It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, February 18, 2025
Could microRNAs help us understand why different birds react differently to being infected with bird flu?
Researchers once thought that microRNAs were just junk in cells. Now it may help us better understand how an organism reacts to viral infections
Norwegian University of Science and Technology News Release 18-Feb-2025
Ruddy turnstones fly over long distances, and probably play an important role in spreading bird flu.
Can their microRNA help us understand more?view more Credit: Photo: Louis Westgeest
Is there a connection between bird flu and microRNA, the tiny bits of RNA which have different tasks in regulating genes and producing the body’s building blocks?
“MicroRNA is quite stable, and interesting for us who research wildlife. It may tell us something about how animals react to various stress factors in the environment,” said Veerle Jaspers, an NTNU professor who is head of a project that is examining this issue.
Researchers have checked microRNA in blood samples from ruddy turnstones (Arenaria interpres) from Australia.
Ruddy turnstones fly over long distances, and probably play an important role in the spread of bird flu. This virus is widespread in wading birds and rarely causes disease, but can mutate into a highly pathogenic form that is a threat to both wild birds and the poultry industry. So it is useful to know as much as possible about them.
But to understand why this matters, it’s important to know a little more about what microRNA is. MicroRNA is not just useless junk
Just over 30 years ago, most scientists believed that microRNAs were useless fragments that moved around in our cells and bloodstream without doing anything important.
But microRNAs have a far more important role than previously understood.
“Victor Ambros and Gary Ruvkun received this year’s Nobel Prize in Physiology or Medicine for the discovery of microRNAs and the role they play in gene regulation,” said Anne-Fleur Brand, a PhD research fellow at NTNU’s Department of Biology.
In short, microRNAs help cells control the types and amounts of proteins they make. What microRNAs actually do
DNA is the large genetic material in our cells. It is organized into chromosomes and genes. DNA contains recipes that determine how we look and how our bodies function. Based on these recipes, the body produces various proteins that are the body’s building blocks.
The recipes from DNA are carried by messengers called messenger RNA or simply mRNA. Does this sound familiar? Several of the COVID-19 vaccines are based on mRNA. We have known about these messengers since around 1960.
What scientists didn’t know about until around 1990 were microRNAs, which are even smaller. And they didn’t realize that microRNAs were important until a decade later. MicroRNAs can attach to mRNA so that it doesn’t send too many messages to cells to make proteins.
You could say that microRNAs help the cell fine-tune protein production, making sure it doesn’t make too much or the wrong kind at the wrong time. The ruddy turnstone’s blood tests
But back to the ruddy turnstone, the small bird that may play a big role in spreading bird flu. The researchers took blood samples from the birds that correspond to about a tenth of a teaspoon from each. But this was enough to find out a lot.
“We found 163 different forms of microRNA in the ruddy turnstones. Two of these are new and unique to birds,” said Brand.
The researchers checked which variants of microRNA they could find in both healthy birds and birds that were infected with a less pathogenic variant of bird flu called low pathogenic avian influenza.
“We did this to see if we could find out more about how the birds react to the infection,” she said.
And they found something that could be useful. Different birds react differently to being infected with bird flu.
“We found differences in the amount of specific microRNAs in the infected birds. It seems to be related to both sex and age,” Brand said.
These findings could help develop a new tool for investigating how bird flu affects wild birds.
Researchers looking at microRNA in ruddy turnstones found 163 different forms of microRNA, two of which are new and unique to birds. They also found differences in the amount of specific microRNAs in birds infected with bird flu.
Circulating miRNAome of avian influenza-infected ruddy turnstones Arenaria interpres
Article Publication Date
18-Feb-2025
The CSIC-UNESPA expedition confirms the spread of the highly pathogenic avian influenza virus in the Weddell Sea
The results obtained aboard the Australis sailboat show the presence of the HPAI virus in all animal species analyzed on six islands located north of the Antarctic Peninsula
The CSIC-UNESPA scientific expedition has been underway since last January with the aim of monitoring the presence of the highly pathogenic avian influenza virus (HPAI H5N1) in Antarctica. The first results of the campaign, led by Antonio Alcamí, a CSIC research professor at the Severo Ochoa Molecular Biology Center (CBMSO-CSIC-UAM), have confirmed the presence of the virus in all species detected on six islands in the Weddell Sea, Antarctica.
