“Due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of global surveillance,” WHO said in a statement. “This case does not change the current WHO recommendations on public health measures and surveillance of influenza,” it added, rating current risks to the general population as “low.”

The man had been bedridden for three weeks for other reasons, before the onset of acute symptoms, according to WHO. His symptoms first appeared around April 17 and included fever, shortness of breath, diarrhea and general malaise.

He sought medical attention on April 24 and was hospitalized at the National Institute of Respiratory Diseases in Mexico City. He died later that day.

Other subtypes of H5 avian flu have spread to humans, but evidence from previous events have so far suggested that the viruses “have not acquired the ability to sustain transmission between humans,” WHO said. People who came in contact with the man shortly before his death have so far not tested positive for H5N2, it added.

Bird flu in general threatens the international poultry supply and comes with some risk of spreading to humans, typically through direct contact with an infected animal or contaminated environments. There are no known cases of an individual catching bird flu from eating properly cooked meat, according to the U.S. Centers for Disease Control and Prevention.

A highly pathogenic form of bird flu was detected in a goat in March, the first confirmed case in the United States involving a domestic ruminant animal (i.e. cattle, sheep and goats). Within days, avian influenza was found in several U.S. cows and rapidly spread across state lines, with a dairy worker in Texas testing positive in April for H5N1, a different subtype than the one detected in the man in Mexico.

Experts have criticized federal agencies in the United States for being slow to track and control the outbreak, with nine states observing outbreaks in cows as of Tuesday. Forty-eight states have recorded outbreaks in poultry, according to the CDC.

Four human cases of avian flu have been reported in the United States since April 1; three of the infections followed exposure to dairy cows in Texas and Michigan, while one followed exposure to poultry in Colorado, the CDC said.

For those in places with known avian influenza outbreaks, WHO recommends avoiding contact with livestock as well as places where animals could have been raised, slaughtered or may have spread their feces. Basic hygiene such as frequent hand-washing is also recommended.