A Better Method For Stopping Ebola And Yellow Fever

IRA FLATOW: This is Science Friday. I’m Ira Flatow. The Democratic Republic of the Congo has experienced 10 outbreaks of the deadly Ebola virus since 1976. For 10 weeks earlier this year, the virus reemerged in the country, killing 33 people. Ministry of Health officials finally declared the crisis over on July 24. But just one week later on August 1, the DRC reported a new outbreak of the Ebola virus in the northern part of the country.

Here to tell, give us an update on the situation in the DRC is Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the NIH and recipient of the Presidential Medal of Freedom. Welcome back to Science Friday.

ANTHONY FAUCI: Good to be with you, Ira.

IRA FLATOW: Tell us about this current outbreak. Give us some of the ABCs of it, please.

ANTHONY FAUCI: Well, it’s in a totally different location than the first outbreak that we had early in the year that you mentioned, Ira, which was in the western part of the country. This is 2,500 kilometers to the east of this. It’s in the northeast part of the country right by the border of Uganda and Rwanda. It is already considerably larger than the first outbreak earlier in the year that have been now as of last night 103 total cases with 63 deaths.

The situation there is a bit more problematic than we’re used to. Democratic Republic of the Congo, as you said, has considerable experience over the years. This is their 10th outbreak. The problem is that the outbreak is occurring right at or near the area of rebel fighting with a number of different rebel groups making it a real security issue of being able to do the kind of identification contact tracing and the contacts of the contacts, which is the way that you put down these kinds of epidemics.

So it is still in the escalating phase. We have to watch it very carefully. We’ve deployed the vaccine that we used with some success in the West Africa outbreak already in the ring vaccination approach, which means vaccinating the contacts and the contacts of the contacts of people who are known cases. There have been 2,625 vaccinations thus far, and we’ve also deployed some experimental drugs that are being given there, monoclonal antibodies and other drugs that have been developed.

So there’s some good news in the sense of we have interventions that we didn’t have a few years ago with the West Africa outbreak, but the sobering news is the location of where it’s occurring, which is in a high security place.

IRA FLATOW: So you’re actually using some of the new vaccine to try to fight.

ANTHONY FAUCI: Yes. The vesicular stomatitis virus, the V, as V-vectored vaccine that we did and are still involved in a clinical trial to determine immunogenicity and safety that we utilized in a ring vaccination program in Guinea back a couple of years ago during the ’14, ’15, ’16 outbreak. That is being deployed now on the contacts and the contacts of the contacts, and that’s the 2,600 plus vaccinations that we were using right now literally as we speak.

IRA FLATOW: And how long do you think this outbreak might run its course?

ANTHONY FAUCI: You know, Ira, it really is impossible to say because the way that you can put these down and get control of them is if you identify the cases themselves, put them in isolation. Because as you well know from the previous outbreaks, the most susceptible people are the people who are taking care of the individuals who are sick, either family members or health care providers, people who bury the bodies when people die.

And the situation is, we’re seeing that same sort of thing. We’re seeing a number of health care workers who’ve gotten infected. Having said that, it’s impossible to predict until you get the cases all accounted for who are the contacts. It’s a 21-day incubation period, and to say that something is over, you have to go through two cycles of 21 days without a new case.

So it would have to be 42 days from the last identified case. And we’re still in the upswing of the outbreak. So I think we’re far away from saying that this is over by any stretch of the imagination.

IRA FLATOW: I want to thank you again, Dr. Fauci, for keeping us up to date and coming on Science Friday, and we’ll be following up with you.

ANTHONY FAUCI: Good to be with you.

IRA FLATOW: Thank you. Anthony Fauci, director of the National Institute of Health, the Institute of Allergy and Infectious Diseases at the NIH.

Public health officials may not be able to control when and where an outbreak occurs, but with the right strategy, they can keep it from becoming an epidemic. Researchers are testing a new strategy out on yellow fever, a virus that emerged in Brazil last year and threatened major population centers like Sao Paolo and Rio de Janeiro.

Dr. Nuno Faria is Royal Society research fellow at the University of Oxford in the UK. His team was the first to use real-time genome sequencing of yellow fever virus to track where it came from and which groups might be at risk. He joins me now. Dr. Faria, welcome to Science Friday.

NUNO FARIA: Thank you. Thank you very much for the invitation.

IRA FLATOW: Well, we know that yellow fever is different from Ebola in that it’s carried by a mosquito, and I understand there are two ways of transmitting it. Can you explain what those are?

NUNO FARIA: Yes. So there is this sylvatic or jungle yellow fever transmission, and there’s the urban yellow fever transmission. So at the jungle yellow fever transmission is the transmission of the virus between non-human primates, for example monkeys and mosquito species that are found in the forest canopies. And those normally are [INAUDIBLE] mosquitoes, so these viruses that are transmitted by the mosquitoes from non-human primates to humans when humans are visiting or working in the forest.

