General
The virus that causes chickenpox can remain silent within cells and is non-infectious but can later reactivate and cause shingles.
What is a latent infection?
Is the Polio Virus naked or enveloped?
Naked!
What type of genome does the Polio Virus have?
ss(+)RNA
What is the causative agent of the flu?
Influenza Virus
Enveloped, ss(-)RNA x 8, HA, NA, M2 Ion Channels
The virus that causes hepatitis B can continue to give rise to more viral particles even when the infected person has no symptoms.
What is a chronic infection?
What type of genome does the Polio Virus have?
ss(+)RNA
Hosts to the Polio Virus?
Humans only!
What are the signs and symptoms of the flu?
After an incubation period of about 2 days patient develops
Headache, fever, sore throat, dry tight cough, chest pain, extreme fatigue, muscle aches, weakness.
Prevention and treatment of the flu?
Prevention
flu shot - inactivated/attenuated
Treatment:
Bedrest
Medications - M2/NA
Which of the following would result in the production of memory cells?
1. naturally-acquired passive immunity
2. naturally-acquired active immunity
3. artificially-acquired passive
4. immunity artificially-acquired active immunity
2 & 4
Treatment for Polio?
No cure for polio exists
The focus is on increasing comfort, speeding recovery and preventing complications.
If a population of 100,000 were all infected with the polio virus, how many are likely to develop paralytic polio?
less than 1,000
What is antigenic drift?
acquiring mutations, changing antigens/epitopes, our memory/developed antibodies no longer recognize
What is antigenic shift?
New virus. A mix of two different influenza viruses, error in packaging = reassortment
If an ELISA protocol uses enzyme labeled anti-human IgG, you can assume that the test is... direct/indirect?
Indirect
Paralytic Polio symptoms?
Headache, fever, stiff neck muscle pain, spasms-muscles shrink
(paralysis of muscles)
Respiratory paralysis in severe cases
What percentage dies from polio?
Most susceptible population to infection and paralysis from the Polio Virus?
Infection = Children <5 years
Paralysis = Older children and young adults
What population is the most susceptible to the flu?
Children less than 5 yo, and Seniors older than 65 yo
Why are we not immune to the flu?
High mutation rate, EVERY replication has mutations. (replicase is very sloppy)
Which of the following would most likely require a booster shot? A vaccine composed of.....
1. attenuated virus
2. attenuated bacteria 3. inactivated virus
4. killed bacteria
5. a toxoid
3,4&5
Polio Virus Pathogenesis?
•fecal-ora•throat and intestial tract cells, less than 1% cross blood-brain barrier - binds to CD 155 receptor of motor neurons of spinal cord
•endocytosis of virus
•viral RNA released - replicase made, host machinery shut down
•virus induced cell death so it can escape
Prevention for Polio?
IPV (inactivated) - IgG Ab
OPV (oral/attenuated) - IgG/IgA Ab
Influenza Virus Pathogenesis?
•Respiratory tract through virus inhalation;
•HA attach to sialic acid on ciliated epithelial cells to help gain entry into cell --> die.
•Damage = cilia not beating mucus out.
•NA aids in release from mucus and budding.
•Enter by receptor mediated endocytosis.
•M2 aids in acidifying inside of virion to release genome.
Which influenza viruses cause seasonal epidemics in the US?
A & B