Interwoven Threads of Avian Influenza and One Health with Dr. Greg Gray

WEBVTT

00:00:09.230 --> 00:00:16.728
This is a podcast about one health the idea that the health of humans, animals, plants and the environment that we all share are intrinsically linked.

00:00:17.420 --> 00:00:21.089
Coming to you from the University of Texas Medical Branch in the Galveston National Laboratory.

00:00:21.760 --> 00:00:22.905
This is infectious science.

00:00:22.905 --> 00:00:24.745
We're enthusiasm for science.

00:00:25.399 --> 00:00:26.021
It's contagious.

00:00:26.021 --> 00:00:33.503
Hey everyone, thanks for tuning in.

00:00:33.503 --> 00:00:34.347
This is Danielle.

00:00:34.820 --> 00:00:35.762
Hey Danielle, how are you?

00:00:36.003 --> 00:00:38.609
Good, this is Matt this is Matt Dashow.

00:00:38.609 --> 00:00:39.972
And we're also here with Dennis.

00:00:40.280 --> 00:00:41.844
I almost thought you could forget me here.

00:00:43.320 --> 00:00:44.543
You are all the way across the room.

00:00:44.804 --> 00:00:51.810
Yes, so this past year there's been reports all over the news of mass bird diopsis associated with influenza.

00:00:51.831 --> 00:01:04.447
Yeah, I remember I was traveling in Peru earlier in the year and I was with an epidemiology colleague and we were taking a walk on the beach and on the beach there must have been dozens of dead seabirds and it was kind of a startling thing to see.

00:01:04.447 --> 00:01:10.069
And then he told me about there had been some hundreds of sea lions that had washed up in Peru as well.

00:01:10.069 --> 00:01:13.153
Oh gosh, yeah, that also had been affected by bird flu.

00:01:13.153 --> 00:01:17.248
So this seems to be a pretty significant pandemic of bird flu across the world.

00:01:17.831 --> 00:01:24.965
Yeah, and you might have noticed the huge increase in the price of eggs and chicken in the grocery store kind of earlier this year.

00:01:24.965 --> 00:01:26.465
It was pretty devastating.

00:01:26.560 --> 00:01:30.507
We are egg fanatics in my family and so, yes, we felt it in our pocketbook.

00:01:30.686 --> 00:01:34.266
Yeah, so if you're on a ketogenic diet, you know you're probably noticed.

00:01:35.840 --> 00:01:47.144
So to help us talk a little bit more about the biology of avian influenza and generally issues in one health, we invited an expert to come speak with us, Dr Greg Gray.

00:01:47.144 --> 00:01:54.629
He's a professor here at UTMB and he's also one of the leading experts we have on respiratory pathogens in one health.

00:01:54.629 --> 00:01:55.632
So thanks for coming.

00:01:56.079 --> 00:01:59.328
Thanks for inviting me, daniel and Matt and Dennis Pleasure to be here.

00:01:59.489 --> 00:02:01.784
Yeah, we are so happy to have you here.

00:02:01.784 --> 00:02:06.870
This is a One Health podcast and we are actually getting to speak with a One Health expert.

00:02:07.221 --> 00:02:09.026
Yeah, this is a long overdue right.

00:02:09.567 --> 00:02:10.629
Yeah, yeah.

00:02:10.629 --> 00:02:13.907
So let's jump into some of the meat and potatoes.

00:02:13.907 --> 00:02:18.150
Really, what is avian influenza and how is that different from human influenza?

00:02:18.621 --> 00:02:31.930
Well, there are many different strains of influenza and it's the influenza A group that causes the avian types and so there's four types influenza A, b, c and D.

00:02:31.930 --> 00:02:39.181
That's correct, and it's the influenza A's that troubles us, both in the human and animal kingdoms, the most.

00:02:39.181 --> 00:02:52.588
And getting back to your question, the influenza A's there's some 18 different hemaclutinin types and some 11 different neuraminidase types, and the vast majority of those types can infect birds.

00:02:53.000 --> 00:03:01.526
So when you say that you're talking about like the H1N1, H5N1, those naming kind of things that we all hear, when that's correct.

00:03:02.199 --> 00:03:08.709
Those are identifiers that help you differentiate the different subtypes, right Like there are certain proteins that are on the virus itself.

00:03:09.520 --> 00:03:17.848
Yeah, they're considered glycoproteins and they've long been followed and as the most important antigenic components of the virus.

00:03:17.848 --> 00:03:22.165
What are immune systems see and their ability to attach and evade cells?

00:03:22.165 --> 00:03:24.991
Or what defines disease in different animal species?

00:03:25.352 --> 00:03:25.671
Right.

00:03:25.671 --> 00:03:28.687
So these are the proteins that are on the surface of the virus, right?

00:03:28.687 --> 00:03:32.169
And that they're the primary proteins involved in cell entry.

00:03:32.169 --> 00:03:45.569
So they're really what is defining not only what species is being infected, but what tissues within that species is being infected, so if it's their lungs or their upper respiratory tract or their intestines or something like that, right.

00:03:45.689 --> 00:03:46.651
Yeah, that's correct, Danielle.

00:03:46.651 --> 00:03:47.532
Yeah, okay, good.

00:03:48.442 --> 00:03:51.175
I remember virology 101.

