News Release
Friday, March 1, 2024
NIH researchers explore hidden, vulnerable region of influenza neuraminidase.
WHAT:
Researchers at the National Institutes of Health have identified antibodies targeting a hard-to-spot region of the influenza virus, shedding light on the relatively unexplored dark side of the neuraminidase (NA) protein head. The antibodies target a region of the NA protein that is common among many influenza viruses, including H3N2 subtype viruses, and could be a new target for countermeasures. The research, led by scientists at the National Institute of Allergy and Infectious Diseases Vaccine Research Center, part of NIH, was published today in Immunity.
Influenza, or flu, sickens millions of people across the globe each year and can lead to severe illness and death. While vaccination against influenza reduces the burden of the disease, updated vaccines are needed each season to provide protection against the many strains and subtypes of the rapidly evolving virus. Vaccines that provide protection against a broad range of influenza viruses could prevent outbreaks of new and reemerging flu viruses without the need for yearly vaccine reformulation or vaccinations.
One way to improve influenza vaccines and other countermeasures is to identify new targets on the viruss surface proteins in conserved regionsportions that tend to be relatively unchanged between different strains of the virus. Influenza NA is a surface protein containing a globular head portion and a narrow stalk portion. The underside of the NA head contains a highly conserved region with targets for antibodiesknown as epitopesthat make it vulnerable to antibody binding and inhibition of the virus, as well as not being impacted by mutations common in drug-resistant strains. This region is termed the dark side due to its partially hidden location and relatively unexplored characteristics.
The researchers isolated human antibodies that target the NA dark side from the blood of two people who had recovered from influenza type A subtype H3N2, a major subtype of seasonal flu viruses. In lab tests, the antibodies inhibited propagation of viruses from subtype H2N2, the subtype that caused pandemic influenza in 1957-58, and H3N2 viruses from humans, swine, and birds. The antibodies also protected mice from lethal infection by a subtype H3N2 virus when given to the animals either one day before or two days after infection, showing that the antibody may treat and prevent influenza in this model.
The scientists analyzed the structure of two of the antibodies while bound to NA using advanced microscopy techniques known as cryogenic electron microscopy. Each antibody targeted different, nonoverlapping regions of the dark side, demonstrating that this region has multiple areas that may be useful to explore for countermeasure development.
These findings show that the NA dark side has unique, previously untapped epitopes that could be applied to the development of new vaccine and therapeutic strategies. They suggest that antibodies targeting the NA dark side could be useful in combination with antivirals or other types of antibodies for interventions against influenza, as they are effective against influenza viruses with drug-resistant mutations. The researchers also note that NA dark side targets could be included in the next generation of broadly protective vaccines against influenza.
REFERENCE:
Lederhofer, J. et al. Protective human monoclonal antibodies target conserved sites of vulnerability on the underside of influenza virus neuraminidase. Immunity. DOI: 10.1016/j.immuni.2024.02.003 (2024).
WHO:
Masaru Kanekiyo, D.V.M., Ph.D., Chief of the Molecular ImmunoEngineering Section at the NIAID Vaccine Research Center, is available to discuss this research.
NIAID conducts and supports researchat NIH, throughout the United States, and worldwideto study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID website.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
NIHTurning Discovery Into Health
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The emergence of the H5N1 avian influenza virus in marine environments, a pathogen capable of crossing species barriers, has raised significant concerns within the wildlife conservation community.
A recent collaborative study by the University of California, Davis, and the National Institute of Agricultural Technology (INTA) in Argentina has shed light on the viruss adaptation and its implications for both marine and bird populations along the Atlantic coast of South America.
Researchers focused their investigation on a collection of brain samples from deceased sea lions, a fur seal, and a tern found in Argentinas most affected sea lion rookery.
The analysis confirmed H5N1 infection in all specimens, revealing a near-identical virus sequence across the samples.
This uniformity included specific mutations known for mammalian adaptation, previously identified in marine mammals and a human case across Peru and Chile, and, notably, in a tern for the first time.
Agustina Rimondi, a virologist from INTA and the studys first author, emphasized, This confirms that while the virus may have adapted to marine mammals, it still has the ability to infect birds. It is a multi-species outbreak.
The presence of mammal-adaptation mutations in the terns virus sequence highlights the potential for transmission between marine mammals.
Despite these findings, Marcela Uhart, a senior author and wildlife veterinarian at the UC Davis School of Veterinary Medicine, reassures that the virus currently poses a relatively low risk to humans.
However, she warns of the potential for increased concern if the virus continues to replicate in mammals. Uhart underscores the importance of ongoing surveillance and early warning efforts to mitigate this risk.
