#12 – Zoonosis From the Sea: Covert Mortality Nodavirus

00:00:06: What is known, this leads to elevated ocular pressure.

00:00:12: So basically higher pressure in the eye and that can lead to irreversible damage of the optical nerve... ...and in a long run it could lead severe vision impairment.

00:00:23: so not a good thing to have.

00:00:46: Birological with Florian Kramer Birolojical was recorded on April twenty-sixth twenty-twenty six in New York.

00:00:56: And today we're talking about a very crazy story... ...about new human pathogen.

00:01:04: I newly discovered human pathogens, actually the pathogen was known but it wasn't here that would cause disease in humans.

00:01:13: and this pathogen virus is called covered mortality nodovirus or CMNV.

00:01:20: The story really is that this first virus can jump from crustaceans basically shrimps or fish to humans.

00:01:31: So this virus infects all kinds of crustacean fish and it was known as a problem there, I'll get into that in few minutes.

00:01:42: but now became clear CMNV is a nodovirus.

00:01:52: Nodoviruses are actually known for quite some time.

00:01:56: The first one was discovered in nineteen fifty six In the mosquito, a cool ex-mosquito... ...in a village in Japan and the village's name is Nodomura And that's where their names come from.

00:02:07: We do know there're two different types of nodovirus Alpha nodoviresis and better nodovirs.

00:02:14: The alpha nodoviruses are known to infect insects, and the beta-nodoviruse is also known as fish.

00:02:22: These viruses have a positive sense single stranded RNA genome that codes for approximately four thousand five hundred nucleotides.

00:02:33: so basically the genome has about four thousand Five hundred letters.

00:02:38: And an interesting part here.

00:02:40: this actually is segmented virus.

00:02:42: it has two segments So it's similar to influenza virus.

00:02:47: In that respect, influenza viruses have eight or influenza C and D viruses have seven segments.

00:02:55: And here we have two segments.

00:02:58: The first segment is called RNA-I That encodes the polymerase B protein counteracts immune responses in host cells.

00:03:09: Then second segment is known as RNA-II and that codes for the capsid.

00:03:16: It's a very simple virus actually, it is approximately twenty-nine to thirty five nanometers in diameter doesn't have a lipid envelope but only has two capsids and the capsit as a very nice structure symmetric structures.

00:03:32: three of these capsits come together into form three-fold symmetry, and then this whole thing assembles into the virus particle.

00:03:43: And in the end you have hundred eighty copies of capsid burr particles.

00:03:47: The virus is also very stable.

00:03:49: It's BH stable between BH two and BH nine.

00:03:53: it's also relatively temperature stable... ...and it replicates in the cytoplasm.

00:03:58: We know about notaviruses but what special about this?

00:04:02: covered mortality notavirus So in two thousand nine problems appeared in Chinese shrimp farms.

00:04:12: Basically, you know... In some instances part of the population that they had in these shrimp farms died off often not full-population just a percentage and it became clear this was specifically problem if temperature rising above twenty eight degrees Celsius.

00:04:32: but there was not so much of an issue at cooler temperatures.

00:04:37: And, this was investigated in the year that caused this disease, these diodes were isolated and characterized.

00:04:48: it turned out to be a nodovirus called covered modality And in two thousand sixteen the same virus was also identified in Thailand and I think now it's found worldwide in aquaculture but also involved called seafood and fish.

00:05:07: The idea is that original version of the virus actually coming from krill, Arctic Krill those are also crustaceans live in arctic waters basically look a little bit like small shrimp And the idea is that the virus originally came from these animals.

00:05:28: As mentioned, the virus infects fish, crustaceans and achanodermes which are basically sea urchins for example similar creatures.

00:05:40: It's not only causing disease in shrimp but also in fish often farmed fish.

00:05:45: when they're infected They don't feed much Start to swim in a very uncoordinated way.

00:05:52: So again, this can be pretty big problem in aquaculture But for long time the idea was okay.

00:06:00: This is a shrimp and fish virus.

00:06:02: It's not necessarily an issue for people consuming infected infected animals.

00:06:09: but In two thousand nineteen new disease was characterized.

00:06:15: And so the idea was, okay this virus is a problem in fish.

00:06:19: This virus has problems in crustaceans but it's not a problem for humans.

00:06:25: So In two thousand nineteen A new disease Was detected and characterized in China.

00:06:31: The name of these diseases Is quite long and complicated.

00:06:35: It was termed persistent ocular hypotensive viral anterior UVitis.

00:06:43: I also had to look up a lot of these words.

00:06:45: Basically persistent is clear, it's kind of long term right?

00:06:51: Ocular just means eye right?

00:06:54: Hypotensive means that the pressure is higher.

00:06:59: viral is clear anterior just means in front and UVIDs basically mean inflammation of the urea which is one of three layers of the eye.

00:07:09: And the uvia has actually three components the iris, the cilia body and the coroid.

00:07:16: And with this persistent ocular hypotensive viral anterior UVitis or for short BOHVAU mostly the irus is affected and inflamed... ...and I guess that's why it's called anterior because the irous in front of the cilia body and a coroid so thats anterior.

