H3N2

Management of the influenza A (H3N2) virus

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Influenza A is responsible for flu pandemics owing to the presence of 2 surface proteins on the virus- haemagglutinin (H) and neuraminidase (N). The subtypes of the influenza A virus, H1N1 and H3N2, have been found to cause flu pandemics. Both these subtypes change genetically as well as antigenically to produce variants. H3N2 tends to change more rapidly, both genetically and antigenically, compared to H1N1. As per the World Health Organisation (WHO) report, H3N2 viruses have been responsible for considerable mortality.

Symptoms:

The symptoms associated with the H3N2 virus resemble other respiratory viruses, including fever, sore throat, nasal discharge, headache, coughing, myalgia, and nasal discharge. In severe cases, pneumonia and bronchitis could happen, thereby leading to death. 

Diagnostic evaluation:

H3N2 influenza virus detection techniques have been classified into four categories:

  • Traditional methods: Virus culture comes under the class of traditional methods.
  • Serological methods: These include:
  1. Immunofluorescence assays
  2. Complement fixation
  3. Immunodiffusion test
  4. Virus neutralisation method
  5. Haemagglutination method
  6. Rapid antigen testing.
  • Advanced quick methods: These methods are based on the molecular biology of elements. It includes:
  1. Rapid influenza technique
  2. Real-Time polymerase chain reaction (PCR)
  3.  Multiplex PCR
  4. Non-PCR-based RNA-specific detection methods, such as nucleic acid sequence-based amplification (NASBA)
  5. Conventional PCR.

It has been found that nasopharyngeal swabs yield higher rapid detection of influenza instead of nasal and throat swabs.

  • Bio-sensing methods: These methods include:
  1. Optical biosensors
  2. Giant magneto-resistance biosensors
  3. Aptamer-based biosensors
  4. Electrochemical biosensors.[1]

Comparative analysis of the detection techniques:

Treatment:

Symptomatic therapy is advised for patients that are not from a high-risk group. They are also recommended to stay home to minimise the risk of disease transmission to other members of the community.

Preventive measures:

Influenza vaccines, though, generally have variable and only moderate efficacy; they remain a critical preventive strategy for controlling the disease and its consequences.

The egg-based quadrivalent vaccines have been recommended by the Indian Council of Medical Research (ICMR) for administration in the 2020-2021 northern hemisphere influenza season containing the following composition:

  • An A/Guangdong-Maonan/SWL1536/2019 (H1N1) pdm09-like virus;
  • An A/Hong Kong/2671/2019 (H3N2)-like virus;
  • A B/Phuket/3073/2013 (B/Yamagata lineage)-like virus; and
  • A B/Washington/02/2019 (B/Victoria lineage)-like virus.[2]

The Centers for Disease Control and Prevention (CDC) recommendations for patients at high risk:

The people who are at high risk of serious flu complications, including individuals 65 years and older, children younger than 5 years,  pregnant women, and individuals with certain chronic medical conditions (like diabetes, asthma, heart disease, weakened immune systems, and neurological or neurodevelopmental conditions), are advised not to go to areas where pigs are present.

Management of the influenza A (H3N2) virus

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Influenza A is responsible for flu pandemics owing to the presence of 2 surface proteins on the virus- haemagglutinin (H) and neuraminidase (N). The subtypes of the influenza A virus, H1N1 and H3N2, have been found to cause flu pandemics. Both these subtypes change genetically as well as antigenically to produce variants. H3N2 tends to change more rapidly, both genetically and antigenically, compared to H1N1. As per the World Health Organisation (WHO) report, H3N2 viruses have been responsible for considerable mortality.

Symptoms:

The symptoms associated with the H3N2 virus resemble other respiratory viruses, including fever, sore throat, nasal discharge, headache, coughing, myalgia, and nasal discharge. In severe cases, pneumonia and bronchitis could happen, thereby leading to death. 

