FLU

Orthomyxoviridae

Eight segmented pieces of RNA, a structure that permits the introduction of new RNA. This is called genetic reassortment. This is called antigenic shift. The hemagglutinin spikes which provide viral attachment to cell membranes. They are strain specific antigens that mutate frequently because of inefficient proofreading by RNA polymerase. This is called antigenic drift. And ditto for the Neuraminidase spike, which provides release from cell membranes

FAQ’s Type A: The Main Player –It causes annual outbreaks –It mutates easily. This is called antigenic drift and is why the vaccine changes every year, usually causing an epidemic affecting 10% to 20% of the population. –It is susceptible to RNA reassortment, where a portion of avian influenza RNA is inserted. This is called antigenic shift and is responsible for pandemics or infections occurring over a wide geographic area and affecting a high proportion of the population. –It is characterized by the H and N antigens.

Type B and Type C

Five Pandemics 1918: Possibly an avian influenza strain that adapted to infect humans and 1968: A human/avian reassortment strain. 2009: A human/swine/avian reassortment virus.

SWINE FLU What does this mean?

Transmission Person to Person Viral shedding—day prior to symptom onset—5-7 days after symptom onset Can get from pigs not from eating pork

Vaccination EVERYONE >6months and older IM (inactivated) Intranasal (live attenuated) Intranasal NOT USED IN: chronic disease, immunsuppression, pregnancy, prior h/o GB from prior vaccinations SMALL AMOUNTS of EGG in each Anaphylaxis is rare What do we carry? Efficacy: 50%-80% rate of protection if closely matched

Vaccine Three strains: (always A-A-B) this year: -A-California h1n1-”like” virus -A-Perth h3n2 ”like” virus -B Brisbane Every year the strains are selected based on worldwide surveillance for most active strains– a little guess-work involved

“I don’t want it today Doc…”

Suspected Cases Fevers, Myalgias TEST—flu swab, nasal

Treatment & PPX Oseltamivir: TAMIFLU Zanamavir: Ralenza Rx for Type A &B Low levels of resistance In 48 hours TREAT (as per Dr. Chung) PPX: NH Residents within 48 h, Case by case Babies, pregnant women

PRACTICAL CONCERNS HOW TO ORDER THE VACCINE HOW TO BILL FOR IT ALLERGIES: EGGS!!! Relative Contraindication No inhaled form of vaccine here Rapid antigen—Nasal swab in 6 th floor Micro ?????s