“There is confirmation of transmission” of H5N1 avian influenza virus highly pathogenic “between cattle and cattle and from cattle to poultry”, according to what emerges “from viral sequencing”. “Cases of asymptomatic dairy cattle are also confirmed”, but “with H5N1 infection”, although “the extent of testing is unclear”. The American scientist highlights this Eric Topol, executive vice president of Scripps Researchfounder and director of the Scripps Research Translational Institute, in an analysis of the results of the closed-door summit organized in recent days by the Department of Agriculture (USDA), the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration ( FDA), to take stock of the avian emergency in dairy cows in the United States.
Overseas fears over the spread of the avian pathogen in farms are growing, so much so that work is already underway on a “preparation plan in case human transmission” of the virus occurs, which has never been confirmed until now. Federal officials, Topol reports, “explained that Tamiflu”, the antiviral drug oseltamivir, “would be effective” in combating the infection in humans “and that supplies of it have been stockpiled”. Furthermore, “if necessary, the US could divert its annual production of influenza vaccines to produce anti-H5N1 vaccines on a large scale.” There are currently “2 candidate vaccines available against H5N1 that match well with the current sequence” of the virus, and by exploiting mRNA technology “there is the possibility of increasing the supply of vaccine” if needed. Today “it seems very unlikely” that we have to get to that point, that is, to having to deal with an avian flu epidemic in humans, “but the more the H5N1 virus spreads uncontrolled – experts warn – the greater the reservoirs” in which it can proliferate “and the chances of further functional mutations occurring. So it's best to plan for the worst case scenario.”
At the moment the only human case of highly pathogenic H5N1 infection documented in the context of the epidemic among cattle is that of a worker in the dairy sector, who became infected through direct contact with animals in Texas and presented conjunctivitis as the only symptom. To contain the further spread of the epidemic, a federal order was issued requiring testing and reporting of infected animals. As for routine tests on pigs, 'special observation' because they could represent a bridge for the virus to humans, “so far they have been negative”.
“Epidemic more extensive than thought”
L'virus epidemic of highly pathogenic H5N1 avian influenza occurring among dairy cows in the United States it would have started already at the end of last yeartherefore several months ahead of the first case confirmed by the health authorities at the end of March 2024, and is probably more widespread than you think, he further underlines.
Cases of infection have so far been recorded in 8 US states, recalls Topol. But the recent FDA report on the virus positivity of several samples of pasteurized milk on the market, the scientist highlights, “strongly” supports the hypothesis that the spread of the infection on farms “is much wider” and goes “beyond these 8 States”. For Topol it is “important to highlight that the PCR test” used in milk analyzes looks for “virus fragments, not the live virus” whose presence in the food would be “unlikely after pasteurization”. To evaluate the presence of live virus, the FDA will have to carry out other culture-type tests, but those conducted so far – although “limited” – are “to date all negative for any live virus in milk”.
Another fact highlighted by the American scientist concerns the outcome of the “great work” done by the evolutionary biologist from Arizona Michael Worobey, who “heroically analyzed the 239 H5N1 sequences released for the first time on Sunday night”, concluding that the epidemic derives likely from “a single onset of viral transmission from birds to cows. The USDA also said it believes the outbreak among dairy cattle in the United States began in late 2023, initially in Texas.”
#Avian #flu #humanhuman #contagion #risk #alarm #plan #worst #case #scenario
