Carl Abraham, M.D. | Source | Assistant Professor (NYITCOM-Arkansas) at New York Institute of Technology

The genes of influenza viruses frequently mix in each animal that is infected with different strains of the virus. This gene mixing, or recombination, can result in influenza viruses that are able to act in new ways, for example, infect new species, cause new symptoms, and worsen the severity of illness. Presumably, a recent recombination event has made an avian influenza transmissible to and between domesticated cattle.

Since this is a highly pathogenic strain (H5N1), it is not surprising that the virus is spreading beyond the respiratory tract into mammary glands and, thus, cow’s milk. Since pasteurization destroys influenza viruses, it’s also not surprising to find fragments of the virus in milk, but these fragments contain too little of the virus to cause illness or spread infection. H5N1 influenza is not the only virus that can have fragments present in cow’s milk, and that is why pasteurization is so important.

“Right now, there isn’t a need for the general public to be vaccinated against monkeypox, but we shouldn’t underestimate the potential impact of this virus, especially among the immunocompromised. Containing its spread will require an all-hands-on-deck public health response,” he says.

Bird flu, or avian influenza, infects more than 100 species of wild birds. It is rare for these strains of influenza to infect humans, although there are increasing reports of bird flu cases in other mammals such as tigers, polar bears, elephants, seals, mink, and pet dogs and cats. In birds, it causes a respiratory illness that is categorized as either highly pathogenic or low pathogenic. Pathogenicity relates to how sick the infected animal is, and highly pathogenic avian influenza has the ability to spread beyond the respiratory tract to infect multiple organs, often resulting in death in birds within 48 hours.