Lec 8 - Acute Viral Infections

Question 1

acute virus general pattern

Answer 1

• Infected
• Multiplies
• Immune response kicks in
• Virus eradicatied
• And antibody response generated to protect in future

Question 2

lymphocytic choriomeningitis virus

Answer 2

the hamster one
is a persistent virus

Question 3

2 examples of slow virus infection

Answer 3

• measles
• HIV

Question 4

how can reinfection occur after acute virus

Answer 4

• usually have life long immunity
• but if seriologically distinct
  then can be reinfected

Question 5

name of immune response against acute viruses

Answer 5

first is innate repsonse ie primary natural defences

then, adaptive response kicks in

Question 6

what replication strategy do acute viruses have

Answer 6

R replication strategy

serial infection of hosts allows the growth of virus to be maintained
= no limit as long as susceptible hosts

Question 7

what replication strategy do persistent viruses have

Answer 7

K replication strategy

rate of propagation is slow
- new susceptible hosts are rare/non existent
- there’s a cap in how many can be infected

Question 8

what is the diff between short and long incubation period

Answer 8

short = virus stays at primary site
long = systemic spread, primary AND secondary viremia

Question 9

what would make for a successful, well adapted acute infection (for the virus)

Answer 9

• no/mild symptoms
• sufficient virions to maintain infection in population, but not to cause overwhelming disease in host

Question 10

example of inapparent acute infection

Answer 10

polio
90% subclinical

Question 11

examples of viruses that cause acute infection

Answer 11

• influenza
• polio
• measles
• rotavirus
• rhinovirus
• rabies

Question 12

what family of viruses is measles in

Answer 12

paramyxoviridae

Question 13

what type of virus is measles

Answer 13

• ssRNA

Question 14

what is needed to maintain measles in a population

Answer 14

growing population of 300-500k of susceptible hosts

Question 15

how many serotypes of measles

Answer 15

one

Question 16

what is primary site of infection of measles

Answer 16

respiratory epithilia

Question 17

what kind of cells does measles infect initally

Answer 17

macrophages and dendritic cells first
which then migrate to lymph nodes

Question 18

after entering the lymph nodes, what cells does measles virus then infect

Answer 18

B and T cells
which enter circulation to cause primary viremia

Question 19

where do the infected B and T cells replicate

Answer 19

in Reticuloendothelial organs
(and then reenters circulation = 2dary viremia)

Question 20

what happens after 2dary viremia of measles

Answer 20

spreads to all body surfaces
(causing all the symptoms)

Question 21

how does measles virus enter epithelium

Answer 21

at cell base via nectin 4

Question 22

how does measles compromise the immune system

Answer 22

B and T cells get destroyed
and now susceptible to secondary bacterial infection

Question 23

what can be given to attenuate the measles infection

Answer 23

vitamin A
(nutrition is important in progression of disease) = reduces morbidity and mortality

Question 24

symptoms of measles

Answer 24

cough
runny nose
Kopliks spots
skin rash
(all related to where virus spreds in 2dary viremia)

Question 25

when are antibodies made against measles

Answer 25

day 14 after infection

Question 26

what are 60% of measles deaths caused by

Answer 26

2dary pneumonia infection due to immunosuppresant effect of measles

Question 27

what is sspe

Answer 27

subacute sclerosing panencephalitis

Question 28

what does sspe cause

Answer 28

-* Mild cognitive decline (such as memory loss) * Changes in behavior (such as irritability) * Disturbances in motor function, including uncontrollable jerking movements of the head, trunk or limbs called myoclonic jerks * Seizures may occur * Some people may go blind

Question 29

what caused decreased vaccination of measles

Answer 29

Wakefield 1998 linking vaccination to autism = lead to increased outbreaks in UK and ireland