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Vital Signs with Dr. Sanjay Gupta

Zoonotic Diseases Can Jump From Animals To Humans. Aired 2:30- 3p ET

Aired December 17, 2016 - 14:30   ET


[14:30:15] DR. SANJAY GUPTA, CNN CHIEF MEDICAL CORRESPONDENT: They are known as zoonotic, these diseases that can jump from animals to humans. From (INAUDIBLE), stinks or birds, with disease names like SARS or MERS. At a time when international travel has connected the world more than ever before, it takes a coordinated global effort to prevent a widespread outbreak.

This is VITAL SIGNS. I'm Dr. Sanjay Gupta.

Their titles might sound like something out of a flashy novel, virus hunter, disease detective. But don't let that fool you. These men and women are doing crucial work all over the globe. In the United States, the Centers for Disease Control and prevention oversees ten global detection centers worldwide. Their job, monitor viruses, help curb potential outbreaks through emerging infectious diseases. In fact, they constantly monitor 30 to 40 public health threats every day. One of these centers is in South Africa, where CNN's David McKenzie met up with the team in the field for a closer look at the depths they go literally to do their job.


DAVID MCKENZIE, CNN INTERNATIONAL CORRESPONDENT (VOICE-OVER): It's a slow and cumbersome descent, hindered by head to toe protective suits and respirators. But these are the only things standing between safety and exposure.

So we are heading into the depths of the earth in the (INAUDIBLE) cave. And the aim is to find one of three bat species that could pose a threat, a viral threat.

In this cave are thousands of bats, any number of which could contain deadly pathogens.

So what are we seeing here?

WANDA MARKOTTER, UNIVERSITY OF PRETORIA: So this is (INAUDIBLE) or the long fingered bat.

MCKENZIE: And these are insects?

MARKOTTER: Yes. There are huge colonies or large colonies in South Africa. MCKENZIE: There are a lot of bats here.

These are researchers from the University of Pretoria. And they are virus hunters. Their job, catch bats to catch diseases before they transfer to humans.

MARKOTTER: So this is (INAUDIBLE). And the reason they are called their common name is the long fingered bat is because these forearms are so long. And if you can stretch the wing. And this is a mile (ph).

MCKENZIE: Why can these bats pose a threat?

MARKOTTER: So this specific specie had been implicated in some of the rabies like the viruses (INAUDIBLE). And there are came high (INAUDIBLE). And people that come into caves come in contact with it. There are other thing is also that they risk this a lot of other species that come more into contact with humans. So they can also transfer pathogens to other species of bats.

MCKENZIE: Something that might surprise you is where this working is taking place. This is not some remote cave. We are only miles away from the city of Johannesburg, a heavily populated urban area.

I mean, this looks almost cute, but not this specific species, but bats in general harbor zoonotic diseases.

MARKOTTER: They are one of the species. And I think, unfortunately, that it's been implicated quite a bit and they separate reasons for that. They are 20 percent of all mammals. So they are a huge group. Not just this bat, there are 240,000 species almost worldwide. And today, they represent a big group of mammals. And that's probably why we find a lot of viruses in them. But there's not a lot of research on how many of those viruses actually made people sick or made animals sick. I mean, even with the e-bola, there's not a direct link between human outbreaks from bats. We see some evidence in the bats and we human outbreak. But we can't say that bat caused the human outbreak, you know. So a lot is still unknown, yes.

MCKENZIE: A lot is still unknown. And a lot to keep track of.

UNIDENTIFIED MALE: If we look over here, you can see the global disease detection operations center. That shows where we are tracking infectious disease threats.

MCKENZIE: That's why having a central command center is critical for this type of work. And you'll find it at the centers for disease control and prevention headquarters in Atlanta, Georgia.

Dr. Jordan Tappero is the director of the global health protection center here at the CDC.

DR. JORDAN TAPPERO, DIRECTOR, CDC GLOBAL HEALTH PROTECTION CENTER: Only about 30 percent of countries even self-report that they are able to prevent, detect, and respond to infectious disease outbreaks. And that's through international health regulations. And so, we are working around the world to try to improve capacity so we have partners everywhere to respond quickly.

[14:35:08] MCKENZIE: But within this organization, how many threats, if you will, are sort of being assessed, evaluated?

TAPPERO: Yes. One of the things that we have in our division is the global disease detection operation center (INAUDIBLE) op center. Let's just use for example the 24-month period that we were activated for the e-bola response here in the emergency operations center. During that time we were tracking almost 300 infectious disease outbreaks of concern in 145 countries. Many of them, because of the communication with our partner, ministries of health, WHO, animal health organizations, we were enabled them to be thwarted. Some of them have taken bigger response.

MCKENZIE: That's a huge number, 300 potential disease outbreaks, 145 countries, just about every country in the globe. Do you have enough resources? What does it take to stay on top of all that?

TAPPERO: That's a very good question. To start off, those 300 outbreaks that I have just mentioned, there are 145 countries, that's just the ones we're critically monitoring. We have had over 1,700 outbreaks that we have participated in over the last six years alone. Those are more common outbreaks that we don't raise to that threat that we are really monitoring every day.

