Medical name: influenza

Major symptoms: body aches, fevers and chills, and generally feeling terrible (usually not associated with upset stomach, vomiting, and diarrhea).

Caused by: three varieties of influenza — influenza A, B and C.  Influenza A varieties are further named according to viral protein coatings with an “H-number-N-number” sequence.  For example, H1N1 was a doozy in 2009 and H3N2 is gearing up to be the big variant this year.

How you catch it: by coming into contact with the respiratory secretions of an infected person (i.e. coughs, sneezes, runny noses, and dirty objects that have been contaminated by these things).  After exposure, there’s a quiet incubation period for 1-4 days, then the infection rears its head.

How long am I contagious? And how do treat it? Most people are contagious for a day before symptoms and about a week after first showing symptoms.  Oseltamivir (Tamiflu, $50+) can be prescribed within the first 48 hours of symptoms but has a long list of side effects and has been shown to reduce symptoms in otherwise healthy people by only a day, on average.  Aside from oseltamivir, treatment for the flu is just rest and recover! (Shameless plug for getting your flu vaccine: the flu vaccine helps reduce the risk of getting the flu by 40-60%, on average, and it doesn’t cause the flu.  I recommend everyone get the vaccine, as I’d take a 40% reduction in risk of getting the flu any day!)

It can turn into: pneumonia! Keep an eye on loved ones with the flu, as the most common complication is a lung infection.  Influenza, in rare cases, can also affect your heart or nervous system.  Reach out to your doctor if you have any concerns that things are worsening.