There have been 61 confirmed cases of bird flu in the United States, including one 65-year-old Louisiana man who is hospitalized in critical condition from the illness.

Most human cases of bird flu, caused by avian influenza A(H5) virus, have been mild so far, and most were in people who had known exposure to sick or infected animals.

The severity of illness associated with bird flu has ranged from mild to severe, including death, according to the Centers for Disease Control and Infection. The reported signs and symptoms of bird flu in humans have varied. Eye redness has been the predominant symptom among recent U.S. cases. Respiratory symptoms and fever were also reported.

The two groups of people most at risk for catching bird flu are farm workers who work with cows or poultry and people who keep backyard flocks of chicken, said Michael Osterholm, the director of the Center for Infectious Disease Research and Policy at the University of Minnesota.

He told CNN that the virus can be shed by chickens and land up in the air so direct contact isn't needed to catch the disease. The virus can also live on the udders of milking cows, and it's been found in raw and unpasteurized milk.

The best way to protect yourself is to avoid sources of exposure. The virus that causes bird flu can't be destroyed with refrigeration but can be killed though pasteurization, so stick to pasteurized products.

People who work in potentially infectious environments, such as on a farm or rescue setting, should wear personal protective equipment pr PPE, notes the CDC:

• Goggles
• Disposable gloves
• Face masks such as N95s
• Coveralls
• Rubber boots

The Food and Drug Administration says that eggs purchased in retail markets are most likely safe to eat because there are safeguards in place to test infected poultry. However, the FDA still advises that eggs are stored properly and cooked thoroughly before eating.

According to USA Today, in other countries the bird flu has killed about half of people that became infected, but in the U.S. there have been no deaths so far and most cases are mild.

Health officials haven't recommended vaccination against the bird flu, although they have prepared about 10 million doses of H5N8 vaccine that they believe will be effective against the H5N1 bird flu virus that is currently circulating. In Finland, health officials distributed that vaccine to people who work with minks.

The virus has not been transmitted between humans to date, but that is one of the red flags officials will be looking for before taking more aggressive action to quell the spread of bird flu.