By Jodi Diperna
We live in confusing times, bombarded with both a dangerous virus and dangerous misinformation. At the Current, when we have a science question, we like to ask an actual scientist.
The Pittsburgh Current recently sat down with Zandrea Ambrose, PhD, via Zoom, for a talk about coronavirus, pandemics and how viruses work generally. Ambrose is an Associate Professor of Medicine at the University of Pittsburgh where she also runs an HIV research lab and has recently received a pilot grant to study SARS-COVID. (Answers are lightly edited for length.)
Q: Can you talk about what a virus is, and how it attacks the body, and how that’s different from bacteria?
Ambrose: In a way, it’s like a parasite — many viruses are. They don’t have everything they need to replicate themselves, so they need to infect a cell — the human cell provides them things to replicate. They can’t do it on their own. That distinguishes them from bacteria or protozoa. They have smaller genomes and can’t do everything themselves, so they hijack our cells to propagate themselves.
Q: So they hijack and then use raw materials from our cells?
Ambrose: Exactly. They co-opt materials and make their own DNA or RNA. But viruses are all different — there are viruses that have DNA genomes and ones that have RNA genomes. This coronavirus, all coronaviruses, have RNA genomes.
Q: What differentiates a pandemic from an outbreak?
Ambrose: It’s just the severity of the outbreak. There’s outbreak, epidemic, and pandemic. Globally, a pandemic simply affects more people. The characteristics of the specific virus will determine how bad the disease is and how easily it is spread and transmitted between people or how pathogenic it is.
Q: I read that the infection ratio for the common cold is one to one, so if I have a cold, I’ll infect one other person. The ratio for the 1918 Influenza was one to two; and COVID-19 is a one to three ratio, which feels like the Spanish Flu hopped up on Red Bull and rage. Do scientists even know what makes this so contagious?
Ambrose: Probably the most easily transmissible virus we know of is measles. That one is so easy to transmit, one kid can infect all of Disneyland, if people are not vaccinated. We just don’t know everything about this virus yet, but it does appear to be easily transmissible. Another difference between this virus and influenza is it seems to be transmitted not just via the respiratory route, but also fecal-oral transmission may be in play here. There are scientists who are detecting the virus in sewage: instead of testing people, they’re testing sewage to see how prevalent the virus is in different areas. The more I read, the more scientists are thinking there is a fecal-oral connection and there are definitely GI symptoms in a portion of infected people. That makes it somewhat different than most flu viruses.
Q: I feel like the symptoms are always changing. First we were to look out for a dry cough and fever, but now we’re seeing the GI stuff and blood clotting issues.
Ambrose: I don’t think the virus is changing; I think our knowledge is changing. This is something that we’ve never seen before. What we realize now is this virus can infect a lot of different types of cells. The gastrointestinal tract and the respiratory tract. There are reports of loss of taste and smell. There are reports about some cognitive disorders, so there is something going on with the central nervous system. (It’s not clear if those cells are getting infected directly or if there is an inflammatory process.) Kidneys are affected. And the biggest one is the cardiovascular system. It’s clearly doing something to blood vessels, making cardiovascular diseases worse and making people with those diseases more susceptible. But it’s still new and it’s still early — there are probably a lot of people who are undiagnosed.
Q: There have been problems with the tests. Is this virus especially hard to test for?
Ambrose: There wasn’t a great response from the federal government; they had problems with the testing. I’m not sure why it was a problem or why it took so long to figure it out. There’s nothing special about the test. It’s called a PCR (polymerase chain reaction). Usually, to start out, you look at other coronaviruses and this is the seventh known coronavirus that infects humans. Lots of labs did it — UPMC has their own test. Because the federal government didn’t get things together, some cities with major hospitals and research focused health centers were able to get their own tests up and running. So, the test in Seattle isn’t exactly the same as the UPMC test. Because it’s not standardized, it’s hard to compare regions. We often see a disparity between countries, but it is insane that it is happening within our country — every county and town is their own little thing.
Q: How do pandemics end?
Ambrose: It’s a factor of isolation and stopping transmission — the prevention methods we are doing in Allegheny County, but not all over the country. It helps if you have therapeutics — some way to treat people. And then vaccines. We saw this with polio. A lot of kids and young people were getting infected and it all stopped when we had a vaccine.
Q: Let’s talk more about vaccines.
Ambrose: One step to a vaccine is identifying something that is effective. The other step that is concerning is dissemination of that vaccine. The current administration wasn’t great at disseminating tests, so how are they going to be at distributing a drug that really works (not hydroxychloroquine) or an effective vaccine? That’s a challenge.
Q: It’s a real challenge for people at the forefront of public health. And the polio vaccine worked because we all got vaccinated.
Ambrose: Exactly. First, you need to have scientists working. This can’t be done in your basement. You need a lab and you need funding. It’s not cheap to do. And, you need political will. It’s a matter of scaling up. We have millions of people who were not infected. How are we going to make enough vaccines? And probably we won’t be able to right away, so how do we determine who gets it. Will that be older people? People at higher risk? How are you going to distribute it? I’m concerned about that.
Q: What are the most dangerous misconceptions that people have about this virus?
Ambrose: I have had so many interesting conversations. I’m surprised that people still have this conception that it’s just another flu. I don’t know why people don’t think it’s scary. Another misconception is that everyone who is infected has a fever. Depending on the study, somewhere around a third of infected people have a fever, so the idea that you can take your temperature and know if you’re infected is or not, isn’t a perfect marker.
People think that it’s only spread through the respiratory tract, but that’s not the case. So if you wear a mask, if you’re not washing your hands, that’s probably helping it spread. There is also the idea that it is all over. That’s a problem. Because we shut down early, we didn’t have a high incidence rate, relatively speaking. Allegheny County did a good job of flattening the curve. We’re opening up, and we’re probably ready for that because of a low prevalence rate, but there are places that have higher numbers and higher rates of infection so a one-size-fits-all approach won’t work.
If somebody travels to a hot spot like New York or New Jersey, they could bring it back and it could spread again. The misconception is, we’re doing fine, so we can re-open and go back to normal. That’s not going to work. I don’t know how we’re going to keep hotspots from spreading the virus without testing and contact tracing.
Q: Why is coronavirus not like the regular flu?
A: It’s a different virus. The way that it enters cells is different; the cells that it infects are different; the way it replicates is different. Its genome is huge compared to the regular flu. It’s a huge virus, actually. It’s completely different — like trying to compare a human to a cat. They’re both mammals, but they’re very different. That’s the best way I can explain it — it’s literally like a different species.
Jody Diperna is a reporter for the Pittsburgh Current, where this story first appeared.