MCKENZIE: That monitoring starts with teams on the ground, in caves like this one.

So they have to crawl through the narrow gaps into the different chambers. Because in each chamber could be a different type of bat which could have different viruses.

Each of these bat has the potential to carry rabies, Marburg, perhaps even e-bola. Some of the planet's deadliest but least understood viruses. Do you ever get nervous doing this work?

MARKOTTER: The risk is low. I mean, it probably looks scary if you look at what we are wearing. But the risk is really low. I mean, these bats we caught were flying around, so they're probably healthy. So we will probably look for antibodies that can just show it (INAUDIBLE).

MCKENZIE: But why is it important to do this work for public health?

MARKOTTER: So if you don't know what's in the animals, you won't be able to identify human outbreaks quickly. So most of the time we only respond when there's a lot of data, if we knew where the virus or pathogen came from. So if we know what's in the populations, we can actually tell people beforehand to be careful. And if we know how they transmit, through your own feces or a bite, then you can help public outbreaks prevention about it. Otherwise you just react and there are already a lot of people dead, like in the e-bola outbreaks.

MCKENZIE: Back on the surface, a makeshift lab is set up right outside the entrance to the cave. Samples are collected from the bats' fur, mouth and wings. Everything meticulously recorded. With the samples now from the bat cave, it's time to move on to the next location.


GUPTA: Next, David and the team are heading to a horse farm near Johannesburg where tiny mosquitoes threaten the health of these large animals and also serve as an early warning system for humans.



[14:41:50] GUPTA (voice-over): Gail Foxcroft is professional show jumper in South Africa. And her horses are more than just prize winning investments. They are part of the family.

GAIL FOXCROFT, SHOW JUMPER: You are asking so much of the horses. You also want to step for you. It is not about force. It is about really is a partnership. You're asking them to do a huge athletic endeavor that you ask from them. And the more they work with you, the easier it is and the more likely you are to succeed.

GUPTA: When her champion horse, Lyndonberg (ph), became sick, it was devastating.

FOXCROFT: He couldn't put weight on his front feet. So we will (INAUDIBLE) as thought it was just an inflammatory disease. Then he started to get really shaky and eventually he sort of sat down. He couldn't control his back -- obviously it's all neurological symptoms. And then eventually he lay down and we couldn't get him up. He actually could not stand up.

GUPTA: Were you trying to lift him up?

FOXCROFT: Yes, we tried to do everything with him. And he couldn't stand up. And then as I said, eventually he could still lift his head but he couldn't breathe properly, he had to have a tracheotomy.

GUPTA: The neurological symptoms became so bad, Gail made the painful decision to put Lyndonberg (ph) down. But the symptoms didn't quite line up with the original diagnosis. It was eventually determined that Lyndonberg (ph) had Schoony (ph) virus, one of the first cases here.

FOXCROFT: I think that was the biggest thing that we need to know. Another, yet another virus out there that we had to be careful of and we have to vaccinate for.

GUPTA: Like less (INAUDIBLE) and Zika, Schoony virus is transmitted by mosquitoes. So now Gail invite researchers to her horse farm to trap and test the insects.

FOXCROFT: (INAUDIBLE) that at some stage last year, they found a huge number of the (INAUDIBLE) mosquito that carries it. But they didn't find any of the virus in the mosquitoes. And we need to know, we need to know how to control it, what steps we take, and eventually hopefully how to combat the disease, because it's something that has a huge mortality rate.

GUPTA: It's all part of the disease monitoring taking place here in South Africa, one of ten global disease detection centers worldwide. The health of these horses is actually an early warning sign for what could be coming to humans.

Why is it important to have an early warning system?

MARIETJIE VENTER, CDC: So it's difficult in Africa, relative for example to the United States. (INAUDIBLE) emerge in the United States as of this time. (INAUDIBLE) these actually originated with resistance many of the times because there viruses have been around for many years. So we can't use (INAUDIBLE) as an early warning system. But what we do is to being look for animals with the type of signs that we know is associated with virus infections caused by these (INAUDIBLE) viruses. Say for example, neurological symptoms, encephalitis symptoms, if we see paralysis, if we see fever outbreak in lots of animals, (INAUDIBLE), that's a way we can then see, they could potentially be a fever going around or the viruses in this specific study that have neurological signs in animals, could be things like (INAUDIBLE) virus and then these African viruses such as schoony virus (INAUDIBLE).

[14:45:31] MCKENZIE: So why do you have to keep surveying the virus threats all the time?

VENTER: So by actually doing continued surveillance from month to month, we can see what the seasonality of these viruses are. We can see, when outbreaks happen, we have an early warning system to determine if there is an increase in virus and in the vectors that carry them and we can potentially do something about preventing infections in humans and animals.

GUPTA: For Gail, it's not just about protecting humans but are horse too.

FOXCROFT: You know, you spend years and years bringing a horse up, apart from the emotional impact it has on you. It has all the other impacts. It's financial. It's also, you know, you have a tough competitor starting his career, and the next thing, you've lost it. And it takes years and years, takes a minimum of like six or seven years to get a horse to the top level.

