Pneumotropic (Viral Influenza) – Basic microbiology, parasitology, and immunology; nature, reproduction, growth, and transmission of common microorganisms and parasites in Bangladesh; prevention including universal precaution and immunization, control, sterilization, and disinfection; and specimen collections and examination. Students will have an understanding of common organisms and parasites caused human diseases and acquire knowledge about the prevention and control of those organisms.
Pneumotropic (Viral Influenza)
Influenza Virus:
Influenza viruses are the only members of orthomyxovirus family.
Influenza viruses are members of the family Orthomyxoviridae. This family represents enveloped viruses the genome of which consists of segmented negative-sense single-strand RNA segments.
Diseases:
- Influenza A virus causes worldwide epidemics (pandemics) of influenza.
- Influenza B virus causes major outbreaks of influenza.
- Influenza C virus causes mild respiratory tract infections but does not cause outbreaks of influenza.
Properties:
- Family: Orthomyxovirus.
- Genome: 8 Segmented single stranded RNA genome
- Nucleocapsid: Helical.
- Envelope: Enveloped virus (Lipoprotein)..
- Proteins: Haemaglutinine (HA) & Neuraminidase (NA), virion contains RNA-dependent
- RNA polymerase, which transcribes the negative-polarity genome into mRNA.
- Replication: Replicates in the nucleus.
Laboratory Diagnosis:
Although most diagnoses of influenza are made on clinical grounds, laboratory tests are available.
➤ Specimen: Nasal or throat washings, nasal or throat swabs and sputum.
➤ Tests:
- Direct fluorescent antibody
- Polymerase chain reaction (PCR)
- Cell culture
Treatment:
Drugs like amantadine & rimantadine are being used & have been found useful because it can block entry of influenza virus A into the cell if administered early. They act by inhibiting viral activities by targeting M2 membrane proteins.
Prophylaxis:
Various preparation of virus vaccines are on trial. Major antigenic variations make the prospects difficult. Killed formalin inactivated influenza vaccine is however available every year.
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