Update on “Cow Flu”

The VetSalus website reported recently on the spread of avian flu amongst dairy cattle in the USA ^{(1, 2)}

Over the summer months the problem has not disappeared. A recent edition of New Scientist ⁽³⁾ reports that six more people have tested positive for the virus in October, all of whom reported recent contact with sick cows or birds and thankfully reported mild symptoms. Worldwide, since 2020, when the H5N1 strain of the influenza virus began its rapid spread through avian populations, over 900 people have been confirmed with H5N1 and around half of them died of the infection.

The situation in the USA is concerning. To date 299 herds are known to be infected across14 states. There have been no confirmed reports of the virus spreading between humans but this may well be only a mutation or two away. Every time H5N1 infects a bovine species it has the potential to become better at infecting any mammalian species and the infection of dairy cows places them in close proximity to people. As the magazine article states:

“.....those things are not good in terms of a virus that has that pandemic potential.”

As the flu season begins in the USA, that country’s Centers for Disease Control and Prevention has stepped up its monitoring activity and is currently testing between 65,000 and 155,000 human samples weekly, with further testing capacity being developed. This should rapidly lead to a much fuller picture of the magnitude of the threat from the virus to the human population. Wastewater monitoring is also in place.

In a separate story, from France, the same magazine reports that the spread of the virus among farm poultry has been significantly reduced by vaccination of ducks. Duck farming is a major industry in France and in the 2022 -23 season there were over 400 farm outbreaks. After the introduction of a nationwide vaccination program, there have been only 10 reported outbreaks this season.

VetSalus noted that the use of the new vaccine provides stunning evidence on the benefits of a well timed and deployed vaccination program to animal welfare, economic loss and sustainability.

LMG  (Adapted from New Scientist 19/10/2024)

References

1. Will Avian flu become Cow flu? | VetSalus

2. How cows transmit avian flu to humans - is milk the missing link? | VetSalus

3. https://www.newscientist.com/  (subscription required for some stories)