Episode 20 – Fowl threat: is avian flu going viral?

Intro (00:09:22)  

Science on the Menu, a podcast by the European Food Safety Authority.

James (00:20:04)

Hello everyone and welcome to this episode of Science on the Menu, EFSA’s podcast. My name is James Ramsay and today we're returning to the topic of avian influenza, something that we first discussed last year in an episode back in March 2023. 

As those of you who follow the news closely will know, the topic of avian influenza is something that's still grabbing headlines over a year later. We're going to explore why that might be the case with a couple of EFSA’s animal health experts. So, I'm very happy to welcome to the podcast Lisa Kohnle and Alessandro Broglia, who are both from the animal health team here at EFSA and who have been contributing their knowledge and expertise to the scientific advice we have produced on avian influenza.

So, Lisa, Alessandro, a warm welcome to you both. How are you both doing? 

Lisa (01:08:14)

Thanks a lot for the invitation. Very busy on the topic as usual. 

James (01:12:11)

Good, good. And I’m going to call you ‘Ale’, is that okay? So, we refer to you affectionately as Ale instead of Alessandro.

Alessandro (01:16:16)

Very much okay, as everyone calls me.

James (01:22:23) 

Very briefly, just give people a sense of who you are and what it is that you do here at EFSA. Maybe starting with you, Lisa.

Lisa (01:31:18)

Yeah, so thanks for the introduction. I'm Lisa Kohnle. I'm originally from Germany but have travelled quite a bit around the world since I finished my veterinary degree. Most importantly, maybe to mention, I did a PhD on avian influenza which brought me to Bangladesh, a completely different setting than which I'm working in right now. But it gave me, I think, the right field experiments to really understand what the data means that I'm working with nowadays. 

And fortunately, after my PhD, I had the opportunity to come back to EFSA to work as a scientific officer on actually a variety of different topics, but recently more and more on avian influenza as it is such a big issue for all of us. So, I'm happy to continue my work here.

James (02:20:00) 

Okay, so very qualified to be talking to us today about avian influenza. Can you match that, Ale? What's your background and what do you do here at EFSA?

Alessandro (02:28:23)

Thank you, James. I'm also a veterinarian and in EFSA since 15 years already now, so pretty long. And in my former life, I spent many years in Africa, more in the field, also dealing with animal health issues and animal diseases. So, from the field to more the theory. But I have to say that in the last years we did a lot, and more and more with epidemics. And here we are. I mean, it's not a new topic, but still changing its aspect every day in the news. So yes, very challenging, but also very intriguing to discuss this today with you.

James (03:16:16)

Great, so let's jump straight in. You mentioned that avian influenza is still a topic that you see being reported in the news a lot and we were talking about this a year ago. I wanted to get a sense, first of all, about how the situation has developed since then. So maybe Lisa we could start with you on that one?

Lisa (03:40:10) 

Yes, sure. So, when you recorded the last episode of the podcast, I think you were just at the beginning of spring where we would expect that the cases go down a bit during the summer period. But what we actually experienced last year in Europe is that the cases didn't decline over the summer months because they were so widespread in the wild bird population, especially in the sea birds in a lot of different gulls and tern species that actually we were seeing mass mortality events throughout summer in many different wild bird colonies, especially seabirds across Europe. So, for example, the United Kingdom was heavily affected, there was a lot of population decline and a lot of wild bird species. And of course, this also leads to a very high contamination of the environment, which then poses a risk to poultry because then it's easier for them to get infected. So, at the same time, we were seeing still a lot of outbreaks in poultry during those months that are usually very quiet. So of course, that's a challenge for our stakeholders in Europe because usually during those months they can maybe relax a little bit, they can maybe prepare for the following season, which starts around September, October. But they were kept busy throughout those months.

James (04:58:03)

Why would we normally see a kind of dip in the summer months and rise in the winter months? Is that to do with the migratory patterns of wild birds? 

Lisa (05:08:17) 

Yes, exactly. So usually in autumn wild birds would come from different parts of the world to Europe. They would mix, they would roost, they would breed in certain areas and that would give a lot of potential for transmission, for exchange between different species. But once we reach a stage where there is so much virus in the environment, as it was for example last year even during the summer months, the virus doesn't disappear anymore because normally under certain environmental conditions, high temperature etcetera, it doesn't have good chances to survive in the environment. But if it is there in such high concentrations like last year, it remains in the population.

James (05:54:01) 

Okay, so that's a bit the situation in Europe. Obviously one thing that we can't avoid mentioning is what's happened in the US in recent months - so the outbreaks that have been seen in herds of dairy cattle. Can you talk to us a bit more about that, what we know, what we don't know, and maybe most importantly does this pose a risk? Does this new development give us reason to be concerned?

Lisa (06:20:16) 

Yeah, so what we see since the beginning of the current season, which started last year in October, is that the situation in Europe is actually improving due to certain factors. For example, those wild birds that I mentioned have declined, so there are not many susceptible birds around anymore and some of them might also have acquired a level of immunity. Whereas in other parts of the world where the virus has arrived later, such as in the Americas, it met certain species, certain animals (birds and also mammals) that were never exposed to the virus before. And that is always when a peak in cases occurs, when there is a lot of clinical signs, a lot of mortality, when really a new species is affected. 