Labelled as this new monster by Uhart, the clade 2.3.4.4b variant of H5N1 emerged in 2020 amidst the global COVID-19 pandemic, initially impacting sea birds in Europe before spreading to South Africa, and then to the Americas, threatening poultry and wild bird populations.
By February 2023, the virus had reached Argentina, demonstrating its lethal potential by August 2023 among sea lions at Tierra del Fuegos Atlantic coastline, and then moving northward with devastating effects on marine mammals and seabirds alike.
A staggering toll has been observed, with at least 600,000 wild birds and 50,000 mammals, including elephant seals and sea lions across Argentina, Chile, and Peru, as well as thousands of albatrosses in the Malvinas/Falkland Islands, succumbing to the virus.
A significant outbreak documented by Uhart and her team resulted in a 70% mortality rate among newborn elephant seal pups during the 2023 breeding season in Argentinas Pennsula Valds.
The viruss southward trajectory towards Antarctica has prompted urgent wildlife surveillance efforts by Uhart and her colleague Ralph Vanstreels, aimed at assessing the risk to previously unexposed species.
The potential consequences of such exposure could be dire, necessitating a vigilant approach to monitoring and prevention.
The study embodies the One Health concept, recognizing the interconnectedness of human, domestic animal, wildlife, and environmental health. It calls for a unified response from public, wildlife, agricultural, and health sectors worldwide to address the challenges posed by interspecies disease outbreaks.
In concluding remarks, Uhart reflects on the necessity of giving a voice to affected wildlife populations, highlighting the importance of long-term observational data and global collaboration in preparing for future challenges.
We are trying to be at the forefront of documenting, recording, and providing early warning, she states, emphasizing the critical role of scientific and conservation efforts in addressing the sprawling impact of the H5N1 virus.
In summary, this disturbing study by the University of California, Davis has illuminated a critical shift in the behavior of the H5N1 avian influenza virus, revealing its newfound ability to infect and spread among marine mammals, alongside its traditional avian hosts.
Their research underscores the viruss escalating threat to global wildlife conservation while highlighting the imperative for heightened surveillance and international collaboration to mitigate its spread.
By tracing the genomic footprints of H5N1 across species and continents, scientists offer a clarion call to action, urging a unified approach to safeguard the health of our planets diverse ecosystems against this formidable viral foe.
The H5N1 avian influenza virus, commonly known as bird flu, represents a significant threat to both avian and human populations worldwide.
Identified initially in 1959 during an outbreak in Scottish chickens, H5N1 has since evolved into a highly pathogenic strain that inflicts severe respiratory disease in birds and poses a zoonotic risk to humans.
H5N1 primarily affects birds, both wild and domestic, with waterfowl and poultry being particularly susceptible. The virus transmits through direct contact with infected animals, their secretions, or contaminated environments. Notably, migratory birds play a crucial role in spreading the virus across continents, facilitating outbreaks that can decimate poultry industries and threaten food security.
Human cases of H5N1 infection are rare but have occurred, primarily among individuals with close contact with infected birds or contaminated environments. Human-to-human transmission remains extremely limited, but the potential for the virus to evolve and gain this capability is a source of global concern.
In birds, H5N1 causes severe respiratory problems, leading to high mortality rates. Symptoms in infected birds include sudden death, uncoordinated movement, and decreased egg production.
In humans, H5N1 infection can cause severe respiratory illness, including pneumonia. Symptoms often begin as typical flu-like symptoms but can rapidly progress to severe respiratory distress and other complications. Treatment typically involves antiviral medications, and early intervention is crucial for improving outcomes.
Preventing H5N1 spread involves rigorous biosecurity measures, including surveillance of poultry farms, culling infected animals, and vaccinating poultry.
Public health initiatives focus on reducing human exposure to infected birds, improving hygiene practices, and preparing for potential pandemics through vaccine development and strategic planning.
The H5N1 avian influenza virus remains a potent threat to global health and economy, necessitating ongoing vigilance, research, and cooperation among nations to mitigate its impact.
While primarily an avian disease, its potential to evolve and spread among humans underscores the importance of preparedness and response strategies to protect public health.
The full study was published in the journal Emerging Infectious Diseases.
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Elephant seals lie dead on a beach in Argentina following an outbreak of avian influenza in the region in 2023. Credit: Maxi Jonas
Key points:
The highly pathogenic avian influenza virus H5N1 has adapted to spread between birds and marine mammals, posing an immediate threat to wildlife conservation, according to researchers from the University of California, Davis.
For the study, scientists collected brain samples from four sea lions, one fur seal and a tern found dead at the most-affected sea lion rookery in Argentina. All tested positive for H5N1.