00:03:51.175 --> 00:03:51.778
It's good.

00:03:52.562 --> 00:03:53.728
You've surpassed my knowledge.

00:03:53.728 --> 00:03:55.585
Now I'm learning now.

00:03:56.319 --> 00:03:59.870
Sometimes we have to review these things because I don't always remember my basic virology.

00:04:01.042 --> 00:04:07.325
So, greg, I was talking about this a little earlier with kind of the birds were on the beach, the sea lions were washing up.

00:04:07.325 --> 00:04:22.560
We've heard about certainly in the news, there's all of this news about some other animals like minks up in some of the Scandinavian countries coming down with bird flu, and so it seems like the avian influenza can infect all kinds of different species.

00:04:22.560 --> 00:04:24.608
Can you say a little bit about that and how that works?

00:04:24.800 --> 00:04:35.761
Yeah, we're continuing to learn new species that are susceptible, if you will, to infection, and there have been a tremendous number of outbreaks among avian species here in the last 10 years.

00:04:35.761 --> 00:04:43.934
The World Organization for Animal Health has documented some 21,000 outbreaks in recent years, oh geez.

00:04:43.934 --> 00:05:10.476
And because so many animals have died, carnivores in particular have been eating those scarcasses and we've suddenly seen strange carnivores manifesting serious illness and dying from an ingesting birds that died from avian flu, and then they too, including things like grizzly bears, which is totally unknown, and so we're seeing outbreaks and carnivores and outbreaks and other domestic animals.

00:05:10.476 --> 00:05:11.360
It's been quite interesting.

00:05:11.841 --> 00:05:13.185
I wanted to ask you, greg, is this?

00:05:13.185 --> 00:05:21.350
I mean, what I've been reading is that this is maybe among the worst and longest outbreaks of avian influenza in the world.

00:05:21.350 --> 00:05:22.151
Is that the case?

00:05:22.740 --> 00:05:30.630
Yeah, of course our diagnostics and ability to characterize viruses have increased over time, but certainly in the last 20 to 30 years this seems to be the largest.

00:05:30.630 --> 00:05:58.855
In fact, the virologists have indicated that for the various different strains of virus, there are at least 34 different avian influenza subtypes that have caused these outbreaks, which is astounding, and a lot of these are particularly H5 and they're in zootically saying animals through many parts of the world and it's got a lot of people very concerned that if they should develop increased morbidity characteristics or ability to spill over to humans, we could be in trouble.

00:05:59.245 --> 00:06:12.879
So this is one of the things that really gets me is, I think when we name things or when we colloquially refer to things as avian flu or swine flu, it kind of gives us this really misleading sense of security.

00:06:12.879 --> 00:06:14.163
This isn't really a bird flu.

00:06:14.163 --> 00:06:16.651
This is just a bird adapted flu.

00:06:16.651 --> 00:06:20.625
It doesn't take a big jump for it to adapt to something else.

00:06:20.625 --> 00:06:22.309
Right, Evolution is constantly happening.

00:06:22.309 --> 00:06:27.093
So I think the naming, the way we talk about these things is misleading a little bit, right.

00:06:27.112 --> 00:06:38.997
Yeah, I think that's a very good point and I think it's very easy for the public to also then think if it's called avian flu, then you all of a sudden turn into a bird or something like that when you get infected.

00:06:38.997 --> 00:06:43.391
I know that's memes that come out, but I think the naming is a very good point, danielle.

00:06:43.713 --> 00:06:49.343
And I think sometimes it's even had really devastating consequences where there might be an outbreak of swine flu.

00:06:49.343 --> 00:07:04.959
So people just start culling pigs around the world, or they'll start culling birds around the world, because we have this idea that this virus is circulating and even if there's no exposure, in order to keep ourselves safe in an era of fear, we kind of don't always behave in an intelligent way.

00:07:05.245 --> 00:07:08.132
I wanted to nerd out real quick with a question for you, Greg.

00:07:08.132 --> 00:07:14.459
We know that there are some differences between, let's say this, avian flu and then human influenza.

00:07:14.459 --> 00:07:15.704
Are those different viruses?

00:07:15.704 --> 00:07:16.468
Are they different?

00:07:16.468 --> 00:07:17.713
Hs and Ns?

00:07:17.713 --> 00:07:18.475
How do they differ?

00:07:18.697 --> 00:07:42.178
Well, yeah, so I mentioned earlier that there's some 18 different hemagglutinins and 11 different neuraminidases, and 16 of those 18 affect birds, and about nine of the neuraminidases affect birds, and so birds harbor almost all the permutations of those 16 by 11 variants, and some of them are really innocuous in the birds, quite well tolerated.

00:07:42.178 --> 00:07:59.052
Some of them cause severe disease, particularly the H5 and the H7 variants, and we're basically susceptible as humans to a number of these, but in particular the highly pathogenic H5 and H7s in the birds have caused the most severe illness in humans.

00:07:59.454 --> 00:08:07.716
Okay, so correct me if I'm wrong, but avian influenza has a pretty hard time infecting humans, am I right?

00:08:07.937 --> 00:08:20.831
Yeah, I think that's been demonstrated quite clearly just by the numbers of avian species that have been infected in a close contact with humans and the really sparse number of humans that have manifested clinical signs and symptoms.

