Avian flu, virus found in pasteurized milk: what it means and what the experts say

Fragments of avian influenza virus have been detected in samples of pasteurized milk in the US, where a highly pathogenic strain of H5N1 has been infecting dairy cows in several states for several weeks. This was announced by the Food and Drug Administration (Fda), which together with the Centers for Disease Control and Prevention (CDC) and the Department of Agriculture is investigating the avian flu epidemic on farms. The news bounces around the American media, along with a clarification: “There are no risks for consumers”, reassure the health authorities.

The PCR test, the analysis that made it possible to identify the presence of the virus, looks for traces of genetic material, so a positive result does not mean that the virus found is alive and infectious. “Based on available information, pasteurization is likely to inactivate the pathogen, but is not expected to eliminate the presence of viral particles,” explains the FDA. “To date – the agency points out – we have not observed anything that would change our assessment that the commercial supply of milk is safe”.

Burioni: “It's not good news but no alarms”

“Avian influenza virus in milk. No alarms, but a sign that the avian virus is moving between species, moreover it is its job and it does not surprise us. But be careful. It is not positive news. We will talk about it”. As Roberto Burioni, professor of microbiology and virology at the Vita-Salute San Raffaele University of Milan, comments on social media on the discovery of highly pathogenic H5N1 fragments in some milk samples in the USA, where an avian flu epidemic is underway on the farms of several States. In communicating the news, the FDA reassured that consumers are not at risk and that the milk on the market is considered safe.

Ciccozzi: “Siren to increase surveillance and prevention

“The finding of fragments of H5N1 in bovine milk in the USA should not be surprising because in the past it was found, using PCR, in waste water. We must therefore avoid alarmism, but it is certainly a siren to improve transparency in data communication, surveillance on farms and the prevention of any 'escapes' of the virus”. Thus epidemiologist Massimo Ciccozzi spoke to Adnkronos Salute.

Ciccozzi is among the authors of a study, currently being published in the journal 'Travel Medicine and Infectious Disease', which analyzed the genomic sequences of the virus in question. In the conclusions of the work, the researchers – with Ciccozzi also Francesco Branda of the Campus Bio-Medico University of Rome and Fabio Scarpa, Biomedical Sciences of the University of Sassari – highlighted that cases of H5N1 in cattle “are a significant cause for concern” and “require urgent action to mitigate potential risks to public health, animal welfare and economic stability in the dairy sector.”

The Italian study highlighted that there is “selective pressure in the hemagglutinin (Ha) gene that could alter binding to the receptor, leading to viruses better adapted to binding to human receptors. Today the primary host remains birds, but phenomena of genetic drift cannot be excluded.” For this reason, in the conclusions the scientists suggest “a rapid implementation of robust surveillance, the need for rapid and rigorous response mechanisms, the presence of biosafety protocols which are fundamental to safeguard both human and animal well-being and maintain the resilience of the dairy sector -dairy”.