[ad_1]
The Minister of Health, Roberto Speranza, has signed an ordinance with which he has ordered the suspension of activities in mink farms in Italy, to reduce the risk of a further spread of the coronavirus. In recent months, several countries had reported finding infections among these animals, with cases of transmission to breeders, to the point of requiring the slaughter of millions of minks as a precautionary measure. Researchers are working to understand why minks are more exposed to coronavirus than other animals and why they can also transmit it more easily to humans.
Coronavirus and animals
After their identification in the 1960s, researchers found that different types of coronaviruses affect animals other than humans, although in some cases the dynamics of the infection are not yet fully understood. The pandemic has allowed further research on this topic and it has been found that the current coronavirus (SARS-CoV-2) can infect non-human primates, dogs, cats (and other felines), bats, pangolins, hamsters, and various species. mustelids, including minks.
Parenting and coronavirus
The first cases of infection among minks were detected in the Netherlands at the end of last April. The analyzes in some farms, used for the production of skins, had led to the discovery of cases of human contagion to these animals, which in turn had infected other farmers. Therefore, the Dutch government had decided to accelerate the already planned closure of farms planned for 2024, due to the difficulties of the sector and the protection of animal health. In the following months, several other countries had detected cases of infection among minks on farms.
In Europe, the problem mainly affects Denmark, one of the world’s largest mink fur producers. Farms are mainly concentrated in the northern and eastern part of the country and, as in the Netherlands, they have been suffering from a crisis related to reduced demand for several years.
For months now, the Danish government has launched an extensive program of analysis and control of plants, not only to reduce the risk of new infections, but also to prevent the passage of the coronavirus between different species (minks on the one hand, humans on the one hand) others) leads to mutations of the virus, with consequences difficult to predict.
A mink farm in Bording, Denmark (Ole Jensen / Getty Images)
Mutation
In early November, the Danish government also announced the slaughter of millions of minks, to avoid further risks after detecting a first SARS-CoV-2 mutation in some humans, which is believed to have spread through herds of mink. . These animals. The variant (“Group 5”) has been shown to be slightly more resistant to our neutralizing antibodies and therefore could reduce the effectiveness of coronavirus vaccines currently in development and testing.
However, according to the World Health Organization (WHO), the mutation would not render already developed vaccines useless. To avoid risks, in recent weeks Denmark ordered an isolation of the areas where the mutation had been detected in the population. On November 19, the Danish institute that deals with contagious diseases (Statens Serum Institut) announced that the lockdowns and massive tests, carried out to detect possible infections, have probably led to the extinction of Cluster 5.
So far, at least six countries have notified the WHO that they have detected cases of coronavirus among farmed minks. In addition to Denmark and the Netherlands, Sweden, Spain, Italy and the United States did. Greece has started some investigations after receiving news of some suspicious deaths among minks on its farms.
Why precisely minks?
Minks, like other mustelids, are very sensitive to the coronavirus because the cell membranes of their respiratory system have a receptor (ACE2) that is exploited by the virus to evade cellular defenses and inject them with the genetic material (RNA) to make them. produce new copies, continuing the infection. ACE2 is present in different tissues of our body and has been identified as the main entry point of the coronavirus into our cells.
The presence of this receptor is considered a valid indicator to evaluate whether or not a species is exposed to the risk of contagion. Each species naturally has different characteristics, so not all of them suffer from the presence of the coronavirus in the same way. Researchers believe that many animals can become infected but do not develop symptoms as a result of the infection. However, knowledge about the spread of the coronavirus in animals is limited for now, although there are numerous ongoing investigations that could also help us better understand how the current pandemic originated.
By having a version of ACE2 similar to ours, minks can in some cases be infected by a human and consequently can infect other humans. By accessing cells, the coronavirus multiplies in mink, causing symptoms that can be severe, to the point of killing infected animals. The process takes place relatively easily given the similarities of the receiver.
It was thanks to the first suspicious deaths that veterinarians in the Netherlands became aware of the presence of the coronavirus on farms. After ruling out bacterial causes and detecting the presence of coronavirus-positive workers on the farms, the veterinarians conducted molecular tests and finally found the presence of the coronavirus among the minks.
In farms of this type, minks coexist in rather small and crowded cages, where contagion can easily occur. The methods of propagation are still not entirely clear, but from some experiments carried out with ferrets (which we can consider close relatives of minks) it is clear that the infection occurs by inhalation of the particles of mucus and saliva emitted by the specimens. contagious.
Mink farmers Holger and Ruth Rønnow, among the many specimens they had to euthanize due to the risk of coronavirus infection, Herning, Denmark (Ole Jensen / Getty Images)
Generally, the cages on farms are separated from each other with panels that prevent the passage of air currents, while the upper part is open. When they cough or sneeze, minks spread virus particles from one cage to another, infecting a considerable number of animals in a short time. If they develop a viral infection, these minks tend to infect others as well.
However, the methods of contagion between minks and humans are currently less clear. Analyzes conducted on farms in the Netherlands found that more than 50 percent of operators had contracted the coronavirus. Further studies on the collected samples found a link between the version of the virus in farmers and that of mink. The researchers therefore believe that it is highly likely that several operators have been infected, directly or indirectly, by mink.
Other animals
Infections on farms are accelerating the decline of the mink economy, but they are also a precious opportunity to discover how the coronavirus spreads between different species and with what risks to our own. Sampling is done not only on sick minks, but also on healthy ones to detect the possible presence of antibodies. In this way, for example, it can be understood if some specimens contract the coronavirus without later becoming ill, as it happens in humans.
The analyzes also refer to pets that live on or near farms, such as dogs and cats. In the Netherlands, for example, infected cats were found in at least six mink farms, while none of the dogs tested positive for coronavirus.
To date, around 20 verifiable cases of cats testing positive for coronavirus have been reported worldwide, and only one of them appears to have died from symptoms developed after infection. There have also been sporadic reports of infections among dogs, but with no particular details or news of deaths related to the presence of the coronavirus.
For animals raised for their meat, the risk of contagion is currently considered extremely low. Pigs and poultry are not sensitive to the coronavirus and there is no evidence that livestock and fish are susceptible to this type of virus.
[ad_2]
