Avian flu, caused by the H5N1 strain of the virus, is raising serious concerns among global health authorities. Originally identified in birds, this virus has crossed the species barrier to also infect humans and other mammals, such as cows, thus representing a growing threat.
This alarming spread has led the World Health Organization (WHO) to express major concerns about the evolution of the situation.
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The H5N1 virus has been responsible for several human infections, with sometimes fatal outcomes. From the beginning of 2023 until April 1, 2024, the WHO has recorded 889 human cases in 23 countries, resulting in 463 deaths, which corresponds to a mortality rate of 52%. This viral strain presents a particularly high risk of mortality in humans, although human-to-human transmission has not yet been proven.
The modes of virus transmission are diverse, ranging from inhalation of contaminated particles to direct contact with infected animals. Poultry, the main carriers of the virus, can infect other animal species such as cats, pigs, and cows. Humans can be infected through contact with these sick animals, which raises growing concerns about a possible increase in human transmission cases.
Despite progress in monitoring and detecting infections, the virus's capacity to adapt remains a major source of concern. Jeremy Farrar, Chief Scientist at the WHO, emphasizes the importance of understanding the true extent of infections, as this is where the virus's adaptation takes place. Concerns are even more serious given that the virus could acquire the capacity for human-to-human transmission, thus initiating a potential pandemic cycle.
In light of this looming threat, calls for action are increasing. Experts warn about delays in researching an effective vaccine for humans. The president of the Committee for Vigilance and Anticipation of Health Risks, Brigitte Autran, points out that the virus would become a serious threat if pigs were contaminated, paving the way for easier transmission to humans.
Article author: Cédric DEPOND