It had to happen and it has. In January 2022, the UK became the first country in Europe to detect a case of the H5N1 flu. Since this week, Spain has become the second. This is relevant because we are talking about a strain that, according to the WHO, has a mortality rate that can reach 60%. But, if we put it in context, we realize that it is excellent news.
What we know about the Spanish case. As confirmed by the National Center for Microbiology, the first positive for H5N1 avian influenza in a human being in the country was a worker on a farm in Guadalajara who, in fact, was suffering from an outbreak of the virus among his birds. The worker (the only one who has tested positive) did not show symptoms at any time and only the positive was found because in these cases all staff are checked.
Is rare? Not too much. Spain has gone through the worst outbreak in history this year. Until now, the country had managed to emerge unscathed from most major outbreaks of bird flu. However, what began with four wild swans and a common stork dead along the Segre riverbed, turned into a huge epidemic that confined farms in half the country and has caused more than 665,000 birds to be culled in a single month. .
And it’s not just something Spanish. The European Food Safety Authority defined the 2021-2022 avian flu season as the largest recorded in Europe and, according to the World Organization for Animal Health, in 2021 there were more cases than in the previous five years combined: 462% more than cases and 150% more deaths in birds compared to 2020
Good news. The fear of many experts is that these huge outbreaks will end up facilitating the appearance of variants of this strain with greater transmissibility in humans. Something that, taking into account its mortality rate, could be a health problem of the first order. However, in the context of the largest outbreak in history, having found a single case of influenza in humans is within reason (the WHO has documented 864 cases in the last 20 years) and confirms that this strain continues to have enormous difficulties in spreading. jump from one species to another.
What can we expect? Little bit. As I say, cases of H5N1 flu in humans are not something to worry about at the moment. Above all, if we talk about the general population. But it does represent a warning about the need to maintain a proactive epidemiological surveillance that is capable of locating, isolating and intervening on realities so new that it is still difficult for us to imagine them.
Image | Thomas Iversen