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CDC
Animals: Influenza A viruses have been identified in many different domestic animal species, such as poultry, pigs (swine), horses, dogs, and cats. With respect to wildlife, avian influenza is most typically associated with wild birds; however, other wildlife species (e.g., marine mammals, foxes, bears, etc.) are also susceptible to infection. Occasionally, influenza viruses can be transmitted between animals (e.g., birds and pigs) and humans, and this is called zoonotic influenza. When a host is simultaneously infected with different flu viruses, the viruses can combine with each other to produce a new viral strain, which has the potential to cause greater disease severity or be more transmissible in both humans and animals. In birds, viruses are classified into two categories: low pathogenicity avian influenza (LPAI) viruses and highly pathogenic avian influenza (HPAI) viruses. These categories refer to the molecular characteristics of the virus and the viruss ability to cause disease and mortality in chickens, not to the severity of illness in humans. In poultry, some LPAI can evolve into HPAI. Susceptible birds become infected when they have contact with the virus, as it is shed in the saliva, nasal secretions, and feces of infected birds or through contact with contaminated surfaces. Wild birds may have additional routes of exposure, including contaminated water and eating infected waterfowl. Because avian migratory pathways around the world are connected, avian influenza can be introduced into new places. In the U.S., poultry are not vaccinated for Avian Influenza. Currently, AI vaccines to protect poultry are being explored and considered for future use. When domestic poultry are infected, the risk increases for humans that work with poultry. Human infections have occurred uncommonly and sporadically. The CDC reported the first case of human HPAI H5 bird flu in the U.S. in April 2022. The case occurred in a person who had direct exposure to poultry and was involved in the depopulating of poultry with presumptive H5N1 bird flu. There have also been four human infections with LPAI in the United States, resulting in mild-to-moderate illness.
Swine influenza, also caused by type A influenza viruses, do not usually cause infections in humans, but rare human infections have been reported. Flu viruses in pigs can be transmitted to people through droplets, but transmission from eating pork is not known to occur. Influenza vaccines for swine are available, although they are not 100% effective.
Equine influenza, which occurs in horses, can cause an antibody response in some people but has not been known to cause human illness.
Environment: Flu viruses can live in the environment for up to 48 hours. Flu viruses are killed by heat above 75 C and can be killed by common household products, including products containing chlorine, hydrogen peroxide, detergents (soaps), iodine-based antiseptics, and alcohols. See Resource section below for resources on on specific disinfectants that will kill flu viruses.
PREVENTION
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Influenza D, a relatively recent addition to the alphabet of flu viruses, most commonly infects cattle. But experts have their eye on the threat it could potentially pose to humans.
Veterinarians first identified influenza D in pigs in 2011 and later sleuthed out the viruss primary host: cattle. Scientists have since been watching for any signs that this bovine flu is infecting humans, as flus from birds and pigs sometimes do. Theres currently no definitive proof, but there are worrying hints that human infection is possibleand that if luck favored the virus on a couple key fronts, it could begin spreading among people.
I think its fair to say that influenza D has everything it needs to infect humans from a scientific standpoint, says Feng Li, a virologist at the University of Kentucky, who helped identify the virus as a new type of influenza.
Scientists have identified four different types of influenza virus, most of which infect humans. The flu vaccines distributed in the U.S. each fall are tuned to two strains each of influenza A and B. Influenza C is very common but typically mild, except for some cases in infants, and there is no vaccine for it. Influenza D is the most recently identified type and the only one that has not been confirmed to infect humans.
Influenza D is believed to be most prevalent in cattle. A nationwide survey in 2014 and 2015 showed that about 75 percent of the animals carried antibodies to the virus. It seems to cause only mild bovine infection, says Mayara Maggioli, a veterinary immunologist at Oklahoma State University. Its a very subtle disease, she says. Its very well adapted. Infected cattle can have symptoms that arent so different from the flu we all know: runny noses or eyes, increased heart and breathing rates and a fever, cough or reduced appetite. Its very similar to what we see in humans, Maggioli says. Experiments have shown that inoculation can protect cattle from infection, but there is no commercially available vaccine for them.
