Amid the COVID-19 pandemic currently affecting 210 countries and over 2 million people worldwide, it’s easy for misinformation to quickly spread regarding the source of the disease, the rate at which it may spread, and how it could possibly evolve over time. With that said, it’s important to know basic information to better understand how all of that may be.
Zoonotic diseases are those caused by germs spread between animals and human beings. Examples of these diseases include rabies, brucellosis, malaria, and ringworm, among many others. These can cause sporadic outbreaks that can typically be easily contained, but have the potential to spread across the globe. COVID-19, specifically, is related to SARS, which we saw a large outbreak of in 2003. Because of this, it is likely that we will continue to see different strains of coronavirus transmitted from wildlife in the future. First, however, it is important to address a few important facts on how zoonotic diseases are spread.
Exposure to Wild Animals
Many people may think that simply coming in contact with a wild animal is all that it takes to contract ebola, for example. It is true that hunting, butchering, and then trading wild meats puts human beings performing these activities at a higher risk. However, not much evidence exists regarding how often diseases are contracted through these methods.
Wet markets also pose a risk of spreading zoonotic viruses, but this is a much less popular form of trade and is often confused as a mainstream type of market because of its depiction in the media. Another consideration is the fact that wild meats eaten throughout China and Vietnam are farmed, and consumed only in restaurants, partially eliminating the possibility of exposure to zoonotic diseases.
A majority of diseases throughout history came about through the transmission of biting insects that acted as vehicles between animals and humans. Lyme disease, for example, comes from bacteria found in wild mammals, which is then transmitted to humans via the bite of a tick. Cases of lyme disease can escalate rapidly due to a variety of factors, one such being hunting season. Deer frequently carry ticks that then come into close contact with humans, which the same can be said for with foxes, wolves, bears, and other mammals subjected to being hunted. This actually causes an adverse reaction in which smaller mammals that carry the disease then flourish due to their natural predators slowly declining.
While many people may assume zoonotic diseases originate strictly from wild animals, various strains have been transmitted from domestic animals due to how often humans associate themselves around them. For example, cows, sheep, and chickens are all potential hosts for salmonella, leading to food poisoning. Bird flu, specifically H5N1, is a much deadlier disease often carried by chickens. Antibiotics used in these farm animals can also lead to antibiotic resistance among bacteria, causing stronger strains and an incubation period for numerous multidrug-resistant bacterias within the livestock.