SAO PAULO, May 18 (Reuters) - Brazil is investigating a suspected case of avian influenza A (H5N1) in a person living in the southeastern state of Espirito Santo, where this week the first ever confirmed cases in wild birds were detected, the Health Ministry said.

A 61-year-old man, who worked at the park where three wild birds tested positive for Highly Pathogenic Avian Influenza (HPAI), is being monitored and in isolation after he showed mild flu symptoms, the ministry said in a statement.

A reference lab in Espirito Santo is analyzing samples from the man and 32 other people who also work at the park, it added, pointing out that no confirmed cases of influenza A have ever been reported in the country.

While humans can contract H5N1, cases remain rare, and global health officials have said the risk to humans is low.

Brazil, the world's largest poultry exporter, is adopting an extra cautious stance after the detection of the H5N1 subtype in wild birds.

Transmission of the highly pathogenic virus subtype to the country's commercial flock would risk nearly US$10 billion of chicken exports as trade bans may be imposed by importing nations.