Diagnostic evaluation:

H3N2 influenza virus detection techniques have been classified into four categories:

  • Traditional methods: Virus culture comes under the class of traditional methods.
  • Serological methods: These include:
  1. Immunofluorescence assays
  2. Complement fixation
  3. Immunodiffusion test
  4. Virus neutralisation method
  5. Haemagglutination method
  6. Rapid antigen testing.
  • Advanced quick methods: These methods are based on the molecular biology of elements. It includes:
  1. Rapid influenza technique
  2. Real-Time polymerase chain reaction (PCR)
  3.  Multiplex PCR
  4. Non-PCR-based RNA-specific detection methods, such as nucleic acid sequence-based amplification (NASBA)
  5. Conventional PCR.

It has been found that nasopharyngeal swabs yield higher rapid detection of influenza instead of nasal and throat swabs.

  • Bio-sensing methods: These methods include:
  1. Optical biosensors
  2. Giant magneto-resistance biosensors
  3. Aptamer-based biosensors
  4. Electrochemical biosensors.[1]

Comparative analysis of the detection techniques:

Treatment:

Symptomatic therapy is advised for patients that are not from a high-risk group. They are also recommended to stay home to minimise the risk of disease transmission to other members of the community.

Preventive measures:

Influenza vaccines, though, generally have variable and only moderate efficacy; they remain a critical preventive strategy for controlling the disease and its consequences.

The egg-based quadrivalent vaccines have been recommended by the Indian Council of Medical Research (ICMR) for administration in the 2020-2021 northern hemisphere influenza season containing the following composition:

  • An A/Guangdong-Maonan/SWL1536/2019 (H1N1) pdm09-like virus;
  • An A/Hong Kong/2671/2019 (H3N2)-like virus;
  • A B/Phuket/3073/2013 (B/Yamagata lineage)-like virus; and
  • A B/Washington/02/2019 (B/Victoria lineage)-like virus.[2]

The Centers for Disease Control and Prevention (CDC) recommendations for patients at high risk:

The people who are at high risk of serious flu complications, including individuals 65 years and older, children younger than 5 years,  pregnant women, and individuals with certain chronic medical conditions (like diabetes, asthma, heart disease, weakened immune systems, and neurological or neurodevelopmental conditions), are advised not to go to areas where pigs are present.

Progress on ‘Universal’ Flu Vaccine

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The United States is in the grip of a tough flu season, and the current influenza vaccine is only partially effective. However, scientists say they’re getting closer to a “universal” flu shot for the leading strain of the illness — a vaccine that wouldn’t need to be redeveloped and readministered each year.

Trials in mice found that the new shot triggered lasting immunity against influenza A virus strains, which are responsible for up to 90 percent of cases this year.

“Vaccination is the most effective way to prevent deaths from influenza virus, but the virus changes very fast and you have to receive a new vaccination each year,” explained lead researcher Dr. Bao-Zhong Wang. He’s associate professor at the Institute for Biomedical Sciences at Georgia State University.

“We’re trying to develop a new vaccine approach that eliminates the need for vaccination every year,” Wang said in a university news release. “We’re developing a universal influenza vaccine. You wouldn’t need to change the vaccine type every year because it’s universal and can protect against any influenza virus.”

Currently, flu vaccines have to be changed every year to match the flu viruses predicted to be the most common in the upcoming flu season. However, the vaccines miss the mark in some flu seasons.

The experimental vaccine against influenza A targets flu viruses in a different way. As the researchers explained, the typical seasonal flu vaccine is engineered to focus on the microscopic head of the virus’s exterior surface protein. But this part of the flu virus mutates easily, so it’s a “moving target” each year.

The new vaccine goes deeper — aiming at the interior “stalk” of the virus, which is much less quick to change.

“This way you’re protected against different viruses because all influenza viruses share this stalk domain,” Wang said.

Using super-small protein “nanoparticles” to help target the stalk, Wang’s group found that the vaccine shielded mice against a wide range of influenza A viruses, including strains H1N1, H3N2, H5N1 and H7N9.

Of course, much more work needs to be done, since experiments that work in animal studies often don’t pan out in humans. The next step is to test the vaccine in ferrets, which are more similar to humans in terms of their respiratory system, Wang’s group said.

Two flu experts said such a shot is desperately needed.

“Any vaccine technology that can potentially result in a ‘universal’ vaccine is welcome news,” said Dr. Sunil Sood, chair of pediatrics at Southside Hospital in Bay Shore, N.Y.