00:08:20.831 --> 00:08:29.004
Of course there's always the suggestion and serologic studies have borne this out that there are subclinical infections going on that we're missing.

00:08:29.004 --> 00:08:35.927
But it's true there's a huge species barrier between avian species infected with flu and that moving over to spill over to humans.

00:08:36.269 --> 00:08:39.856
I think it's kind of really interesting to me about how this happens.

00:08:40.164 --> 00:08:52.024
So from my understanding, there's really two types of salicylic acid on the surface of cells, which is where influenza is binding to, and in humans in the lower respiratory tract.

00:08:52.043 --> 00:08:55.861
So, like your lungs, we have both, but in your upper respiratory tract you only have one.

00:08:55.861 --> 00:09:08.865
And human influenza viruses are really well adapted at infecting and binding to cells that are in your upper respiratory tract and then from there they can spread to your lungs and that's where you're really going to get a lot of the significant disease.

00:09:08.865 --> 00:09:21.107
But avian influenza viruses or avian adapted influenza viruses aren't really able to readily infect the cells in your upper respiratory tract, so that's why they have a hard time establishing infection.

00:09:21.107 --> 00:09:41.746
But if they are able to get down into your lungs, that's where they're able to infect and establish an infection, and that's why you have these really severe outcomes of people that are infected with an avian influenza but they're not able to transmit it because their upper respiratory tract isn't involved, so like their nose and throat, and that's where you're breathing in, exhaling virus or you're breathing it in.

00:09:41.746 --> 00:09:44.107
So that has more to do with the transmissibility.

00:09:44.220 --> 00:09:46.966
I've read, that is, that yeah, I think that's accurate, very accurate.

00:09:46.966 --> 00:09:53.730
It's the occupational exposures where there's intense aerosolization of viral particles.

00:09:53.961 --> 00:09:55.539
When you say occupational, what are you talking about?

00:09:55.600 --> 00:10:03.846
Well, people that work in live bird markets all day, especially live bird markets where there are inzotic many different strains of live avian flu.

00:10:03.846 --> 00:10:15.908
It just makes sense that those people have a tolerance from the chronic insults to their immune system with those antigens and people that are totally immunological and naive or at risk when they go into those environments.

00:10:16.721 --> 00:10:32.740
And I think what we've learned from COVID is the particle size also matters, right, if a droplet is formed and it's a fairly large droplet through sneezing or something like that, it doesn't travel very far in the environment and it also doesn't travel very far in our respiratory tracts, right.

00:10:32.740 --> 00:10:37.720
But if the particle size is very small, then it travels deeper into our lungs.

00:10:37.720 --> 00:10:41.980
So the way something is aerosolized also matters in that regard.

00:10:41.980 --> 00:10:43.773
Interesting, interesting.

00:10:43.793 --> 00:10:52.470
That's exactly right, and I'll just say that we've done some bio-aerosol sampling in very large bird markets One bird market near Hanoi, vietnam.

00:10:52.470 --> 00:11:19.139
Almost half the aerosamples had molecular evidence of avian flu and some of those were viable in this system which isn't really that great at capturing a live virus and preserving it, and so some of these settings are naturally aerosolizing virus and feather and dust particles and it's no wonder that one of the exposures that people have who develop avian flu is contacting those live bird markets.

00:11:19.139 --> 00:11:21.148
Often one of the exposures Right.

00:11:21.440 --> 00:11:27.437
I think the only case that I saw, that at least we've seen in the US, was a poultry farmer in Colorado.

00:11:27.437 --> 00:11:28.059
Is that correct?

00:11:28.059 --> 00:11:29.888
I think there's only been maybe one or just a couple.

00:11:30.041 --> 00:11:33.625
Yeah, there have not been many here that I know of in recent years.

00:11:33.860 --> 00:11:36.904
But the fear is that I would be able to become more transmissible.

00:11:37.145 --> 00:11:41.721
Yes, If it were to develop the capacity to move from human to humans.

00:11:41.721 --> 00:11:43.148
We're in trouble.

00:11:43.148 --> 00:11:47.859
Just look at all the detections of these H5 strains here in the United States.

00:11:47.859 --> 00:11:56.025
If you look at the USDA's map of those in wild birds or even in the domestic flocks, those are virus that quite widespread in their distributions.

00:11:57.241 --> 00:11:59.969
I want to intersect right there and just ask a question.

00:11:59.969 --> 00:12:08.365
I think for us as scientists and risk communication, like you just mentioned, greg, if this adapts more to humans, we're in trouble.

00:12:08.365 --> 00:12:16.448
So, as virologists, we have the task to educate the public, but often the public will perceive this as fear mongering.

00:12:16.448 --> 00:12:19.869
At the same time, we have the duty to educate them.

00:12:19.869 --> 00:12:25.830
How do you think, in terms of science communication and risk communication, we should inform the public.

00:12:25.980 --> 00:12:29.827
Well, dennis, I think the best measure is not to hide truth from the public.

00:12:29.827 --> 00:12:36.551
We've been shown time and time again that doesn't work, and so a realistic measurement of risk is prudent.

00:12:36.551 --> 00:12:57.047
And right now the species barrier between avian flu as infecting avian species and transferred to humans is very high, and that has to do with our host immunity, that has to do with the receptivity of the virus, and so I'm not as alarmed with the threats of avian flu as I am with some of the other flu viruses.