Whether humans can be infected with influenza D is less clear. Theres evidence out there that suggests it might be happening, but its far from conclusive, says Richard Webby, a virologist at St. Jude Childrens Research Hospital in Tennessee. The data thats out there could go either way. NPR reported on the viruss potential to jump to humans last month.
Influenza D has scientists particularly concerned for people who spend long hours in close contact with cattle, especially in confined spaces. And recent research has found hints of the virus in this population. A 2022 study found viral particles on nasal swabs from cattle workers, but viruses can be present without actively infecting a person. A 2016 study found that cattle workers carried antibodies that reacted to influenza D, but influenza C is similar enough that antibodies for the latter can respond to the former as well, Webby says.
Although scientists have plenty of experience monitoring potential influenza spillover from animals, those efforts have focused on birds and pigsnot cattle. Thats because avian and swine influenzas have caused pandemics in humans, including the 1918 flu pandemic, which was caused by a virus that originated in birds, and the 2009 swine flu pandemic. Bovine viruses, as far as scientists know, have never wreaked such havoc. An avian influenza recently infected nearly 60 million poultry birds in the U.S. but has only infected one human, and no cases have been reported in humans in the U.S. since April 2022, according to the Centers for Disease Control and Prevention.
From the flu perspective, certainly cows have never really been thought about in studies of spillover, Webby says, although he notes that some groups are starting to investigate human-cattle interactions more closely. Its definitely an understudied interface. We absolutely need to know more about it.
If influenza D were to start infecting humans, the first sign would likely be respiratory symptoms in cattle industry workersand even the studies that show potential human immune reactions to the virus havent documented any sick workers. The second key piece of information would be if people with no direct interaction with cattle began to get sick, which would suggest the virus was spreading among humans.
Even if those two developments occurred, its not certain that influenza D would be disastrous among humans, especially given its relatively benign effects on cattle. In a human, I think probably, disease-wise, it should be mild, Li says. But as we all know, Mother Nature cannot be predicted.
All three experts Scientific American spoke with say theres no guarantee the virus wont eventually start infecting humans. Weve absolutely got to treat it with respect. Weve absolutely got to learn more about it, Webby says. You cant say theres no risk of this virus at all. I think that would be a naive statement.
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This Cow and Pig Influenza Virus Could Infect Humans: What We Know So ...
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Scientists in China have identified strains of the influenza A-H3N2 virus circulating in dogs that might be gaining the capacity to spill over into humans.
Influenza-A viruses in animal reservoirs have repeatedly crossed species barriers to infect humans. H3N2 avian influenza or bird flu viruses were first transmitted to dogs around 2006 and have since formed stable canine lineages.
A team from the China Agricultural University analysed swabs from more than 4,000 dogs.
The findings, published in the journal eLife, showed that the H3N2 canine influenza viruses (CIVs) can recognise the human-cell receptors and hold the potential to replicate in humans.
"We found that, during adaptation in dogs, H3N2 CIVs became able to recognise the human-like receptor, showed gradually increased hemagglutination (HA) acid stability and replication ability in human airway epithelial cells," they wrote in the paper.
Further, they found that "human populations lack immunity to H3N2 CIVs, and even preexisting immunity derived from the present human seasonal influenza viruses cannot provide protection against H3N2 CIVs".
"Our results showed that canines may be intermediates for adapting avian influenza viruses to humans. Continuous surveillance coordinated with risk assessment for CIVs is necessary," the researchers said.
To evaluate the infectivity and transmission ability of H3N2 CIVs in dogs, the team deliberately inoculated six dogs with the known dog flu strains.
The dogs became mildly ill, with the most severe symptoms including fever, sneezing, wheezing, and coughing.
