8: Measles

Question 1

measles as a killer

Answer 1

important cause of death

most frequent cause of vaccine-preventable childhood deaths

Question 2

measles viral life cycle

Answer 2

simple virus making 8 proteins

lytic virus
- lyse the infected cells where it comes in, infects the cell and pokes holes in the membrane
- virus either has to get out or the cell has been too damaged by the virus
- virus is not purposefully lytic but just killing the host cell

Question 3

measles transmission

Answer 3

R0 is 12-18
- one of the fastest, most infectious viruses

infects mucous membranes, then spreads through the body causing acute infection

spread through close person contact
- respiratory transmission

Question 4

measles epidemiology

Answer 4

only found in humans with no animal reservoir
- not a zoonosis

no latent/persistent infections

transmission higher in densely populated areas and areas with high HIV prevalence

Question 5

measles vaccine

Answer 5

live attenuated vaccine introduced in 1963

given in combination with MMR
- measles as the strongest vaccine improving reactivity of mumps and rubella

no revirulence of measles vaccine

Question 6

measles immunosuppression

Answer 6

biggest reason for death is immunosuppression

can directly cause death but also leads to immunosuppression which causes you to die from other infections

Question 7

measles disease

Answer 7

in unvaccinated people, measles spreads throughout the body and normally causes a characteristic rash all over the body

Question 8

cycle of disease

Answer 8

comes in through the lungs, infects lung cells and disseminates through the body

can infect almost all the cell types in the body (macs, DCs, skin cells, T/B cells), etc.
- systemic disease killing a lot of immune cells

Question 9

big issue with measles

Answer 9

can destroy memory T cells and B cells to whatever else you’ve been infected with

provides protection against measles and also improve childhood immunity to other infections

Question 10

rare CNS complications

Answer 10

infects neurons in the central nervous system instead of motor neurons like polio

can infect brain neurons and spinal cord neurons
- leads to permanent brain damage

Question 11

measles encephalitis

Answer 11

inflammation or swelling of the brain

Question 12

measles meets criteria for eradication

Answer 12

human transmission only

specific clinical diagnosis (almost 100% symptomatic in contrast to polio)

effective vaccine

low antigenic variation

interrupted transmission in specific geographic area for prolonged time periods

Question 13

elimination vs eradication

Answer 13

elimination
- no infection

eradication
- no possible cases anywhere in the world

Question 14

but no eradication because

Answer 14

decrease in infections but far from eradication

elimination about coverage and getting everyone vaccinated as soon as possible