Blood for typhoid fever for the sanitary book. Serological testing for typhoid fever

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Typhoid fever is considered an infectious disease from the category of anthroponoses with a characteristic fecal-oral route of infection. Although in our time the number of cases of typhoid fever in humans has significantly decreased, to completely solve this problem so far failed.

Especially often people get sick in countries with unfavorable environmental conditions. In any case, the symptoms and treatment of typhoid fever are considered the prerogative of the doctor, since the pathology has a very complex course.

Typhoid fever - what is it?

Typhoid fever is an acute intestinal infection with a cyclical course. With the development of pathology, damage is observed lymphatic system intestines, intoxication of the body and exanthema.

Infection with typhoid fever occurs through the alimentary route. Wherein incubation period lasts approximately 2 weeks. As the disease progresses, skin rashes, intoxication syndrome, and fever appear. In special situations, people experience hallucinations and inhibition of reactions.

Pathogen and transmission routes

The development of typhoid fever is the result of infection with the bacterium Salmonella enterica. It is a mobile gram-positive rod with large quantity flagella. This microorganism remains viable in the environment for several months and tolerates freezing well, but dies as a result of the action of chemical disinfectants and boiling.

A sick person becomes a source of infection with typhoid fever. By the end of the incubation period of typhoid fever, the pathogen begins to be released into environment, and this continues throughout the entire period of the disease. Sometimes the process is observed even after the elimination of symptoms. With the development of chronic carriage, the patient becomes a source of bacteria for life.

Selection pathogenic microorganisms It is carried out with feces and urine, while they usually enter the body with water or food. Infection occurs when drinking water contaminated with feces, or untreated food.

• Flies often carry the bacteria. That is why the peak incidence is observed in summer and autumn.

The incubation period lasts on average 10-14 days, but sometimes this interval is 3-25 days. As a rule, the pathology develops gradually, but sometimes it is possible acute course. With the smooth progression of the disease, a slow increase in temperature is observed and the indicator reaches high values about 4-6 days.

• There are symptoms of intoxication of the body - weakness, insomnia, loss of appetite, headache, muscle discomfort.

The feverish period lasts about 2-3 weeks, and significant temperature changes are often observed during the day. One of the first symptoms of typhoid fever in humans is dryness and blanching of the skin.

The rash occurs approximately on the 8-9th day of the disease - small red spots appear on the skin, not exceeding 3 mm in diameter, when pressed, they turn pale for a while. The rash is present for 3-5 days. If the disease has a complex course, the spots become hemorrhagic in nature.

During the physical examination, the doctor visualizes the thickening of the tongue and the appearance on it white plaque. Palpation of the abdomen allows you to establish swelling resulting from intestinal paresis. On the 5th-7th day of the disease, the size of the spleen and liver sometimes increases.

At the beginning of the development of the disease, a cough often occurs. At the peak of the disease, relative bradycardia appears, accompanied by severe fever. In this case, the pulse rate does not correspond to body temperature. Heart sounds become muffled, arterial pressure decreases.

At the height of the disease, there is a pronounced progression of symptoms and severe intoxication. Toxic defeat nervous system manifests itself in the form of hallucinations, inhibition of reactions.

When the temperature drops, the patient's condition improves markedly. AT individual cases after regression of symptoms, fever and intoxication develop, and exanthema appears. In this case, the typhoid infection is exacerbated.

Testing for typhoid fever

It is not possible to diagnose typhoid fever during the incubation period. On the initial stage development of the disease, the following activities are carried out:

1. Serological analysis - in this case, the patient's serum is used to carry out the agglutination reaction.
2. Bacteriological method - consists in performing tests of urine, feces and blood. Through their implementation, it is possible to draw the appropriate conclusions.

A timely examination for typhoid fever allows you to choose effective treatment and cope with this disease.

Treatment of typhoid fever, drugs and diet

Treatment of typhoid fever is carried out in a hospital, the patient must be kept in bed until the temperature drops. Usually, from the 8th day after a decrease in this indicator, it is allowed to sit, and on the 11th day - to move around.

A partially ill person is transferred to parenteral nutrition. This avoids perforation of the intestinal wall. Food should be as gentle as possible from a mechanical and chemical point of view, but rather high-calorie foods are recommended.

Be sure to exclude dishes that provoke an increase in intestinal peristalsis. These include black bread, beans, cabbage. The basis of the diet is eggs, boiled meat, dairy products. It is also useful to eat fruits and vegetables, but they are best consumed in chopped form.

Etiotropic treatment is aimed at combating the causative agent of typhoid fever. Antibacterial drugs are used to help cope with the Salmonella enterica bacterium - levomycetin, ampicillin, amoxicillin, etc.