While so far, there is no human infection reported with the H3N2 CIVs, the team cautioned that "dogs might increase the opportunity of viral cross-species transmission to humans".
According to experts, the research highlights pet dogs' role as a possible "patient zero" for a future dog flu outbreak, The Telegraph reported.
It is "pretty clear" the bird flu H3 strain has become a dog-specific virus, Prof James Wood, the head of the department of veterinary medicine at the University of Cambridge, was quoted as saying.
"The changes in the canine virus apparently are making it better adapted to transmit within mammals, as you might expect after such a long period in dogs," he noted.
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The above article has been published from a wire source with minimal modifications to the headline and text.
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'Dog Flu' Virus Could be Mutating to Infect Humans, Warns China-Based ...
Dog flu Is Mutating Into A Virus That Could Infect Humans, Chinese Scientists Warn Beware! Dog flu-causing virus is mutating and scientists in China believe that it has the ability to spill over into humans. Read on to know everything.
Are we not done with virus infections yet? From SARS-CoV-2 to Monkeypox, in the last 3 years, the world has battled several virus attacks. These viruses were all new to the environment and carry the ability to mutate and form new variants with more efficacy towards causing an infection. As the world continues to fight the virus attacks, Chinese scientists have issued a fresh warning against a new threat.
On Tuesday, Chinese scientists revealed that they have identified strains of the influenza A-H3N2 virus, which is currently circulating in dogs. And these strains have the ability to spill over into humans and cause virus infection, just like COVID and other viral illnesses. Speaking to the media, the scientists warned, "Humans could one day be struck down by 'dog flu' a mutated form of avian influenza which is slowly evolving."
In the study, a team of researchers in China analysed the swabs from more than 4,000 dogs. The findings, published in the journal eLife, stated that the H32 canine influenza viruses (CIVs) are mutating faster than usual and are able to recognise the human-cell receptors. This feature of the H3N2 canine virus makes it potential to replicate in humans.
In the published research paper, the scientists wrote: "We found that, during adaptation in dogs, H3N2 CIVs became able to recognise the human-like receptor, showed gradually increased hemagglutination (HA) acid stability and replication ability in human airway epithelial cells."
What is this H3N2 canine virus that scientists are warning humans about?H3N2 was discovered in dogs almost two decades ago. The virus infection can cause pooches to suffer from a runny nose and cough and can turn deadly in rare and extreme cases.
At a time when we are already dealing with rising COVID cases, the news about the certain worrisome mutation in the Dog flu-causing virus shouldn't be ignored. The reason why one should be aware of the infection is because of the fact that the human population lack immunity to the H3N2 CIVs, and even preexisting immunity gained from the present human seasonal influenza viruses cannot provide any protection against the H3N2 CIVs.
The H3N2 CIVs, also known as canine flu strains of H3N2 were first discovered in 2006. It has evolved from a strain of bird flu called H3N2. As per studies, the H3N2 CIVs can cause severe respiratory illnesses in dogs. Some of the serious symptoms associated with this virus are fever, sneezing, and coughing.
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Dog Flu Mutating Into a Virus That Could Infect Humans: Chinese ...
'Dog Flu' Virus Could be Mutating to Infect Humans, Warns China-Based Study The Weather Channel
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'Dog Flu' Virus Could be Mutating to Infect Humans, Warns China-Based Study - The Weather Channel
H3N8 'bird flu' virus: What you need to know Gulf News
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People who get influenza could be six times more susceptible to having a heart attack in the days following a flu diagnosis, a new study from the Netherlands has found.
The studys conclusions were scheduled to be presented on April 18 at the European Congress of Clinical Microbiology & Infectious Diseases in Copenhagen, Denmark, as reported by Medscape.
The lead researcher, Dr. Annemarijn de Boer with the Julius Center for Life Sciences and Primary Care at the University Medical Center Utrecht, analyzed test results from 16 labs in the Netherlands, as well as medical and death records.
