With Europe suffering its worst ever outbreak of avian influenza (AI), perhaps it was inevitable that someone, somewhere in Europe, would become infected with the virus, and reports have now been released revealing that two poultry farm workers in Spain have been infected with the H5N1 virus strain.

Where human cases of H5N1 are concerned, Europe has, until recently, been in the enviable position of having nothing to report. This, however, changed at the start of the year, with the announcement of a case in the U.K. The number of infections has now risen to three. This may be low compared to some regions, but the AI situation in Europe is predicted to worsen over the months ahead.

What happened?

The 2021-2022 AI season in Europe has seen unprecedented numbers of infected birds. Over 48 million domestic poultry have been culled, while colonies of seabirds have been particularly affected.

In late September, H5N1 was confirmed on an egg farm, in the province of Guadalajara, in Spain’s central region of Castilla-La Mancha, a good distance from the Atlantic coast, where numerous infections in seabird colonies have been reported.

Over 600,000 layers were culled as part of disease control measures, but it was not only the layers that had been infected.

Two farm workers

A 19-year-old male farm worker, one of a team of 12, also tested positive for the disease, despite not showing symptoms, and remained in isolation until subsequently testing negative.

In October, farm workers were re-tested and this time, a 27-year-old make worker, thought to have been involved in control measures, including cleaning and disinfection, also tested positive, despite having used personal protection equipment. He also showed no symptoms and remained in isolation until subsequently testing negative.

H5N1 is an ongoing public health concern and, while in Europe there may only be three known cases of the virus jumping from birds to humans, this is not the case globally.

World Health Organization (WHO) data reveals that, between 2003 and October 21st this year, a total of 868 H5N1 human cases, including the three in Europe, were recorded. These infections resulted in 456 deaths – a case of fatality rate of 53%. The infections were detected across 21 countries.

There are, of course, other strains of the virus that have infected humans and resulted in fatalities. Some regions have, clearly, been much harder hit than others, but it should never be forgotten that disease knows no boundaries, while climate change is thought to making the spread of some diseases ever easier.

WHO notes that whenever AI viruses are circulating in poultry there is a risk for sporadic infection and small clusters of human cases.  Fortunately, the two Spanish workers quickly cleared the infection, but there are growing concerns that H5 may have become endemic in Europe, and so more human cases can probably be expected.