On May 22, the Centers for Disease Control and Prevention in America announced a new human infection with the H5 avian influenza virus. This virus, which has pandemic potential, has been rapidly spreading among dairy cows in the country. This marks the second identified human case linked to the cow outbreak, both of whom are farm workers. They contracted the virus through contact with infected animals and only experienced mild symptoms.
While there is currently no evidence of human-to-human transmission, public health authorities in America are closely monitoring the situation. In preparation, half of the national pandemic stockpile of H5N1 vaccine is being prepared for deployment.
Influenza viruses have the ability to infect many different species. Occasionally, a virus will cross over and infect a species that is not its usual host, which can be highly lethal for the new host species. H5N1 is an avian influenza virus that has crossed over into numerous bird and some mammalian species, presenting a potential pandemic threat as there is no existing immunity to it in humans. Since its first detection in geese in China nearly three decades ago, there have been approximately 900 known human infections worldwide, mostly from contact with infected poultry or other birds. Nearly half of these cases were fatal, though it’s possible that mild or asymptomatic cases went undetected, which would lower the overall fatality rate.