00:12:57.399 --> 00:13:03.008
I think that the thing that is unique about avian flu, though, is how fast it can spread.

00:13:03.008 --> 00:13:19.529
Just because we are living a very global economy, people are moving all over the place, but birds themselves are migrating without the assistance of humans, so even if we were to quarantine or stop movement, the virus would still presumably circulate on its own.

00:13:19.529 --> 00:13:20.464
Is that that's correct?

00:13:21.643 --> 00:13:27.245
Yeah, it's pretty amazing If you chat with the wildlife biologists who monitor avian species.

00:13:27.245 --> 00:13:43.985
The thousands of miles some of these species travel and how they form up before they do their migrations in areas that other species form up, how they mix during those migrations, basically accelerate the cross species transmissions in the avian populations.

00:13:43.985 --> 00:13:54.830
And I've heard it expressed as these birds are dropping many bomblets of fecal material over vast geographical areas and that's particularly what makes our poultry farms threatened.

00:13:54.830 --> 00:14:09.565
It's very easy to move the virus through the migrating birds and if your biosecurity and your poultry farm lets that virus be introduced by one measure or another, your farm can have an explosion in avian influenza viral infections.

00:14:09.886 --> 00:14:10.450
So wait a minute.

00:14:10.450 --> 00:14:11.956
How is it spread among birds?

00:14:11.956 --> 00:14:24.326
It's a GI virus, yeah, yeah, because when I think of flu, I think of respiratory pathogens, but it's only a respiratory pathogen in us yeah, the oral fecal is thought to be the primary method of transmission in birds.

00:14:24.820 --> 00:14:39.966
Humans can actually acquire the infection through multiple different ways direct contact, aerosolization, as we mentioned, and possibly oral ingestion, and until recently we didn't give much credence to the aerosolization threat.

00:14:39.966 --> 00:14:48.769
But I think SARS-CV-2 has really got us concerned now, because we certainly know that virus moves quite readily in the air, as Dennis said, in small particles.

00:14:49.000 --> 00:14:49.623
Yeah, I was going to ask.

00:14:49.623 --> 00:14:57.427
As you were talking, I was envisioning these things that happen naturally as birds are preparing to migrate and they cluster and they're around other animals.

00:14:57.427 --> 00:14:59.827
What about on poultry farms?

00:14:59.827 --> 00:15:02.828
What about where there is industrial poultry farming?

00:15:02.828 --> 00:15:06.285
What do they do if they have an outbreak or how do they detect it?

00:15:06.620 --> 00:15:23.490
I think we have some of the most biosecure poultry, beef and pork farms in the world and they follow very strict biosecurity procedures to reduce, we say, barn-to-barn transmission on a farm and particularly to reduce farm-to-farm transmission.

00:15:23.490 --> 00:15:44.528
And so there are a lot of different measures that people use rodent control, because rodents can physically carry it, passerine birds control, access with screening, the wearing of personal protective gear in humans, filtration in some cases of some of the airs, the feed in the water not having any contaminants.

00:15:44.528 --> 00:15:49.389
So there's a lot of things that can be done and are done to protect poultry farms.

00:15:49.389 --> 00:15:53.168
But these tricky viruses, they often have a way to circumvent things.

00:15:53.639 --> 00:16:02.889
And when that does, you see an explosive outbreak and the farmer must report this to the agricultural experts, usda and AFIS.

00:16:02.889 --> 00:16:11.528
And then there's a mass culling effort to remove the threat to other farms with some compensation, although many would argue it's not enough.

00:16:11.700 --> 00:16:15.059
Right, and I'm sure that's country-specific right and like region-specific.

00:16:15.059 --> 00:16:18.327
Well, that's the United States, the story is quite different than other countries.

00:16:18.740 --> 00:16:28.488
Yeah, the biosecurity is in some cases not very good and the mitigation strategies may not be as well rehearsed and the reporting requirements perhaps less enforced.

00:16:28.488 --> 00:16:33.748
I came from Duke not long ago and I got to know some of the folks.

00:16:33.748 --> 00:16:39.450
They had something like 200 volunteers to respond to an avian flu outbreak.

00:16:39.450 --> 00:16:43.009
They had a whole lot full of foaming gear and everything.

00:16:43.009 --> 00:16:57.006
It looked like an army reserve center of equipment that they would move to the farm and kill the birds rapidly and dispose of them in a safe way so that no other birds would be infected or no other carnivores would eat the carcasses.

00:16:57.248 --> 00:16:57.870
Yeah, that's neat.

00:16:58.100 --> 00:17:00.688
Wow, it's just gotta be so devastating and difficult.

00:17:00.688 --> 00:17:02.547
Do you think of it from a public health standpoint as?

00:17:02.547 --> 00:17:04.467
Oh well, of course, you just have to cull the flock.

00:17:04.467 --> 00:17:13.268
But wow, if you're a farmer and this is your livelihood and you're depending on the productivity of these animals and you care for them, this has gotta be just devastating.

00:17:14.221 --> 00:17:18.885
I just had a quick question, since you brought up the efforts to contain the virus and so on.

00:17:18.885 --> 00:17:26.404
There are many different influenza networks around the world that try to predict and also stop the spread of different influenza strains.

