Two Spanish poultry farm workers tested positive for avian influenza following an outbreak in poultry, in what appears to be the first known human infections in Spain and the second in Europe since 2003, reported Reuters, citing the World Health Organization on Thursday.

The poultry outbreak was confirmed by authorities on September 20 and there has been no evidence to date of human-to-human transmission related to this event, the WHO said.

The infections with influenza A (H5N1) of the two workers - males aged 19 and 27 - were detected in September and October, likely triggered by exposure to infected poultry or contaminated environments at the farm in Guadalajara in central Spain.

Both men did not have any symptoms and were isolated until they tested negative. Following the poultry outbreak, all farm workers and their close contacts were tested.

Spain's Health Ministry did not immediately respond to a request for comment.

Avian influenza infections in humans may range from asymptomatic or mild upper respiratory infection to rapid progression to severe pneumonia, acute respiratory distress syndrome, shock and even death.

From 2003 to October 21, 2022, a total of 868 human cases, including the two cases in Spain, and 456 deaths have been reported globally from 21 countries, according to the WHO.

A total of three human cases of infection, one case from the United Kingdom in 2021 and the two cases from Spain in 2022, have been reported in Europe to date, it said.

The reports of these two cases do not change the current WHO recommendations on public health measures and surveillance of influenza, the organization said.