestinal infections is possible when the following conditions are combined:

· There is a possibility of pathogens entering the water with excretions of patients or bacillus carriers;

· Pathogens retain viability and virulence in water for quite a long time;

It will be possible for contaminated water to enter the human intestines.

In the presence of pathogens of infectious diseases in drinking water, water can serve as a source of their spread and is dangerous in epidemiological terms. Diseases such as cholera, typhoid fever, paratyphoid B, dysentery, tularemia, leptospirosis are transmitted through water. Of lesser but still definite importance is the water way of transmission for such diseases as brucellosis, hepatitis A and E, poliomyelitis.

In addition to the pathogens of cholera, typhoid fever, dysentery, so-called conditionally pathogenic microorganisms can be present in tap water, which can cause diseases under certain conditions. These are Proteus, Klebsiella, Citrobacter, Pseudomonas, Aeromonas, which have many features in common with true Escherichia coli - a recognized indicator of fresh fecal contamination. In addition to the so-called coliform microorganisms, there are other opportunistic pathogens in the water - clostridia, yersinia, fecal streptococcus, parahemolytic vibrio, hafnia. All these microorganisms can cause intestinal dysfunction with diarrhea, which in official medical statistics are classified as acute intestinal infections (AII) of unknown etiology. Every year in Russia, an average of 0.7 million people fall ill with acute intestinal infections, of which about 60% are young children; deaths among sick children reaches 4000 per year.

In recent years, large epidemics of typhoid fever, similar to those that occurred in the 19th and first half of the 20th century, are not recorded, and the remaining low incidence is associated not with water, but with contact transmission. Nevertheless, the epidemiological trouble for typhoid fever persists where there are prerequisites for its spread through drinking water.

The incidence of waterborne dysentery (Flexner's dysentery) remains high.

A relatively “young” (the first epidemic was described in 1943) epidemic disease is viral hepatitis A. A large number of cases of this disease occur when this pathogen is transmitted by water.

In recent years, among the infectious morbidity associated with the water factor, the proportion of escherichiosis, deseterium-like diseases caused by pathogenic strains of E. coli, has increased.

Table 1. The incidence of AII

Pathogenic organisms have a number of properties that distinguish them from chemical pollutants:

· Pathogenic organisms are presented as discrete organisms, and are not in the form of a solution;

· Pathogenic organisms often agglomerate or adsorb to suspended solids in the water, so that the infective dose obtained cannot be accurately calculated from their average concentration in the water;

· The likelihood of being exposed to a pathogen depends on the degree of its invasiveness and virulence, as well as on the immunity of the individual exposed to the pathogen.

2.1 Entry of pathogenic microorganisms into water and their survival in the aquatic environment

At the same time, unpolluted rivers, lakes and reservoirs, in which normal flora and fauna develop, not only do not represent a favorable environment for the development of pathogenic pathogenic bacteria, but, on the contrary, are a powerful barrier preventing their spread. There are many factors that have a negative impact on the vital activity of pathogenic microbes.

Finally, in reservoirs and watercourses (especially when contaminated with a significant amount of fecal sewage), a large number of microbes develop that are antagonists against pathogenic bacteria. Antagonist microbes secrete various antibiotic substances into the water, as a result of which the life span of pathogenic bacteria in the water is significantly reduced.

Pathogenic microbes remain the longest in sterile water, where foreign microflora is completely absent. Thus, the antagonistic relationship between saprophyte microbes and pathogenic bacteria is explained by a seemingly paradoxical fact - the purer the water, the longer pathogenic microbes remain in it.

Thus, the most effective and powerful factor leading to the death of pathogens of infectious diseases in natural waters is the biological population of reservoirs and watercourses, which, in the course of their life activity and the established relationships of a symbiotic and antagonistic nature, leads to the disappearance of pathogenic microorganisms that have entered the natural water.

Pathogens of diseases enter the water of open reservoirs with wastewater from populated areas and individual facilities, mainly hospitals. The causative agents of tularemia, leptospirosis, brucellosis enter the water with the secretions of rodents and cattle, as well as with the corpses of dead rodents. Microorganisms that are the causative agents of water infections remain viable in water for a sufficiently long time. In this regard, in cases where untreated river water is used for drinking purposes or there are violations in the treatment of water in water pipes, as well as when contaminated well water is used, water mass outbreaks of gastrointestinal diseases can occur. There are also cases when the cause of the outbreak of intestinal diseases was the contamination of water in the water supply network.

