The recent detections of High Pathogenicity Avian Influenza (HPAI) in cattle, as well as its ongoing spread in various regions of the world, are raising international concerns.
Among those that is closely monitoring the situation to assess the risks to animals and humans is the World Organization for Animal Health (WOAH), which on April 5 reminded its 183 members that, based on the information currently available, restrictions on the movement of healthy cattle and their products are not recommended.
While HPAI primarily affects poultry and wild birds, avian influenza can occasionally be transmitted to mammals, including humans. In the last two years, an increasing number of H5N1 avian influenza cases have been reported in terrestrial and aquatic mammalians animals.
Clinical signs of recent detections of HPAI in U.S. dairy cattle have included decreased lactation, reduced appetite, lethargy, fever and dehydration. According to WOAH and others, the concerns is that such infections of cattle could indicate an increased risk of H5N1 viruses becoming better adapted to mammals, and potentially spilling over to humans and other livestock.
Initial investigations so far have revealed no specific adaptation to either humans or mammals. Regardless, several studies are being carried out to further explore the virulence and transmissibility of these viruses, including among cattle, and to assess the risk of transmission to animals and humans, which is currently considered very low, stated WOAH.