Of 26,221 cases of influenza between the years 2008 and 2019, 401 people experienced at least one heart attack within a year of the diagnosis, the report said.
HEART DISEASE RISK COULD BE AFFECTED BY ONE SURPRISING FACTOR, NEW STUDY FINDS
Additionally, people had a 6.16 times higher likelihood of having a heart attack in the week after getting the flu compared to the year before or after, the researchers found.
However, when excluding the deaths that occurred outside the hospital, the increased risk was 2.42 times instead of 6.16.
People who get influenza could be six times more susceptible to having a heart attack in the days following a flu diagnosis, a new study from the Netherlands has found. (iStock)
This is likely because most flu testing in the Netherlands is performed in the hospital, which means patients are more likely to have severe illness, according to de Boer.
Similar findings came from a 2018 Canadian study led by Dr. Jeffrey C. Kwong from the Dalla Lana School of Public Health in Toronto, Ontario.
Researchers found that participants were 6.05 times more likely to have a heart attack in the week after diagnosis.
Board-certified cardiologist Dr. Mary Greene with Manhattan Cardiology in New York City was not involved in the study, but reviewed the findings.
HEART DISEASE, THE SILENT KILLER: STUDY SHOWS IT CAN STRIKE WITHOUT SYMPTOMS
"While the methodology of this particular Dutch study did not yield as much robust data, the study certainly echoes previous studies that have come to similar conclusions," Greene told Fox News Digital.
"Seemingly common colds can turn into serious medical issues."
"I do agree that a flu diagnosis can increase the odds of heart attack in a select group of patients, especially those with underlying heart disease," she added.
The increase in heart attacks among patients diagnosed with influenza, said Greene, largely stems from the inflammatory process and the environment that is created within the body when someone is fighting off the flu or other viral illnesses.
To help minimize the risk of heart attacks, all people should have a cardiovascular screening starting at age 40, or earlier if there is a history of early heart disease in the family, says one cardiologist. (iStock)
"Such inflammation in the body can make cholesterol plaques more vulnerable to rupture and blood more likely to clot, which is the underlying mechanism of both myocardial infarction (heart attack) and ischemic stroke," she said.
Dr. Craig Bober, a family medicine physician at Inspira Medical Group Primary Care Mantua in Sewell, New Jersey, who was also not involved in the Dutch research, noted a key limitation of the study.
"It is important to note that the study was not designed to reflect the generalized population, as it looked at only those tested in hospital settings these patients tend to be the sickest and usually elderly," he told Fox News Digital in an email.
FDA APPROVES FIRST AT-HOME TEST TO DETECT BOTH FLU AND COVID
"However, the study certainly emphasizes the dangers of seemingly benign virus-mediated infections."
Fox News Digital reached out to the study author for comment.
To help minimize the risk of heart attacks, all people should have a cardiovascular screening starting at age 40, or earlier if there is a history of early heart disease in the family, said Greene of New York City.
The increase in heart attacks among patients diagnosed with influenza, said one cardiologist, stems from the inflammation that occurs when someone is fighting off the flu or other viral illnesses. (iStock)
"I also recommend that all patients with underlying coronary artery disease, history of stents, history of heart attack and history of heart failure have their annual flu shot," she said.
"Cardiovascular patients see a larger benefit from influenza vaccination in terms of protection against a heart attack should they become infected with the influenza virus."
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These findings should serve as a reminder that seemingly common colds can turn into serious medical issues, Bober of New Jersey said.
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"Anyone with concerning chest pain or shortness of breath especially those with high-risk medical conditions such as underlying heart disease, lung conditions, diabetes or kidney disease should seek medical attention sooner rather than later," he added.
Melissa Rudy is health editor and a member of the lifestyle team at Fox News Digital.
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Flu diagnosis could significantly raise heart attack risk, new study ...
Species of virus
Influenza B virus is the only species in the genus Betainfluenzavirus in the virus family Orthomyxoviridae.
