The Hidden Dangers in Raw Milk: From Bird Flu to Rift Valley Fever

Recent headlines have highlighted a concerning discovery: widespread samples of raw milk containing H5N1, commonly known as bird flu. This prompted the U.S. Department of Agriculture to launch a milk testing program in December to track the virus. However, bird flu is just one of many pathogens that can lurk in unpasteurized milk, including E. coli and Listeria.

New Research on Viral Persistence in Raw Milk

Stanford Medicine researchers have made a significant discovery about another virus that affects both animals and humans - Rift Valley fever virus. Their research shows this virus can remain active in raw milk samples for as long as the milk would typically be consumed. This mirrors previous Stanford findings that showed flu viruses can remain infectious in refrigerated raw milk for up to five days.

Dr. Brian Dawes, an infectious disease fellow at Stanford Medicine who led the research, stated: "We think Rift Valley fever virus in milk is a big unidentified threat, and our findings show that there's potentially a big problem there that needs to be looked at more closely."

Key Research Findings

The study examined how long Rift Valley fever virus remains infectious in milk under different storage conditions:

• In refrigerated milk, there was virtually no change in the amount of infectious virus over five days
• Even in warmer conditions, the virus remained active for roughly as long as someone would safely drink the milk
• PCR tests showed RNA levels remained constant during all conditions, suggesting milk could be used for surveillance purposes
• Pasteurization effectively killed the virus, confirming its importance as a safety measure

The One Health Connection

This research highlights the concept of "One Health" - the idea that human and veterinary health are closely linked and should be addressed simultaneously. Animal products carry risks of zoonotic infections, especially from emerging viruses like H5N1 and Rift Valley fever.

Despite these risks, surveillance systems in many parts of the world are limited or nonexistent. For instance, widespread surveillance for H5N1 in cow's milk in the U.S. only began about a year after the virus was detected in cattle. The researchers emphasize the need for more proactive disease surveillance and research.

Key Takeaways

The study underscores two crucial points:

1. Pasteurization is vital: The process effectively kills viruses and other pathogens in milk, making it a critical public health measure that has saved countless lives.

2. One Health approach is necessary: Human and animal health are deeply connected. Addressing these challenges requires close coordination between human and animal healthcare providers and agencies.

As we continue to face threats from zoonotic diseases, understanding the persistence of viruses in food products like milk becomes increasingly important for public health safety and prevention of future outbreaks.

Link to original article