18. Viral diseases Flashcards
name 2 points of entry for viruses
bloodborne
respiratory
give an example of a blood borne virus
hepatitis B
where does hepatitis B replicate
in the liver, it circulates the blood stream until it reaches the liver
name a respiratory virus that spreads to the rest of the body
measles
why doesn’t bird flu spread in humans
bird flu binds to cells that present carbohydrates on their surface - these are found deep in the respiratory tract
why do seasonal flu viruses Infect better than bird flu
bind to cells in the upper respiratory tract - means they can infect you directly through the nose
how can diseases be transmitted
direct contact aerosol vector borne sharing needles sexually
what are fomites
surfaces on which pathogens can be found
what occurs in the prodromal infectious period
the patient has no symptoms yet are infective
describe the stages of HIV infection
- flu like symptoms
- CD4 t-cells decline and immune system declines, anti-HIV antibodies rise
- anti-HIV can no longer be produced, virus become prevalent and can survive outside t-cells
- virus reproduces uncontrollable = fatal
how does influenza enter the body
via the respiratory tract
which 2 influenzas are included in the seasonal vaccinen
influenza A and B
why is influenza C & D not included in the seasonal vaccine
causes milder infections
what is the molecular sequence for:
spanish flu
hong kong flu
H1N1
H3N2
what launches new pandemics of infleunza
antigenic shift
how can new strains be rpduced
once a animal virus is in a human host it can reassort with human viruses
these produce hybrid strains that are responsible for new pandemics
what is it assumed Spanish flu was a product of
a bird flu reassorting with a human virus
what is the incubation period
the number of days between when your infected and when symptoms may appear
what is the serial interval
the time between symptoms occurring in an initial patient and the onset of symptoms in a secondary infected individual
name 2 diseases spread by the faecal oral route
hepatitis A
foot and mouth disease
what is the vector for foot and mouth disease
humans transmitting the pathogens from farms
when are viral titres at their highest in hepatitis A
following infection before the onset of clinical illness
what is the vector for yellow fever virus
aedes aegypti
- insect vector
why is the issue of climate change important in disease spread
disease such as yellow fever virus are transmitted via insects suited to warmer climates
as temps climb in the north, the insect vector can survive and transmit the disease to these new regions
