Infection of Respiratory Tract. Introduction, morphology, pathogenesis, symptoms, diagnosis.
The respiratory tract comprises of upper and lower tract. There are different organisms infecting the upper respiratory tract and lower respiratory tract. The organisms of URI ( upper respiratory tract infections) are Streptococci groups, cornea bacterium diphtheria, Borrelia, Adenovirus, Rhinovirus, mumps infection.
The organisms of lower organism Klebsiella pneumoniae, pseudomonas, mycoplasma, etc
Introduction
Influenza is categorize in URI ( upper respiratory tract infection). It comes under family Orthomyxoviridae. This is a envelope RNA virus.
Morphology
The influenza virus has a lipid envelope. The envelope contain two types of glycoprotein spikes- Hemagglutination (HA) facilitate viral attachment to the host cells & entry, Neuraminidase (NA)- it assist in the release of newly form from infected cells.
There are surface membrane protein known as M proteins. This M protein contains M1 & M2. So M1 provide structural integrity & M1 is the ion channel.
The influenza viruses are classified into 3 seri types i.e A, B, C based on different antigen.
Pathogenesis
2. Attachment :- The viruses attaches to & penetrate respiratory epithelial cells in the upper & lower respiratory tract. This attachment is mediated by the interaction between the viral Hemagglutination (HA) protein & sialic acids on the host cell surface.
3. Replication of virus :- The virus replicate in the respiratory tract destroying the host cells.
Clinical symptoms
Laboratory diagnosis
2. Sore throat.
3. Rapid diagnosis of influenza by demonstrating virus antigen on the surface of nezofaringles cells by immunofluorescence.
4. RT-PCR ( reverse transcription polymerase chain reaction) this test is consider as gold standard for diagnosing influenza it involves extracting viral RNA from clinical specimen then amplify the PCR product.
5. NAAT ( Nucleic acid amplification test) :- This test is used for influenza diagnosis with amplification RNA. NAAT is a highly sensitive and specific diagnostic method used to detect and amplify genetic material (DNA or RNA) of pathogens, cells, or other biological entities.
6. Direction fluorescent antibody test :- is it also known as immunofluorescent antibody test, is an antigen based test routinely employed for diagnosis of influenza viral infection.
Isolation of virus/ viral cultural
Virus isolation is achieved during first two- three days during illness and cultured in primary monkey kidney cell.
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