Learn about the roots of the novel coronavirus that has put the world on pause in 2020.
COVID-19 or SARS-CoV-2 is one of four common human coronaviruses, named for the crown-like spikes that line the viral surface. Other common human coronaviruses include MERS-CoV, the virus that causes Middle East Respiratory Syndrome, as well as
SARS-CoV the virus that causes severe acute respiratory syndrome. SARS-CoV, otherwise known as SARS, is not the same disease as COVID-19, but they are genetically related. SARS, which was responsible for a major disease outbreak in 2003, targets the respiratory system (i.e. the lungs) but is more deadly and far less infectious than our current COVID-19. Thankfully, there have not been any outbreaks of SARS since 2003. On the other hand, COVID-19, a highly infectious disease, is currently widely dispersed across the globe. Like other coronaviruses, it is characterized by respiratory tract symptoms, which include sneezing, sore throat, pneumonia and more severely, acute respiratory distress. Acute respiratory distress refers to fluid build up inside tiny air sacs of the lungs (alveoli). The specific origin of this virus is unknown but it is believed to be zoonotic in nature. A zoonotic disease refers to a disease that arises from animals and is then passed to humans. For the case of COVID-19, the first human cases of the virus were identified in Wuhan City, China in December 2019. However, it is not yet known what caused the jump from animals to humans or even precisely which animals it may have been passed from. Comparing this outbreak to the SARS (SARS-CoV) outbreak in 2003, novel coronavirus most likely was passed from an animal reservoir to humans and then spread between human populations. In the case of SARS, the animal reservoir that passed the disease to humans was the civet cat, a farmed wild animal. Similarly, it is believed that COVID-19 jumped the species barrier and infected humans, most likely through an intermediate host. This intermediate host refers to another animal that tends to be in closer contact with humans, allowing for the jump. For example, these hosts include domestic animals, wild animals that live near human spaces, and domesticated wild animals, like the civet cat. As of now, researchers and public health officials have yet to explicitly name the animal species behind this global pandemic, but it has been hypothesized to be bats. This theory comes from the fact that related viruses to COVID-19, like SARS, have been isolated in bat populations. Thus these bat populations have the potential of carrying or having carried similar viruses like COVID-19. Therefore, the most probable ecological reservoir for SARS-CoV-2 is a bat species. However, this has yet to be officially determined and is as of now only a theory. Taking the time to understand and evaluate a disease origin and its relation to other viruses is a vital tool in the public health field. Knowing how a disease relates to others we have seen before allows for public health officials to understand more concretely how the disease of interest may spread and even suggest possible treatment options. In a similar way, evaluating disease origin allows governments and people to analyze what steps need to be taken to prevent the spread of this disease and future outbreaks. As an individual, it is important to take the time to do your own research on this virus and follow public health and official guidelines. We are all in this together. Don’t forget to wash your hands!