Influenza A virus, IgG antibodies
Why this test?
This test is an additional method of laboratory diagnosis of the influenza A virus and is aimed to detect IgG class antibodies in the blood.
In what cases is it prescribed?
- After the flu, to find out whether immunity to the influenza A virus has been formed.
- After vaccination.
Information about the test
Influenza is an acute infectious disease of the respiratory tract, the cause of which is the influenza virus type A, B or C.
The influenza A virus is characterized by significant antigenic variability, which creates the risk of disease every year and need the annual vaccination. The natural reservoir of the influenza A virus is waterfowl. Sometimes it is transmitted to other birds, can also infect domestic birds, from them - pets and then humans, leading to epidemics and pandemics.
Influenza is transmitted from a sick person through the air with droplets of saliva, mucus or sputum. Infection can also occur through household items (personal hygiene items, dishes, toys). Influenza is prone to rapid (epidemic) spread in a fairly short period of time due to its following properties:
- The infection has a short incubation period (10-48 hours) and is mostly mild;
- Air-droplet transmission;
- High susceptibility;
- Risk of re-infection - immunity is specific only to a certain serotype, and not to all influenza viruses.
Also, a feature of this viral infection is that patients during the incubation (asymptomatic) period or with minor symptoms of the respiratory system practically do not pose an epidemiological danger.
When the flu virus enters the body (or after the vaccination), B-lymphocytes begin to produce special protective proteins - antibodies, which are called immunoglobulins. First, IgM antibodies appear, and then IgG. The latter can circulate in the blood for many years after the infection.
However, the flu can develop again. As mentioned earlier, influenza A virus antigens are incredibly variable, so the body does not always have the exact specific IgG antibodies to new virus mutations. Nevertheless, IgG immunoglobulins during repeated contact even with a different subtype of the influenza A virus can cause the disease in a milder form without the complications development.