Genome sequencing revealed that the virus was nearly identical in each of the samples. The samples shared the same mammal adaptation mutations that were previously detected in a few sea lions in Peru and Chile, and in a human case in Chile. Of note, the scientists found all these mutations also in the tern, the first such finding.
This confirms that while the virus may have adapted to marine mammals, it still has the ability to infect birds, said first author Agustina Rimondi, a virologist from the National Institute of Agricultural Technology (INTA) in Argentina. It is a multi-species outbreak.
We know this because the virus sequence in the tern retained all mammal-adaptation mutations. Such mutations suggest a potential for transmission between marine mammals.
This virus is still relatively low risk for humans, said senior author Marcela Uhart, a wildlife veterinarian with the UC Davis School of Veterinary Medicines One Health Institute. As long as the virus continues to replicate in mammals, it may make it a higher concern for humans. Thats why its so important to conduct surveillance and provide early warning.
In 2020, avian influenza began killing tens of thousands of sea birds in Europe before moving to South Africa. In 2022, it entered the U.S. and Canada, threatening poultry and wild birds. It migrated to Peru and Chile in late 2022. Then, in February 2023, highly pathogenic avian influenza entered Argentina for the first time. In August 2023, the virus was found in sea lions at the tip of South America on the Atlantic coastline of Tierra del Fuego for the first time. From there, it moved swiftly northward with deadly results, first for marine mammals and later for seabirds.
Since 2022, H5N1 in South America has killed at least 600,000 wild birds and 50,000 mammals, including elephant seals and sea lions in Argentina, Chile and Peru, and thousands of albatrosses in the Malvinas/Falkland Islands. Recent studies also show a large outbreak killed 70% of elephant seal pups born in the 2023 breeding season. Mortality rates reached at least 96% by early November 2023 in the surveyed areas of Pennsula Valds in Argentina.
The virus is now heading southward from South America, and scientists are concerned about its potential impact on penguins and other wildlife in Antarctica.
FRIDAY, March 1, 2023 (HealthDay News) -- Bird flu has mutated to spread more easily between birds and marine mammals, increasing the potential risk to humans, a new study warns.
Four sea lions, one fur seal and a tern found dead in Argentina all tested positive for the avian influenza virus H5N1, researchers report.
Further, genetic analysis revealed that the virus was nearly identical in all the animals, and shared adaptations were previously detected in a human case in Chile as well as in sea lions in Peru and Chile.
The fact that the same virus was found in the tern indicates a multi-species outbreak, researchers noted.
This confirms that while the virus may have adapted to marine mammals, it still has the ability to infect birds, said lead researcher Agustina Rimondi, a virologist from the National Institute of Agricultural Technology in Argentina.
The current variant of H5N1 -- clade 2.3.4.4b -- is considered a new monster by senior researcher Marcela Uhart, a wildlife veterinarian with the University of California, Davis.
This virus is still relatively low risk for humans, Uhart said in a university news release.
However, as long as the virus continues to replicate in mammals, it may make it a higher concern for humans," he added. "Thats why its so important to conduct surveillance and provide early warning.
The new variant emerged in 2020, during the pandemic, and began killing tens of thousands of sea birds in Europe before moving to South Africa.
In 2022, the variant entered the United States and Canada before migrating to Peru and Chile and entering Argentina in February 2023.
Six months later, in August 2023, the variant was first found in sea lions at the tip of South America, on the Atlantic coastline of Tierra del Fuego. It then moved swiftly northward, sickening and killing first marine mammals and later seabirds.
A recent paper co-authored by Uhart reported a large outbreak that killed 70% of elephant seal pups during the 2023 breeding season, with mortality rates reaching at least 96% in surveyed regions of Argentina.
When it first came to Argentina, we didnt know if it would affect elephant seals, Uhart said. We never imagined the magnitude of what was to come.
Since 2022, the H5N1 bird flu has killed at least 600,000 wild birds and 50,000 mammals in South America. The deaths included elephant seals and sea lions in Argentina, Chile and Peru, and thousands of albatrosses in the Malvinas/Falkland Islands.
The virus is also headed southward from South America, and researchers are worried about a potential outbreak among penguins and other wildlife in Antarctica.
The new study was published Feb. 27 in the journal Emerging Infectious Diseases.
We need to keep an eye on the ability of this virus to reach species that have never been exposed to an H5N1 infection before, Rimondi said. The consequences in those species can be very severe.
More information
The U.S. Centers for Disease Control and Prevention has more about H5N1 bird flu.
SOURCE: University of California, Davis, news release, Feb. 28, 2024
Its that time of year again, when the misery of norovirus strikes much of the U.S. Each year the pathogen causes an average of 900 deaths, 109,000 hospitalizations, 465,000 emergency room visits, and 19 to 21 million illnesses, according to the Centers for Disease Control and Prevention.
