spooky viral pathogenesis Flashcards
What are the 8 mechanisms of viral transmission?
- respiratory - areosols
- fecal-oral
- contact - lesions, saliva, fomites
- zoonoses
- blood
- sexual
- maternal-neonatal
- Genetic
THe susceptibility and severity of a viral disease depends on what four things?
- nature of the exposure
- viral dose
- status of the person
- virus-host interactions
What are some of the features of the innate immune response in the respiratory tract?
- goblet cells - mucus
- cilia
- brush border
How is a virus in the GI tract disseminated?
It can infect M cells and easily reach the blood stream
What is the function of an M cell in the gut?
It samples the gut contents and presents it to underlying immune cells
What is primary viremia?
Virus spreads from lymph nodes to blood stream and then replicates in internal organs
—can occur without symptoms
What is secondary viremia?
Dissemination of the virus to organs where it is shed
Is exposure to infected blood a means of transmission?
Yes - it is now very common
What are some common organs that are locations for primary viremia?
- muscle
- Liver
- Spleen
- Blood vessels
Where is most of the HIV virus located in a PCR assay of an infected patient?
-Plasma, lymphocytes, CSF
Define a successful virus
One that will avoid destruction by the immune system and avoid destroying the host before replication is finished
-Transmission to a susceptible host
What are the three types of chronic infections?
persistent, latent, progresses slowly
In which type of chronic infection is there a period where the virus is present but cannot be cultivated: persistent, latent, or slow progression?
-Latent
Varicella -zoster is an example of what type of pattern of infection?
Latent - It is not demonstratable for a period of time in which it is noninfectious, and then there is a second disease episode later on
What pattern of infection does HepB have?
It is a chronic infection and the virus sheds throughout the person’s lifetime - persistent
What pattern of infection does creutzfeld-jacob disease show?
It is a slow progressing chronic infection - the virus sheds for a long period of time before a disease episode occurs
What pattern of infection would the common cold have?
Acute infection
Cell injury is caused:
_____ by viruses
_____by host
- Directly by viruses
- indirectly by the host
What is the main cause of the symptoms of a viral disease?
Host response to infection
What are two ways a virus can directly effect a cell?
- Cell lysis -polio virus
2. cell inactivation - RSV –> syncytium
When would a vaccination make a viral infection worse?
When the host immune response is severe and detrimental
