Dairy cows in a number of US states have fallen unwell with chook flu, based on the US Department of Agriculture (USDA). The virus has killed thousands and thousands of birds worldwide, however that is the primary time it has been detected in cattle.

What number of cows are affected by chook flu?

As of 25 March, milk samples collected from two dairy farms in Kansas and one in Texas have examined optimistic for a subtype of avian influenza known as H5N1, based on The New York Times. This pressure is very deadly in birds. A cattle throat swab taken from a dairy farm in Texas additionally examined optimistic. No cows have died from the virus thus far.

US companies started testing cattle for chook flu on 22 March after farms in Texas, Kansas and New Mexico reported some dairy cows had fallen unwell, and that lifeless wild birds had been on their properties.

On the affected farms, about 10 per cent of milking cows look like sick, most of whom are older. It’s unclear if chook flu is accountable for the entire animals’ diseases. US companies are transferring shortly to conduct extra testing.

How did the cows catch the virus?

The USDA says it seems the cattle caught the virus from contaminated wild birds. Nonetheless, it’s unclear precisely how the virus transmitted between the species.

Most mammals who fall unwell with chook flu are carnivores, equivalent to foxes or seals, which means they almost definitely contracted the virus from consuming lifeless and contaminated birds. As cows don’t eat birds, it’s more durable to clarify the supply of transmission, says Richard Webby at St. Jude Kids’s Analysis Hospital in Tennessee. It might be that faeces or saliva from wild birds contaminated the cattle’s water or meals.

“The most important query I can’t fairly get my head round is find out how to clarify infections throughout such a geographic unfold of states,” says Webby.

The worst-case state of affairs is the virus unfold among the many cows, however that is maybe unlikely, he says. That’s as a result of we haven’t discovered proof that chook flu can transmit between mammals.

Do the sick cows improve the danger of chook flu spreading to individuals?

The chance of contracting chook flu stays low for most individuals. Preliminary testing of samples from contaminated cattle haven’t discovered genetic modifications that will counsel the virus has turn into extra transmissible to people.

But any time a mammal turns into unwell with chook flu, it offers the virus a chance to realize the mandatory mutations to transmit between mammals, says Webby. “However we nonetheless want some solutions to place this into perspective: most of all, what number of cows present proof of being contaminated with the virus?” If few cows are unwell, this can almost definitely be one other lifeless finish for the virus, very like foxes, bears and different beforehand contaminated animals had been.

Is milk secure to drink?

Sure, milk remains to be secure to drink. The USDA already requires that dairy farms solely ship milk from wholesome cattle in for processing. Milk from contaminated cows has additionally been destroyed so it received’t enter the meals provide.

Even when some contaminated milk entered the provision chain, pasteurisation kills micro organism and viruses, together with influenza.