Equally important is the use of immunomodulating agents. Such drugs speed up the process of therapy, making it more effective.

• For general strengthening organisms use probiotics, prebiotics and symbiotics. Often, doctors prescribe a complex immunoglobulin preparation and vitamins.

Prevention

To prevent the development of typhoid fever, it is recommended to observe the following precautions:

1. Adhere to the rules of hygiene, carefully process food, control the quality of drinking water.
2. Make for the condition of people who have had symptoms of the disease.
3. After contact with the patient, it is important to monitor your condition for at least 21 days.
4. Disinfection of areas where pathogenic microorganisms spread.

The typhoid vaccine protects against this dangerous disease. For vaccination, a special sorbed antityphoid injection is performed.

Typhoid fever is considered very serious illness capable of provoking fatal outcome. To prevent this, it is very important to engage in the prevention of the disease. If his symptoms still appear, you should immediately consult a doctor for a detailed examination.

Required for accurate identification pathogen, it is desirable to undergo diagnostics before the start antibiotic therapy. The disease is dangerous and the carrier of the pathogen not only endangers his own health, but also becomes a source of infection for others. Therefore, at the first suspicion of a pathology, an urgent appeal to the clinic is necessary.

When are tests for typhoid fever ordered?

The infection develops as a result of the active activity of salmonella. However, the signs are not specific, often observed in other diseases of the gastrointestinal tract:

1. Emptying disorder. Both constipation and severe diarrhea are possible.
2. Bleeding of the gastrointestinal tract. There is blood in the stool.
3. Nausea and vomiting.
4. Insomnia, apathy, weakness, loss of appetite.
5. Strong thirst.
6. Skin rash.
7. The temperature rises up to 40 degrees.
8. Soreness in the abdomen and right hypochondrium.
9. The tongue is coated with a gray tint, but the tip is still red.

In severe condition clinical picture includes delirium and disorientation in space.

The Russian Federation provides for a mandatory annual examination for typhoid fever for workers in the food industry, hospitals, and children's institutions. It is advisable to undergo diagnostics for tourists who have returned from exotic countries where pathology is common.

It is easy to isolate the pathogen in the first 2 days. Therefore, you need to go to the hospital at the initial signs.

Where can I take biomaterial for analysis?

Today, research is carried out in municipal and private laboratories, as it is necessary for issuing a sanitary book. Naturally, in a paid clinic, you will have to pay a small amount for a certificate. But you can get results much faster.

The cost of a blood test for typhoid fever

According to statistics:

1. Serological diagnosis will require 600-800 rubles.
2. A general blood test will cost 300-400 rubles.
3. Bacteriological culture in 700–900 r.
4. Biochemistry at 300–400.
5. ELISA and RIF on average 500–800 r.

Of course, a decent amount is obtained, but for an accurate diagnosis, a comparison of several types of studies is necessary. Deciphering the results helps not only to identify the pathogen, but also to determine the therapy program.

In the municipal clinic, most of the work on the study of blood, urine or feces samples is performed free of charge.

Types of analyzes

Basically, they prefer to take biological materials for study. If typhoid fever is suspected, use various ways laboratory diagnostics.

General blood analysis

The method is applied in the first place, but does not give a full guarantee. Indirect indicators are taken into account - an overestimated ESR, a decrease in the concentration of leukocytes, an increase in the level of lymphocytes, and the absence of eosinophils. The results help to establish the presence of an infection, an inflammatory process.

To examine a patient in vitro, in laboratory conditions, it is enough to take a sample from a finger or a venous vessel.

Should be done before antibiotic therapy. It takes 5-10 ml to detect proteins in the acute phase, which are produced by the body in typhoid fever.

Serological blood test

You need to take a sample from the capillary. The period is 4–5 days from the moment of infection, when antigens of the type O, Vi and H, characteristic of salmonella, are present in the plasma. The study is repeated on the 8–10th day of the patient's stay in the inpatient department.

RIHA (reaction of indirect hemagglutination)

The RPG method for typhoid fever helps to detect antibodies and antigens based on the rate of erythrocyte precipitation. The sampling is done on an empty stomach, as with other methods of examination. It is necessary to refrain from food for 8 hours. The material is taken from the cubital vein.

A positive result is diagnosed with minimal indicators - for O titer 1:200, for Vi 1:80.

RPHA (passive hemagglutination reaction)

The main direction is the search for antibodies present in the serum. This analysis blood for typhoid fever is carried out by the end of 2 weeks of illness and repeated after 5 days. At acute form pathology, an increase in titers is noted.

