Monday, March 4

What we know about the first case of H5N1 avian influenza in humans detected in Spain

The National Center for Microbiology has confirmed the first positive for H5N1 avian influenza in a human being detected in Spain, according to what Animal’s Health announced yesterday. This is the worker of a poultry farm located in the province of Guadalajara who remained asymptomatic and isolated until testing negative. It is the second case detected in Europe after the United Kingdom declared its case in January this year.

What happened?

The National Center for Microbiology has found the first positive for avian influenza H5N1 in a human being in Spain, as advanced Animal’s Health. This is a worker from a farm located in the province of Guadalajara (Castilla-La Mancha) who suffered an outbreak among birds. The positive has been detected during the active surveillance tasks to which the personnel of these places are subjected. The confirmation arrived on September 27 and the sample was from the 23rd. The patient remained asymptomatic until giving a negative result on the 28th, and no more cases have been found among the rest of the staff.

What is this H5N1 flu?

Influenzavirus A subtype H5N1 is an influenza virus that causes a highly contagious and severe disease in birds, commonly known as “bird flu.” The numbers in the name refer to two proteins on the surface of the virus, hemagglutinin (H) and neuraminidase (N), used to classify influenza subtypes.

Avian influenza is also divided into two types: high and low pathogenicity (IAAP and LPAI, respectively). The first is the greatest threat to birds and the poultry industry due to the high mortality it causes in animals, and it is the one detected in this case.

Why is it important that a person has tested positive in Spain?

This is the first person in Spain in which a positive for H5N1 flu is detected. It is also the second case in Europe: the first took place in UK in January 2022. They are not the only countries that have found their first case this year: The United States did it in April.

Human cases are rare, but the mortality rate can reach 60%, according to the WHO. At the moment it does not spread well between people and almost all cases so far have been in people exposed to infected birds, such as farm workers. However, its high lethality, added to the fact that in recent years there has been an explosion of cases in people and birds, worries experts, given the possibility that the virus mutates to spread better.

Where did it come from?

The so-called “poultry plague” has been known since the end of the 19th century, but the H5N1 flu was found in a goose in China in 1996. I was going to change everything: in 1997 it was seen to be able to jump between species. He infected 18 people in Hong Kong, a third of whom died. In 2003 it reappeared in Asia and since 2005 has been spreading and causing outbreaks among wild and domestic birds all over the world.

The current strain of H5N1 was detected in 2021 and since then it has cost the lives of almost 90 million birds based only on data from the United States and Europe, the majority due to the sacrifice of domestic specimens to try to control outbreaks.

Spain, United Kingdom, United States… Why now?

In recent years, there has been an H5N1 avian flu pandemic in various parts of the world, causing the slaughter of millions of animals and huge economic losses. The European Food Safety Authority (EFSA) listed the 2021-2022 bird flu season as the largest recorded in Europe to datewith more than 5,000 cases in 36 countries.

In 2021 there were more cases than in the previous five years combined, according to data from the World Organization for Animal Health facilitated to The Telegraph. This was 462% more cases and 150% more deaths in birds compared to 2020. With these figures it is not surprising that the virus has more opportunities to jump to a human host.

Just this week, the ECDC shared new data over the 2021-2022 season: 2,467 outbreaks in poultry, 48 million animals slaughtered in Europe and 37 countries affected.

And why in Spain?

Spain is highly vulnerable to bird flu as it is the destination of more than one and a half million wintering migratory waterfowl from infected countries. “The susceptible population of wild and domestic birds in Spain is very high, and the potential economic impact is high given that the Spanish poultry sector ranks second in livestock production,” explained two researchers from the Animal Health Research Center (CISA). in a forum published in the Science Media Center Spain that analyzed the unprecedented wave that our country faced this year.

There have been millions of cases in birds, and in humans?

According to the WHObetween 2003 and March 31, 2022, 864 cases of influenza A H5N1 in humans have been recorded, of which 456 died (representing a lethality per case of 52%).

It is not transmitted between people and the risk lies in those who are in contact with birds. Can I get infected if I eat chicken?

It is not possible to get it by eating cooked meat. Viruses depend on a living organism to survive, so they begin to disappear as soon as their host dies. In the unlikely event that supermarket-bought chicken still contained viable viruses, these would be destroyed during cooking. It is important to maintain good hygienic practices when handling meat and cooking it well, but the reasons for this go far beyond the H5N1 flu.

According to the WHO, “a large number” of human infections have been linked to the slaughter and handling of infected birds at home, before cooking. Although this is not a problem for most of the inhabitants of developed countries, who buy in the supermarket, these are the practices with the highest risk and the ones that should be avoided the most.

Do I have to worry about another pandemic?

“The higher incidence in recent epidemics makes these viruses a threat to public health. This, and the fact that they are viruses with a high rate of mutations, makes it necessary to maintain constant vigilance in both birds and people”, CISA researchers Irene Iglesias and Ana de la Torre warned in their gallery.

H5N1 flu detections in humans should not concern the general population at the moment, but they should remind us that avoiding the next pandemic requires active vigilance, effort, research and investment.