The agency reports national norovirus trends as three-week moving averages of positive test rates. So far in the 202324 season, infections peaked the week of Dec. 30, 2023, at 13% positivity. Rates have since oscillated, with 12.3% positivity the week of Feb. 17, 2024.
Heres what you need to know to avoid the common wintertime menace known for sickening whole familiesand schools, conferences, and cruise shipsat once.
Norovirus, commonly called the stomach flu, though its unrelated to influenza, spreads with remarkable ease, Dr. William Schaffner, professor of infectious diseases at Vanderbilt University Medical Center in Nashville, tells Fortune. Its nicknames include winter vomiting disease and the cruise ship virus, as it easily spreads among those in close quarters, he adds.
The illness usually moves from person to person via fecal-oral transmission. You can catch it by consuming contaminated food or water, and its the leading cause of foodborne illness in the U.S., according to the CDC. You can also get it by touching a contaminated surface like a doorknob or light switch and then touching your mouth.
It takes a very small amount of virus to get sickso miniscule a microscope cant always detect it, Dr. Ali Alhassani, head of clinical at subscription-based pediatrics service Summer Health and a pediatrician at Boston Childrens Hospital, tells Fortune.
Because the virus is primarily passed through particles of feces invisible to the naked eye, its easy to unknowingly spread and contract the diseaseif, for example, you dont wash your hands well after using the restroom or changing a babys diaper. It doesnt take a lot to get people pretty sick, Dr. Georges Benjamin, executive director of the American Public Health Association, tells Fortune. Thats the main reason its so infectious.
Whats more, if youre near someone who is projectile vomiting, you can actually be infected via aerosols, Schaffner adds.
Kateryna Kon/Science Photo Library via Getty Images
In general, norovirus is very violent and inconvenient, Dr. Luis Ostrosky, an infectious diseases specialist at the University of Texas Health Science Center at Houston, tells Fortune.
According to the CDC, common symptoms include:
Symptoms usually occur within 1248 hours of exposure, and last for one to three days. Because norovirus can cause repeated vomiting and diarrhea, the biggest risk is getting very dehydrated, Benjamin advisesespecially among the young, the elderly, and those with other medical conditions.
Unfortunately, there is no specific treatment for the illness. Antibiotic drugs, which fight bacteria, cant treat norovirus.
You should be sure, however, to keep hydrated, to replace fluids lost from vomiting and diarrhea. If youre caring for a child with norovirus, watch for signs of dehydration, including crying few or no tears and being unusually sleepy or fussy. If you think youre severely dehydrated or that someone youre caring for is, call your health care provider, the CDC advises.
While sports drinks and other caffeine-free and nonalcoholic drinks may help treat mild dehydration, the CDC stresses that those fluids might not replace nutrients and minerals. The agency recommends over-the-counter rehydration fluids, such as Pedialyte.
Norovirus is a common winter virus, though its also known to circulate via gatherings at other times of the year, like at spring or summer weddings or cruises. The virus typically makes waves from November through March, Alhassani tells Fortune.
Well all be experiencing infectious diseases more frequently, now that pandemic restrictions have been universally lifted, experts cautionat least for the near future. Remember, were basically going from almost no cases of anything [during COVID lockdowns] to a bunch of cases of something, be it RSV, flu, or norovirus, Benjamin advises.
Were out and about sharing germs with each other again.
February is a typical time for norovirus to gain ground, Schaffner adds, and its really taking advantage of our having gotten together for the first time in several years.
Nuttawan JayawanGetty Images
The best advice, experts tell Fortune:
Dr. Alice Pong, clinical medical director of infectious diseases at Rady Childrens HospitalSan Diego, advises adults to be extra diligent about washing their hands before they eatand to have their kids do the same. Alcohol-based hand sanitizers dont work well on some viruses, including norovirus. So ditch the hand sanitizer in favor of actually washing your hands, she advises.
And dont forget the laundry: Soiled clothes and linens should be washed with detergent and hot water for the maximum available cycle, the CDC says. Machine-dry them at the hottest setting.
Alhassani recommends choosing household cleaners that promise to kill 99.9% of viruses. Such labeling informs consumers that products kill norovirus, a notoriously difficult task, he advises.
If youre sick, be sure to stay home and avoid serving and preparing food for others, Ostrosky cautions, emphasizing the importance of paid sick leaveparticularly for food workers, in the case of a pathogen like norovirus.
There is not yet an approved vaccine for norovirus, though scientists are working on it, according to Schaffner. Thankfully, for most, this is an illness that makes you miserable for two to three days, but then you recover, he says.
For more on gut health:
Additional reporting by Lindsey Leake.
