TThe Centers for Disease Control and Prevention (CDC) confirmed on Wednesday the first “severe” human case of H5N1 avian influenza – or avian influenza, a zoonotic infection that has fueled fears that it could become the next global pandemic.

The serious case is a resident in southwest Louisiana who was reported as presumptive positive for infection last Friday. The infected patient “is suffering from a severe respiratory illness associated with H5N1 infection and is currently hospitalized in critical condition,” said Emma Herrock, spokeswoman for the Louisiana Department of Health. Further information on her condition is being provided at this time for patient confidentiality reasons not disclosed.

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It is the 61st case of human H5N1 bird flu infection in the country since April this year. However, the CDC said the pathogen’s overall risk to the public remains low and no associated deaths have been reported in the U.S. to date.

Here’s what you should know.

What caused the severe infection?

The CDC said in its Dec. 18 announcement that during an ongoing investigation, it was determined that the patient had connections to sick and dead birds in backyard flocks, making it the first known case of infection in the U.S. with these causes.

Of the 60 other cases, 58 were linked to commercial farming – 37 from dairy herds and 21 from poultry farms and culling. The sources of exposure for the other two human cases in the United States remain unknown.

What is the current status of H5N1 infections in humans?

Of the human infections recorded in the U.S. this year, 34, or more than half, occurred in California, with all but one exposure to cattle. In response, Governor Gavin Newsom declared a state of emergency on December 18th.

The CDC said that given cases in other countries, an infection as “severe” as that in Louisiana should be expected. In Vietnam, a patient with H5N1 infection was found who died in March after being diagnosed with “severe pneumonia, severe sepsis and acute respiratory distress syndrome,” according to the World Health Organization. The U.S. appears to be leading the world in H5N1 infections this year, according to CDC data on bird flu cases reported to WHO.

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How can infection be prevented?

The CDC issued a series of protective measures, including avoiding as much direct contact with wild birds and other suspected infected animals as possible and their bodily waste. People who work with cattle and poultry on affected farms are at higher risk of infection and should therefore pay attention to possible symptoms of infection.

Properly cooked poultry and poultry products are safe, and the CDC says that while unpasteurized (raw) milk from infected cows may pose risks to humans, it is not yet known whether bird flu viruses can be transmitted through consumption.