1 / 11

Orthomyxoviruses

Orthomyxoviruses are negative-sense RNA viruses with segmented genomes, causing influenza A, B, and C. Learn about their structure, replication, genetic diversity, and impact on humans and animals. Discover the role of hemagglutinin and neuraminidase glycoproteins, annual epidemics, and periodic pandemics.

markdsmith
Download Presentation

Orthomyxoviruses

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Orthomyxoviruses • Negative-sense RNA virus • Segmented genome • Enveloped • Hemagglutinin glycoprotein: viral attachment protein and fusion protein-It elicits neutralizing, protective antibody responses

  2. Orthomyxoviruses • Replicates in cell nucleus but assembles and buds from the plasma membrane • Segmented genome promotes genetic diversity caused by mutation and reassortment of segments on infection with two different strains • Influenza A, B and C • Influenza A infects humans, mammals, and birds (zoonosis)

  3. Orthomyxoviruses • Only influenza A and B viruses cause significant human disease • Annual epidemics (mutation:drift) • Periodic pandemics(reassortment:shift) 1918-19:20 million death 1947 1957 1968 1977 2009

  4. Orthomyxoviruses • Pleomorphic: spherical and tubular • Hemagglutinin(HA): Mutation derived changes in HA causes shift and drift. Shift occur only in influenza A and different HAs are formed (H1, H2...) • Neurominidase(NA): also undergoes antigenic changes

  5. Orthomyxoviruses • Hemagglutinin(HA): viral attachment protein, binds to sialic acid on epitelial cell surface receptors,hemagglutinates human, chicken and quinea pig red blood cells, elicits protective neutralizing antibody response • Neurominidase(NA):It facilitates the release of virion from infected cell

  6. Influenza virus • Matrix and nucleoprotein are type-specific: Influenza A, B and C virus Subtypes: according to HA and NA Strains of Influenza A: A/Bangkok/1/79 (H3N2): Type/place of original isolation,date of isolation/antigen

  7. Influenza virus • Virus likes cool,humidity (winter) • Spread by inhalation of small aerosols • Cell culture • Antigen • PCR

  8. Influenza virus • Rimantadine,Amandatine: inhibits uncoating of influenza A • Zanamavir and oseltamivir: NA inhibitors • Influenza vaccine: trivalent formalin inactivated, every year

More Related