A new research printed Friday supplies extra proof of the potential hazard of ingesting unpasteurized, or uncooked, milk containing H5N1 avian flu viruses.
The work, printed within the New England Journal of Medication, confirmed that mice that had been fed milk from H5N1-infected cows turned very in poor health.
The research can not show that what occurred to the mice would undoubtedly occur to individuals who drink uncooked milk containing the harmful virus, but it surely underscores the possible danger, consultants stated. Research like this can’t be carried out in individuals, for moral causes.
“Uncooked milk is clearly extremely suspected of transmitting [H5N1] to animals,” stated Michael Osterholm, director of the Heart for Infectious Illness Analysis and Coverage on the College of Minnesota. “It’s nonetheless unclear what the danger is for people. However I wouldn’t wish to take my possibilities on it.”
Thijs Kuiken agreed. A pathologist within the division of viroscience on the Erasmus Medical Heart in Rotterdam, the Netherlands, Kuiken has lengthy studied the impact of H5N1 viruses on mammals, together with cats. On this outbreak in dairy cattle, there have been a number of experiences of farm cats dying, presumably after ingesting contaminated milk.
“Based mostly on the load of proof from our information of [this lineage of H5N1], to which this letter contributes, it’s doubtless that folks ingesting uncooked milk from contaminated cows would contract systemic illness,” Kuiken advised STAT in an e mail.
The Meals and Drug Administration has lengthy suggested towards ingesting uncooked milk, which might comprise various harmful pathogens corresponding to E. coli, Salmonella, and Listeria. The company has reiterated that recommendation within the context of the present outbreak of H5N1 in dairy cattle.
As of Friday, the U.S. Division of Agriculture has confirmed infections in 63 herds in 9 states; testing on two further herds in Michigan is pending USDA affirmation. Two human infections in farm staff have been detected for the reason that outbreak was first detected in late March.
Neither Kuiken nor Osterholm was concerned within the analysis, which was carried out by researchers on the College of Wisconsin–Madison. The senior writer was Yoshihiro Kawaoka, a number one influenza virologist who has studied H5N1 for many years.
Kawaoka advised STAT in an e mail that the mice had been euthanized on day 4 of the research “as a result of we didn’t wish to see mice die earlier than [tissue] sampling.” Research that contain exposing animals to doubtlessly deadly pathogens don’t permit them to expertise lingering deaths.
There have been a number of parts to the research, which was carried out in early April earlier than the FDA and different educational teams introduced findings of analysis that confirmed that energetic virus couldn’t be grown from milk merchandise that had undergone pasteurization.
Along with the work that concerned feeding uncooked milk to mice, the group simulated a few totally different approaches to pasteurization, which makes use of warmth to inactivate pathogens in milk, to see whether or not they may develop energetic virus from the heat-treated samples. One of many approaches they used killed all of the virus within the milk, although one other, which concerned heating for a brief time frame, solely lowered the quantity of energetic virus within the milk to low ranges.
The researchers cautioned that their approaches to treating the milk weren’t similar to what milk processors use when they’re pasteurizing business milk.
One more side of the research concerned storing uncooked milk containing the virus at fridge temperature for a number of weeks to see whether or not the quantity of virus declined over time. They noticed solely a minor discount within the quantity of energetic virus within the milk, suggesting “virus could due to this fact stay infectious for a number of weeks in uncooked milk stored at 4°C.”
Keith Poulsen, one of many authors, stated that discovering was not a shock. “Flu likes chilly and moist,” stated Poulsen, who’s director of the Wisconsin Veterinary Diagnostic Laboratory and a professor of huge animal inside medication on the College of Wisconsin-Madison.
Apparently, the researchers additionally famous H5N1 virus within the mammary glands of two of the mice after they had been finding out the place the virus was present in mouse tissues after euthanization. Mammary tissues of dairy cattle seem like extremely prone to the virus, with contaminated lactating cows shedding terribly excessive ranges of virus of their milk.
This text has been up to date to incorporate remark from the senior writer.
