The Boma

Covid-19: Finding the origins of a pandemic

April 14, 2021 International Livestock Research Institute Season 1 Episode 2
The Boma
Covid-19: Finding the origins of a pandemic
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Covid-19 has had the world at a stand-still since early last year and yet we are still trying to find out how the pandemic started. Did the virus come directly from a bat, a different wild animal, was it spread by frozen food, or was it even leaked from a lab?  A report published at the end of March by the World Health Organization and a joint team of scientists begins to unravel the mystery of the origins of the coronavirus, SARS-CoV-2.  

Tim Offei-Addo sat down with Hung Nguyen-Viet, co-leader of the Animal and Human Health Program at ILRI, to discuss his experience traveling to Wuhan as part of the team trying to find the origins of the pandemic. 

Tim: Welcome back to The Boma

A podcast hosted by the international livestock research institute discussing livestock issues that impact the global South.

My name is Tim Offei-Addo and I'm your host.

COVID-19 has had the world at a standstill since early last year. But even as more and more people are receiving the covid-19 vaccine we are still figuring out where COVID-19 came from. 

Last month the World Health Organization and a joint team including 10 international experts published their report about the origins of the pandemic. That team included Hung Nguyen-Viet, co-leader of the animal and human health program at ILRI who went to Wuhan to investigate the origin of the virus. The team came up with four scenarios about how the pandemic started I asked him to explain more


Hung: So if I go really from the most likely to less likely scenarios, we start first with the transmission of the virus to human through an intermediate host. It means that the hypothesis or the scenarios would be the virus started with host reservoir and jumped into another animal before jumping to humans. So that that was evaluated as the most likely scenarios in the report. The second one is the direct spillover from the host reservoir to human. The third one is linked to the food environment. The virus of course emerged somewhere and this can be transmitted on the frozen food. Because actually the Chinese found some evidence from food package and food imported from other country. So it was ranked as possible to likely. And the last one was linked to the lab leak and that was ranked as extremely unlikely based on the knowledge at that time.


Tim: What was your role on the team? I know you are a biologist by training…? 

Hung: Actually we had 17 international experts. Some of them worked for WHO and 10 experts were selected by WHO for that mission. Because of the nature of the study, the composition of the team is very much in the One Health spirit. It means that you have really different experts from different disciplines. I was not the only biologist in the team. So basically you had a medical doctors, you had virologists, you had epidemiologists, you have biologists, ecologists both on the WHO side and on the Chinese side. 


Tim: When you arrived in Wuhan what were the first things that you did? Were you first having meetings with the Chinese scientists, getting on the same page, or did you directly go and start studying the four scenarios that you mentioned earlier? 

Hung: Okay so before coming to China we already had several meetings between the WHO expert and Chinese colleagues to define the scope of work, make planning, but also we started discussing the results of different study conducted by Chinese colleagues. And once we were in Wuhan we started our two weeks quarantine in a hotel. But we started immediately having meeting amongst the group, but also with Chinese colleagues. so we had a meeting together every day and after two weeks and we really met Chinese colleagues in person, and there we had meeting face to face and we visited a different site we analyzed data together, having a lot of discussion meeting partners and  lastly we came up with these four scenarios I presented earlier. 


Tim: Okay so it's really a collaborative mission from the very beginning, even before you travel to Wuhan? 

Hung: That is correct and actually we always kept in mind that that was a joined themes or a joint study. Because it was not an study alone. It was really a collaboration a partnership between WHO and China. Because that this international team, we only had 28 days in China and that time really it was not a plan for us to really go out to the in the field collecting samples, doing analyses, etc. It was really the time for us to sit to work with Chinese partner who most of them conducted study before. So we reanalyzed the data, discussed different options, and came up with a conclusion and wrote up the report.


Tim: So the first outbreak of COVID-19 happened at the web market in Wuhan. Did you go there and could you tell us about what that research was like, and also describe the market?

Hung: The market was already closed since one year ago when we came. So I think that we were the first foreigners to visit the market since the closure. They show us how the markets worked and we walked around we identify the place where different cases took place, I mean the human case of COVID-19 case took place. And I was part of the animal and environment working group in this mission so we particularly were interested in understanding what was sold in the market at that time. 

So it's very interesting to learn that from outside point of view when people heard about seafood market or a wholesale market, people might think that it was really for the purpose of wholesale. But no that was that was quite traditional market where you had about 600-700 small stores of about 20 square meters where people sold many things, mainly seafood. But they did sell other type of animal source food like chicken, pork, but also a vegetables and other types of things. And they found, the study found so, 10 stores sold wildlife meat, wildlife products. 

