Brucellosis In Humans

2024 Author: Josephine Shorter | [email protected]. Last modified: 2024-01-07 17:49

Brucellosis in humans

What is brucellosis?

Brucellosis is a zoonotic infectious disease caused by pathogenic microorganisms from the Brucella family, and is characterized by a sluggish inflammatory process in all organs and tissues with a predominant lesion of the lymphatic, osteoarticular and nervous systems.

Domestic animals (cows, goats, horses, rarely pigs) are the classical environment for the circulation of pathogens. There are several types of brucella, which predominantly affect each of the species of these animals. A person is in varying degrees susceptible to any type of brucellosis infection, which contributes to the spread of the disease among people who are engaged in agricultural activities and animal husbandry. The possibility of developing brucellosis and its specific forms among people is determined by the activity of the immune system and the virulence of pathogens.

Brucella are microorganisms with a polymorphic structure (cocci, small sticks) and moderate virulent pathogenic properties. They are very stable in the external environment, which plays an important role in their ability to spread and circulate between susceptible macroorganisms. In infected untreated milk and meat, they can survive for about 3 months. They die during pasteurization and heat treatment at higher temperatures for several minutes. They do not produce exotoxins. Pathogenicity is caused by antigenic components of the cell wall, which are released into the blood when the immune cells destroy Brucella.

Human infection with brucellosis occurs in the following ways:

1. When consuming milk and meat from infected animals, or containing viable brucellosis pathogens;
2. When brucella comes into contact with human skin from the wool of cattle;
3. Inhalation of brucella with dust or wool particles.

Once in the human body, brucella quickly and actively penetrate into the intercellular spaces and lymphatic ducts, where they are captured by immune cells from the macrophage system. This moment in the pathogenesis of brucellosis is the central link in the duration of the course of this disease, which can last for years. The intracellular location of pathogens, along with their low antigenic activity, does not allow the body to fully destroy them, since for this it is necessary to destroy the body's own cells.

The first focus of accumulation and reproduction of brucellosis pathogens are, regional in relation to the place of introduction, lymph nodes. Of these, pathogens are periodically released into the systemic circulation and are carried to organs consisting of reticular tissue: liver, spleen, bone marrow of long bones. After the reproduction cycles in these tissues, young brucella is released into the bloodstream with damage to new organ cells and the introduction of infection by macrophages into the joints and nerve tissues (spinal cord roots). An untreated process takes on a long sluggish course.

Symptoms of brucellosis in humans

The clinical picture with brucellosis is nonspecific, as it captures a lot of symptoms, which gradually join each other. Depending on this, acute, chronic and residual forms of the disease are distinguished. Their symptoms are almost identical, only the degree of their severity and the activity of the inflammatory-infectious process differ.

The stage of the increase in the clinical picture of brucellosis can be traced by different symptoms:

• Fever. It is represented by a temperature reaction in the form of hyperthermia up to 38-39.7 ° C. As a rule, such leaps are noted periodically and coincide with the periods of the release of pathogens into the bloodstream from the foci of the affected organs. In the periods between the maximum temperature rise in acute brucellosis, subfebrile condition persists, and in a chronic process, the temperature may be normal.
• Chills and sweating with a febrile attack. The classic triad for acute brucellosis. Paradoxically, despite the high temperature, intoxication and disturbance of the general condition are practically absent.
• Lymphadenopathy. It is represented by an increase, first of all, of one of the groups of regional lymph nodes. Chronic and protracted acute forms of brucellosis are characterized by the gradual involvement of various lymphatic collectors in the process, which is manifested by their increase throughout the body.
• Hepatosplenomegaly. From 2-3 weeks of a febrile period with an acute process, an increase in the size of the liver and spleen occurs. This is due to a sluggish inflammation that occurs in response to the introduction of pathogens. In parallel with them, immune cells destroy normal tissues.

• Inflammatory processes in the genitals. In this respect, we are talking about men. Most often, the testicles are affected, which is manifested by typical one- or two-sided orchitis. This manifestation of the disease is due to the high activity of blood flow in the germ cell tissues of these organs, where brucellae are retained, passing through the blood-testicular barrier.
• Signs of damage to the central nervous system. Manifest in the form of headache, meningeal symptoms, irritability and emotional lability, autonomic disorders (irregular heart rate, sweating, drops in blood pressure, feeling hot or cold).
• Osteoarticular pain. They arise almost always with a long course of brucellosis, accompanying each of its exacerbations. As a rule, they are caused by the addition of secondary brucellosis arthritis. One of the large joints, often knee joints, is affected in the form of edema, soreness, impaired support on the affected limb.
• Radicular syndrome. It is characterized by the occurrence of shooting or persistent aching pain in the back like lumbodynia. It intensifies with loads and torso turns. Refers to the criteria for the chronic and long-term course of the disease.
• Signs of a residual process. They are characterized by joint deformities, their stiffness, curvature of the spine, osteoporosis, disorders of the structure of internal organs, neurological abnormalities, skin rashes and granulomatous elements on the skin of the extremities and hands.

