At least 16 people have died from a new strain of swine flu in Mexico, according to news reports, and scientists from the Centers for Disease Control and Prevention are investigating whether those infections are related to a swine-flu strain in California and Texas that has infected 7 people. Mexico is taking precautions, including closing some schools, and Canada has issued a travel advisory. The CDC has confirmed that the swine flu virus is contagious in California and Texas and that it can be spread from human to human.

According to the World Health Organization, the majority of the Mexican infections have occurred in young adults who were otherwise healthy. Symptoms of swine flu are similar to the seasonal human flu, including fever, lethargy, lack of appetite, and coughing. Some people with swine flu have also reported runny nose, sore throat, nausea, vomiting, and diarrhea and in some cases the flu has resulted in severe illness and disease, including pneumonia and respiratory failure.

If you develop flu-like symptoms, contact your health-care provider to discuss whether testing or treatment is necessary. The flu can be diagnosed by testing a respiratory specimen, but usually only during the first 4 to 5 days of illness, while the patient is still shedding the virus. The CDC recommends treating or preventing swine flu with the antiviral drugs oseltamivir (Tamiflu) or zanamivir (Relenza). Human flu vaccines won’t protect against the swine flu.