Typhoid fever develops when a salmonella bacteria enters the body. It can be entered into the intestines through unwashed food, contaminated water, neglecting hygiene rules( for example, when using towels at the same time as a person who is a carrier of a bacterium).
The pathway of infection is fecal-oral. Since the clinical picture of the disease does not have specific symptoms, it is necessary to perform an abdominal typhoid test to confirm the diagnosis, which will help determine the presence of the pathogen in the body.
When an analysis is made for typhoid fever
Blood test for typhoid fever may be given in two cases:
- when the clinic displays a characteristic for intestinal infection;
- for the prevention of epidemics( is mandatory analysis when extending the health book).
If the patient turned to the doctor with a complaint about problems with digestion and hyperthermia, then the doctor, based on the manifestations of the disease, will make an assumption about the development of intestinal infection. The presence of typhoid fever is indicated by the following complaints of the patient:
- abdominal pain;
- signs of poisoning( nausea, vomiting, weakness, loss of appetite, hyperthermia);
- problems with stools( constipation, somewhat less frequent diarrhea);
- dehydration( severe thirst, tongue covered with white coating, skin peeling);
- may cause the formation of roseol( a rash appears on the skin a week after infection, when it disappears, and then reappears.) The number of rashes from 4 to 25 elements).
Typhoid fever, as a rule, proceeds as follows. Acute onset of the disease in 30% of cases. Symptoms of poisoning, worsening of sleep, pain in the head, weakness gradually increase. Body temperature increases over several days and reaches febrile values. There is a retardation of reactions, the stomach is swollen, there is flatulence, rumbling.
Once a person has recovered with typhoid fever, he develops a permanent immunity to the
abdominal rod. The typhus in fresh water can remain viable for up to a month, and in agricultural products up to 10 days, in dairy products it multiplies and accumulates. The housefly is also able to transfer the bacteria to food.
The first signs of the disease appear on the 7-23 days after infection, so it is extremely difficult to establish the source exactly. Typhoid fever must be differentiated from tuberculosis, brucellosis, typhus, cholera, plague and other diseases in which the patient develops fever and intoxication.
What tests are performed by
To confirm typhoid fever, laboratory tests are scheduled, which should be performed before antibiotic therapy is initiated( taking antibacterial drugs may affect the correctness of the diagnosis).
For examination, you can take blood, feces, urine, bile, spinal fluid( with a suspected complication).Depending on the stage of the disease and the symptoms, the following tests for typhoid fever may be prescribed.
Serological examination of
Blood plasma is studied. It is necessary to detect specific antibodies produced by human immunity. The analysis can be carried out only after 4-5 days after infection with typhoid fever, because previously the body does not synthesize antibodies.
General blood test
Assigned to determine the quantitative characteristics of all blood cells. When typhoid becomes infected, normal blood counts change.
There is leukopenia( the number of white blood cells decreases), aneosinophilia( there are no eosinophils), the number of lymphocytes increases, which indicates the presence of an infection in the blood.
Also during typhoid fever, the level of neutrophils, leukocytes, synthesized by the body during inflammation increases, the number of platelets responsible for clotting of blood decreases.
An extensive blood test is mandatory when entering hospital care and during therapy to track the dynamics. For the study, a blood test is taken from the vein or from the finger.
Biochemistry of blood
Detects the proteins of the acute phase, it must be done before the antibiotic. The test requires 5-10 ml of blood from the vein, the results of the study can be found within 24 hours.
Bacterial sowing
There are few bacteria in the sample of blood, therefore it is transferred to a nutrient medium( meat-peptone broth) and placed in a thermostatic apparatus. The microorganism under favorable conditions will begin to form a large colony that will be suitable for research.
After use the chemical reagents and establish the kind of bacteria. A similar test is performed by the entire patient with hyperthermia, as well as when testing for typhoid fever. Results can be obtained on the 4th-5th day after the analysis, a preliminary answer will be given after 2 days. Tank seeding is the most accurate laboratory diagnosis of typhoid fever.