Diagnosis of brucellosis

Diagnosing brucellosis is not always easy. It is much easier to do this when there is a typical history of agricultural workers and in acute forms of the disease. A long, sluggish process in people without an appropriate history leads to the fact that brucellosis is perceived as oncopathology, leukemia, and other infectious diseases.

The following analyzes can help to understand the situation:

1. General blood analysis. Determines the relative neutropenia due to an increase in the percentage of lymphocytic and monocytic blood cells against the background of normal leukocyte count. ESR is usually moderately accelerated. Prolonged course of brucellosis leads to pancytopenia (a decrease in the level of all blood elements);
2. General urine analysis. Does not define specific changes. There is a constant increase in protein content in a series of repeated urine tests;
3. Blood chemistry. Determines a persistent and long-term slight increase in hepatic cytolysis (ALT, ASAT), mild hyperbilirubinemia due to both fractions, hyperglobulinemia against the background of hypoalbuminemia and a normal level of total protein;

For specific verification of the pathogen, the following methods are used:

1. Cultural. The most reliable, but very laborious and time consuming. For research, you can take any biological fluids (blood, bile, urine, cerebrospinal and intraarticular fluid, punctate from the lymph nodes). They are sown on nutrient media. The results of the study are assessed after 3-4 weeks by the presence of growth of characteristic Brucella colonies;
2. Serological. The most widely used method in the diagnosis of brucellosis. Informative already from the first week of illness. The principle of serological diagnostics is based on the detection of immunoglobulins (antibodies) in the patient's serum to specific brucellosis antigens. By their title and class, one can judge the duration and activity of the process. For this, specific reactions from Wright and Headllson are used. Their diagnostic titer is 1: 160-200 and 1: 100, respectively;
3. PCR diagnostics. The method is modern and is based on the detection of specific components of the DNA chains of brucella in the study of any biological tissues of the patient;
4. Allergic tests. Intradermal administration of brucellin (a component of brucella) is used. By the reaction of the skin to the injection, the presence of sensitizing properties of the body's immune cells in relation to these pathogens is judged. The method does not provide information about the activity of the process, but only indicates the previous contact of the organism with Brucella.

Treatment of brucellosis in humans

Due to the intracellular parasitism of brucella in the human body and the long course of the disease, treatment should also be prolonged. Its main components should be etiotropic (destruction of the pathogen), pathogenetic (impact on the mechanisms of starting and maintaining the inflammatory process), symptomatic (elimination of anxiety symptoms).

Etiotropic therapy

It is carried out by using antibiotics. It is important to follow some rules:

1. Simultaneous use of two drugs that are active against brucella;
2. The optimal duration is at least 5-6 weeks;
3. Continuity;
4. Prescribing antibiotics only in case of exacerbation of the process. Antibiotic use in the interictal period will do more harm than good;
5. Using high dosages.

Of the specific treatment regimens, combinations have shown themselves well:

1. Tetracycline with streptomycin;
2. Rifampicin with doxycycline;
3. Doxycycline with streptomycin or erythromycin;
4. Azithromycin or clarithromycin with biseptol;
5. Doxycycline with amikacin.

Pathogenetic therapy

It is represented by infusion detoxification measures for an acute process or exacerbation of a chronic one (glucose-saline solutions, rheosorbilact), vitamins (ascorbic acid, tocopherol, cyanocobalamin, thiamine, pyridoxine, milgama, multivitamin complexes), antihistamines (diazetiriinodiotinum (Roncoleukin, Cycloferon, Imunofan, Echinacea). Glucocorticoids can be used exclusively with strong generalization of the process and its pronounced exacerbation.

Symptomatic treatment

Symptomatic treatment - the introduction of non-steroidal drugs with anti-inflammatory action (diclofenac, rheumoxicam, movalis), painkillers, hepatoprotectors, calcium preparations.

Prevention of brucellosis

Preventive measures for brucellosis are non-specific and are represented by the fight against the spread of pathogens among animals. This can be achieved by early detection, isolation and elimination of sick individuals. Careful monitoring of livestock products (milk, meat, wool and hides) must be carried out.

It is imperative to vaccinate livestock in brucellosis epidemic foci on the basis of a brucellin test. Only by avoiding the possibility of human contact with brucella, it is possible to prevent the disease. Vaccination among people is extremely rare, only when the disease spreads epidemic, because it does not provide reliable immunity and protection.

Author of the article: Alekseeva Maria Yurievna | Therapist

Education: From 2010 to 2016 Practitioner of the therapeutic hospital of the central medical-sanitary unit No. 21, city of elektrostal. Since 2016 she has been working in the diagnostic center No. 3.