Virological tests

Virological studies - studies, to highlight viruses and study of their properties, as well as identifying causative connection viruses with certain diseases.
The material is taken depending on the place of predominant reproduction of virus in the body of the patient and the ways of their allocation in the external environment. The material is collected in a sterile utensils, quickly delivered to the laboratory and stored up studies in frozen or on ice. Before using the material to highlight the virus is treated with antibiotics (penicillin and streptomycin) to suppress foreign flora and subjected to centrifugation to remove large particles.
The selection of viruses carried by infected vaccinated material laboratory animals, chick embryos, tissue culture. The choice of the method of allocation depends upon the causative agent of the disease. So, tissue culture (see) use when working with viruses pathogenic for animals or when viruses in tissue culture are revealed earlier than when the infection in animals. Chicken embryos infect for selecting pathogens influenza, infectious parotitis (in the amniotic and allantoin cavity), psittacosis (yolk SAC), smallpox (chorioallantoic shell).
From laboratory animals to highlight the viruses most frequently used white mice, then rabbits, rats, Guinea pigs, monkeys. For arboviruses most effective introduction vaccinated material in the brain or spinal cord, for pantropic viruses on the mucous membrane of the respiratory tract, for viruses, malware, virus, herpes - on skalpirovaniya the cornea.
The selection of the virus is most effective in the acute period of the disease. An essential aspect in the establishment of the viral nature of the disease are the results of serological studies sera, taken again from the same patient at the beginning of the disease and during convalescence. Detection of antibody to selected viruses in the second serum titer of 4 and more times more than in the first, indicates etiologic link viruses with this disease.
Early and rapid method for detection of viral antigens is the method of IgM antibodies based on the specific commit fluorochrome-labeled antibodies to the surface antigen. Antigen easily detected with fluorescent microscopy (see) because of the bright fluorescence adsorbed on antigen antibodies. Method of fluorescent antibody explore swabs taken from the patients, histological sections of diseased tissues, preparations of tissue culture. To detect elementary cells (virions) is also used electron microscopy (see). From other morphological methods used by those who expose intracellular viral inclusion in the sections of the affected organs and tissues. Detection of inclusions evidence of infection and in some cases contribute to the diagnosis of viral diseases. For the detection of viral antibodies in the blood of patients and to study of the antigenic structure of viruses use a variety of serological reactions. The neutralization reaction is used in almost all viral infections. It is based on the ability of antibodies, immune serum neutralizing infectious properties of viruses with the introduction of the mixture in the body susceptible animals or tissue culture. To determine the index of neutralization constant dose serum is mixed with different dilutions of viruses, and to determine the antibody titre - various dilution of serum with a constant dose of viruses. Control is the infection of animals (or tissue culture) mixture of viruses with normal serum or physiological solution. The reaction of neutralization put not only for the detection of antibodies, but also to determine the type of virus.
The reaction of binding complement [e.g., Board - Zhang reaction (see)] is used to detect as viral antigens and antibodies. In the first case, in response interact known immune serum and material, which assumes the presence of antigens: serum, nasopharyngeal aspirates, extracts tissues infected. In the second case - known antigen (diagnostikum) and serum of the patient or reconvalescence.
RAC is used for the diagnosis of diseases caused by viruses of influenza, smallpox, polio, mumps, adenoviruses and arboviruses.
The reaction of precipitation , agar-based education strip precipitation at the site of contact antigen antibody layer agar between holes filled viral antigens and immune serum. The reaction used for the study of the antigenic structure of viruses and to diagnose some infections - smallpox, polio epidemic of hepatitis.
The reaction of haemagglutination, based on the property of many viruses cause agglutination (bonding) of erythrocytes of different animals (chickens, geese, Guinea pigs and humans, used for virus detection. Antivirus serum inhibits hemagglutinins activity viruses, and this phenomenon is called the reaction of haemagglutination inhibition (RTG) is widely used for the diagnosis of influenza, mumps, smallpox, some encephalitis.