Here’s some urgent news for you: The USDA has ordered mandatory testing of all dairy cattle before they are moved across state lines – a measure aimed at halting the spread of the highly pathogenic H5N1 avian influenza. This action follows the discovery by a lab at Ohio State University of genetic material from the virus in a whopping 38% of retail milk samples. This finding strongly suggests that the current outbreak of the disease is more widespread than reported.
In a concerted effort to safeguard the U.S. livestock industry from the threat posed by this avian influenza, various actions are being implemented with federal partners to contain the spread of the disease. As it now stands, before dairy cattle can be moved interstate, they must test negative for the influenza A virus at an approved National Animal Health Laboratory Network (NAHLN) laboratory.
Owners, please listen closely: if your dairy cattle test positive, you’ll be required to submit epidemiological information, including details on the animals’ movement. Added to that, any dairy cattle being transported interstate must strictly adhere to conditions laid out by APHIS.
“Future guidance will be released, but for now, these steps are immediately applicable for lactating dairy cattle. The rules for other classes of dairy cattle will be tailored as per scientific factors concerning the virus and its evolving risk profile,” says the USDA.
Importantly, labs and state veterinarian offices are now mandated to begin reporting results of influenza A nucleic acid detection diagnostic tests, which involve PCR or genetic sequencing, in livestock.
Though the highly pathogenic H5N1 avian influenza was not a reportable disease in livestock, it is proving to be an emerging threat for dairy cattle. Surprisingly, some cows not presenting any signs of illness, are still testing positive for the virus—this has raised a few eyebrows at the USDA and the U.S. Centers for Disease Control and Prevention(CDC). Nonetheless, these institutions assure the public that the current risk remains low.
Meanwhile, in a comforting gesture, the FDA has reassured consumers about the safety of pasteurized milk, even after retail milk samples tested positive for fragments of HPAI H5N1. They added that these detectable pieces do not indicate a live virus, hence posing no risk to human health. However, according to researchers, it does underscore that avian influenza within the nation’s dairy herd is perhaps more common than what’s currently being reported.
Now listen to this: A lab at Ohio State University, part of the NIH network for the Centers for Excellence in Influenza Research and Response, has found virus material in 38% of retail milk samples. The team tested 150 samples, from which 58 tested positive for viral RNA. These samples were then sent to St. Jude Children’s Research Hospital for further study.
The major point of contention? The difference between finding viral RNA (which is genetic material) versus a live virus. This distinction not only reassures consumers about the safety of U.S. milk supply but simultaneously serves as a key indicator to track the extent of the virus spread. As Bowman, an influenza researcher, points out, “The viral RNA identified in retail milk does not cause sickness in humans. It is merely an indication of how widespread the virus is in the US dairy cattle herd.”
As researchers scramble to comprehend the full extent of this outbreak, the question at the forefront remains: how the virus continues to spread among livestock? Bowman’s lab, having worked with influenza viruses for over a decade, suggests that addressing influenza is no easy task. Animals infected but asymptomatic could be unknowingly spreading the virus.
Bowman philosophically observes that with influenza, it’s always a question of who’s giving it to whom. As more data is collected, researchers hope to gain a clearer understanding of the situation.