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A deadly type of bird flu has been confirmed on the mainland of Antarctica for the first time, scientists said, a potential risk for the southern region's huge penguin colonies.
"This discovery demonstrates for the first time that the Highly Pathogenic Avian Influenza virus has reached Antarctica despite the distance and natural barriers that separate it from other continents," Spain's Higher Council for Scientific Investigation (CSIC) said on Sunday.
The presence of the virus was confirmed on Saturday in samples of dead skua seabirds that were found by Argentine scientists near the Antarctic base Primavera, CSIC added.
POPULAR PENGUIN EXHIBIT AT ALBUQUERQUE BIOPARK ZOO CLOSES DUE TO BIRD FLU CONCERNS
The confirmed case on the Antarctic peninsula, coming after cases on islands nearby, including among gentoo penguins, highlights the risk to colonies in the region to the H5N1 avian flu that has decimated bird populations around the world in recent months.
The southern region of Antarctica's penguin colonies are potentially at risk for bird flu as scientists say the virus has reached the mainland. (REUTERS/Ueslei Marcelino)
"Analysis has conclusively shown that the birds were infected with the H5 subtype of avian influenza and at least one of the dead birds contained the highly pathogenic avian influenza virus," CSIC said in a statement.
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Argentina's Antarctic Institute on Monday said that the South American country had worked with Spanish researchers to test samples from dead birds found earlier in the year near the Argentine base, which confirmed the presence of the virus.
Hundreds of thousands of penguins gather in tightly packed colonies on the Antarctic continent and nearby islands, which could enable the deadly virus to easily spread.
Data from the Scientific Committee on Antarctic Research also showed a now-confirmed case at the research base.
Elephant seals dead in Argentina from bird flu (Maxi Jonas) Courtesy: Katherine E Kerlin, UC Davis News
(NewsNation) The H5N1 bird flu virus has adapted to spread to marine mammals, threatening wildlife conservation efforts, according to a new study from the University of California, Davis and the National Institute of Agricultural Technology (INTA) in Argentina.
Researchers collected brain tissue samples from four sea lions, one fur seal and a tern found dead at the most affected sea lion rookery on the Atlantic shore of Argentina, and all tested positive for the highly pathogenic H5N1 avian influenza virus.
Genome sequencing showed the virus collected from the samples shared mammal-adaptation mutations previously found in a few sea lions in Peru and Chile and a human case in Chile.
The researchers said it was of particular note that the mammal-adaptation mutations were also found in the tern, which is a bird, in the first such finding.
This confirms that while the virus may have adapted to marine mammals, it still has the ability to infect birds, first author Agustina Rimondi, a virologist from INTA, said in a statement. It is a multi-species outbreak.
The study was published in the journal Emerging Infectious Diseases.
This virus is still relatively low risk for humans, said senior author Marcela Uhart, a wildlife veterinarian with the UC Davis School of Veterinary Medicines One Health Institute and director of the Karen C. Drayer Wildlife Health Institutes Latin America Program.
As long as the virus continues to replicate in mammals, it may make it a higher concern for humans. Thats why its so important to conduct surveillance and provide early warning, Uhart said.
This new monster, as Uhart calls the current variant of H5N1, clade 2.3.4.4b, emerged in 2020. It killed tens of thousands of sea birds in Europe then moved on to South Africa. In 2022, it entered the U.S. and Canada, threatening food poultry along with wild birds, then migrated to Peru and Chile later that year.
It entered Argentina in February 2023, and in August of that year, the virus was first detected in sea lions on the Atlantic coast of Tierra del Fuego at the tip of South America. From there, it moved north, proving deadly for marine mammals.
Uhart co-authored a previous paper showing that the virus killed 70% of elephant seal pups born in the 2023 breeding season. In the surveyed areas of Argentinas Pennsula Valds, mortality reached at least 96% by early November 2023.
When it first came to Argentina, we didnt know if it would affect elephant seals, Uhart said. We never imagined the magnitude of what was to come.
Scientists say that since 2022, H5N1 has killed at least 600,000 wild birds and 50,000 mammals across South America, including elephant seals and sea lions in Argentina, Chile and Peru, and thousands of albatrosses in the Malvinas/Falkland Islands.
Researchers say the virus is now moving south, posing a serious threat to the penguins and other wildlife in Antarctica. Uhart and Ralph Vanstreels, her colleague at UC Davis Latin America Program in the School of Veterinary Medicine, are conducting wildlife surveillance in Antarctica this month.
We need to keep an eye on the ability of this virus to reach species that have never been exposed to an H5N1 infection before, Rimondi said. The consequences in those species can be very severe.