The sample is taken from the cubital vessel, on an empty stomach. A positive result corresponds to a reading of 1:40 for Vi antibodies and 1:200 for O.

Bacterial culture

There is not enough Salmonella in the blood, so the tissue taken for analysis is placed in a nutrient broth and cleaned in a thermostat. Reproducing, the microorganism forms colonies. Laboratory research allows you to determine the type of bacteria.

The result is ready for 4-5 days. Of all the methods, bacterial culture is the most accurate. Helps identify antibiotics that are effective for typhoid fever. Blood, urine are suitable for work, if about a week has passed since the infection, feces can be used.

Immune fluorescence reaction (RIF)

A quick way to identify pathology in the initial development. Antibodies pre-labeled with specific substances are introduced into the biomaterial. In the presence of antigens, microscopic examination of the sample reveals a characteristic glow.

Enzyme immunoassay (ELISA)

A highly sensitive method that detects the presence of antibodies and antigens, helping to clarify their concentration. It is important both for diagnosis and for monitoring the dynamics in the patient's condition.

Bacteriological examination of feces (coproculture)

Most often, a patient takes blood for typhoid fever. But after 1–1.5 weeks, the pathogen is present in the feces. It is used to identify infected, but not sick.

Bacteriological examination of urine (urine culture)

8–10 days after infection, the pathogen can be detected in urine. At the same time, leukocytosis is noted - an increase in the concentration of white cells in the initial stage of the disease and a sharp drop in the rate after a week.

For the reliability of the analysis, careful preparation is needed: it is necessary to stock up on a sterile container and rinse the external genitalia. It is enough to collect only 40-50 ml of liquid.

Bacteriological study of bile (biliculture)

The analysis is used if about 2 weeks have passed since the onset of infection. By this time, salmonella has disappeared from the blood serum, but spreads to other fluids.

Sometimes a bone marrow puncture is taken for research. The technique is complex, but reliable, since the presence of pathogens of other pathologies is excluded.

How are tests done?

In order for the diagnosis to be as accurate as possible, it is necessary to prepare in advance for the collection of tissue samples:

1. For 72 hours, it is advisable not to take any pharmacological agents especially antibiotics. Otherwise, it is necessary to inform the doctor about the type of drug, time of administration, dosage.
2. It is optimal to donate blood in the morning from 8 to 11.
3. In the evening they refuse dinner. The day before the analysis, stop drinking alcohol, fried, fatty, hot spices, dairy products and eggs.
4. Do not smoke for several hours before sampling.

It is better to refrain from physical exertion, to be less nervous, since even these factors can affect the biochemical composition of the material.

How to read test results?

With typhoid fever, there is an overestimated content of leukocytes in the first 2 days and a decrease in the level in the future. At the same time observed:

1. An increase in the concentration of lymphocytes.
2. Increase in platelets.
3. High ESR.

After a serological analysis, a certificate is issued in which the verdict is affixed. When "positive" is the number of antibodies.

Does a “negative” result on a form always indicate the absence of the disease?

Optional means that the person does not have the pathogen. Characteristic protein compounds sometimes appear in the blood later, therefore, when the patient enters the hospital, they are not detected at first. Then conduct an additional examination after a few days.

The absence of antibodies often indicates that the patient was sick, but managed to recover.

What does the result of the analysis say "positive"?

This verdict means 2 options:

1. The disease is in the acute phase.
2. Presence of inactive salmonella.

Carriers of the pathogen are 3-4% of people who have had typhoid fever. There are risks of infecting others.

Which doctor should I contact?

With severe symptoms, it is necessary to ensure the rapid admission of the patient to the hospital. But sometimes a person visits a medical facility on his own, complaining of signs of poisoning. In this case, it is better to go to an appointment with an infectious disease specialist, but even an experienced therapist will suspect the clinical picture of typhoid fever.

Conclusion

The disease is easily transmitted through personal contact, with food and household items. To protect yourself and loved ones, it is advisable to perform all recommended tests at the first symptoms.

Laboratory diagnosis of typhoid fever includes general clinical methods studies and specific reactions. As a result comprehensive survey the specialist will be able to draw a conclusion about the severity of the disease, the properties of the pathogen (including sensitivity to antibiotics), the degree of danger of the patient to others (his contagiousness). All necessary studies are carried out at the beginning of the disease (when the patient enters the hospital) and before discharge. If necessary, the analysis for typhoid fever is repeated several times.

Is the child often sick?

your child constantly sick?
A week in kindergarten (school), two weeks at home on sick leave?