And this is what happened in the Americas last year. It actually started in the Southern part, in South America, where we have seen massive mortality events in sea lions, southern elephant seals, etcetera. So, there were really thousands and thousands of deaths around the coastlines of South America. And then towards the winter months from November, December onwards, the focus was really on North America.

And it started with a lot of outbreaks in poultry. During the last couple of months, outbreaks in poultry are really focused on North America, more than 80% of poultry outbreaks worldwide are focused on North America. And in the following weeks, months, we became aware of these cases in mammals, and in many different mammal species, which is concerning so many new species in the Americas.

And finally, also in ruminants. It all started in March with the first reports of goat kids that showed neurological signs and died in the United States. And a few days later we became aware of the first detections in cattle. This is concerning to us because this is a species group that we were not so much looking into because ruminants, there have been some experiments in the lab before on those species, but they were never really considered to be naturally infectable. But then we learned something different, we were taught otherwise. Unfortunately, what also now contributes to the picture we have been seeing is that this was detected much later than when it first happened because of the reason that we were not expecting it in that species.

James (09:06:15) 

Okay, that's interesting. I'm going to bring Ale in here, maybe just to try and put a bit of all of this in context. I mean, particularly if we talk about the situation in the U.S. dairy cattle, there have been reports of the virus also being found in milk. When we think about risk to humans, the risk of transmission via food, what do we know, what do we say at the moment about that? Where do things stand.

Alessandro (09:33:116) 

At the moment, I mean we have no strong evidence that the virus can be transmitted through food to humans. Of course, the issue of finding the virus in milk was very scary because it's kind of a staple food consumed by a lot of people. But, if we are talking about pasteurized milk, there is no evidence that this represents a major risk.

So, the concern with food is probably not the main one with avian influenza. What is maybe more worrying and that we are maybe nowadays more at that step, of checking which risks represent, are the people in touch with these animals. So, in domestic farms, of course, you have, workers and people, in very close contact with these animals, the so-called ‘occupationally exposed people.’ And that category of people is really to keep monitoring because they are the front end of this risk of ‘spillover’. Spillover means when the virus is transmitted from one species to another. And of course, humans can be also one species that may receive this. In fact, we have seen luckily very few cases seen in humans from those in contact with either cows or other infected animals.

James (11:11:13) 

So, I think that it's the European Centre for Disease Prevention and Control, one of our sister agencies, that talks about risk to human health. If I'm correct, they say that the risk to the general population from avian influenza is still low, but occupationally exposed people, so workers in farms and so on, who come into contact with wild birds or poultry or whatever it may be, that the risk is slightly elevated for them.

Alessandro (11:36:11)

Exactly. That’s why we also collaborate very closely, especially with avian influenza, with ECDC, and in different projects we have now basically always together. It's kind of a One Health issue now, in the real sense of the term, and yes that's why we collaborate so strongly now.

James (11:59:00) 

Okay. I want to just to take a step back. I know that a lot of the kind of work that we do at EFSA is about looking at what might increase the likelihood of spread of this virus. So, can you talk to us a bit about what are the drivers that make the spread of avian influenza more likely?

Alessandro (12:21:15)  

As Lisa mentioned before, of course the first concern is in the bird population. We have wild birds that are carrying the virus here and there through migration and so on. And then our domestic, poultry farms have, in reality, been the most affected by this. So, with huge infections and then it brought the culling a lot of birds and this environmental contamination with a lot of virus in the environment. 

Of course, every practice, concerning human activities in farming animals and in general in agricultural practices, these also can represent the kind of drivers for spread of the infection because it may increase somehow the exposure of animal species, or of humans, or even certain environmental compartment to the infection with the virus. So, whenever we deal with different animal species, maybe farming together, farming very closely or a lot of poultry farms in the same environment or very close to certain wetlands - we know that wetlands represent the place of aggregation for wild birds that may carry the infection. These are all kind of, let’s say, risky steps and we should take care about these. 

This is where we should actually plan our preparedness. We should not wait for having this, what people are worried about is that you have these human-to-human transmission then, because it may become a large epidemic or even a pandemic - we don't want to use this word again, but we don't have to arrive there. So, we have to really work much in advance. And, I mean, collecting information and being vigilant at that stage, even at different animal species, where we breed them - this is actually where preparedness should be.

James (14:21:00)  

Okay, that's great, it leads on to the next question I was going to ask you Lisa actually about what can we do to prevent the spread, either as me and you - you know average people, men and women on the street - or others in society who are coming into contact with birds or indeed as regulatory authorities, governments, I don't know - what is there that we can do to help prevent this spread?