To detect antibodies to typhoid fever, the radioimmunoassay or enzyme immunoassay method
is used. It is used for the detection of a person who is a carrier of typhoid bacillus, as well as for control of the effect of vaccination against typhoid fever, using PGNA( indirect haemagglutination reaction) or passive hemagglutination( RPHA).This method helps detect antigens and antibodies with the help of red blood cells that precipitate on contact with the antigen.
Erythrocytes, on which antigens are adsorbed, are glued together upon contact with the antibody. Immunological examination determines the level of these antibodies. In a person who suffers from typhoid fever, he may be at the level of 1:40, and for the defeated infection 1: 2000, therefore the diagnosis is carried out with an interval of 5 days to monitor the dynamics.
Bacteriological examination of feces
This analysis is rarely prescribed, as the typhoid rod exits the body only 8-10 days after infection. This method is used to identify people who are carriers of the infection, but do not get sick themselves.
Urinalysis
A typhoid bacterium is found in urine only 1-1,5 weeks after infection. Urinalysis can indicate such indirect evidence of typhoid fever as leukocytosis( at the initial stage of the disease, the number of white blood cells rises and falls sharply for 7 days), leukopenia, increased ESR, aneosinophilia, and relative lymphocytosis.
Before collecting urine, the patient should conduct hygiene of the external genitalia, then collect the material for analysis in a sterile jar.40-50 ml of urine will be enough for diagnosis. To test for infection, a sediment is used, which is transferred to a dense nutrient medium.
The ability to detect a pathogen of typhoid with microbiological methods is directly related to the amount of bacteria in the biological fluid and the use of antibacterial therapy. A week after infection with S. typhi salmonella serological agglutination tests( RPHA on typhoid fever) give a positive response.
Serological tests are less specific than bacteriological methods, since a positive response may indicate a previous infection caused by another type of salmonella. An additional study after five days helps to monitor the growth of the titer, which is characteristic of acute infection.
Bacteria in the blood are found only in diseased people, in urine and feces the stick can be either in a sick person or in a bacterium carrier
. Is it necessary to prepare for the
test? The blood test for typhoid fever should be given not only by patients with characteristic signs of the disease, but alsothose who work with a lot of people or food. This is done for the purpose of preventing the spread of typhoid fever, because the infected person is able to spread the infection for a long time.
The most bacteria isolates the patient with feces from the first to the fifth week of the disease, and with urine for 2-4 weeks. Every tenth infectious person secretes a typhoid rod in the environment for 3 months, and 3-5% of the total number of typhoid patients are chronic carriers of the infection, spreading the wand for several years.
During the passage and prolongation of the hospital book, the analysis on typhoid fever is mandatory. Many do not know where the blood is taken for testing. For the diagnosis, the patient takes venous blood from the area of the elbow bend.
The study is carried out in vitro, which in literal translation means "in vitro".How much time the test is made depends on the workload of the laboratory, at least the result will be ready in two days. How to properly take the test for typhoid fever is specified by the doctor who prescribes the direction.
If there are no clarifications, then the following recommendations should be adhered to:
- need to give blood on an empty stomach;
- a day before the meeting, you can not eat too hot, salty, fatty or smoked food;
- it is necessary to exclude the intake of weak and strong alcoholic beverages, medicines at least three days before blood donation;
- drinking mode is not required to change, but it is better to refuse coffee;
- one hour before the analysis is not allowed to smoke.
To avoid false positive or false negative analysis, it is necessary to approach the delivery of blood responsibly
. If antibodies to typhoid are not found, then this is confirmation that the person is not the carrier of the infection. If symptoms of the disease are present, and the test does not show the presence of a specific protein, then it is possible that an immune response has not yet been formed, since pathology is at an early stage.
A false positive result of the analysis is possible if there is a bacterium from the genus Salmonella in the body, but causes another disease, that is, the microorganism is and immunity reacts with the production of antibodies. What tests to hand over at the supposed typhoid fever or when testing for bacteriocarrier, and also where it is better to hand over biological material, the doctor will indicate.
If typhoid fever occurs in acute form, the patient will be hospitalized in an infectious disease hospital. The patient is prescribed antibiotics, diet and bed rest. Avoid any overvoltage, even when visiting the restroom. Typhoid fever, in the absence of adequate treatment, can lead to toxic shock, perforation of the intestinal mucosa. Therapy lasts from 2 to 4 weeks.