00:07:40: And it's known that uveitis can be caused by many different viruses, but also other pathogens.

00:07:47: For viruses most often is caused by cytomegalovirus or herpes-simplex virus so herpesviruses.

00:07:56: But this new form of the disease wasn't associated with any of these other pathogens that are known to cause uveides.

00:08:05: You know People looked and typically these cases tested negative for other viruses or pathogens that can cause UVitis.

00:08:15: What is known, this POHVAU.

00:08:21: so new UVitis syndrome leads to elevated ocular pressure So basically higher pressure in the eye And it could lead to irreversible damage of optical nerve Also, corneal endothelial loss.

00:08:41: The iris can be damaged and in the long run it can lead to severe vision impairment.

00:08:46: so not a good thing to have but this can be treated.

00:08:50: typically symptoms get better when its traded.

00:08:54: another thing that was recognized is often affects older people which also interesting This was first recognized in two thousand nineteen, that there's a new form of uv radius.

00:09:08: And now in March of twenty twenty six so basically few weeks ago paper came out in nature microbiology.

00:09:18: So it is a journal published by the Nature group and study was performed by number state key laboratories.

00:09:29: also the China Center for Disease Control and Duke NUS in Singapore was also involved with this study.

00:09:37: What did they do?

00:09:38: They wanted to really get to bottom of it, find out what is causing these new diseases.

00:09:44: so they acquired iris tissue from patients who had disease first looked by electron microscopy then identified virus particles actually a lot of viruses in that tissue And these virus particles looked like nodoviruses.

00:10:03: They also performed sequencing and developed a PCR for the virus, it turned out that you could find the genome of the virus in iris tissue but also in blood infected patients.

00:10:20: The interesting part was they could see antibodies develop against this Nodovirus in disinfected individuals.

00:10:29: And when they sequenced the virus, it had a ninety-eight point ninety six percent identity.

00:10:39: and When they sequence the virus It has ninety eight point ninety-six percent similarity to this covert modality nodoviruses that circulate in aquaculture In China.

00:10:53: They went further...they also wanted to basically prove That these viruses could infect mammals and could cause this disease.

00:11:02: So basically they were trying to fulfill cox postulates, so the infected mice got infected actually developed issues with their eyes also high pressure or cooler pressure.

00:11:18: They showed that the virus does cause these diseases in mammals actually is.

00:11:27: and so they went, got samples from markets about three hundred fifty samples.

00:11:33: And they found that approximately fifty-five percent of fish samples were positive for this virus but twenty eight percent of shrimp samples sixty two percent of crab samples fifty nine percent of mollusks that they sampled... ...and forty seven percent of samples from octopus and squid and so on and so forth.

00:11:54: That doesn't mean Prevalence is really that high, it could of course be when you know at seafood markets fish are processed.

00:12:02: When animals are processed there's cross-contamination.

00:12:05: so maybe some animals have a lot of the virus and then other ones just get contaminated with this.

00:12:12: they actually don't carry the virus but still the number is relatively high.

00:12:16: It seems that this virus is relatively prevalent in food items.

00:12:22: They also looked at distribution from where these different samples came, and they found that thirty six percent of the samples to get products from Antarctica were positive.

00:12:36: Twenty percent of African products are positive.

00:12:39: Sixteen percent of American products were positive meaning North and South America And then sixty percent of Asian products.

00:12:49: The virus seems to be around quite a bit, and it seems people get exposed through food on the regular basis if you consume fish or seafood.

00:12:58: And so they also looked at an epidemiological site.

00:13:02: what risk factors would be for getting this disease in becoming positive for this cobert mortality nodovirus.

00:13:12: They found that number one risk factor was basically work with fish and seafood processing efficient seafood specifically when people had little cuts or injuries.

00:13:25: For example, if they worked with fish often very spiny their scales can be relatively sharp.

00:13:31: so you get these little injuries and that seems to be associated with getting infected with this new notovirus.

00:13:42: what also was a risk factor is eating raw seafood and raw fish.

00:13:46: so that's bad news for people who like sushi, like me.

00:13:49: And another risk factor was to in general have contact with fish crustaceans or work at aquaculture or in the fishing industry.

00:14:01: So this is super cool.

00:14:03: of course a lot of confirmation is needed.

00:14:06: This was the first study made disconnection between covered mortality nodovirus ocular, this new eye disease in China.

00:14:18: I don't think the new disease has been diagnosed anywhere outside of China so far and it's also as i said knew they started to detect to see that in two thousand nineteen.

00:14:32: So I believe a number of additional studies have to be performed really confirm these findings.

00:14:40: but its super interesting that a virus seems crustaceans and fish into humans, cause disease there.

00:14:49: That's the first time something like that has really been reported And I'm super interested in it because i also work on influenza viruses that infect fish.

00:15:01: It is completely unclear if they can cause diseases of course not regular influenza virus.

00:15:08: So its a very interesting topic.

00:15:11: We'll see in that regard coming out and what the counter measures will be to avoid these infections.

00:15:20: So thanks for listening, as always if you have any questions comments concerns please just send an email to Virological at podcastworks.com And If You Like This Podcast Feel Free To Support Us On Steady!

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