Brucella | Antibodies (IgG, IgM)

General Information

Brucella is a gram-negative coccobacillus that does not form a capsule and does not produce spores. The disease caused by this bacterium – brucellosis – is a zoonosis that can spread from animals to humans.

Goats are infected with Brucella (Brucella melitensis), cattle (brucella abortus), pig (Brucella suis), dog (Brucella canis ), sheep (Brucella ovis) etc.

The following species are pathogenic for humans:

• melitensis
• abortion
• suis

The infection spreads from animals to humans in several ways:

• By skin contact with an infected animal or secretions released by animals.
• Inhalation of polluted air
• By eating incompletely thermally processed cured meat.

Brucella is an intracellular bacterium that can exist and reproduce only in the host's phagocytes. The bacterium located in monocytes and macrophages penetrates into various organs and tissues of the reticulo-endothelial system: lymph nodes, liver, spleen and bone marrow.

Human brucellosis is an acute systemic disease characterized by:

• Acute phase of bacteremia (the presence of bacteria in the blood) and sensitization
• Bacterial localization in internal organs and the chronic phase of the disease
• inactive latent phase

Symptoms

The acute stage of the disease includes: fever with chills, general weakness, anorexia, headache and muscle pain. These symptoms develop suddenly, 2-4 weeks after infection. Noteworthy are lymphadenopathy (enlargement of lymph nodes) and hepato-splenomegaly (enlargement of liver and spleen). In untreated cases, the fever is prolonged and has a wavy character. Since the infection is systemic, any organ can be involved in the process.

Chronic brucellosis is usually caused by the prolongation of the focal acute process and the formation of an abscess.

Recovery in some patients is prolonged, with general symptoms of infection and high titers of antibodies.

Complications of brucellosis

• Acute inflammatory process in the small intestine, rarely in the pancreas
• Hepatitis - with different histological changes, depending on which species is infected.
• Osteomyelitis is a very common complication. Sacroilitis (inflammation of the joints of the gava-iliac segment of the spine), spondylitis, osteomyelitis dominates. In brocellosis, arthritis spreads to the hip and knee joints.
• Acute or chronic meningitis, encephalitis. Brain abscesses, epidural granulomas, vasculitis and demyelinating processes may develop.
• Endocarditis and pericarditis - often fatal.
• Interstitial nephritis, pyelonephritis, glomerulonephritis, orchitis and others are worth mentioning among the complications of the genitourinary system.
• Ulcer-abscess skin lesions, erythema nodosum, vasculitis.
• Eye: uveitis, rarely endophthalmitis.

Brucellosis immune response is characterized by specific IgM Antibodies develop at the end of the first week and the end of the second week after infection IgG with the appearance of antibodies in the blood. After the end of the disease, the titer of antibodies decreases at a slow rate for 2-3 years. IgG A prolonged increase in concentration is a sign of a chronic infectious process. The final diagnostics of the disease is based on the isolation of bacteria from the tissue material - the method of bacteriological research.

Diagnosis is also based on serological data: determination of total specific antibodies and IgM and IgG titers in dynamics.

Preparation of the patient: it is not necessary

Material for examination: Venous blood

Referral norms:

Brucella IgG: <16 RU/mL;

Brucella IgM: <0.8 Index.

Interpretation

Individuals vaccinated against tularemia and cholera may have false-positive serological data for brucellosis.