Many factors are to blame for this. From bad ecology, to weakening of immunity with ANTIVIRAL DRUGS!
Yes, yes, you heard right! By stuffing your child with powerful synthetic drugs, you sometimes do more harm to a small organism.

In order to radically change the situation, it is necessary not to destroy the immune system, but to HELP IT ...

There is one more important nuance: differential diagnosis typhoid fever and paratyphoid fever is possible only on the basis of a specific laboratory examination. Neither clinical details nor general clinical diagnostic methods can distinguish the causative agent of typhoid fever from the causative agents of paratyphoid A, C or B. This information can be of significant importance in terms of possible infection surrounding, as well as the formation of only type-specific immunity.

General characteristics of research

Where to take the test to diagnose typhoid fever? This question should not disturb the patient, since modern medical protocols imply mandatory hospitalization of patients with such a preliminary diagnosis. In large medical institutions (or within the same city) there is a multidisciplinary laboratory, whose employees will be able to do all the necessary specific and non-specific studies for the full diagnosis of typhoid fever and paratyphoid fever.

There is no universal answer to the question of how many days the patient will know the exact diagnosis. For non-specific studies, only one day is required, the result of specific reactions will come only for 4-5 days or even more.

Identification of the causative agent of typhoid fever and paratyphoid fever is the main direction of a comprehensive examination of not only the patient, but potential carriers (healthy people who excrete the pathogen and infect others). The results of such an examination are entered in the sanitary (medical) book of a person (declared specialized group) working in the food industry, in children's institutions and some other enterprises.

For various diagnostic tests, the patient (carrier) takes the following biological fluids:

• blood;
• fecal masses;
• urine;
• bile.

The need to take a particular biological environment of the patient is determined by the attending doctor. On the other hand, you need to act quickly enough, as prescribed antibiotics reduce the effectiveness microbiological diagnostics typhoid - body fluids should be taken before starting treatment.

General clinical methods

Standard procedures, such as a general clinical analysis of blood and urine, in this case really have diagnostic value, since the identified changes are very characteristic.

In a general blood test for typhoid-paratyphoid diseases, the following are detected:

• leukocytosis in the first 1-2 days, which is replaced by leukopenia;
• uncharacteristic for a bacterial infection lymphocytosis, thrombocytopenia, aneosinophilia;
• in severe cases, pancytopenia (depression of the function of all blood sprouts) can be observed;
• the detection of eosinophils during the recovery period of the patient is a prognostically favorable sign in the course of the disease.

Why is my child's immune system weakened?

Many people are familiar with these situations:

• As soon as the season of colds begins - your child is bound to get sick and then the whole family...
• It seems that you are buying expensive drugs, but they only work while you are drinking them, and after a week or two baby gets sick again...
• Are you worried that your child's immune system is weak very often disease takes precedence over health ...
• Afraid of every sneeze or cough...

  It is necessary to strengthen YOUR CHILD'S IMMUNITY!

In the general clinical analysis of urine, traditional changes are detected (increased levels of leukocytes, erythrocytes), typical of severe intoxication.

When conducting a general clinical study of feces (coprogram), erythrocytes can be detected, which indicates the presence of minor intestinal bleeding. Along with the coprogram, it is customary to prescribe another study of feces for occult blood, in order to exclude diagnostic error and timely diagnosis of bleeding.

In the case of typhoid and paratyphoid diseases, biochemical parameters are examined only in order to identify pronounced dysfunctions. internal organs, for example, with the development of specific hepatitis or pyelonephritis.

Specific Methods

Microbiological diagnosis of typhoid fever is the basis for the final diagnosis and further anti-epidemic actions. On examination special groups of the population (decreated group), a mark on a negative result of a blood test for typhoid fever for a sanitary book is admission to the workplace. Specific Analysis for typhoid fever includes bacteriological and serological studies.

Bacteriological method

It involves the taking of biological material from the patient and subsequent sowing on special nutrient media (most often - bile broth). The study of morphological, biochemical and many other properties of a microorganism makes it possible to identify it with 100% accuracy. In addition, modern microbiology provides for such mandatory step as antibiotic sensitivity, without which the process of effective antimicrobial therapy is significantly hampered.

It is better to donate blood for typhoid fever in the first week of illness. A positive blood test for typhoid fever, that is, a positive blood culture, is an absolute confirmation of the diagnosis. Detection of typhoid salmonella in urine and feces can be observed to the same extent in a sick person and a carrier, that is, other additional studies are required.

Serological method

The basis of many reactions that implement the serological method of research is the combination of a known antigen (typhoid) and antibodies that are synthesized in the patient's blood. Serological diagnosis of typhoid fever is the Vidal test, the reaction indirect hemagglutination(RNGA), if necessary - reaction with Vi - antigen.

