Due to the global concern over the evolving swine flu outbreak, this morning the European Union’s health commissioner issued a warning advising Europeans to avoid travel to Mexico or the U.S., unless it is deemed “essential.” This follows this weekend’s news of 20 cases of swine flu being diagnosed in the U.S. (eight of them in New York City; all students who had recently traveled to Mexico), and after one man hospitalized in eastern Spain tested positive for the flu strain.

The U.S. has issued its own public health emergency as well, with plans to enact border screenings.

For HIV-positive travelers, 365gay.com has posted an AP report that stresses “while anyone could be susceptible to contracting swine flu, people with weakened immune systems, such as those with HIV, are at particular risk.”

Over 100 people in Mexico have died from causes related to the recent outbreak of swine flu, though generally the disease seems to manifest itself with less critical flu-like symptoms. (The Center for Disease Control offers a good primer on “What is Swine Flu?”) The virus is not transmitted by eating pork products, but spreads via person-to-person, generally as a result of coughing or sneezing.

So, should you cancel your trip to Mexico? (Or to New York City, for that matter?) At present, the CDC has not issued any official recommendations for travelers to avoid Mexico (or the U.S.), but they do offer a list of safety guidelines which all travelers should consider.

If you are heading to Mexico, your visit could be a quiet one. Right now, reports are coming in that all over Mexico many public sights are closed and due to local health advisories people are staying indoors, and those who are venturing out are doing so wearing surgical masks. When a big soccer match sees empty bleachers, you know it’s serious.

Travel safely!