Influenza viruses Flashcards
what is influenza?
acute respiratory illness
is influenza infectious?
highly
can spread rapidly from person to person
TF: adults shed the virus for longer than children and are less unwell
false
how many strains are there? how do they differ?
3: ABC
in severity
which type of influenza is most significant and why
type A
it changes strain
meanest of the flu viruses
what does type A infection
birds and other animals as well as humans
what does type B and C infect
humans only
which type causes pandemics
type A
B and C don’t
where did influenza A come from?
the bird
why are strains which start in birds hard to trace
don’t produce symptoms in birds
onset of influenza
sudden and makes you very unwell
symptoms of influenza
fever headaches muscle aches severe weakness respiratory symptoms
how does influenza spread?
person to person through coughing and sneezing
also touching something that has it on then touching your face
what does antigenic shift result in
seasonal changes which our immune system don’t recognise
what makes some years worse than others
degree of shift
how can we predict what the next years flu will be like
looking at other sides of the world who have their winters at different times
what is an influenza pandemic? who has immunity
new again strain acquires the ability to infect people and spread easily
has to be something never seen before
no one has immunity
2 ways in which influenza pandemics can occur?
reassortment
mutation
what is reassortment?
an exchange of seasonal and avian influenza genes in a person or pig infected with BOTH strains
what is mutation?
an avian strain becomes more transmissible through adaptive mutation
what major change in the virus causes occur in mutation and reassortment
changes in the surface antigens
TF: pandemic flue most often cause severe disease in the very young, the very old and those with chronic illnesses over seasonal flu?
false- seasonal flu does
what age range had the highest mortality rate in the 1918-19 pandemic? why?
20-40 years
good inflammatory response- harmed the lungs and made them die
spanish flu HN?
H1N1