And actually one of the interesting information is in fact some of these species who are susceptible to coronavirus - Chinese colleagues tracked back this product to the origin where this came from. And so some of these species came from the wildlife farming in south of China. In Hunan province in Guangdong in Guangxi for example, and you might remember that  some of the study before showing that in that provinces in particular, in Hunan, they found coronavirus in bats and that coronavirus is was very closely linked to the SARS-CoV-2. So you see we made some link and interpretation on the potential transmission of diseases in in that context. So that is one of the key points in the report. 

The second point is in fact many samples was collected actually in this Huanan market, they collected almost 1000 samples and they found mostly positive samples in a positive SARS-CoV-2 virus from the environmental samples. Mostly from surface and sewage this kind of thing. But they didn't find any positive samples from meat or from the wildlife. But you see this sample, the wildlife meat samples, in terms of number it was quite small. So even we didn't find virus in that product, one of the main recommendations is really to conduct a tracing batch study to understand these animals, and how they were in contact with people, and also more importantly the contact with wildlife in in nature. 


Tim: There's also been in the media a lot of pressure and amplification about this idea that it could be in a lab leak. Did you go visit a lab for instance and what were the conclusions there? 

We could agree with Chinese to visit actually a few labs in Wuhan during our stay. But the most important visits from the labs, that was the first visit to Wuhan Institute of Virology and actually we had a tour of the lab where the senior management showed us how it functions, how it works, the different types of work they doing. And after the tour we had a quite long meeting in meeting room week with different members of the lab, where they really went in depth to present us what they do in terms of research with what type partnerships, and  the research performance in China. So it was very impressive and we spent three or four hours really to start the Q and A session where the expert in one site, we asked the questions that we wanted, and they really responded to us and exchanged information. And also during that mission as I mentioned before that was a joint team so Chinese colleagues were always with us and they also asked questions in in this meeting 


Tim: What were some of the questions that you asked or like were asked and then what were the like takeaways as a mission from those conversations? 

Hung: Yeah so some people keep asking us how did we do the audit of the lab. I would say that that was not an audit as such because we had a few hours and we really targeted different type of questions that people wanted to know. So for example we questioned about how the lab was managed and how was the health of staff were recorded and taken care by management, this type of question was answered by the senior management member of the lab. For example, they said that they had a very good recording system of health of their staff and during that time in particular of course they regularly tested their stuff, and no one was positive so far at that time. So we asked the questions how the data is managed, what type of diseases, before we brought up some of the I would say sensitive questions around the lab leak theory. And based on the response they have we come up with the recommendation. 

Because actually at that time I think that we discussed also the possibility of the lab leak, accidents, different labs in the world, and also the evidence we have in the literature and the discussion with people from Wuhan Institute of Virology. So really the conclusion of the team really based on that information we had at that time. Now people can say that we didn't really do a very careful audit of the lab, that is true - that was not the job we were asked to do.


Tim: You went to the market you went to a couple of labs and you also want other places what are the recommendations and then also the next steps?

Hung: We recommended that  we should pursue the first transmission pathway from a horse reservoir to immediate host to human, because all the information and evidence we found suggested that that is the most likely way that the virus emerged and was transmitted to humans. If you go back to that report and what to do next, that should be the first priority. We recommended the least likely scenario in the report was about the lab leak. And media talk a lot about this recommendation as well. 

And I need to really remind that that the lab leak is one of the four pathway we put in the report. It means that it's still there. We rank it as an extremely unlikely because of the knowledge and of the evidence from the group we had in Wuhan. But it doesn't mean that the group ruled out these scenarios, because maybe more information comes. It is a really involving process for any scenarios of any pathway or transmission of the study, if the information come more, people can change the mind and change the recombination of the report. Because we didn't have enough knowledge maybe to rank different things at that time, that's why I can tell you at the last meeting of the WHO member states last week, the member of the study was invited to attend this meeting and we listened to the comments of Dr Tedros. And he said that maybe we need to do more properly this study on the lab. But maybe that is a one of the options that China would pursue in the future.


Tim: Hung and his colleagues recommended that further research should focus on the wildlife farms in the south of China, because that's where animals at the market in Wuhan may have come from. And while the mission was still in Wuhan they were told that a virus closely related to COVID-19 have been found in Cambodia and Thailand. If the World Health Organization's mission to find the origin of the virus continues it will probably have to expand beyond China.

Hung is just one of ILRI's scientists working on COVID-19 and other zoonotic diseases. To find out more visit and stay tuned for the future episodes of The Boma where we'll discuss One Health - optimal health for people, animals, and the environment in more detail. Special thanks to Hung for interviewing with us and Jeremy Cherfas and Annabel Slater for production and technical support. Keep joining us at The Boma where we will continue to bring you more stories from the lab desk and field. Don't forget to subscribe wherever you get your podcast and leave with a review if you appreciate the show!

The four scenarios for the origin of the virus
Who was on the WHO team?
What did the WHO team do first in Wuhan?
What did the team do at the market in Wuhan?
What about the 'lab leak' theory?
What did the team conclude and why?
Where should the investigation go next?