Mink, like people, often dies of a virus infection, and no one knows why. “This is critical,” said Perlman. “Why do people get sick? Why do we react so differently to these viruses. ”He said he had thought about studying mink, but the challenges, involving their genetic diversity and the lack of an established set of biochemical tools to study infections in them, made the prospect difficult.
Some parts of the mink puzzle fit together easily. They live in overcrowded conditions in rows of cages on mink farms, like people in cities, and are in constant contact with the humans who care for them. It is not surprising, then, that they not only caught the virus from people, but also passed it on to us.
And the mink infection and the potential danger it poses is a reminder that it is not just wild animals that are the cause of overflow events. Human herds housed in closed rooms have always transmitted diseases to humans and acquired diseases from them. But large human settlements were necessary for the appearance of epidemics and pandemics.
In a 2007 article in the journal Nature, several infectious disease experts – including Jared Diamond, the author of “Weapons, germs and steel: the fate of human societies” – wrote about the origins of diseases that spread only in relatively human populations. dense. Measles, rubella and whooping cough, they wrote, are examples of collective diseases that need populations of several hundred thousand for sustained spread. Human groups of this size did not emerge until the advent of agriculture, some 11,000 years ago.
The authors listed eight diseases of temperate regions that affected humans from domestic animals: “diphtheria, influenza A, measles, mumps, pertussis, rotavirus, smallpox, tuberculosis”. In the tropics, more disease came from wild animals, for a variety of reasons, the authors wrote.
Diseases range from wild animals to farm animals and then to people. Influenza viruses jump from wild waterfowl to poultry and sometimes pigs and then to people who are in close contact with the farmed creatures. As with mink, viruses continue to mutate in other animals.
There may even have been a previous coronavirus epidemic that came from cattle. Some scientists have speculated that one of the coronaviruses that now cause the common cold, OC43, may have been responsible for the 1889 flu epidemic that killed one million people.