While outbreaks of avian flu have been identified in the North and in Belgium, Why Doctor takes stock of the risks for humans.
- The H5N1 bird flu virus was first spotted in 1997 in Hong Kong, killing six people. It reappeared at the end of 2003, first causing epizootics in poultry in several Asian countries, followed by the first human cases.
- In all proven human cases of avian flu (873 cases, for 438 deaths, according to a researcher interviewed by Les Echos), the people were in direct contact with infected birds.
- But the spread of infection among birds increases the likelihood of the appearance of a new influenza virus in the human population. And the ability of the virus to “mutate over time” but also “to exchange its genes with influenza viruses belonging to other infectious subtypes of other species” makes the threat real, according to the Pasteur Institute.
After the detection at the end of December of outbreaks of avian flu in bird farms in the North and Belgium, the prefecture issued an order to restrict hunting activities in the areas concerned. An essential precautionary measure to stem the spread of the viral disease, which could become a real threat to humans. Reminder of the risks.
The H5N1 virus can infect other species
Although most avian viruses occur in poultry, some sometimes manage to infect other species: this is the case with the H5N1 virus, which is pathogenic for humans. In all proven human cases of avian flu (873 cases between 2003 and 2022, for 438 deaths, according to a researcher interviewed by The echoes), people were in direct contact with infected birds, and “the very rare cases of human-to-human transmission of the H5N1 virus have remained episodic”, recalls the Pasteur Institute.
However, the spread of infection among birds increases the probability of the appearance of a new influenza virus in the human population. And the ability of the virus to “mutate over time” but also “to exchange its genes with influenza viruses belonging to other infective subtypes of other species” makes the threat real.
“The appearance of an influenza virus belonging to a viral subtype completely unknown to the human population, such as H5N1, renders ineffective the immune memory of the general population generated during seasonal epidemics due to classic influenza viruses, explains the Pasteur Institute. This is in favor of a pandemic, a rapid and global spread of the virus.
Preventive measures against bird flu
How does bird flu spread to humans? “Avian influenza viruses are excreted in large quantities in the droppings of infected birds as well as in their respiratory secretions, writes Santé Publique France. They are thus found in the environment (contaminated dust, bodies of water, etc.). Transmission to humans occurs by inhalation of contaminated dust or aerosols, or by contact when handling infected birds (plumage, evisceration, etc.).”
One of the main safety measures to contain the disease is therefore to observe good hygiene practices (regular hand washing, wearing a mask). All individual protection measures are detailed on the website of the Ministry of Agriculture and Food Sovereignty.
There is no risk of contamination of humans through the consumption of meat, eggs, foie gras and more generally any food product, reassures Santé Publique France.