This positive result was obtained in 42 animals, including 28 carcasses of species such as crabeater seals, skuas, gulls, snowy sheathbill, Adélie penguins, and Gentoo penguins, as well as 14 live individuals of skuas and Adélie and Gentoo penguins. “The viral load in the dead animals was very high, indicating a risk of exposure to the virus in the proximity to the carcasses,” explains Alcamí.
The finding, according to the researcher, will allow national polar programs to be prepared and to consider measures to prevent the transmission of the infection through human means, especially the spread to people, as many of the locations where the virus was detected are frequently visited by tourist and research vessels.
The presence of the HPAI (Highly Pathogenic Avian Influenza) virus was confirmed through multiple laboratory tests, including specific PCRs for influenza virus and the H5 subtype, followed by sequencing of the protease cleavage region, which defines the presence of the HPAI virus with 100% certainty. “We performed PCR tests on swab samples to identify the virus M and H5 genes. Subsequently, the presence of the virus was confirmed by sequencing using the Oxford Nanopore technology.”
Additionally, the researchers identified the HPAI virus in penguin colonies through air sampling. “We collected air samples with a pump connected to a nanofiber filter developed by CSIC, which captures the virus. PCR tests on the filter confirmed the detection of the pathogen. These results indicate that air sampling is a valid method for detecting the virus without the need to handle animals,” highlights the CBMSO researcher.
Of particular significance is the presence of highly pathogenic avian influenza in apparently healthy penguin colonies. Its detection in live Adélie and Gentoo penguins suggests that the infection may be spreading in colonies without causing significant mortality. “We do not know if the penguins were exposed to the virus last year and have protective immunity or if they are more resistant than expected.”
Geographically, the most notable case is Tay Head (Joinville Island), where the virus prevalence is particularly high. In this area, the infection has severely affected crabeater seals.
After sampling seven areas of the Weddell Sea (including Devil, Beak, Beagle, and Heroína islands), the CSIC-UNESPA Antarctic Expedition will move south of the Antarctic Peninsula to study new areas and gain a better understanding of the virus's spread. “Our goal is to conduct a comprehensive study of the virus’s distribution,” concludes Antonio Alcamí.
Research aboard the Australis yacht
The scientific expedition led by CSIC and funded by a hundred insurance companies affiliated with UNESPA, the Spanish insurance business association, is analyzing the presence of the pathogen over six weeks in the Antarctic Peninsula, the South Shetland Islands, and the Weddell Sea. This work is being carried out aboard the Australis sailboat, a vessel with extensive experience navigating Antarctica. It allows access to difficult-to-reach locations and is equipped with the most modern satellite navigation and communication systems. The facilitating role of the General CSIC Foundation has been crucial in securing access to this vessel and other essential resources for the expedition.
The team is made up of three crew members and eight scientists from different nationalities and disciplines, including veterinarians specializing in wildlife, virologists, and molecular biologists. A real-time PCR molecular diagnostic and virus sequencing laboratory has been installed on the sailboat, enabling the team to diagnose cases quickly. Additionally, all samples collected during the expedition are obtained following strict safety protocols.
The project, supported by the Spanish Polar Committee, will allow Spanish research to continue leading international studies on the detection of avian influenza in Antarctica.
The evolution of the virus in Antarctica
The highly pathogenic H5N1 strain of the avian influenza virus initially evolved in domestic poultry but recently adapted to spread among wildlife. Since 2020, its spread has caused significant mortality among wild birds and mammals worldwide, and in 2022, its arrival in South America was confirmed.
Its expected spread to Antarctica was first confirmed on February 24, 2024, thanks to discoveries by CSIC researchers Ángela Vázquez and Antonio Alcamí. In March 2024, the results of the HPAI Australis Expedition, involving Begoña Aguado and Antonio Alcamí, revealed the spread of highly pathogenic avian influenza virus in the Antarctic Peninsula, where high mortality levels in skua birds were observed.
In July, this discovery was followed by the confirmation of the virus’s presence in Antarctica for the first time in a marine mammal. Since then, researchers have been working to determine the virus’s spread and impact in Antarctica.
The current project involves the Severo Ochoa Molecular Biology Center (CBMSO, CSIC-UAM); the Faculty of Veterinary Medicine and Animal Science of the University of São Paulo (Brazil); the Aquatic Mammals Institute (Brazil); the Karen C. Drayer Wildlife Health Center, a program of the University of California-Davis’s Faculty of Veterinary Medicine (USA); and Ocean Expeditions (Australia).
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