The World Health Organization on Wednesday (July 12th) expressed concern that the increase in cases of avian flu in mammals is helping the virus to spread “more easily” to humans. “Bird flu viruses normally spread among birds, but the increasing number of cases of H5N1 avian flu detected in mammals – which are biologically closer to humans than birds – raises concerns that the virus is adapting to infect humans more easily,” the WHO said in a statement.
In the warning, also signed by the Food and Agriculture Organization of the United Nations (FAO) and the World Organization for Animal Health (WHO), the organizations call on countries to work together “to save the as many animals as possible and to protect populations”.
Since its appearance in 1996, the H5N1 avian influenza virus has caused essentially seasonal epizootics. According to the WHO, since 2020 a variant of this type of virus has caused an unprecedented number of deaths of wild birds and poultry in many countries in Africa, Asia and Europe. In 2021, the virus spread to North America, and in 2022 to Central and South America. These epizootics are synonymous with massive deaths of wild birds and the slaughter of tens of millions of poultry.
The three organizations are also concerned that certain mammals could serve as “mixing reservoirs” for influenza viruses, leading to the emergence of new viruses that could be even more dangerous to animals and humans.
Recently, there have been increasing reports of deadly outbreaks in mammals, they note. Since 2022, ten countries on three continents have reported outbreaks in marine and land mammals to OMSA, but the organizations consider it likely that outbreaks have not yet been detected or reported in other countries. Avian flu has so far been detected in at least twenty-six species of mammals, including farmed mink, seals and domestic animals such as cats and dogs.
“Monitor and Detect”
According to the WHO, human infections can cause serious illness with a high mortality rate. The human cases detected so far are mainly the consequence of close contact with infected birds or with contaminated environments.
“Based on the information available so far, the virus does not appear to be able to transmit easily from person to person, but we must remain vigilant to identify any evolution of the virus which could change this”, points out Sylvie Briand , head of WHO’s Epidemic and Pandemic Preparedness and Prevention Service. “We encourage all countries to improve their ability to monitor these viruses and detect any human cases. This is all the more important as the virus is now affecting countries that have limited experience in avian flu surveillance,” she continued.