00:17:26.404 --> 00:17:29.808
We know the migratory bird routes of birds.

00:17:29.808 --> 00:17:36.788
Is there a targeted approach to have sentinels in certain areas on these migratory routes?

00:17:36.989 --> 00:17:37.710
Can I jump in?

00:17:37.931 --> 00:17:38.111
Yes.

00:17:38.700 --> 00:17:39.846
We do not know.

00:17:39.846 --> 00:17:41.944
This is my pet peeve.

00:17:41.944 --> 00:17:44.969
We do not know the migratory patterns of birds.

00:17:44.969 --> 00:17:49.165
We have oversimplified the migratory patterns of birds to make them convenient.

00:17:49.165 --> 00:17:52.809
They're more like administrative migratory patterns of birds.

00:17:52.809 --> 00:18:07.028
Sorry, this was a big point of contention during my dissertation and it's one of my pet peeves about the way we kind of make birds fly at certain times of years and under these very narrow corridors which only really are reflecting a very narrow species.

00:18:07.028 --> 00:18:12.125
But bird migration is infinitely more dynamic than these little maps that we circulate.

00:18:12.527 --> 00:18:12.948
That's true.

00:18:12.948 --> 00:18:17.326
At the same time, though, there's certain bottlenecks that birds have to go through right.

00:18:17.359 --> 00:18:18.605
Yes, I absolutely agree.

00:18:19.599 --> 00:18:22.328
I mean we're seeing flamingos here on the island that shouldn't be here.

00:18:22.328 --> 00:18:24.726
So you're right.

00:18:24.726 --> 00:18:34.068
But getting back to Dennis's excellent question, there are concerted efforts and they've waxed and waned over the years, many of these for surveillance in birds, for viruses.

00:18:34.068 --> 00:18:43.067
Many of these have been led by the Centers of Excellence in influenza sponsored by the NIAID, and particularly St Jude's Center of Excellence.

00:18:43.067 --> 00:18:59.469
They've been sampling ducks on the East Coast, migrating birds, shorebirds, for a long time, but people probably would argue that it's not enough and they've reduced that migrating bird surveillance, with exception when they're die-offs in recent years?

00:18:59.740 --> 00:19:01.267
This is actually a question for Matt.

00:19:01.267 --> 00:19:10.647
So now where your primary care physician hat your internal medicine hat, do you think you would recognize a human with avian influenza infection?

00:19:10.839 --> 00:19:12.306
That is a great question.

00:19:12.306 --> 00:19:21.987
In the process of trying to make a diagnosis for a particular disease, there are many times where we don't even send confirmatory diagnostic tests.

00:19:21.987 --> 00:19:35.170
We treat empirically because we know what the epidemiology is right and it's only if someone fails to improve or are manifesting other unique symptoms that we might start to trigger other types of workups.

00:19:35.170 --> 00:19:51.449
And I would answer that question differently, probably five years ago, before really starting to work with folks like yourselves and One Health, where now my history taking in the clinical encounter is much more broad, to where someone especially manifesting symptoms of infectious disease.

00:19:51.449 --> 00:19:57.924
I'm asking about a lot more animal exposures, not just travel, but, you know, farm, environmental exposures.

00:19:57.924 --> 00:20:01.740
So I think maybe the astute clinician might think about it.

00:20:01.740 --> 00:20:08.571
But especially if it's something we're not a customer seeing, we might miss it and we might not even know where to go for the diagnostic testing I mean.

00:20:08.571 --> 00:20:10.356
So it's, you know, rapid flu test.

00:20:10.356 --> 00:20:13.153
I can send it and I have a result within minutes, right?

00:20:13.294 --> 00:20:15.019
Would a rapid flu test distinguish?

00:20:15.340 --> 00:20:16.083
No not.

00:20:16.223 --> 00:20:19.453
Usually you would just know that you've got influenza A.

00:20:19.453 --> 00:20:37.183
So you wouldn't really know if it's avian flu, influenza A, yeah, and particularly you wouldn't know unless there's a lot of concern that it would be swine flu, because the hemagglutinin types of human and swine are very similar H1s and H3s and there's a subset of influenza A.

00:20:37.183 --> 00:20:41.741
Positive specimens are studied to detect novel viruses.

00:20:41.741 --> 00:20:49.221
But I think Dr Daschau was correct in that the sensitivity of picking them up, who knows?

00:20:49.521 --> 00:20:53.635
Yeah, it's probably pretty low and you'd have to request sequencing.

00:20:53.817 --> 00:21:04.094
Yeah, I mean, if you had a severe disease, you're definitely going to work it up, but if it's just a mild disease and seems to resolve on its own, you know why spend all that time when he's studying it Exactly.

00:21:04.094 --> 00:21:13.323
So, I think that's why a lot of these zoonotic influenza A's that we think are happening by serologic data are being missed in the clinics.

00:21:14.211 --> 00:21:14.933
That's so interesting.

00:21:14.933 --> 00:21:16.402
I was going to ask a question.

00:21:16.402 --> 00:21:25.939
Actually, kind of coming back to something, greg, you mentioned animals eating the carcasses of birds that have died or other animals that have passed from this, and that that could be sort of a route for transmission.

00:21:25.939 --> 00:21:32.670
What about eating the meat or eggs of infected birds that come from poultry farms that may have had an outbreak?