We are trying to be at the forefront of documenting, recording and providing early warning, Uhart said. Weve been in this area for 30 years. We know these species. We work with scientists who have 30 years of data on these populations, so we can know what will be important for the future. We have to give voice to these poor creatures. Nobodys taking note of how big this is.
TMX contributed to this report.
Norovirus, a highly contagious stomach bug that causes diarrhea and vomiting, is on the rise across the United States. Also known as the "stomach flu" or winter vomiting bug, norovirus is very common and spreads easily from person to person.
Noroviruses are a group of viruses that cause acute gastroenteritis, or an inflammation of the lining of the stomach and intestines, which leads to nausea, vomiting, diarrhea and stomach cramps. Symptoms are often severe and start suddenly. If youve ever had norovirus, you know how miserable it can be.
Anyone can get infected with norovirus, and it spreads year-round, but outbreaks are most common during the colder winter months.
A recent outbreak of norovirus in North Carolina made headlines when more than 240 people complained of illness after dining at a sushi restaurant in Raleigh. The Wake County Health Department confirmed three cases of norovirus linked to the local restaurant, according to a statement.
Last month, health officials in Evanston, Illinois, also investigated a norovirus outbreak connected to a dollar-burrito event for students at Northwestern University, NBC Chicago reported.
Unlike its nickname suggests, norovirus is not related to the flu, which is caused by influenza viruses.
Annually, norovirus causes 19 to 21 million cases of vomiting and diarrhea in the U.S., 465,000 emergency room visits, 109,000 hospitalizations, and 900 deaths, per the CDC.
Last winter, cases and outbreaks surged in the U.S., peaking in March 2023, and norovirus activity remained high well into the late spring. After a summer lull, cases are expected to keep rising.
England also had an exceptionally severe norovirus season this past winter. In March 2023, cases soared to the highest levels seen in over a decade, according to the U.K. Health Security Agency.
Whats more, norovirus outbreaks on cruise ships spiked in 2023, reaching the highest levels seen in 11 years. Between January and June 2023, there were 13 confirmed norovirus outbreaks on U.S. cruise ships thats more outbreaks in six months than there have been during any full year since 2012, according to CDC data.
The 20232024 norovirus season is already underway, and cases are ramping up in most parts of the country as temperatures drop.
According to the most recent data from the CDC, the rate of norovirus tests coming back positive, averaged over three weeks,was nearly 13% as of Dec. 30. This is down from a peak of 17% in March but more than double the rate in September and October. During this time of year in 2022, less than 10% of tests were coming back positive.
Norovirus is expected rise across the U.S. through the end of 2023 and early 2024 because it has a wintertime seasonality in the U.S., Kate Grusich, CDC spokesperson, tells TODAY.com. In temperate climates, activity tends to peak during the colder winter months.
Historically, the vast majority of outbreaks have occurred between November and April, according to the CDC.
While other intestinal viruses are more common in the summer, norovirus is known as the "winter vomiting disease," Dr. William Schaffner, professor of infectious diseases at Vanderbilt University Medical Center, tells TODAY.com.
As the holiday season approaches, there will be an uptick in indoor gatherings and travel which can unfortunately spread germs like norovirus as well, says Grusich.
We can expect norovirus to sweep the country in the coming months, but it's too early to tell whether norovirus will surge like it did last winter or surpass the previous season's peak.
While its unclear how severe the upcoming 2023-2024 season will be, understanding why norovirus spiked last winter may offer clues into what we can expect this winter.
During the initial months of the COVID-19 pandemic, norovirus outbreaks plummeted to unusually low levels, per the CDC, and rates remained relatively low until the 2021-22 season. Prevention measures implemented to curb COVID-19 were likely effective in preventing norovirus outbreaks as well, says Grusich.
During 2022-2023 season, cases began ramping up in December and surged in the first few months of 2023. Dr. Ali Alhassani, a pediatrician at Boston Childrens Hospital and head of clinical at Summer Health,told TODAY.com in February that norovirus cases at the time were going up quickly and it started pretty suddenly.
CDC data show that norovirus cases peaked between February and March of 2023. Norovirus activity remained high in the U.S. through the late spring, causing numerous outbreaks in schools.
In June, Dr. Luis Ostrosky, an infectious disease specialist at UTHealth Houston and Memorial Hermann in Houston, told TODAY.com that its not unusual to be see (norovirus) cases in April and May, (and) we are continuing to see many cases.
Ostrosky also told TODAY.com back in February that in 2023 norovirus activity (was) higher and earlier than usual, but definitely not a big outlier compared to pre-pandemic levels.
One CDC chart shows that the highest number of outbreaks (106) reported per week during the 2021-2023 seasonal years was higher than the peak number of outbreaks (92) reported per week through the 2012-20 seasonal years.