Influenza B virus is known only to infect humans, pigs and seals.[4][5] This limited host range is apparently responsible for the lack of associated influenza pandemics in contrast with those caused by the morphologically similar influenza A virus as both mutate by both antigenic drift and reassortment.[6][7][8] There are two known circulating lineages of Influenza B virus based on the antigenic properties of the surface glycoprotein hemagglutinin. The lineages are termed B/Yamagata/16/88-like and B/Victoria/2/87-like viruses.[9] The quadrivalent influenza vaccine licensed by the CDC is currently designed to protect against both co-circulating lineages and has been shown to have greater effectiveness in prevention of influenza caused by Influenza B virus than the previous trivalent vaccine.[10]
Further diminishing the impact of this virus, "in humans, influenza B viruses evolve slower than A viruses and faster than C viruses".[11] Influenzavirus B mutates at a rate 2 to 3 times slower than type A.[12] Nevertheless, it is accepted that Influenza B virus could cause significant morbidity and mortality worldwide, and significantly impacts adolescents and schoolchildren.[13]
The B/Yamagata lineage might have become extinct in 2020/2021 due to COVID-19 pandemic measures.[14][15]
The Influenza B virus capsid is enveloped while its virion consists of an envelope, a matrix protein, a nucleoprotein complex, a nucleocapsid, and a polymerase complex. It is sometimes spherical and sometimes filamentous. Its 500 or so surface projections are made of hemagglutinin and neuraminidase.[16]
The Influenza B virus genome is 14,548 nucleotides long and consists of eight segments of linear negative-sense, single-stranded RNA. The multipartite genome is encapsidated, each segment in a separate nucleocapsid, and the nucleocapsids are surrounded by one envelope.[16]
The subtypes of influenza A virus are estimated to have diverged 2,000 years ago. Influenza viruses A and B are estimated to have diverged from a single ancestor around 4,000 years ago, while the ancestor of influenza viruses A and B and the ancestor of influenza virus C are estimated to have diverged from a common ancestor around 8,000 years ago.[17] Metatranscriptomics studies have also identified closely related "Influenza B-like" viruses such as the Wuhan spiny eel influenza virus[18] and also "Influenza-B like" viruses in a number of vertebrate species such as salamanders and fish.[19]
In 1936, Thomas Francis Jr. discovered the ferret influenza B virus. Also in 1936, Macfarlane Burnet made the discovery that influenza virus may be cultured in hen embryonated eggs.[20] This prompted research into the properties of the virus and the creation and application of inactivated vaccines in the late 1930s and early 1940s. Inactivated vaccines' usefulness as a preventative measure was proven in the 1950s. Later, 2003 saw the approval of the first live, attenuated influenza vaccine.[21] Looking into influenza B specifically, Thomas Francis Jr. isolated influenza B virus in 1936. However, it was not until 1940 when influenza B viruses were discovered.[22]
In 1942, a new bivalent vaccine was developed that protected against both the H1N1 strain of influenza A and the newly discovered influenza B virus.[23] In todays current world, even while some technology has advanced and flu vaccines now cover both strains of influenza A and B, the science is still based on findings from almost a century ago.[24] The viruses included in flu vaccines are changed each year to match the strains of flu that are most likely to make people sick that year since flu viruses can develop swiftly and new mutations have appeared each year, like H1N1.[25]
Even though there are two different lineages of influenza B viruses that circulate during most seasons, flu vaccinations were long meant to protect against three different flu viruses: the influenza A(H1N1), influenza A(H3N2), and one influenza B virus.[26] The second lineage of the B virus was since added to provide greater defense against circulating flu viruses.[27] Two influenza A viruses and two influenza B viruses are among the four flu viruses that a quadrivalent vaccine is intended to protect against. All flu vaccines in the United States today are quadrivalent.[28] The four main types of Type A and B influenza viruses that are most likely to spread and make people sick during the upcoming flu season are the targets of seasonal influenza (flu) vaccines.[29] All of the available flu vaccinations in the United States offer protection against the influenza A(H1), A(H3), B/Yamagata, and B/Victoria lineage viruses. Each of these four vaccine virus components is chosen based on the following criteria: which flu viruses are infecting people ahead of the upcoming flu season, how widely they are spreading, how well the vaccines from the previous flu season may protect against those flu viruses, and the vaccine viruses' capacity to offer cross-protection.[30]