Vidal reaction- this is a modification of the agglutination reaction, the diagnostic value lies in the increase in antibody titer as the disease progresses. This reaction may be false-positive in other salmonellosis, so another typhoid serodiagnosis is required. For example, RNGA with different antigens is more specific. Some laboratories are RPGA- reaction of passive agglutination of antibodies by known antigens.

If typhoid fever is suspected, specific diagnostics can confirm or refute the diagnosis of this infectious disease, and also, possibly, find out where this infection came from.

It might be interesting:

If a child is constantly sick, his immunity DOES NOT WORK!

The human immune system is designed to resist viruses and bacteria. In babies, it is still not fully formed and does not work to its full potential. And then parents "finish off" immunity antiviral agents accustoming him to a relaxed state. The poor ecology and the wide distribution of different strains of the influenza virus make their contribution. Must be tempered and pumped immune system And you need to do it IMMEDIATELY!

How are tests for typhoid fever performed? What are they? Typhoid fever is classified as an acute intestinal infection, but it stands apart. Usually with intestinal infections students begin to study the course of infectious diseases, and the first of them is usually typhoid fever and paratyphoid A and B, the causative agents of which form a typhoid paratyphoid group.

Why does this complex course begin with typhoid fever? Yes, because this disease develops in well-defined stages, proceeds predictably, tests for typhoid fever and the principles of diagnosis are standard and uncomplicated, and using the example of typhoid fever, you can fully to get acquainted with the typical course of acute intestinal infection.

About typhoid fever

Where does typhoid fever come from? It is a disease of "dirty hands" and contaminated water. The causative agent of typhoid fever is a large microorganism Salmonella from the genus Enterobacteriaceae, and the causative agent of typhus is extremely small rickettsiae.

Usually, when people talk about typhus, the harsh years come to mind. civil war. But then there were epidemics mainly of typhus. And today every year more than 20 million people, or the population of two cities like Moscow, become infected with typhus. Nearly 900,000 of them die every year. Such outbreaks occur in hot African countries, India, Colombia and Malaysia, Indonesia and Afghanistan. Therefore, a great danger lies in wait for those travelers who underestimate the likelihood of infection.

It is very easy to catch typhoid fever, and the severity of this disease lies, first of all, in the fact that it begins as a slight malaise with normal food poisoning. Such features of this infection have led to the fact that all the so-called decreed persons working in the food industry, in educational institutions and medical organizations, should be tested annually for typhoid fever and checked for carriage of typhoid bacilli. The same examination must be carried out by persons working in the food trade.

Features of the course of infection

Typhoid fever occurs with a gradually increasing high temperature, the appearance of abdominal pain, general symptoms of intoxication, characteristic of all infections. A feature of typhoid fever is the multiplication of pathogens that have penetrated the intestinal wall into the organs of the immune defense of the intestine - into the lymphatic follicles, into the liver, into the cells of the immune defense. In these follicles, pathogens multiply, and then they penetrate the blood through the thoracic lymphatic duct and this coincides with the beginning acute period diseases. The danger characteristic of typhoid fever is intestinal bleeding, intestinal perforation, or necrosis of lymphatic follicles.

At the same time, typhoid fever is a unique disease that requires an abdominal operating room in an infectious diseases hospital. The fact is that a patient diagnosed with typhoid fever and with intestinal bleeding, in no case should you be hospitalized in the general surgical department, since it is very contagious. Therefore, a special operating room is equipped in the infectious diseases hospital for such a case, and, if necessary, surgeons are called in to perform an emergency operation.

Typhoid is transmitted only by humans, it is impossible to catch typhoid from animals. You can get sick, I communicate not only with the sick, but also with a healthy carrier. One of the most famous figures in history is the so-called Typhoid Mary. Clinically healthy, she worked as a cook in the early 20th century in the United States and, as a result of her food work, a total of about 47 people died, whom she personally infected. Typhoid pathogens multiplied in her gallbladder and released into the environment along with faeces. The situation was aggravated by the fact that she refused to be examined and denied the preventive value of handwashing.

But a huge number of victims, which regularly and still appear in countries with a hot climate and a low standard of living, are associated with the use of food products and, above all, with infected water and milk, which are contaminated with faeces and sewage in the absence of centralized sewerage.

The outcome of typhoid fever can be both recovery and transformation of the patient into a chronic carrier. No more than 5% of all recovered patients become chronic carriers, and this causes a certain epidemiological danger.