One possible reason for the surge in 2023, according to experts, is that many children who evaded the stomach bug over the past few years were exposed to norovirus and other viruses that tend to circulate among schools in the winter and early spring.
"We've always had seasonal increases and waves of norovirus, and our hospitals would be filled with kids," Dr. Albert Ko, infectious disease physician and professor of public health, epidemiology and medicine at Yale School of Public Health, tells TODAY.com. "What kind of took us off was the pandemic," Ko adds.
Now that pandemic restrictions have relaxed and many children and adults have given up measures like distancing or masking, the number of norovirus outbreaks has returned to levels similar to pre-pandemic years, the experts note.
The post-pandemic tourism boom may have also played a role. As travel increases, travel-related illnesses are expected to surge, as well, said Ostrosky. I think our travel frenzy after COVID is partially fueling this continued spread (of norovirus), he added.
"I think ... post-COVID ... there may have been a bit more (norovirus) infections, just as there has been with many other (viruses) now that people are behaving in a pre-COVID manner,"says Schaffner.
Norovirus is highly contagious and it only takes a few virus particles to cause infection.
It is spread primarily through the fecal-oral route or "when bacteria or viruses shed in stool ends up on our hands and surfaces then eventually ends up in our mouth and we ingest it and get infected," said Alhassani.
Norovirus may be transmitted directly from an infected person or indirectly through contaminated surfaces, objects, foods or drinks.
"Anybody who is in close contact with someone who has an active infection with norovirus is at high risk of getting it," said Alhassani. Norovirus can spread through activities like caring for an infected person, changing diapers or sharing utensils.
"Norovirus is so infectious that even if somebody throws up and there's droplets of vomit aerosolized in the air, that can actually cause infection," Alhassani added.
It takes a very small number of virus particles to transmit the disease, said Ko, which is why norovirus causes so many explosive outbreaks. Per the CDC, less than 100 norovirus particles can make you sick, and infected people typically shed billions of particles.
Most people are infectious from the time symptoms begin until about two or three days after symptoms resolve, Ko said, but some people can remain contagious or up to two weeks after recovery.
Outbreaks often occur in congregate settings such as schools, day cares, health care settings, nursing homes and cruise ships, says Schaffner.
According to the experts, the most common signs and symptoms of norovirus include:
Vomiting
Diarrhea
Nausea
Stomach pain or cramps
Other possible symptoms include a headache, body aches and a low-grade fever, says Ko. Norovirus symptoms usually develop within 12 to 48 hours after exposure, per the CDC.
"Norovirus ... will just last a few days," said Ostrosky. "For the majority of the population, its going to be just a nuisance."
Those at higher risk of developing severe or prolonged symptoms include babies, the elderly and the immunocompromised, said Ostrosky. If symptoms transition into chronic diarrhea and weight loss, this can lead to complications like dehydration or poor absorption of medications, he added.
"There's actually no specific treatment or antiviral for norovirus," said Ostrosky. Hydration is key to replenish fluids lost from vomiting and diarrhea, the experts noted, which means drinking plenty of water, Pedialyte or sports drinks.
"Then it's just eating bland foods and trying to let it pass through the body, which usually takes like one to three days," said Alhassani, adding that over-the-counter anti-nausea medicine and pain relievers may also be used to ease symptoms.
The vast majority of people can be managed at home and, in fact, should be isolated at home until theyre improving, given how contagious norovirus can be, said Ostrosky.
However, it's important to watch for signs of severe dehydration and to contact a health care provider if these occur, the experts noted. These include dry mouth, decreased urination, dizziness and, in children specifically, crying without tears, fussiness or unusual sleepiness, per the CDC.
Children under the age of 1, immunocompromised people, and those with prolonged or severe symptoms should also be seen by a physician, said Alhassani.
A person can be infected with norovirus multiple times in their lifetime. After recovering, you may possibly develop some short-term immunity, said Ko, but it won't be robust and wanes quickly.
It's only partial immunity ... because there are different types of norovirus, and being exposed to one doesnt give you complete protection to another, he explained.
"We do not have a vaccine against norovirus yet, although there are scientists trying to create a norovirus vaccine but that's down the road," says Schaffner. However, there are steps you can take to prevent infection and transmission.
Hand hygiene is extremely important but the way you clean your hands matters, Ostrosky noted, and it has to be with soap and water. Hand sanitizer does not work against norovirus.
Norovirus is one of the few viruses that doesnt get deactivated by alcohol. You actually need to use soap and water to physically destroy it and remove it from your hands, said Ostrosky.
Wash your hands after using the restroom, before eating or cooking and after caring for someone with norovirus.