00:21:32.670 --> 00:21:35.661
Is there a risk for humans or if it's cooked, it's okay?

00:21:35.862 --> 00:21:48.478
Well, there's a risk that humans might be infected by touching raw meat from poultry, and it's not just influenza A, but many different, as you know, other organisms, including bacterial strains.

00:21:48.478 --> 00:21:58.292
In general, though, if you handle the meat or the eggs with a modicum of care, they're very safe to eat, and especially if you cook everything thoroughly.

00:21:58.292 --> 00:22:08.243
So I'm not so worried about that, although there have been some incidental reports to suggest that it's a possible mechanism, but that doesn't concern most influenza experts.

00:22:08.430 --> 00:22:10.736
So the message cook your eggs, cook your meat Right.

00:22:11.336 --> 00:22:12.098
And wash your hands.

00:22:12.380 --> 00:22:18.289
The big jug of raw eggs and protein powder that you're taking, Dennis, for your work out every day, Every day.

00:22:18.289 --> 00:22:19.777
You know you got to cook those eggs.

00:22:20.038 --> 00:22:33.164
Yes, I think it's good to know that the measures that we're taking to prevent campylobactyl salmonella whatever chicken meat can bring uncooked right that those measures are good enough to kill off influenza as well.

00:22:33.365 --> 00:22:42.273
Yeah, one could argue that the influenza viruses are less hardy than many of the bacterial pathogens that are potentially in our animal food products.

00:22:42.575 --> 00:22:45.261
Greg, one of the things that I've been following in the news.

00:22:45.261 --> 00:22:53.617
There was an article talking about mink farms in some Scandinavian countries, minks that were becoming infected with COVID, essentially with SARS-CoV-2.

00:22:53.617 --> 00:23:02.392
And these minks are also susceptible both to avian influenza and to human influenza viruses and they can in fact be co-infected at the same time.

00:23:02.392 --> 00:23:14.123
And so there's these ideas that maybe there are certain species that can host multiple viruses together, and is there potential for those to co-mingle, to exchange DNA fragments.

00:23:14.123 --> 00:23:15.553
Can you walk us through that?

00:23:15.553 --> 00:23:17.257
Is that sort of sci-fi or is that?

00:23:17.458 --> 00:23:24.682
No, that's a reality and it's been well documented for many years, the potential for the mixing of these viruses.

00:23:24.682 --> 00:23:27.836
There are three primary ways the viruses can mix.

00:23:27.836 --> 00:23:35.338
One is basically through the sharing of large assortments segments, if you will, large segments of the virus.

00:23:35.338 --> 00:23:43.606
When two or more viruses go into a cell and they start producing progeny viruses, you get sometimes a child virus, if you will.

00:23:43.606 --> 00:23:48.459
That's a mixture of the two viruses and that reassortment can cause major changes.

00:23:48.459 --> 00:23:52.338
Fortunately, when it happens, most of the time it doesn't cause illness.

00:23:52.338 --> 00:23:53.744
It becomes non-functional.

00:23:53.744 --> 00:24:00.249
Another way is to share only part of the segments through something called recombination, and that frequently occurs.

00:24:00.249 --> 00:24:03.155
And then the final way is just through mutation.

00:24:03.155 --> 00:24:09.278
As the virus replicates, it sometimes makes mistakes and you get a unique virus through those measures.

00:24:09.278 --> 00:24:17.923
But influenza viruses and other RNA viruses are really prone to making mistakes through mutations and through changing through recombination.

00:24:18.309 --> 00:24:20.816
Kind of the way I think about this, there's two buzzwords.

00:24:20.816 --> 00:24:23.201
There's anagenic drift and shift.

00:24:23.201 --> 00:24:30.439
Drift, which is the slow accumulation of mutations, and then there's shift, which is the big reassortments that we were just talking about.

00:24:30.439 --> 00:24:35.864
We all know I'm a geek for evolution, so excuse me while I geek out for a minute, but I love this analogy.

00:24:35.864 --> 00:24:49.192
When we're talking about that kind of slow accumulation of mutations, I always think of it as a game of molecular telephone where first you have I'm saying Matt, and then the next person hears cat and then the next person hears mad.

00:24:49.192 --> 00:25:02.484
The virus basically makes mistakes every time it replicates and these kind of incremental little changes is like the mechanism of these huge evolutionary features and phenomenon that we observe in nature all the time, and it can be really powerful.

00:25:02.484 --> 00:25:09.442
And influenza, and I think there's only like a couple of mutations that are required for some of these big host jumps that we see.

00:25:10.632 --> 00:25:23.932
So the way I explain reassortment to my students in the virology course is always like imagine you have two decks of cards right the same decks of cards and one is maybe a red deck and the other one is a blue deck.

00:25:23.932 --> 00:25:41.432
And then you take some of the cards from each deck and you throw them into a bucket or some sort of vessel and if the number and the time is right and you reach into that vessel and you pull the cards out, you might have a full deck, but it's a mixture of the red deck and the blue deck.

00:25:41.432 --> 00:25:45.787
So you have a new mixed deck but it's still possible to play with.

00:25:45.787 --> 00:25:48.113
It's just has very different components.

00:25:48.314 --> 00:25:50.880
But it's a lot more challenging to happen, right?

