Never quite understood this, but ran across a recent NPR podcast that talks a little bit about this:
http://podcastdownload.npr.org/anon.npr-podcasts/podcast/510221/103963708/npr_103963708.mp3

Our immune system’s first reaction is to produce interferon, which tries to hold the virus at bay until the killer T-Cells arrive. The problem lies when the immune system over-reacts (cytokine storm) and all the immune system resources go to fight the virus leaving you exposed to bacterial threat (ex. bacterial pneumonia). That’s why if a flu persists, antibiotics are usually prescribed. It’s also mentioned the virus attacks a particular organ, then that could also lead to death.

If it was me, I would consider a vacation to Cancun “essential travel”. But here is the latest recommendation from the CDC.

http://wwwn.cdc.gov/travel/contentSwineFluMexico.aspx

Sounds like at the very least you should take one of the two the antiviral agents if you go.

who should be tested

for Swine Flu:

Clinicians should consider swine influenza infection in the differential diagnosis of patients with influenza-like illness [ILI, defined as fever ≥37.8ºC (100ºF) and a cough and/or sore throat] who:
1) are a contact to a confirmed swine influenza A (H1N1) case, OR
2) are part of a cluster of people reported with ILI, OR
3) traveled to affected areas including Mexico [check HERE for affected states/countries and HERE for specific affected California counties (California Swine Flu News) ] in the 7 days preceding illness onset, OR
4) were in contact with persons with ILI who were in affected areas during the 7 days preceding illness onset, OR
5) are hospitalized with ILI or pneumonia.

Doctor Jim,

My husband and I are scheduled to leave for Cancun MX on Sunday May 3.

I plan on taking extra hand sanitizer, hospital masks, (which we will use @ the airport and in the cab to the hotel). But I am thinking we should probably up or immune systems, which vitamins do you suggest we increase this week and while we are in MX.

*************************************************
Stephanie,

I am not aware of any vitamins that have been shown to reduce your risk of catching the flu. Many herbal supplement makers have measured markers of immune function in the blood. But when you take someone with a normal immune system and increase those markers, there is no evidence that it prevents infections. Similar to the lack of advantage if you turn on a flashlight during daylight hours. While some of these products may show benefits in future studies. The current best evidence is that you are wasting your money.

Your best bet is hand washing/sanitizers, masks, and avoiding the “hot spots” in Mexico City and other provinces that have Swine Flu cases.

Your biggest risk is traveler’s diarrhea. Take some over-the-counter anti diarrhea agent with you. If you have problems with vomiting, I would see a Mexican doctor and ask for a prescription for Zofran (odanestron). The pharmacy will require a prescription, but that medication will have you back on your feet fast. You might even want to get a prescription from your doctor before you go. But the Mexican office visit will probably be cheaper than your co-pay here.

You are smart. I would not let a few feverish pigs keep me from the beautiful white sand beaches of the Caribbean!

Dr Jim

People have been focusing on birds, while pigs are a bigger concern in my mind. The re-sorting of human and avian viral DNA will likely occur in pigs resulting in a new strain of flu. While the media and most individuals worry about birds, the CDC has been diligent in surveillance of birds, pigs, humans, etc.

Flu “season” is the time when influenza traditionally peaks. Nov thru March in the northern hemisphere and May thru Sept in the southern hemisphere. but we see influenza cases all year long. That’s the great think about this early detection at this time. If these cases herald a major source of Flu for the coming year, we will have ample time to develop a vaccine before the true season strikes.

I am confident that there will be more cases in the coming weeks and months. We’re not done hearing about Swine Flu yet.

A couple years back there was a couple of great segments on Nova about the avian flu, what will make it an (airborn) pandemic, and 2 (of the most important genes that makeup these deadly viruses (H and N… i.e. H5N1, H1N1, H3N2)
http://www.pbs.org/wgbh/nova/sciencenow/3302/04.html
http://www.pbs.org/wgbh/nova/sciencenow/3318/02.html

One thing that still puzzles me though, is why do we call it Flu Season. Do the flu viruses spontaneously die during the summer? Isn’t it possible to get the flu outside of flu season?

This is exactly why good journalists will quote their source so that the reader can “fact-check”. While I try to be one source of fact-checking for the public, I am clearly not perfect either. Thanks so much to listener Beth for taking the time to write and ask. I love the way we can come together on the internet and communicate openly, helping each other stay informed.

Dr Jim