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How was influenza(FLU) discovered?
studies on animal diseases (pigs, in 1918 by J.S. Koen)
Influenze comes from the family _____________. Which are ______ viruses that comprises of 5 genera, 2 main types cause most human epidemics and infections (A & B).
(differentiated by their serotype based on their surface antigens ex:H1N1)
Which virus were there higher morbidity/mortality rates for the very young and middle aged persons ?
Influenza "the Spanish Flu"
Which type of reservoir consists of wild birds & mainly aquatic; also known that humans and pigs carry and transmit various strains of virus?
Which type of reservoir almost exclusively infect humans (besides seals)?
Which type of reservoir is less common than types A & B and usually causes mild diseases in humans and pigs?
How is the flu transmitted?
via small aerosol particles - cough/sneezes (each droplet = 500,000 virus particles)
also thru infected objects (shared drinks), and surfaces.
also seasonal in infection rates
The life cycle of the flu in humans are restricted to what?
the respiratory tract
Pigs create new strains causing an antigenic shift (2 diff strains combined to form new subtype) thru what?
-"mixing vessel" for genetic exchange btwn humans and avian strains
What are antigenic shift mutations?
-process of 2 diff strains combining to form a new subtype
What are the symptoms of the flu?
- severe malaise
- chills followed by fever
- fever (38-40°C/100.4-104°F)
- Myalgia (muscle aches) - back and legs
- Cephalgia (headache)
- Ocular symptoms (photophobia,tears,ache,burning)
- Dry cough, nasal discharge
- aches in joints and throat
What are the complicated symptoms of the flu?
- primary influenza virus pneumonia
- secondary bacterial infection; often involves:
- -Streptococcus pneumoniae,, Staphylococcus aureus,, and Hemophilus
- croup (laryngotracheobronchitis)
- -affects younger children
- -aka "barking seal cough" and sneeze
- -difficulty breathing and stridor "crowing" on inspiration(=have high pitched sound)
Besides antigenic shift, the flu also causes ?
mutations-antigenic drift(process of random mutations over time; lack of RNA-proofreading enzymes)