00:25:50.880 --> 00:25:58.453
Because not only does one person have to be infected with two different viruses, a single cell has to be infected with two different viruses.

00:25:58.453 --> 00:26:08.722
So I think that's what makes people concerned about birds as being a possible mixing vessel where you can have multiple viruses mixing within a bird.

00:26:08.722 --> 00:26:16.022
But I know you are a big fan of the hypothesis that swine are a better mixing vessel.

00:26:16.565 --> 00:26:19.332
Well, yeah, I think humans can be a mixing vessel.

00:26:19.531 --> 00:26:30.982
True, true, true but swine seem to have the ability to be infected with larger numbers of very influenza viruses, and so they've often been given the moniker of a mixing vessel.

00:26:30.982 --> 00:26:37.154
I think there are a number of things about pigs, if we want to talk about pig influenza viruses that are in Zootiekin pigs.

00:26:37.154 --> 00:27:01.838
In contrast to poultry, which may live a couple months, the shortest live pigs or production pigs are six months, and so there's a longer time period for them to be infected with lots of different viruses, and they're in contact with a number of different species, often in the developing world anyway, humans, as I mentioned, passerine birds, sometimes dogs and cats, sometimes ducks and geese are pinned right next to them.

00:27:01.838 --> 00:27:16.390
So there's a tremendous opportunity and their susceptibility to these varied influenza viruses for mixing to go on the pigs, and often it's been said that it's the pigs that have been implicated in a number of influenza A pandemics.

00:27:17.632 --> 00:27:24.647
So is it that you think pigs are a better mixing vessel, or pig adapted viruses are more likely to spill over?

00:27:25.065 --> 00:27:31.232
Well, I think pig-adapted viruses are both, I guess, are more likely to spill over to humans.

00:27:31.232 --> 00:27:38.835
We are closer to pigs and our evolution and we are, I would argue, to a lot of avian species.

00:27:38.835 --> 00:27:40.449
We even share tissues.

00:27:40.449 --> 00:27:48.017
Even today in modern medicine, transplanting, yeah, and so there's organs being transplanted.

00:27:48.017 --> 00:28:07.070
So we have a capability to be infected with those viruses and the serial epidemiologic studies we've done indicate, in very high prevalence pig herds that the workers almost cannot escape being infected with the viruses in the swine that are being amplified if they work with those pigs.

00:28:07.070 --> 00:28:16.038
So it's like more than 90% infection rate if you're susceptible at the beginning of the time period you're following Interesting.

00:28:16.038 --> 00:28:25.792
So that's why I say that the species barriers pig to humans is much lower than the species barrier or avian species to humans?

00:28:26.404 --> 00:28:27.750
I think that's Matt's question.

00:28:27.750 --> 00:28:33.523
It's just really, really interesting and maybe, if you allow me, greg, maybe we can philosophize about this question.

00:28:33.605 --> 00:28:40.234
And it's in his philosophy question, yeah, so I think our society always has this perception of spillovers as like a black or white event, right?

00:28:40.384 --> 00:28:59.369
So, danielle, you've worked a lot with West Nile this theory that a couple from Israel traveled to the US with a bird and that was the one time that all of a sudden, west Nile was introduced into the Western Hemisphere and spread like a wildfire and I think we always have these stories that this is a single event.

00:28:59.369 --> 00:29:04.574
It jumped the species barrier and all of a sudden it just takes off like a wildfire.

00:29:04.574 --> 00:29:06.672
And I always question that.

00:29:06.672 --> 00:29:16.135
And, based on what you say, it sounds like there's always these attempts of spillover and sometimes it occurs, but then it's stopped at some point.

00:29:16.135 --> 00:29:18.184
Sometimes it doesn't even occur in the first place.

00:29:18.184 --> 00:29:22.874
Sometimes it goes a little bit further and then maybe the infection will die out after a while.

00:29:22.874 --> 00:29:25.432
What are your thoughts on these spillover events?

00:29:25.432 --> 00:29:40.080
Do you think those are really single, like we like to portray them in our society, as black and white events, or are these like waves of crashing onto the beach and then at some point, the conditions are right and we have a tsunami?

00:29:40.101 --> 00:30:03.074
Yeah, Well, dennis, I agree with your metaphor of crashing on the beach, because I think when humans are exposed to large populations of animals, whether it be for meat production or wildlife or library markets, there's a great propensity for those animals carrying viruses to challenge the immune system, and the success of those challenges.

00:30:03.074 --> 00:30:06.711
To take a foothold in a new species has got to be extremely rare.

00:30:06.711 --> 00:30:14.473
And for it to continue to adapt once it has begun to take a foothold, in other words, the virus has adapted in the host.

00:30:14.473 --> 00:30:21.330
It didn't really cause human-to-human transmission, but it continues to insult other humans, that takes a long time too.

00:30:21.330 --> 00:30:27.012
And then, finally, when you see limited transmission, the probability of that is even rarer.

00:30:27.184 --> 00:30:50.094
And then efficient transmission and viral evolutions would say the odds of these events happening are extremely low, and the time involved, based on mutations that are seen in the phylogenetic structure of similar viruses, would suggest that we have time to detect these insulting viruses that are beginning to get a foothold, if we only know how to look for them.