MCKENZIE: That is a great tragedy that you lost your prized horse but do you see maybe some good coming out of this research for humans as well?

FOXCROFT: No, no. Absolutely. I mean, the fact that now that medical research is here, every month, to take samples and things, we have to know how it's spread or what the concentration of mosquitoes is in a certain area, at a certain time of the year, to know which are the bad times, when you have got to use a lot more protection, all those kinds of things. I mean, it's vital. And the fact that people can get west Nile as well, it's obviously a huge issue. So it's fantastic. We support it wholeheartedly. GUPTA: So now that the team has samples from bats and mosquitoes,

it's time to visit the lab. Protective gear required again, because this place houses some of the deadliest pathogens known to man.



[14:50:31] GUPTA: In 2014, West Africa saw an unprecedented outbreak of the e-bola virus. Cases were concentrated in New Guinea, Sierra Leone and Liberia. But the disease was first discovered in central Africa in 1976. The recent outbreak was just race against the deadly virus and laboratories all over the world were called to help.

Imagine a workplace where the deadliest pathogens are kept. That's what these labs are working with. And it is also where doctor Thrives, a disease detective in every sense of the phrase. From anthrax to e-bola and now Zika, he has been solving the mysteries of pathogens for decades.


GUPTA (voice-over): At the CDC headquarters in Atlanta, Dr. Sherif Zaki's lab is busy. Under these microscopes are some viruses you and I would likely never have heard of, and wouldn't want to.

Given that you don't know what exactly it is you are going to see under the microscope, how do you know to protect yourself? How can you be 100 percent sure that what you're dealing with isn't something that could make you sick?

DR. SHERIF ZAKI, CDC: That's a good question. So fortunately with pathology, we're interested in a chemical that really kills all -- most infections. So we feel comfortable dealing with it. I think the problems when you start worrying is when you are taking those tissues. As a pathologist at autopsy area, collecting specimen, and that's when you have to worry about having the proper protection. But you know, the universal protections are pretty standard. As long as you're practicing those, I don't have any concerns about it.

GUPTA: Over the last few years, e-bola was a big focus for Dr. Zaki and his team of pathologists.

When you first started looking at e-bola, could have predicted based on what you were seeing how widespread this outbreak would be?

ZIKA: We actually started looking at e-bola, at least myself, in the mid-'90s in Zaire. We actually didn't know how much the virus spreads. If you had asked me ten or 15 years ago, I would have said this was not going to happen. So I would have been totally wrong. And the reasons are the forest borders, you know, ten or 15 years, you wouldn't have the same bus routes, et cetera you used to. Actually, if you had e-bola, they put you in the hut, give you some food or water, and then you either made it or not, so you didn't travel much. But nowadays, what the Global travels, people can be on an airplane before they become symptomatic. It's not surprising that it would get to this magnitude. But that's now hindsight. Again, I would have been wrong. I would not have predicted that it would have happened.

GUPTA: These new emerging infectious diseases typically don't actually cause much disease in humans. We see them, they swap back and forth between animals and humans. Is there anything you're particularly keeping an eye on right now, something that's new, that you're thinking I have to keep an eye on that one?

ZIKA: It's always unknown. I mean, you have to keep your options open in terms of something new. If anything, we have learned to, you know, expect the unexpected basically. And there are new diseases that come with new twists in terms of exposure, et cetera. So I'm more worried about things that we don't know about.

GUPTA: Knowing about these viruses is certainly the first step.

Before some of these pathogens reached Dr. Zaki's lab, they come here. So there's only a few people who have the privilege t/to come in here, right?

David McKenzie has been taking us on this journey with a team of South African virus hunters. The last stop is here, a level four bio-lab in South Africa, the highest biosecurity level. And the only lab of its kind on the African continent.

UNIDENTIFIED MALE: In a bio (INAUDIBLE), we are working and even the most dangerous pathogens known to science. And very often their knowledge about how they were maintaining nature is very enigmatic. So there are many questions about those viruses. But the major issue is that they are very dangerous pathogens. And often we don't have much to offer to people who are actually infected with these viruses. There's no vaccines. There's no antivirus. That's why operators he to be well-protected.

[14:55:16] GUPTA: Researchers have to train for a year before they can even step inside this lab.

MCKENZIE: And what is so crucial about the work that is being done here for public health?

UNIDENTIFIED MALE: What is crucial, this lab is mostly focusing on diagnostics. So we do provide the diagnostic services for these unusual pathogens. And based on the diagnostics can't be done somewhere else, so you need the technology to process the specimens.

GUPTA: From the field to the lab, you have to admire the bravery of these men and women to keep us safe from emerging diseases. In a sterile environment like a laboratory, wearing heavy hazmat suits and breathing through tubes, it can be easy to lose sight of the true impact here. Human lives often depend on this research and into science. So if and when the next viral outbreak happens, no matter where it is, we can be ready for it.

For VITAL SIGNS, I'm Dr. Sanjay Gupta.