Lisa (14:46:17)  

To pick up on also what Ale just said - the spread is actually what follows after the virus has been introduced in a certain, let's say population or farm or human population. So once this has already happened, which we're actually trying to prevent in the first place, you are probably still remember what we did during the COVID 19 pandemic.
So there are certain control measures that you can use, such as restricting movement of animals or people, isolating animals or people, especially for farm animals. We have strict regulations in place. So poultry, for example, would need to be culled, which is of course, the most drastic measure. But it immediately stops the spread to other poultry farms or to humans. What we should actually improve is, even a step before that, we should improve our prevention to prevent the virus from entering such a farm or population in the first place. And that we can only do through very strong early warning systems and also through monitoring and surveillance.

James (1:55:19)  

Okay, we use these terms a lot at EFSA - surveillance, monitoring - they can be quite kind of dry concepts. Can you explain maybe what does that mean in the context of avian influenza when we talk about surveillance and monitoring, what are we actually doing?

Lisa (16:09:02)  

Let's start maybe with monitoring. Monitoring just means that we are looking out for signals that tell us something important and then we see how to deal with it. And, for example, in EFSA here for the avian influenza monitoring, of course we are continuously collecting data from a variety of different sources, for example from member states, from international organizations on the outbreaks that they are experiencing. So those are actually reported confirmed outbreaks, meaning those animals have been sampled, they have been tested, and they are really positive. This would be, let's say, our most reliable data that we are collecting.

But then what we have recently started here at EFSA, and which has proven very successful so far, is also monitoring other kinds of signals. So, we are currently monitoring the news media and a lot of social media for other kinds of signals that are published by either people posting on social media or government reports in other languages, because this is where you really receive information firsthand. It's also very important because in other parts of the world, the report and notification channels take much more time than in Europe. 

So, if we want to know what is cooking in Asia and Africa, we actually need to rely on those grey channels. Here, of course, the challenge is we really need to judge is this information trustworthy or not? Can we use this as an official communication or not? And then we have to follow up with those countries, we would probably request additional information etcetera but it's very interesting.

James (17:47:19) 

So you have some creative strategies for getting the information you need.

Okay, very good. I’ll go back to Ale - just one other aspect of the debate which has come up in recent weeks and months is this topic of vaccination, vaccination as a preventative strategy. So can you talk to us a bit more about what that might mean? And then obviously the work that we're doing at EFSA in that area? 

Alessandro (18:17:14)   

Yes, of course. When we deal with infectious disease and especially with viral disease, we think about vaccination because it sounds like the biggest solution and magic wand to solve the problem. So you just get your shot and then you are immune for the rest of your life. That would be really nice. In this case, vaccinating poultry against avian influenza is something really new, that only in France is running in certain categories of poultry because we had huge epidemics in France. So, and then they had to complement, let's say, the preventive measure with something more. But we should not think about vaccination as the one single solution for this. This should be coupled and included in, in a series of measures, in a kind of plan, and seen as a part of the solution to the problem. We cannot imagine that vaccination confers a lifelong immunity. We always have the same level for the animal. So it requires several shots and so on. So huge resources to implement the campaign. Sometimes is not the problem only to have a good vaccine but you have also to implement a good vaccination campaign - which implies personal, structures, means of communication, also awareness and readiness of the farmers to accept the vaccination and so on, and cost of course.

So in this sense this is really something as part of a plan and then you may have, probably you have heard in the news in these days, vaccination for avian flu also for humans, there are some doses that have been allocated for certain categories of people, as we were discussing before, the most exposed ones. So in certain contexts, you may foresee to use vaccination against avian flu in humans.

But besides that since influenza viruses are really, very dynamic viruses and can change every time and recombine and reassort with other viruses. Even the usual seasonal influenza. I mean, we know that we have a vaccine for the population against death that should also be considered because if you get vaccinated against the seasonal influenza, then it means you can control a little bit the probability of reassortment of this virus between avian flu and other influenza viruses. So that's a kind of, multifaceted, preventive measures against the same problem that has still different colours and nuances.

James (21:21:06)   

Sure, Okay. And at EFSA we are providing, and have provided, several scientific opinions or pieces of advice on vaccination. We continue to inform what we call our risk managers, so the European Commission, Member States and so on.

Alessandro (21:28:21)    

Yeah there's a couple of, let's say, two main outputs about the vaccination against avian flu in poultry - very useful for our risk managers, but also for Member States because that was really the scientific base to understand, okay - we go, we don't go - there are vaccines available. What kind of surveillance should be put in place while vaccinating just after vaccination? So to be sure that there is no so-called ‘silent spread’ of the virus among vaccinated poultry population. 

So yes, two scientific opinions that have a real good echo and very well received by politicians and managers. So, I would say that EFSA, yes, in that sense we are very much contributing.

James (22:24:24)   

Very good. Okay, guys, we're going to leave it there. We'll let you get back to your very important work. Thanks very much for being with us on the podcast today. Maybe we'll have you back again. I have a feeling this is an issue that we'll be discussing and talking about in another year's time. So it could be that we get you back on the podcast.

To our listeners, thanks very much for joining us. I hope you found this useful and interesting. if you'd like more information about avian influenza, or any of the work that we do here at EFSA, please make sure to check out our website and our social media channels. And I should also give a plug to our sister agency - the European Centre for Disease Prevention and Control - which as we discussed just now is also working on the topic of avian influenza.

That's it for now. We see you all next time. Thanks very much.