Influenza, commonly called “the flu,” is a contagious respiratory illness caused by viruses. Infection with influenza viruses can result in illness ranging from mild to severe with life-threatening complications. An estimated 10 percent to 20 percent of u.s. residents get the flu each year. On average, 114,000 people are hospitalized, and 36,000 die each year from complications of flu.

Symptoms of flu include fever (usually high), headache, extreme tiredness, dry cough, sore throat, runny or stuffy nose and muscle aches. Gastrointestinal symptoms can include nausea, vomiting and diarrhea. Influenza viruses spread from person to person primarily in the respiratory droplets of coughs and sneezes. Called “droplet spread,” the phenomenon occurs when droplets from an infected person’s cough or sneeze are propelled through the air (generally up to three feet) and deposited on the mouth or nose of people nearby. Though much less frequent, the viruses also can be spread when a person touches respiratory droplets on another person or on an object and then touches his or her own — or even someone else’s — mouth or nose.

Influenza infection among travelers is quite common. It may rank with hepatitis A as one of the most common vaccine-preventable diseases that afflicts travelers. Influenza virus infections cause disease in all age groups. Rates of infection are highest among infants, children and adolescents, but rates of serious illness and death are highest among people older than 65 and among people of any age who have such medical conditions as chronic cardiopulmonary disease. The emergence of new strains of human influenza A virus can lead to global epidemics, increased complications and higher rates of fatality. We experienced this phenomenon in the United States last winter when flu-related deaths among children and the elderly were especially high.

The risk for exposure to influenza during international travel depends on the destination and the time of year. In the tropics, influenza can occur throughout the year, while in the temperate regions of the Southern Hemisphere, most activity occurs from April through September. In temperate climates, travelers can also be exposed to influenza during the summer, especially when traveling as part of large tourist groups with travelers from areas of the world where influenza viruses are circulating.

Getting an influenza vaccination prior to travel is a good idea for people who are at high risk for complications, especially if: They weren’t vaccinated the preceding fall or winter; they’re planning to travel to the tropics; they will be traveling with large groups; or they’re planning to be in the Southern Hemisphere any time from April through September. In North America, travel-related influenza vaccination should be administered by spring when possible, because influenza vaccine can be hard to get during the summer. In the United States, the main option for reducing the impact of influenza is prevention with the inactivated vaccine, available either as an injection or as a nasal spray. The vaccine available this year protects against three strains of the flu.

Three antiviral drugs are approved and commercially available for use in treating flu. All of these medications are prescription drugs, and a doctor should be consulted prior to use. Antiviral treatment lasts five days and must be started within the first two days of illness.

Here are some tips that may prevent the spread of respiratory illnesses like flu:

– Avoid close contact with people who are sick.
– Cover your mouth and nose with a tissue when coughing or sneezing. It may prevent those around you from getting sick.
– Wash your hands frequently to help protect yourself from germs as germs are often spread when a person touches something that is contaminated then touches his or her eyes, nose or mouth.

If, despite precautions, you come down with the flu:

– Get plenty of rest.
– Drink a lot of liquids.
– Avoid using alochol or tobacco.
– Consider taking over-the-counter medications to relieve the symptoms.
– Stay home and avoid contact with other people.
– Cover your nose and mouth with a tissue when you cough or sneeze.
– Wash your hands frequently with soap and water or alcohol-based hand cleanser, especially after coughing or sneezing.

While suffering the flue, be aware of symptoms that require immediate medical attention, such as:

– High or prolonged fever
– Difficulty breathing or shortness of breath
– Pain or pressure in the chest
– Near fainting or fainting
– Confusion
– Severe or persistent vomiting

Remember, most healthy people recover from the flu without complications.