“A layered protein nanoparticle influenza A vaccine, if ultimately tested in humans, could protect against the majority of influenza viruses that circulate yearly, because A viruses almost always predominate,” he said.

Dr. Marta Feldmesser is chief of infectious disease care at Lenox Hill Hospital in New York City. She expressed cautious optimism for the new research.

“While they demonstrate efficacy in mice, whether humans will respond similarly awaits future demonstration,” Feldmesser said.

Source:  Nature Communications.

Take Care of Fido: Dog Flu On The Rise

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If you’re breathing a sigh of relief that you and yours have stayed healthy during this miserable flu season — or finally recovered — not so fast.

Check on Fido.

Canine influenza — yes, doggie flu — is upon us.

“Canine flu is currently experiencing intense flare-ups in defined geographic locations,” says Amy Glaser, DVM, PhD, director of the Molecular Diagnostic Laboratory at Cornell’s Animal Health Diagnostic Center, which tracks canine flu.

Canine flu has not been reported in many states yet, although hot spots include northern Kentucky, southern Ohio, and central California, Glaser says. One case has been reported in Michigan.

Dog flu is also not seasonal, meaning your pet could get it anytime. The flare-ups involve the canine influenza strain H3N2, Glaser says, noting it has been found in 46 states since 2015. Another strain known to affect dogs, canine influenza H3N8, is hardly detected anymore, Glaser says.

Still, In the past 45 days, 109 confirmed cases have been reported to Cornell’s animal health center, and California leads the way with 72.There have been more than 2,600 cases since March 2015, with Illinois reporting 965, the most of any state.

Some good news: You apparently can’t catch the flu from your dog. ”To date, there is no evidence of transmission of canine influenza viruses from dogs to people, and there has not been a single reported case of human infection with a canine influenza virus,” the CDC says.

Recognizing and Treating Dog Flu

Recognizing dog flu isn’t easy, even for vets. A cough or a sneeze can often be the first symptoms, but ”a lot of different things can cause a cough or a sneeze,” says Bernadine Cruz, DVM, a veterinarian in Laguna Hills, CA. “Most of the time, dogs with canine influenza do just get over it,” she says, often with little or no treatment.

Besides coughing and sneezing, dogs may have a discharge from their nose or eyes, fever, and tiredness.

Most dogs recover within 2 to 3 weeks, the CDC says. Some can get secondary bacterial infections, which make the illness more severe and could trigger pneumonia. The CDC doesn’t put an exact number on the fatality rate, but it says the percentage of dogs infected with canine influenza that die ”is very small.”

If you suspect your dog has the flu, call your vet for advice. A vet can take a blood test or nasal swab to confirm the virus, says Jim Evermann, PhD, a professor of infectious diseases at Washington State University, Pullman.

If your dog has the flu, separate him from other dogs for at least 4 weeks. The virus can be spread by coughing and sneezing or by uninfected dogs coming into contact with contaminated objects. Clean and disinfect bedding and other things that infected dogs were in contact with, the CDC says.

Pet owners should be sure their dogs are well-hydrated. And your vet may prescribe an antibiotic if there is a secondary bacterial infection.

Preventing Dog Flu

A vaccine can protect against both types of dog flu or just one. Prices vary, depending on the type and the region of the country.

The American Veterinary Medical Association does not have an official position or policy on canine influenza vaccine, says Michael San Filippo, a spokesman. “We consider it a ‘lifestyle’ vaccine, not a core vaccine,” he says.

“You should talk with your veterinarian to determine if it is appropriate for your pet,” he says.

If your pet is more likely to get the flu, your vet may advise getting the vaccine, says David Clark, DVM, an associate professor of veterinary medicine at Western University of Health Sciences in Pomona, CA. Dogs at high risk include those with a lot of exposure to other dogs, such as dogs in shelters, those that go for frequent grooming, or those in doggie day care.

History of Dog Flu

As far back as the ’70s and ’80s, researchers found that some dogs developed antibodies to flu viruses but had no disease associated with that then, Evermann says.

Then in 2004,  there was an outbreak of H3N8 among greyhounds in Florida, believed to have been passed from horses. Next came Midwestern flare-ups.

