Campus Queries: Coronavirus strain causes, symptoms and context explained
(Firyal Bawab/Daily Bruin)
By Phoebe Chen
Feb. 23, 2020 11:48 pm
Campus Queries is a series in which Daily Bruin readers and staff present science-related questions for UCLA professors and experts to answer.
Q: How do viruses like the coronavirus work?
A: UCLA professors said the recent coronavirus outbreak can cause serious side effects, but it may not be as harmful to everyone. However, it is still important to take precautionary measures to avoid exposure.
The strain of coronavirus responsible for the recent outbreak, named COVID-19, belongs to a family of viruses called Coronaviridae. Coronaviridae share similar physical characteristics, such as crowns of spikes, said Melody Li, a microbiology, immunology and molecular genetics assistant professor.
“When you look at the virus particles, … they all have the crown spikes for getting into cells,” Li said. “They look like a solar corona.”
Roger Detels, a professor at the UCLA Fielding School of Public Health who specializes in epidemiology and infectious diseases, said the density of infected people in an area and the frequency of exposure to the virus might explain the large number of cases in Wuhan, China, where the outbreak originated, compared to other regions.
“It seems to be a much more serious disease in Wuhan, where the density of infected people is much higher,” Detels said. “In the other areas, … the density of infected people is very low and therefore they tend to be milder infections.”
Based on his theory, Detels said he believes people in the United States are at low risk of contracting COVID-19. If individuals plan to travel to areas with higher densities of infected cases, Detels suggested precautions such as wearing a mask.
“I think there’s 15 people among 300 million people (in the U.S.) who are infected,” he said. “The probability that you’re going to be exposed to that sick individual is very, very small … if you’re in an area where there is intense exposure, you probably should wear a mask.”
Experts previously believed coronaviruses were responsible for causing colds; however, the viruses have mutated to cause symptoms more drastic than those associated with a cold, Detels said.
“(The coronavirus) causes the common cold, which is relatively insignificant,” Detels said. “But it has mutated three times in the last 15 years. And the mutation has gone from a benign virus to a virus that is pathogenic for humans.”
One of the three mutated viruses is responsible for severe acute respiratory syndrome, or SARS, which infected over 8,000 and killed 774 people in 2003. There are many similarities between the SARS coronavirus and COVID-19, which concerns many experts, Li said.
“It’s very concerning to (the Centers for Disease Control and Prevention) and (the World Health Organization) when we first … (knew that) this case was associated with this virus because again there’s a link to this seafood and wild animal market,” Li said. “So it’s reminiscent of the SARS outbreak, which means that potentially there’s a cross-species transmission, and the virus could be very virulent.”
The exact mechanisms of COVID-19 are still unclear; however, respiratory viruses usually operate in the same way – by damaging the lungs’ interior linings, said Christopher Tymchuk, an assistant clinical professor of medicine and infectious diseases at the David Geffen School of Medicine.
Many complications, such as bleeding, secondary bacterial infections and fluid accumulation can arise as a result of the lining’s deterioration, which can lead to death, Tymchuk said.
“In general, respiratory viruses like this essentially attach to and can damage the epithelial or cell lining of the airways, … including the nose and mouth, all the way down into the lungs,” Tymchuk said. “It can get to a point where people need extra oxygen, … and sometimes it can be so severe that it can affect multiple organs of the body.”
The mortality rate of COVID-19 is not as high as it was for the SARS outbreak, Li said.
“It appears to be a very mild disease in the majority of cases,” Detels said. “Individuals who die … are individuals who are over the age of 60 and may have some underlying conditions which caused them to be more vulnerable.”
People in metropolitan areas like New York or Hong Kong face potentially serious consequences from COVID-19 because of the cities’ density and traffic, not unlike Wuhan, Li said.
There is debate over whether a virus is alive or not, Li said.
Reproduction is a characteristic of living organisms, but viruses usually rely on other beings to replicate, she added.
“I would say for most viruses they would have to hijack the host machinery, … for example our cells, for it to replicate and multiply,” Li said.
The most severe viruses are those that the immune system has never encountered before, which result in drastic immune system responses, Li said. Pathogenic or disease-causing viruses, such as COVID-19, typically originate from nonhuman animals.
“These are viruses that came from a totally different animal reservoir,” Li said. “It’s not a virus that has been frequently circulated in the human population.”
Despite common perceptions of viruses, many of them can actually have beneficial effects for humans.
Viruses have been able to provide people with new gene functions, such as humans’ ability to develop a placenta during pregnancy, by integrating genetic information into the human genome, Li said. They play a role in our evolution, she added.
“So when you think about that, I guess we have a very intimate relationship with viruses (and) that they’re not just causing horrible diseases in humans,” Li said.
However, in the event that an individual were to be exposed to a deadly virus or COVID-19, UCLA is well prepared for the possibility. Hospitals immediately screen patients and take them to a separate room if they are suspected of having COVID-19. Doctors also can perform examinations in-person as well as virtually to reduce the chance of transmission, Tymchuk said.
“It’s very hard to predict how this virus will play out,” Tymchuk said. “But I’m not expecting this to become a major issue for UCLA, for the (Los Angeles) County or for the UCLA healthcare (systems). But if it does, we’re extraordinarily well prepared and equipped for any potential cases.”