Types of tests for typhoid fever

The most important thing to remember is that a 100% positive result is only the isolation of typhoid bacilli from the patient's blood at the height of the disease, when salmonella overcome the protective barriers of the intestinal lymphatic follicles and a state of bacteremia occurs. Starting from the second week of illness, it becomes possible to determine typhoid bacilli in the feces. Of course, the probability of detecting microorganisms depends on antibiotic treatment and on the initial concentration of microbes in the biological material.

By the end of the first week after the disease, typhoid fever can already be determined by examining the patient's blood for antibodies that develop to salmonella antigens of the causative agent of typhoid fever. These are the ones that are carried out in blood serum tests. The specificity of these tests is lower because they do not directly detect the pathogen. There may also be false positive tests for typhoid if the patient has previously had this disease.

It should be borne in mind that there are many salmonella pathogens for humans. There may be a cross-reaction after salmonellosis, as with some shigellosis or bacillary dysentery. Therefore, in the serological diagnosis of typhoid fever, as in the case of almost all bacterial infections, it is very important to repeat the blood test for typhoid fever in about a week in order to detect an increase in titer, that is, a sharp increase in the number of antibodies. This is what will be characterized by an acute infectious process and then the diagnosis will be confirmed.

Looking ahead, it must be said that it is never used to confirm the diagnosis of typhoid fever. He can show general symptoms acute infectious process: the presence of increased leukocytosis, an increase in the erythrocyte sedimentation rate, and with severe course and the development of infectious-toxic shock, leukopenia and other signs of toxic inhibition of the function of the red bone marrow may occur. But for diagnosis general analysis clearly not enough blood. We list the main methods of laboratory research by which typhus is diagnosed in patients and in clinically healthy carriers:

• Method for isolating blood culture ( bacteriological examination blood).

Hemoculture allows you to get positive results in the first days of the disease. This is a lengthy but inexpensive method. The causative agents of typhoid fever ripen well on media containing bile broth. If we combine a bacteriological study with an immunofluorescent method (RIF), then a culture of the causative agent of typhoid grown within 12 hours can already be preliminarily identified, but then it is imperative to wait for confirmation in the classical way. Usually, blood should be taken in an amount of no more than 20 ml.

Despite the emergence of new diagnostic methods, such as, the method of isolating blood culture has not lost its practical significance. It is not enough for a doctor to know that the causative agent of typhoid fever is in the patient's blood. He needs to know which antibiotics can be used to quickly get rid of an aggressive microorganism. Typhoid bacilli, like any other microbes, are constantly “improved” and acquire drug resistance to various antibiotics. The isolated pure culture makes it possible to determine the sensitivity of the pathogen to antibacterial drugs. This allows, after receiving a preliminary analysis, to begin targeted treatment, to change empirical therapy to a rational one, which, of course, will speed up the patient's recovery.

• Bacteriological examination of duodenal contents, feces and urine.

These tests are extremely important, as they allow you to identify healthy carriers from among those who have been ill before. Therefore, before discharge from the hospital, the patient must pass feces and urine for bacteriological examination, and if the cultures are negative, then the patient is discharged. How is bile taken? In the same way, on average, 7 days before the planned discharge from the hospital, the patient undergoes a diagnostic duodenal sounding. In portions of cystic bile, a search for pathogens is carried out, for which bile is also sown on nutrient media. The so-called typhoid Mary had typhoid pathogens in her gallbladder for life, which multiplied and posed a threat to others.

3 months after discharge from infectious hospital a bacteriological examination of feces, urine and bile is again carried out, since all those who have been ill are under dispensary registration with an infectious disease specialist. If at least one test for typhoid fever after discharge showed the presence of a pathogen, then the patient is hospitalized according to sanitary and epidemiological indications and treated as a carrier. And only in the event that all the results of the crops were negative, the patient is removed from the register. In the same case, if the patient works in the food industry, in educational or medical institutions, then he is under special supervision throughout his working life, regularly donating feces for a disgroup and for typhus;

Since serological methods of research associated with the detection of antibodies can show their presence in long-term patients, it is necessary to repeat them after a few days when acute illness. Enzyme immunoassay is indicated for severe gastroenteritis with an unclear course, in the presence of fever, which is combined with diarrhea and bradycardia. Slow heart rate (bradycardia) is very characteristic symptom typhoid fever caused by the action of antigens and toxins of this pathogen. ELISA is also used to track the dynamics acute process, in patients during dispensary observation, after the disease, as well as for the initial detection of carriers of infection;

• Vidal reaction.

Long years of classical serological reaction, which is included in all textbooks, is the Vidal reaction. How to take this analysis? Simply by donating venous blood, which is then centrifuged to obtain blood serum. The Vidal reaction is a study of the patient's blood serum, which contains antibodies, with a special typhoid diagnosticum. Its role is played by standardized sheep erythrocytes, on which antigens of typhoid pathogens are artificially applied, or, speaking scientific language, sensitization of these erythrocytes is carried out.