Table 2. Survival of microorganisms in water

The largest number of pathogenic microorganisms entering water bodies is found in polysaprobic zones, then they gradually die off in mesosaprobic zones and are practically not found in oligosaprobic zones.



How can you get infected through water

You can get infected:

However, you should not completely refuse to swim in a proven river or lake on a hot day. Even if you take a sip of water, it is not at all necessary that you get sick. First, the water is most likely clean. And secondly, the probability of infection depends on the body's resistance. If the immune system is not weakened, it will easily cope with the infection.

Most often, through contaminated water, you can get an intestinal infection. The causative agents of these diseases are bacteria, more precisely enterobacteria.

Escherichia coli. Pathogenic strains of this bacterium, once in the intestine, secrete enterotoxins, which lead to intoxication and diarrhea, abdominal pain. E. coli is especially dangerous for young children.

E. coli can live in water for several weeks. It is destroyed by boiling water.

Typhoid, paratyphoid, salmonellosis. These infectious diseases are caused by various types of Salmonella. Bacteria infect the small intestine, causing intestinal disorders with severe intoxication, high temperature, rash, clouding of consciousness.

Salmonella can live in river water for about six months, do not die when freezing or drying out. They can be destroyed by boiling or chlorinating water.

Dysentery. " The culprit" of this intestinal infection is the Shigella bacterium. Dysentery bacteria take up residence in the colon and secrete toxins that corrode the intestinal mucosa into bleeding ulcers. That is why dysentery is characterized by bloody diarrhea and acute pain in the abdomen. In fresh water, shigella can live for 3 months. When boiling water, it dies instantly.

The symptoms of dysentery are similar to amoebic dysentery - also a "water" infection, common in the tropics and subtropics. It's called an amoeba Entamoeba hisiolytica.

Cholera. Although this severe infection is no longer as common as in past centuries, nevertheless, epidemic outbreaks still occur today, however, in the poorest countries of Africa, Southeast Asia, and Central America. The causative agent is Vibrio cholerae. It affects the small intestine and causes vomiting and diarrhea. The main danger in cholera is dehydration: the patient loses up to 40 liters of fluid per day, which is a mortal threat.

Vibrio cholerae can exist in river water for up to 3 months, and in sea water even longer. You can destroy the infection by chlorination or acidification of water, as well as heating to 60 degrees.

Leptospirosis

This is a typical "water" infectious disease. The causative agent is Leptospira spirochete. It enters the water mainly with rat droppings. You can get infected both by drinking water with leptospira, and swimming in a "dirty" reservoir.

Leptospirosis can occur in two forms - icteric and anicteric. Both are manifested by high fever, headache, muscle pain. In the icteric form, the liver and kidneys suffer, yellowing of the skin, whites of the eyes, mucous membranes is observed, bleeding occurs: from the nose and intestinal. The disease is deadly: according to WHO, 35% of patients die.

Leptospira are very tenacious: in the river they can live up to 5 months, they are not afraid of freezing. They die during chlorination and acidification of water, an increase in temperature to 30 degrees, they cannot stand sunlight.

poisoning

Water is a good solvent, so toxic chemical compounds that get into the reservoir or into the soil in the water intake area and dissolve in it can cause poisoning.

The most toxic substances are mercury compounds. With the constant drinking of water containing salts of mercury in concentrations above the maximum allowable, chronic poisoning occurs - mercuryism. With a sufficiently long course of the disease without treatment, severe headaches, hallucinations, and depression develop.

Constant drinking of water containing hazardous concentrations cadmium, causes chronic intoxication and the development of itai-itai disease, accompanied by pain in the bones and joints, pathological fractures, and renal failure.

chronic poisoning lead- saturnism - can also occur with prolonged use of water with compounds of this metal. The consequences are very severe - all organs are affected, a fatal outcome is possible.

Viral infections

Viruses are usually transmitted by airborne droplets, but some infections can also be transmitted through water. These are adenovirus, hepatitis A virus, poliovirus (poliomyelitis), Coxsackie virus.

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 number of microbes can seep, this can also lead to poisoning and infection.

IN summer time recreation near water bodies, especially urban ones - rivers, lakes, reservoirs is popular. 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's why people don't want to take risks and don't 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.

Water-borne diseases cause significant damage to health, so you should be careful water procedures, do not visit polluted water bodies, 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.