00:30:50.094 --> 00:31:01.991
And the problem is we don't know how to look for them Among people that have clinical disease very well, because our diagnostics are very tuned in for known pathogens, and so that's been a matter of debate.

00:31:01.991 --> 00:31:10.775
I was just on a World Health Organization call for a group of virus called adenoviruses and maybe I should be careful here because I'm not a disclosure agreement.

00:31:10.775 --> 00:31:17.595
But the bottom line is the most threatening viruses are those that we can't detect in the list of all the adenoviruses.

00:31:17.595 --> 00:31:19.550
And what does that say?

00:31:19.550 --> 00:31:25.588
That means you better come up with some better way to diagnosis in the clinics, or it'll take an epidemic to get you to do so.

00:31:25.805 --> 00:31:32.488
Yeah, and I find health care in general to be pretty reactionary as far as new technologies and development of these sort of things.

00:31:32.488 --> 00:31:37.290
We had a new disease, so we developed diagnostics for it and then it's always there.

00:31:37.290 --> 00:31:51.532
It's always sort of at the downstream, and as clinicians that's sort of where we live, and so we don't always look upstream and start to think well, how do we create something that is a bit less specific and something that would actually serve a different purpose?

00:31:51.532 --> 00:31:54.354
That would be part of early detection or surveillance.

00:31:54.644 --> 00:32:27.249
And we're actually trying to do that here, and we've done that in a number of our epidemiologic studies, and I'm pleased to say that we've had a modicum of success detecting viruses and species that shouldn't have been there, including a very unusual dog-like canine coronavirus, we call it that was found first in eastern Malaysia and then later in Haiti, and so we have argued that, particularly for coronaviruses and influenza viruses, they're probably spilling over a lot more than some of the other viruses and we need to have these pan-species diagnostics up and running for them.

00:32:28.244 --> 00:32:32.932
Before I let you go, greg, I have one more question as a concerned citizen living here in Galveston.

00:32:32.932 --> 00:32:37.035
Galveston is well known for birders around the world.

00:32:37.035 --> 00:32:37.635
People come.

00:32:37.635 --> 00:32:48.855
We have migratory birds stopping here on the way to South America, so I have a bird feeder in my backyard and I know friends that have chicken coop.

00:32:48.855 --> 00:32:50.971
So what is your advice?

00:32:50.971 --> 00:32:53.010
Do you think that's risky?

00:32:53.010 --> 00:32:54.269
Or what do you think?

00:32:54.269 --> 00:32:57.074
Take them down, or just keep an eye on them?

00:32:57.074 --> 00:32:57.989
Or what are your thoughts?

00:32:58.404 --> 00:33:00.753
I don't know that bird feeders have been implicated.

00:33:00.753 --> 00:33:03.954
It has a risk factor for avian flu to go to humans.

00:33:03.954 --> 00:33:06.410
I've never seen that so I wouldn't worry about that.

00:33:06.410 --> 00:33:26.233
We have seen concerns that backyard flocks, so to speak, that are exposed to migrating birds because they're not in a pen or covered in a barn might be more prone to acquiring avian flu and there's been a big educational program by the USDA for those people that keep the backyard flocks.

00:33:26.233 --> 00:33:30.451
But in general if a flu goes in there it burns right through that population.

00:33:30.451 --> 00:33:31.670
It's a small population.

00:33:31.670 --> 00:33:33.490
It's never going to be sustained.

00:33:33.490 --> 00:33:38.753
In contrast, when you have 10,000 chickens and multiple barns you get an avian flu in there.

00:33:38.753 --> 00:33:40.049
That doesn't kill the birds.

00:33:40.049 --> 00:33:45.211
It has a great opportunity to become inzutically, say, and of course that's a concern.

00:33:45.211 --> 00:33:48.469
In this country if they find any avian flu they call the birds.

00:33:48.469 --> 00:33:55.334
But in other countries you have multiple strains that are inzutic in the poultry and that can be a setup for the mixing we talked about earlier.

00:33:55.904 --> 00:33:57.131
I learned a ton today.

00:33:57.131 --> 00:33:59.633
I learned about the transmission dynamics.

00:33:59.633 --> 00:34:03.714
I learned about risk, I learned about what is this virus and how is it characterized.

00:34:03.714 --> 00:34:05.392
Wow, we, really we covered a lot of ground.

00:34:05.605 --> 00:34:06.990
Thank you so much for making time to talk to us.

00:34:07.010 --> 00:34:08.869
Well, thank you, it's been a pleasure and fun chatting with you guys.

00:34:09.985 --> 00:34:12.293
Thanks for listening to the Infectious Science podcast.

00:34:12.293 --> 00:34:20.313
Be sure to hit Subscribe and visit infectiousscienceorg to join the conversation, access the show notes and to sign up for our newsletter and receive our free materials.

00:34:20.864 --> 00:34:29.072
If you enjoyed this new episode of Infectious Science, please leave us a review on Apple Podcasts at Spotify and go ahead and share this episode with some of your friends.

00:34:29.644 --> 00:34:34.193
Also, don't hesitate to ask questions and tell us what topics you'd like us to cover for future episodes.

00:34:34.193 --> 00:34:38.532
To get in touch, drop a line in the comments section or send us a message on social media.

00:34:38.885 --> 00:34:44.525
So we'll see you next time for a new episode, and in the meantime, stay happy stay healthy, stay interested.