( CNN ) -- As reports of swine flu continue to rise in the United States and around the world , the average American is probably asking , `` How should I protect myself ? '' U.S. health officials stress the importance of frequent hand washing during outbreaks of illness . Health officials ' advice is to follow common-sense precautions : Wash your hands , stay home if you 're sick and listen to your local health authorities . `` Very frequent hand-washing is something that we talk about time and time again and that is an effective way to reduce transmission of disease , '' said Dr. Richard Besser , acting director of the Centers for Disease Control and Prevention . `` If you 're sick , it 's very important that people stay at home . If your children are sick , have a fever and flu-like illness , they should n't go to school . And if you 're ill , you should n't get on an airplane or another public transport to travel . Those things are part of personal responsibility in trying to reduce the impact. `` So far , Mexico has been hardest hit by swine flu . Cases have been confirmed in the United States , as well as countries including Canada , New Zealand , Spain , United Kingdom , and Israel . `` In areas with no disease yet , a lot of what we can do sounds simple and repetitive but helps , '' said Dr. Anne Schuchat , interim deputy director of the CDC 's Science and Public Health Program . In addition to washing hands often , she recommends covering your mouth when coughing and sneezing and avoiding touching your eyes and nose in case the virus is on your hands . The World Health Organization calls the situation a `` public health emergency of international concern , '' and the United States has declared a `` public health emergency , '' likened by Homeland Security Secretary Janet Napolitano to preparations for a potential hurricane . No authorities are calling the outbreak a pandemic . The CDC expects U.S. numbers will grow and recommendations will change depending on what happens in individual communities , said the CDC 's Schuchat . The public should pay attention to what is happening nearby and heed the guidance of local health officials regarding school , work and public events . Because so much is still unknown at this point , the main risk factor is people traveling to areas where cases have already been identified . `` However this virus may already be in other places in the United States , '' CDC spokesman Tom Skinner told CNN . `` With enhanced surveillance , we will see more cases and that is why it makes good sense to be proactive , by doing things we know are effective in reducing exposure . '' Explainer : Swine flu facts » . Schuchat noted swine flu symptoms are relatively general and nonspecific . `` So many different things can cause these symptoms . it is a dilemma , '' she said . `` It is a challenge that we are wrestling with . There is not a perfect test right now to let a person or doctor know exactly what this is . '' But Schuchat specifically advised anyone who feels ill after returning from Mexico to see a doctor . Unfortunately , since this is a new strain of influenza , the flu vaccine for this past flu season offers no protection . `` However , we do have anti-virals that work against this swine flu , '' said Skinner , referring to oseltamivir ( Tamiflu ) and zanamivir ( Relenza ) . `` Someone who has [ swine flu ] , if they are treated early , the anti-flu medicines work against this . '' According to Skinner , health officials are still trying to figure out where exactly the virus originated , how transmissible it is and why it is mild in some cases and deadlier in others . CNN 's Mary Carter contributed to this report .
Take standard flu season precautions to prevent infection , CDC advised . Chief risk factor is traveling to countries where swine flu has been reported . No vaccine for new strain exists but antiviral treatment can increase duration .