Viral Infections and Epstein-Barr Virus Flashcards
What are signs and symptoms of a virus determined by?
The interactions between the virus and host - virulence factors and the host response.
For viral survival, what must it be able to do?
Infect host cells, replicate and spread to the final target tissue.
At the target organ, it must infect and successfully replicate.
What are the 3 possibilities of a viral infection?
Acute infection.
Chronic infection.
Latent infection.
What is acute viral infection?
Where the virus undergoes multiple round of replication, resulting in an increase in numbers of the virus and death of the host cells.
What are two examples of acute viral infections?
Poliovirus and influenza virus.
What is a latent infection caused by and what is it?
Caused by DNA viruses or retroviruses, where viral DNA persists as extrachromosomal or integrated within the hosts genome.
The viral DNA is then replicated along with the chromosomes.
What can latent viral infections lead to?
Transformation of cells and cancer.
What is an example of a latent infection?
Herpes simplex virus 1, which is a fever blister or cold sore infection.
How do chronic viral infections differ from acute infections?
Viral particles continue to be shed after the period of acute illness.
The host cells do not necessarily die after infection.
There is less virus produced than seen in acute infections.
What types of viruses cause chronic viral infections?
RNA viruses, such as hepatitis C.
They are often mutated viruses.
What are chronic viral infections often associated with?
Defective host immune responses that are insufficient to clear the infection.
What type of virus is Epstein-Barr virus, and what is its structure?
It is a herpes virus - a double stranded DNA enveloped virus.
What is the route of infection of cells for Epstein-Barr virus?
It first infects the oropharyngeal epithelium and then moves on to infect the B-lymphocytes.
It then results in T-cell proliferation.
When the B-lymphocytes are infected with EBV, what happens to them?
A small number of viral proteins are synthesised and then the viral latency develops.
How is Epstein-Barr virus spread?
It is spread through the saliva, giving it the name kissing disease.
What does EBV look like on a blood film?