After mixing the components, the mixture is incubated for 2 hours at body temperature, and when diagnostic erythrocytes are bound by antibodies, a precipitate appears in the form of whitish flakes, then the reaction is considered positive. The disadvantages of this reaction are obvious: it uses biological material, it is necessary to carefully observe the temperature conditions, as well as certain quantities in order to exclude false positive values. Currently, the Vidal reaction will be supplanted by enzyme immunoassay methods for which it is not necessary to use ram erythrocytes.

Interpretation of results

The most common blood test for typhoid fever is healthy people who get a job in various food production or receive a sanitary book to work as a food seller. If the result is negative, then most likely the person is healthy and has never been sick.

But in the event that the patient is taken to the hospital with diarrhea, with intoxication and with an unclear picture, then in the first four or five days of typhoid fever, he may also have negative results, because the antibodies simply have not had time to work out.

If typhoid antibodies are detected in the patient's blood, then the titer must be indicated as a result of the analysis. When positive analysis There are only four possible scenarios for the development of events: these are:

• acute illness;
• a long-term infection, when circulating antibodies remain for life;
• chronic carriage;
• occasionally there are false positives cross reactions, after suffering salmonellosis, for example.

Therefore, patients positive results serological diagnosis must be examined in the classical way. How much research is being done in this case? This is a bacteriological method for examining urine and feces and the contents of the gallbladder. Hemoculture, like an analysis for typhoid fever, is taken almost exclusively in the presence of signs of the disease.

Diagnosis of typhoid fever is difficult due to the difficult differentiation of the disease from similar symptoms. intestinal disorders, tuberculosis or cholera. Tests for the presence of typhoid fever and other studies are usually prescribed at the stage of fixing a constant febrile (38-39 0 C) temperature and stable characteristic signs. In addition to determining the diagnosis of illness, an analysis for typhoid fever is mandatory for delivery to catering workers, employees of children's and medical institutions, representatives of the sphere of hotel or sanatorium services.

Causes and symptoms of typhoid fever

The causative agent of an infectious disease, the bacterium Salmonella typhi, enters the human body through objects of common use - for example, toys in kindergarten or personal care items, poorly processed dairy products, dirty water. At whatever age the infection occurs, once ill, a person acquires a stable immunity to re-infection.

According to statistics, the threat of Salmonella bacteria penetration is highest in younger schoolchildren, but this does not exclude the fact that older people are carrying the causative agent of typhoid or the disease in an acute form.

An analysis for typhoid fever is given in the presence of all the characteristic signs of the following (with the exception of a rash, which does not occur in all cases of infection):

• constant thirst with a constant feeling of tightness, dry mouth, blanching and peeling of the skin of the face and body, swelling and covering with a whitish coating of the tongue;
• acute recurrent abdominal pain;
• symptoms of intoxication - vomiting, rolling nausea, poor appetite, loss of strength, sweating;
• difficulty in defecation or diarrhea;
• the occurrence of a rash such as roseola, which become faint when pressed.

Symptoms are characterized by a gradual increase, but in a third of all cases, an acute onset of the disease is possible, with the presence of several signs at the same time and, necessarily, a temperature in the range of 38-39 0 C. If the course of the disease is standard, then it will follow this algorithm:

• sudden weakness, poor sleep, problems with stools;
• headaches, increased general malaise, fever;
• the temperature within 3-5 days reaches indicative values ​​up to 39 0 and stops at this mark;
• appear severe pain in the abdomen, gas formation, a person’s reaction to external stimuli are dulled, his condition can be called “inhibited”. In the same period, the appearance of roseola is possible.

Since the onset of symptoms of infection occurs no earlier than the seventh day from the entry of typhoid bacillus into the intestine, determine the origin infectious agent almost impossible.

Types of tests for typhoid fever

Even before receiving the results of laboratory tests, the clinical picture of the totality of symptoms allows the doctor to diagnose typhoid fever and begin treatment of the patient in isolation from patients of other groups of diseases. Despite the fact that the diagnosis is based on a comprehensive study of blood, if typhoid is suspected, other samples will be needed - for example, urine, bile, feces.

• can't be accepted medicines within three days before the delivery of the material;
• no alcoholic beverages should be consumed 24 hours prior to sampling;
• 2-4 hours before the tests, you can not smoke, physically overstrain and refrain from worries and negative emotions;
• all samples are taken in the morning, on an empty stomach of the patient;
• on the eve of the delivery of biological material, you can not eat: eggs, dairy and sour-milk products, smoked meats, pork, lamb, spicy and salty dishes.