So in contrast, urban yellow fever transmission involves the transmission of the virus between humans and urban mosquitoes. Primarily, they’re very commonly found in Aedes aegypti, which is the same mosquito that transmits Zika and chikungunya in many other infectious diseases.

So in this case, the virus usually enters the urban area when it’s introduced from a virionic human that was infected in the jungle.

IRA FLATOW: So how are you able to use genetic sequencing to tell this was a jungle transmission and not the urban transmission?

NUNO FARIA: So we actually combine different sources of information. Genetic [AUDIO OUT] is one of the information that we use. So we know that viruses like yellow fever, Zika, HIV, or Ebola accumulate mutations over time. Sometimes we find mutations accumulated in viruses that have been collected from patients only a few weeks apart or sometimes months or years, depending on how fast that virus mutates or evolves.

That depends on several factors including the own replication, the sharing of the virus. For example, for yellow fever, we know that a yellow fever virus evolves roughly, accumulates roughly 1 to 10 mutations in the genomes over a year at the population level. So we use the information as the number of mutations accumulating per genomes over time to actually reconstruct a phylogenetic tree, so the genealogy of the virus or the evolutionary tree.

And based upon that, I mean based on the evolutionary tree of yellow fever of not only humans, but also non-human primates, we were able to reconstruct ancestral species being non-human primates, in this case, and we were able to reconstruct the spillover events between non-human primates and humans over time.

IRA FLATOW: And knowing this genetic history, does it get you any closer to treating people with the disease or preventing it?

NUNO FARIA: So what we can find with this sort of information, we can find the origins of the outbreak, we can find the source populations of the outbreak, and we can ultimately trace that place and how and when the spillover events were maximum and which locations did this happen and in which specific seasons did it happen the most frequently.

IRA FLATOW: And how does that help in treating people?

NUNO FARIA: Well, ideally, we could incorporate that information. Obviously, this stems from the more general goal of improved surveillance in not only humans, but also non-human primate populations and vector population. So if we increase surveillance in all different populations at the same time, we can definitely benefit from that in the sense that a target vaccination in key areas where there is increased transmission.

IRA FLATOW: That’s interesting. So how fast is this technology moving? Is this the first time it’s been used this way?

NUNO FARIA: So genomic sequencing, portable genomic sequencing using MinION has been actually first used in an Ebola outbreak back in 2016 in Guinea. And then later, we brought that technology to the Zika virus outbreak during our Zebra Project, which we drove 2,000 kilometers in most affected areas in Northeast Brazil with several portable handheld iron sequencers to capture a little bit better the Zika virus epidemic at it’s epicenter. And now we have to use it for real in a few more weeks, and we extended these protocols for reality.

But it’s very easy to extend these protocols to other viruses, and we are currently trying and testing these protocols [AUDIO OUT] the other and mosquito-borne infections that might be the next big Zika or yellow fever epidemics in Brazil.

IRA FLATOW: So you’re limited, from what I hear you saying, to applying this to mosquito-borne infections. Why limit it? Because we were just talking about Ebola. Could you use it for Ebola?

NUNO FARIA: Yes, of course. As I mentioned, it was first used actually to Ebola to tackle the Ebola outbreak back in 2015, and it was essential to track transmission chains in air back in 2015, and it increased [AUDIO OUT] in the current outbreak.

IRA FLATOW: So you think it could be used in this current outbreak?

NUNO FARIA: Yeah. I’m sure. It’s already been here, so that’s the [VIDEO OUT] and also very flexible. So it’s not only being used for viruses, but also for diphtheria and that even reports of flu genomes of humans being actually sequenced using the benign sequencer. So it’s a very portable and very flexible material that can be very easily sort of expanded to a broad range of pathogen in organisms.

IRA FLATOW: But is it expensive to use? Could countries that don’t have a robust health system be able to afford it?

NUNO FARIA: So we were able to generate genomes for under $50 per genome. So that’s quite cheap to other technologies. But indeed, for example, we have also extended our project to other countries in African settings. For example, Angola where we have been recently, we were able inside, without having to be shipped to our samples. So in the country, we were able to generate some Zika virus genomes there. So that’s quite interesting.

To bring the technology to these countries, train people which we have done in Brazil in several different parts of Brazil, but also outside of Brazil, and then make surveillance, improve surveillance, genomic surveillance for this.

IRA FLATOW: All right. We’re going to have to say goodbye. We’re running out of time. Dr. Nuno Faria, Royal Society Research fellow at the University of Oxford.

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