Drinking raw milk at any time attracts dangerous germs. But the unprecedented outbreak of H5N1 avian flu in U.S. dairy cattle has raised the stakes significantly. Health experts have stepped up warnings against drinking raw milk during the outbreak, but the extent of this is still unknown.
But crude oil enthusiasts aren't afraid of the heightened risks. The California-based Raw Milk Institute said the warning was “clearly fear-mongering.” Mark McAfee, the lab's founder, told the Los Angeles Times this weekend that his customers were actually requesting raw milk from cows infected with H5N1. According to McAfee, his customers believe, without evidence, that drinking high levels of the avian influenza virus directly will build immunity to the deadly pathogen.
Expert Michael Payne told the LA Times that the idea was like “playing Russian roulette with your health.” “It goes against all medical knowledge and common sense to deliberately try to infect animals with known pathogens,” added Payne, a researcher and dairy outreach coordinator at the UC Davis Western Institute for Food Safety and Security.
Not much is known about the biology of avian influenza in cattle. Cattle were generally considered virtually resistant to H5N1 until March 25, when the U.S. Department of Agriculture confirmed the virus in a dairy cow in Texas. But since then, the USDA has counted 42 herds in nine states infected with the virus. So far, epidemiological data shows there has been cattle-to-cattle transmission following a single spill event, and 42 outbreak clusters have been linked to the movement of cattle between farms.
Limited data on cattle so far suggests that most cattle suffer mild illness from the infection and recover within a few weeks. Their mammary glands are a prime target for viruses. A preliminary publication published earlier this month found that cow udders are rich in the molecular receptors that avian flu viruses latch onto to cause infection. Moreover, sweat glands contain different types of receptors, including those targeted by human flu viruses and those targeted by avian flu viruses. Dairy cows could therefore potentially serve as mixing vessels where different types of flu viruses reassemble into strains that cause new outbreaks.
While the virus appears to be active in cow udders, researchers found that raw milk was loaded with high levels of H5N1 virus particles. These particles appear to be easily spread to other mammals. In a case study last month, researchers reported that a group of about 20 farm cats became seriously ill after drinking milk from a cow infected with H5N1. Some developed severe neurological symptoms. Within a few days, more than half of the cats died.
deadly virus
Data on flu receptors in both animals may explain the differences between cattle and cats. Although there were different types of flu receptors in the cow's mammary glands, these receptors were less common in other parts of the cow, including the respiratory tract and brain. This may explain why there is a tendency for mild infections. Cats, on the other hand, appear to have more widely distributed receptors, and infected cats have been shown to have the virus invade their lungs, heart, eyes and brain.
Raw milk advocates, who claim without evidence that drinking raw milk offers health benefits over drinking pasteurized milk, dismiss the risk of exposure to H5N1. They confidently claim, without evidence, that the human digestive system will destroy the virus. And they emphasize that there is no documented evidence that humans have been infected with H5N1 by drinking contaminated milk.
The latter claim that there is a lack of evidence for milk-borne H5N1 transmission is true. However, this outbreak marks the first known spread of highly pathogenic avian influenza (HPAI) to the mammary glands of dairy cows. This therefore presents the first known opportunity for milk-based transmission to occur.
Before pasteurization became routine in commercial milk production, raw milk was a common source of infection and provided an abundance of bacteria. According to the FDA, in 1938, milk-borne illnesses accounted for 25% of all foodborne illness outbreaks. Recently, milk has been linked to less than 1% of these outbreaks. According to the Centers for Disease Control and Prevention (CDC), between 1998 and 2018, places where raw milk was sold legally had 3.2 times more cases than places where it was illegal.
“At this time, we do not know whether the HPAI A(H5N1) virus can be transmitted through consumption of unpasteurized (raw) milk and products made from raw milk (e.g., cheese),” the Food and Drug Administration (FDA) said in a question and answer document. He said. However, because of the lack of data and the potential for infection, the FDA recommends halting all sales of raw milk and raw milk products produced from cows infected with or exposed to H5N1. In general, the agency does not recommend consumption of raw milk .
Globally, as of March 28, 888 cases of H5N1 have been reported in humans in 23 countries. Of the 888 people, 463 died. This represents a mortality rate of 52%. However, there may be asymptomatic or undiagnosed cases that can change that rate. In the United States, only one person is known to have been infected with H5N1 so far in connection with the dairy cow outbreak: a farm worker who developed conjunctivitis. The man had no respiratory symptoms and recovered. He did not consent to further follow-up, and researchers did not agree to test the man's household contacts to see if they were also infected.