Human-to-Animal Diseases: How Tragic Could They Go?
The recent outbreak of "Coronavirus Disease 2019 (COVID-19)" provoked an enormous scare in the community. While the source is yet to be confirmed, evidence proves that the virus became infectious in human bodies after consumption of wildlife. We have learned lessons from the avian flu and severe acute respiratory syndrome (SARS). Ever wondered if animals would be infected by human?
The fact is, most viruses and bacteria have more than one infection target. Broadly living in the natural environment, Staphylococcus aureus could easily infect humans and animals with weakened immune system. It has become a superbug due to the abuse of antibiotics in recent years. There were cases of pet cats and dogs those were infected by Methicillin-resistant Staphylococcus Aureus (MRSA) from their owners, who were frequent hospital visitors.
Despite the rarity of close contact with humans, wild animals are not invulnerable to human diseases. In Morocco, endangered Barbary Macaques (Macaca sylvanus) were infected by human respiratory diseases because of contact with tourists, as a study revealed. In Rwanda, Africa, multiple cases of Mountain Gorillas (Gorilla beringei beringei) infected by human respiratory diseases were reported between 2008-2009, including a community that was infected by Human Metapneumovirus. Nearly all the Mountain Gorillas in that community were infected, killing an adult female gorilla and a 3-day-old baby gorilla. At the time, there were only around 700 Mountain Gorillas on the planet. The cause is crystal-clear – the diseases were transferred from humans to Mountain Gorillas during eco-tours. For this reason, the International Union for Conservation of Nature (IUCN) published the Best Practice Guidelines for Great Ape Tourism, suggesting visitors to put on N95 masks when watching great apes, for the sake of the wild animals' health.
Not surprisingly, wild animals could be infected directly, and of course, indirectly, from humans. Leprosy has long existed in Eurasia, but was absent in the Americas. However, the disease was spread to the native Americans as well as the local armadillos by European emigrants, resulting in a great number of armadillos with physical disabilities.
Furthermore, the world-sweeping Batrachochytrium dendrobatidis, which has been extensively wiping out amphibians worldwide, very likely originated from Korea, and spread by trading activities across the globe.No matter which way it is, the outcome of spreading diseases could be disastrous. We should beware of close contact with wild animals, never harm their habitats, and appreciate nature mindfully. Don't let tragedy happen again.