When scientists think about the transfer of microorganisms between animal species, we usually focus on “spillover” events: the transfer of pathogens from animals to humans. The spread of pathogens is not a one-way street . Humans have transmitted the SARS-CoV-2 virus that causes COVID-19 to wild deer, mink, captive gorillas, pet dogs and cats, and other species of animals. This transmission of infection from humans to animals is colloquially referred to as “returning” of the organism. This infection can have significant impacts on wild species as well as humans. Viruses are perhaps the best-studied example of reflux. For example, during the 2009 swine flu outbreak caused by the H1N1 virus, many different animal species—including pigs and ferrets—were infected with humans. Bacterial reflux may be more common than viruses for a number of reasons. Bacteria can replicate in a wider range of species because they generally do not require species-specific receptors on host cells like viruses do. Bacteria may also be better at replicating on the mucosa, skin, or gut of a wider range of animals, which would facilitate species transitions such as spillover or reflux. When infectious microbes replicate repeatedly in different animal species, their evolutionary trajectories may vary in each species, potentially creating new variants that, if reinfected in humans, may evade immunity .
This article is reprinted from: https://www.solidot.org/story?sid=71388
This site is for inclusion only, and the copyright belongs to the original author.