For the 2022-2023 flu season, there are three flu vaccines that are preferentially recommended for people 65 years and older; various influenza (flu) vaccinations are authorized for use in people of various age groups.[31] On March 3, 2022, the FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) convened in Silver Spring, Maryland, to choose the influenza viruses that will make up the influenza vaccine for the 20222023 influenza season in the United States. The committee proposed using A(H1N1)pdm09, A(H3N2), and B/Austria/1359417/2021-like viruses for trivalent influenza vaccines to be utilized in the U.S. for the 20222023 influenza season.[32]
In 1940, an acute respiratory illness outbreak in Northern America led to the discovery of influenza B virus (IBV), which was later discovered to not have any antigenic cross-reactivity with influenza A virus (IAV). Based on calculations of the rate of amino acid substitutions in HA proteins, it was estimated that IBV and IAV diverged from one another around 4000 years ago.[33] However, the mechanisms of replication and transcription, as well as the functionality of the majority of viral proteins, appear to be largely conserved, with some unusual differences.[34] Although IBV has occasionally been found in seals and pigs, its primary host species is the human.[35] IBVs can also spread epidemics throughout the world, but they receive less attention than IAVs do due to their less prevalent nature, both in infecting hosts and in the symptoms that result from infection. IBVs used to be unclassified, but since the 1980s, they have been divided into the B/Yamagata and B/Victoria lineages.[36] IBVs have further divisions known as clades and sub-clades, just like IAVs do.[37]
Hemagglutinin (HA) and neuraminidase (NA) are two virus surface antigens that are constantly changing.[38] Antigenic drift or antigenic shift are two possible influenza viral changes. Small changes in the HA and NA of influenza viruses caused by antigenic drift result in the creation of novel strains that the immune system of humans might not be able to identify.[39] These emerging strains are the influenza virus's evolutionary responses to a potent immunological response across the population. The main cause of influenza recurrence is antigenic drift, which makes it essential to reevaluate and update the influenza vaccine's ingredient list every year.[40] Annual influenza outbreaks are caused by antigenic drift and declining immunity, when the residual defenses from prior exposures to related viruses are incomplete. Antigenic drift occurs in Influenza A, B, and C.[41]
Hemagglutination-inhibition experiments using ferret serum after infection allowed the identification of two very different antigenic influenza type B variants in the years 1988 1989. These viruses shared antigens with either B/Yamagata/16/88, a variation that was discovered in Japan in May 1988, or B/Victoria/2/87, the most recent reference strain.[42] The B/Victoria/2/87 virus shared antigens with all influenza B viruses discovered in the United States during an outbreak in the winter of 1988 1989.[42]
In Japan, influenza B virus reinfection was investigated virologically in 1985 1991 and epidemiologically in 1979 1991 in children.[43] Four influenza B virus outbreaks that each included antigenic drift occurred during the course of this study. Between the epidemics in 1987 1988 and 1989 1990, there was a significant genetic and antigenic change in the viruses.[43] Depending on the influenza seasons, the minimum rate of reinfection with influenza B virus for the entire period was between 2 and 25%.[43] Haemagglutination inhibition assays were used to examine the antigens of the influenza B virus primary and reinfection strains that were isolated from 18 children between the years of 1985 and 1990, which encompassed three epidemic periods. The findings revealed that reinfection occurred with the viruses recovered during the 1984 1985 and 1987 1988 influenza seasons, which belonged to the same lineage and were antigenically close.[43]
Today, reinfection continues as increased influenza activity was reported in the United States in November 2022 due to the winter weather. [44]
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