Bird flu: Viruses now also discovered in beef
In the USA, evidence of the H5N1 bird flu virus has now also been discovered in the meat of a cow. The animal had been killed after he was diagnosed with an infection with bird flu. Previously, only viruses had been discovered in the milk of cows. In the meat of another 95 sick cattle, the testers found no evidence of the virus.
The investigations were carried out with the help of PCR tests, which, however, cannot distinguish between active viruses and virus particles. True infectivity can only be demonstrated on the basis of cell cultures or living animals.
Where does the virus in cows come from?
It seems possible that a single cow in Texas has become infected. Subsequently, the virus could have spread first within the herd and later via animal transport. So far, animals have been affected in around 30 farms in eight US states. The first cases were discovered in February 2014. According to analyses of the virus genome, however, it could have been circulating for much longer. In addition, it could be much more widespread than previously thought.
Can you get infected by eating steak?
Meat from culled animals is not sold. However, it is possible that the 52 affected flocks discovered so far are only the tip of the iceberg and that the bird flu virus is rampant in many more herds. It cannot therefore be ruled out that infected animals originating from this end up in the refrigerated shelves of supermarkets.
Whether a person can become infected by eating infected beef is currently still open. However, this would probably only be possible with raw or very briefly fried meat. This is because heat kills the viruses.
Researchers from the Agricultural Research Service had “vaccinated” 300 g of burger meat with H5N1 viruses each. Both “medium rare” (at 60 °C) and “well done” (at 70 °C) burgers then no longer contained any active viruses.
Even in “bloody” burgers cooked at temperatures of 50 °C (which is “well below the recommended temperature”), the virus was largely inactivated.
How long and how strongly do you have to heat milk?
There are now also test results on the viral load in milk. They have shown that heating milk above 63 °C for several minutes reliably inactivated all viruses. However, heat treatment of 15 to 20 seconds to 72 °C rendered only the majority, but not all, viruses harmless.
This procedure is similar to that used to pasteurize milk. Experts have not yet commented on whether one could become infected even with such small amounts of virus in milk.
Earlier assessments are based on experiments in which milk contaminated with other types of viruses had been pasteurized.
Contaminated raw milk is infectious!
Raw milk from infected cows, on the other hand, contains plenty of active bird flu viruses and proved to be highly infectious in an experiment with mice: The animals fed with it quickly developed symptoms of illness such as shaggy fur and lethargy. The researchers were able to detect the virus in their respiratory tract and some other organs.
Cats that had drunk raw milk on the affected farms also fell ill and died.
In Europe, there has still been no bird flu infection in cattle herds.
Is there a threat of a new pandemic?
A new pandemic could develop when a pathogen is transmitted from person to person. So far, there is no evidence of this in the case of H5N1. In addition, the type of transmission is decisive: Diseases that are transmitted through the air, for example, are particularly contagious. There is no evidence of this in H5N1 either. However, as the Sars-CoV-2 pandemic has shown, viruses are extremely adaptable. The situation can therefore change at any time.
How does the WHO assess the situation?
Based on the available information, the World Health Organization (WHO) estimates the risk to public health as low overall: “In people who come into contact with infected birds or animals or with an environment contaminated by the virus, the risk of infection is classified as low to moderate.”
How does the virus spread?
That is still unclear now. The most likely infection seems to be via the milking utensils. In some cows, for example, only individual teats were infested. In mechanical milking, individual milking cups placed on the teats could therefore also pass on the virus.
It is also conceivable that the high-pressure cleaning of the barns produces virulent aerosols that pass from one farm to the next via equipment or clothing. With one exception, no viruses have been found in the respiratory tract of infected cows. Whether it is still possible to spread through the air remains open.
Precautionary measure here in the UAE
The UAE has been proactive in responding to the bird flu (avian influenza) situation in the region. Recently, the UAE Ministry of Climate Change and Environment (MoCCAE) imposed a ban on the import of live birds and poultry products from Kuwait due to an outbreak of bird flu there.
The primary strain of concern is the H5N1 virus, known for causing severe disease in birds and having the potential to infect humans, although human cases remain relatively rare. The UAE is taking these steps to ensure biosecurity and protect public health, preventing the spread of the virus within the country.