Microorganisms of medical importance Flashcards
what is an epidemic?
a level of disease that is above the usual level for a population/community (influenza)
what is an outbreak?
a sudden or unexpected occurrence of disease within a limited segment of the population (e.g. meningococcal disease)
what is an endemic?
a disease that is constantly present in the population (HIV)
what is a pandemic?
a global disease (Ebola)
what is the flu?
viral infection of the lungs
what is influenza classed as?
orthomyxovirus
how many segments in the genetic information formatted into for influenza?
8
what glycoprotein antigens are on the surface of influenza?
- Haemagluttin (H) - mediates binding of virus to the target cell and entry of viral genome.
- Neuraminidase (N) - involved in the release of progeny virus
what is influenza a/b/c responsible for?
A = regular outbreaks B = sporadic outbreaks of illness in humans only C = respiratory illness; not serious human pathogen
how many subtypes of h and n are there?
16 for H and 9 for N
what subtypes are human influenza viruses?
3 subtypes of H and 2 subtypes of N
what is antigenic drift?
a few changes that prevents the immune system from recognizing it “completely”
-small genetic changes
what is antigenic shift?
massive change in h and n spikes
-genetic reassortment
how does antigenic shift occur?
2 different viral strains co-infect the same cell and form a new subtype having a mixture of the surface antigens of the 2 original strains.
-population has never been exposed to this new thing so no immunity.
what effects airborne transmission?
- humidity
- ventilation
- UV radiation
