Viral infection Flashcards
Give 6 routes of transmission of pathogens.
- Oral/Ingestion of contaminated objects
- Inhalation of infectious droplets
- Direct skin contact
- Trans-placental (Vertical Transmission)
- Sexual Transmission of bodily fluids
- Direct inoculation (Bites, injections, trauma)
Describe the structure of Viruses.
Nucleocapsid formed from
- RNA or DNA Core
- Protein Capsid - made up of capsomeres
Some viruses also have a lipid bilayer envelope with virus-encoded glycoproteins that surrounds the nucleocapsid. This envelope is usually derived from the host cell.
What are the different types of viral symmetries/structure shapes?
Give an example for each one.
- Icosahedral (20 faces) - Adenovirus, Herpes
- Helical - Flu viruses
- Complex - Pox, Rhabdo
What is the effect of having an envelope as part of the structure of a virus?
Determines their mode of transmission
Non-enveloped viruses tend to survive well outside the body and some are bile resistant.
Enveloped viruses survive transiently outside the body so tend to be spread via close contact.
How can different viruses be classified?
- Type of Nucleic acid (DNA or RNA)
- Number of strands of nucleic acid and their physical construction (e.g segmented)
- Polarity of viral genome - Positive (protein can be endcoded directly) or Negative sense strand RNA
- Symmetry of nucleocapsid
- Whether or not they have a lipid envelope
Hepatitis B Virus (HBV)
is a ___ virus that is found and transmitted in the ____. HBV causes _____ _______ of the Liver.
Hepatitis B Virus (HBV)
is a DNA virus that is found and transmitted in the Blood. HBV causes acute inflammation of the Liver.
What virus causes chicken pox?
Varicella Zoster virus (VZV)
What virus family are influenza viruses a part of?
Are these viruses enveloped and what is the polarity of their genome?
Orthomyxoviridae
Enveloped and Negative sense RNA
What virus family is the HIV a part of?
Are these viruses enveloped and what is the polarity of their genome?
Retroviridae
Enveloped and Positive sense RNA
What is meant by the term ‘Viral Tropism’?
In order for viruses to gain entry into a host cell, there needs to be a specific interaction betwwen proteins on the surface of the virus and ‘cognate’ molecules expressed on the surface of the host cell.
The need for a specific cell receptor determines what cells the virus can enter.
To what receptor and co-receptor found on T cells do HIV-1 virions bind to, in order to gain entry?
Primary receptor - CD4
Co-receptor - CXCR4 Chemokine receptor
Give examples of
Describe the process of viral infection and replication.
Describe the process of budding off of new virions from the host cell.
What are the differences between Persistent and Latent infections?
Compare and contrast the different Modes of Infection.
