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A silent, insidious wave of bird flu has been quietly spreading among US cattle for the past months, as recent genomic data analysis reveals. This highly pathogenic avian influenza, or bird flu, is likely to have made a leap from a bird to a cow in late December or early January.
The data lends weight to the likelihood that a significantly larger number of cattle in the US and possibly even neighboring regions may be infected with avian influenza than currently known. It also raises concerns about the time it took for the data to be publicly released – nearly four weeks after the announcement of the outbreak. Timely data is paramount to combating rapidly spreading viruses that have pandemic potential, such as this strain of bird flu.
The outbreak began with what researchers refer to as “single spillover” – when the virus jumped from wild birds into cows in late 2020 or early January. Since then, the virus has spread and mutated within the bovine population. These mutations include changes to a section of the virus’s protein linked to the potential adaptation needed for the virus to spread among mammals.
Researchers also found evidence of the virus jumping back and forth between cows, birds, and cats, leading them to conclude that this is a multi-host outbreak. Amid the race to unpack and understand the data lies a concerning data gap – lack of information about each sample’s collection date and state, making it difficult to understand and control the virus’ spread effectively.
Amid this worrying development, findings from the FDA and Science News dispel some of the fears. Firstly, it should be stressed that “highly pathogenic” refers to the disease’s severity within birds, not humans. Secondly, preliminary results of egg-inoculation tests on retail milk samples reveal that pasteurization is effective in inactivating HPAI – meaning the commercial milk supply remains safe.
Despite some unsettling findings, scientists want to make it clear that the risk to humans remains low – primarily due to the pasteurization process and the nature of how bird flu spreads. The RNA found in milk samples does not indicate the presence of infectious viruses. The FDA does, however, caution against consuming raw, unpasteurized milk.
Understanding the spread of bird flu in the US is an ongoing process – the situation is evolving, and scientists are striving to keep the public informed as new information emerges. The lesson we’ve learnt from past pandemics remains clear: vigilance and timely response are essential in mitigating the risk of a full-blown pandemic.
Information Box:
The Outbreak: Bird Flu in US Cows
– The influenza strain: Highly pathogenic avian influenza or Bird Flu
– When it began: Suspected to have begun in late December or January
– Method and pace of spread: Fast and through multiple hosts (cows, birds and cats)
– Mutation: Yes, thus carrying the potential to spread among mammals
– Impact on humans: Low risk but congestion of raw milk discouraged
– Control measures: Ongoing research and data analysis to understand and control spread
References:
1: Nature, Bird flu virus has been spreading in US cows for months, RNA reveals
2: FDA, Updates on Highly Pathogenic Avian Influenza (HPAI)
3: Science News, Traces of bird flu are showing up in cow milk. Here’s what to know