Lecture 23 Flashcards
Define vaccines
Biological treatments that improve immune response to future exposures to specific diseases
Common vaccine types (3)
Live attenuated pathogens (ex. polio, flu, measles, mumps) Killed pathogens (ex. polio, flu, cholera, hepA) Pathogen subunits (particular antigens/inactivated toxins)
What does the HepB virus vaccine target?
The surface antigen “a” determinant (amino dominant domain)
Describe how mutations in the HepB virus occur and how that works at an advantage for HepB
The virus mutates by changing an amino acid in the “a” determinant
Is an advantage because it makes the virus invisible to vaccines and allows for infection of ppl already infected by the wild type virus
Why are vaccine strains not a major public health problem despite mutation? (2)
Mutant strains are outcompeted in unvaccinated hosts (there must be a cost to increased resistance)
Vaccines still protect against severe diseases and since vaccination rates are low, selection pressure is not strong enough to force increase mutation growth
What does the malaria virus vaccine target?
Target TH2 and TH3 epitopes on the virus
These are areas of high variation
Evolution of virus can be promoted by vaccines and occurs by: (2)
Sorting of existing strains -> favouring non-vaccine strains (strains not appearing in vaccine)
Mutations to new non-vaccine strains
Define childhood/acute infections
What does it invoke out of an individual?
Short/severe infections that either kill the host or are rapidly cleared
Invokes a broad and life-long immunity
Current virus characteristics (2)
Polymorphic (many different strains) -> some strains can infect an host that is immune to other strains
Chronic (immune response not able to clear infection (think: HIV) or pathogen evades immune response)
How does environmental change relate to increased disease susceptibility?
The environment is changing faster than humans can evolve so humans are currently living in environments that are not adapted to
This mismatch results in increased disease susceptibility (due to lack of adaptation)
Define myopia
Near sightedness where individuals cannot see far found to vary in frequency in populations
What is the difference between monozygotic and dizygotic twins?
Mono: from same egg with entire same genetic data
Di: from two different eggs with half the same genetic info
What was the conclusion to the myopia and environment study where modern and traditional nations were compared and myopia frequency was observed to measure environmental effect?
Quickly describe the results
Changing environments do have an effect on health
Younger generations and children who spent less time outside were more susceptible to myopia
Define menopause
Why might it occur? (2)
Marks the cessation of ovulating cycles; when reproduction stops
Theories of occurrence:
Blessing of Modern Life (belief that women are living longer now-a-days)
Good Mother (females stop reproducing to fully care for current offspring/grand-offspring and ensure their survival)
What was the conclusion to the killer whale study where presence of/lack thereof mother was observed and male offspring survival was measured to support the Good Mother menopause theory?
Quickly describe the results
Supports Good Mother theory as mothers who gave up reproduction and cared for offspring had higher fitness offspring
Mothers who died later on in the offspring lifetime showed decreased survival of offspring