All types additional surveys, which can cause discomfort or require separate preparation, should be done after taking laboratory tests.

General blood analysis

A clinical blood test helps to determine the change in the main indicators of the state of the body as a whole. The leading values ​​that indicate the activity of the causative agent of typhoid in the body are the distortion (compared with the norm) of the following data:

• decrease in the level of leukocytes;
• absence of eosinophils in the blood;
• lymphocytosis of relative parameters, which indicates a low immune response;
• high erythrocyte sedimentation rate ESR indicators);
• critically high values ​​of neutrophils;
• low criteria for the presence of platelets.

Blood sampling for research is carried out from the patient's vein immediately upon admission to the infectious diseases department of the hospital. Subsequently, blood will be taken several more times throughout medical process and before release.

Blood chemistry

A biochemical blood test is also taken from a vein before starting antibacterial treatment. The results of the study obtained within 24 hours determine the presence of acute phase proteins synthesized in the liver as a response to an infectious lesion.

Serological blood test

For serological studies, plasma is isolated from the blood of a sick person, where the presence of characteristic antibodies is of decisive importance.

An analysis taken no earlier than the fifth day from the moment the typhoid bacillus enters the intestine is considered effective, since it is this period that the body needs to produce antibodies to the infectious agent.

Overestimated values ​​of detected antibodies indicate high level immune response to infection, which is specific in two cases:

• in the process of recovery;
• if a sick person is a carrier of typhoid bacillus.

To obtain a reliable answer, serological studies are carried out on the 7-10th day from the onset of initial symptoms.

Bacterial culture

Bacterial seeding of biological material allows you to detect the disease on early stage infections. Blood is most often used as the examined fluid - this is called seeding for blood culture. Blood sampling is preferably done at a time when the patient's body temperature is above 38 0 C. For sowing, culture medium Rappoport, in which 15-20 ml of the patient's blood is placed. Then, for ten days, laboratory staff daily observe the growth of bacterial colonies in the sample and, in case of detecting a dynamic development of such, make the next inoculation in a Petri dish. Here, bacteria are analyzed for 24 hours under constant testing, including sensitivity to antibacterial drugs.

Urine culture is indicative at any stage of the disease, but the best period to detect the pathogen is from the 21st day from the moment of infection. The principle of conducting test studies of uroculture is the same as when monitoring the patient's blood.

The study of feces is carried out between the third and fifth week of the disease, while only the liquid substance of the feces is considered suitable for sowing. For infectious patients, this type of analysis is rarely used, but it is considered reasonable for periodic examinations of workers with health records.

Immune fluorescence reaction (RIF) and enzyme immunoassay (ELISA)

RIF is emergency method testing done when typhoid fever is suspected, when symptoms are mild or there is reason to believe that a person may have been infected. A biological sample taken from a patient is injected with special antibodies stained with fluorescent elements, which, when combined with the antigens of an infectious agent, begin to produce a glow. This feature, clearly visible when examining the sample under a microscope, allows us to conclude that there is a typhoid bacillus.

ELISA, unlike the previous method for determining antigens and antibodies, can even accurately estimate their number. Based on the data obtained, the doctor concludes that the treatment regimen is correct.

The reaction of indirect hemagglutination (RIHA)

RNGA is one of the most accurate types of diagnostics for suspected typhoid fever, since this reaction is sensitive to 3 antigens of typhoid bacillus. When carrying out this type of analysis, erythrocytes that have a strong immunity to pathogen antigens are evaluated. RNHA is diagnosed several times, and an increase in O-antibody titers is considered normal for a positive response. If increased titers of H- and Vi-antibodies are detected, this indicates an imminent recovery of the patient or his status as a carrier of a bacterial pathogen.

Prevention of typhoid fever

Prevention of typhoid fever adheres to the most strict control in relation to employees of preschool and health-improving institutions, employees of food points and health care institutions. If a carrier of the infection is found among the employees of these institutions, two disinfection measures are carried out at the place of work of a sick person.

Individual prevention of an infectious disease is personal hygiene, which includes the mandatory isolation of personal items from places public access. To prevent infection through food, you can not eat unwashed fruits and vegetables, unheated dairy products, raw eggs. A great danger is the unboiled tap water or collected from dubious sources, water.

Since the children of the younger or school age more susceptible to typhoid infection than adult population, parents should be more careful to ensure that the employees of the institution visited by their child have all the necessary medical reports on the state of health. This will almost 100% eliminate the possibility of infecting a child with a dangerous typhoid bacillus.