"Goodhand-washingis really important for everyone, especially for people who handle food or are around children, older adults, or people with weakened immune systems," says Grusich.
When cleaning surfaces or objects that may be contaminated with norovirus, Ostrosky suggested using a high-level disinfectant like bleach.
If you or your child are sick with norovirus, isolate to prevent the virus from spreading within the household, said Alhassani. Anyone sick with norovirus should stay home until they feel better. Added Grusich: Avoid food preparation until at least 48 hours after symptoms stop.
It's also important to continue washing your hands often even after you feel better.
"We can expect to continue seeing more viral illnesses, both respiratory and gastrointestinal, in this post-COVID era we're sort of approaching," said Ostrosky, adding that the basics of hand-washing, isolation and respiratory etiquette can go a long way.
This article was originally published on TODAY.com
For the first time ever, a deadly strain of avian flu has been detected on the Antarctic mainland, raising concerns for the penguin colonies inhabiting the region.
According to aSpanish-led research team, the highly pathogenic avian influenza virus (HPAI) was identified on Feb. 24 in two samples taken from dead skua seabirds found by Argentine scientists near the Primavera Antarctic base.
This discovery demonstrates for the first time that the Highly Pathogenic Avian Influenza virus has reached Antarctica despite the distance and natural barriers that separate it from other continents, scientists from the Severo Ochoa Molecular Biology Center of the Higher Council for Scientific Research statedin a press release.
In the past year, the virus has been spreading across the world in both avian and mammals such as seals, polar bears and elephants. In late January, it was detected for the first time in Antarctic penguins found dead off the Falkland Islands coast but not in the actual Antarctic territory.
This highly contagious virus has led to thedeaths of millionsof birds worldwide due to its rapid spread. Scientists warn that it poses a significant threat to Antarctica's wildlife because the region's penguins, which haven't been exposed to the virus before, typically reside closely together in colonies, making it easier to spread to a higher number more quickly.
You have these massive, densely packed together bird colonies and some of those megacharismatic, highly threatened species, which are all packed together down there, Christian Walzer, a wildlife veterinarian and executive director of health at the Wildlife Conservation Society told theScientific American. If [a virus outbreak] does hit, the impacts will be potentially really devastating ... Entire populations may disappear ... This would be a catastrophe.
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Imagine a virus so versatile it leaps from birds to marine mammals, igniting concerns not just for animal populations but potentially for human health as well. This isn't the plot of a science fiction movie, but the reality we face with the H5N1 bird flu virus. A groundbreaking study conducted by the University of California, Davis, and the National Institute of Agricultural Technology (INTA) in Argentina has illuminated this grave new threat to wildlife conservation, revealing that the virus has not only adapted to infect marine mammals but is also spreading with alarming speed and deadliness across continents.
The study, a collaborative international effort, analyzed brain samples from dead sea lions, a fur seal, and a tern found along the Atlantic shore of South America. The results were startling: all samples tested positive for the H5N1 virus, with genomic sequencing unveiling mutations that facilitate the virus's infection of mammals. This isn't just about a virus spreading; it's about it evolving, learning to breach the defenses of entirely different species. These mutations were previously identified in sea lions in Peru and Chile and even a human case in Chile, underscoring the potential for a wider threat to public health. The ability of H5N1 to infect multiple species points to a looming multispecies epidemic, one that could have dire implications if the virus continues to mutate.
Since its emergence in 2020, the clade 2.3.4.4b variant of H5N1 has been a harbinger of death for wildlife, with at least 600,000 wild birds and 50,000 mammals succumbing to the virus in South America alone. The toll includes not just any animals, but hundreds of elephant seals and sea lions along the coasts of Argentina, Chile, and Peru, and even albatrosses in the Malvinas (Falkland Islands). The spread of the virus southward now threatens Antarctic wildlife, including penguins, raising alarms about a potential ecological disaster in one of the planet's last untouched frontiers. This scenario underscores the interconnectedness of human, domestic animal, and wildlife health and highlights the urgent need for global collaboration in disease outbreak management and wildlife conservation efforts.
The findings from this study serve as a crucial early warning. While the immediate risk to humans is currently considered low, the continuous replication of H5N1 in mammals could heighten this risk significantly. It's a stark reminder of the importance of surveillance and proactive measures in managing disease outbreaks. Ongoing wildlife surveillance efforts by researchers are more critical than ever, especially with H5N1's move towards Antarctica. The world has witnessed the devastating impact of pandemics; the spread of H5N1 among wildlife serves as a call to action to prevent another, potentially more catastrophic one.
In facing this unprecedented threat, the global community must come together, pooling resources and expertise to monitor, control, and hopefully halt the spread of H5N1. The health of our planet and its inhabitants, human and animal alike, depends on it.