Evermann says things that play a role in the flu outbreaks include socializing, such as more dogs going to day care and dog parks. A dog’s life today is different than decades ago, he says. “Culturally, things have changed in the past 20 or 25 years.”

What Is the ‘Aussie Flu,’ Exactly, and How Worried Should You Be About It?

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Yet another reason to get your flu shot, like, yesterday.
aussie-flu-symptoms-h3n2

It feels like pretty much every year medical experts say that it’s going to be an awful season for the flu. And this year is no exception. The dominant flu strain that’s circulating this year is something that’s been dubbed the “Aussie flu,” and it’s especially serious.

The Aussie flu (a.k.a. H3N2) got its name after causing several hospitalizations and deaths in Australia, which has its winter during our summer months. The country had more than 233,400 confirmed cases of the flu, which was more than double the number of cases it saw the year before, according to The Sydney Morning Herald. The paper also reports that 745 people with confirmed cases of the flu died in 2017, which is significantly higher than the five-year average of 176 flu deaths per year.

And, lucky us, the Aussie flu has made its way to America.

The ‘Aussie flu’ is just a fancy name for H3N2, a serious flu strain we’ve seen before.

This year, about 80 percent of confirmed flu cases so far are due to this strain of the flu, The New York Times reports. Last year, experts warned that H3N2 would cause a rough flu season, too. “H3N2 is a nastier virus than some of the other influenza viruses,” William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells SELF. “We anticipate that there will be more healthy children and young adults who find themselves in the ER this year.”There isn’t really anything special about the symptoms of H3N2—they’re are the same as other strains of the flu. That means that if you’re infected, you might feel fever, chills, muscle aches, cough, congestion, a runny nose, headaches, nausea, vomiting, and fatigue, infectious disease expert Amesh A. Adalja, M.D., senior scholar at the John’s Hopkins Center for Health Security, tells SELF.

However, H3N2 cases tend to be more severe than other strains and people are more likely to develop serious complications, such as pneumonia and even death, he says. “This is a moderately severe flu strain,” Dr. Adalja says. “We’re seeing increasing cases in hospitals and increasing rates of death.”

The flu vaccine protects against several strains of the flu, but it’s not super effective against H3N2.

The flu vaccine changes from year to year to try to protect the general public against what doctors suspect will be the predominant flu strains of the season. This year’s vaccine targets an H1N1-like virus, a virus with a B/Victoria lineage, and an H3N2-like virus known as A/Hong Kong/4801/2014, per the Centers for Disease Control and Prevention.

Given that H3N2 is on the list, it seems like you’d be good to go with this vaccine, but it’s not that simple. “Traditionally, vaccines don’t work quite as well against the H3N2 strain,” Dr. Schaffner says. When the H3N2 vaccine is made, the H3N2 part of the vaccine tends to mutate slightly, leaving people with some protection against the virus but not as much as you’d probably like, he explains. The flu vaccine was only 10 percent effective against H3N2 in Australia, but the CDC says that it will likely be 30 percent effective against the virus here.

You should definitely still get your flu shot.

No, getting the flu shot isn’t a guarantee that you won’t get the flu, and that kind of sucks. But experts still stress that you should get the vaccine. “The best prevention is still the influenza vaccine,” Dr. Adalja says. “Even though it’s not optimal, it’s still the best we’ve got.” The vaccine may even help reduce the severity of the Aussie flu, if you happen to catch it, Dr. Schaffner says. (By the way, if you haven’t gotten your flu vaccine yet, there’s still time given that season peaks in February, Dr. Adalja says.)

The flu isn’t easy to avoid, but you can do a lot by washing your hands carefully and often (especially after you visit high-traffic areas like malls and public transportation), using hand sanitizer, and trying to keep your distance from people who are coughing and sneezing, Dr. Schaffner says.

If you do get sick, it’s important to stay home for at least your first 24 hours after your fever wears off, the Mayo Clinic explains. “Don’t go to work or the gym—you’ll become a spreader,” Dr. Schaffner says. From there, most cases of the flu in healthy adults resolve on their own with adequate rest and liquids within a week or two.

But if your symptoms are particularly severe (e.g. you’re having difficulty breathing or persistent vomiting), or you’re at risk for complications due to your age or a chronic illness, call your doctor. You may be prescribed an antiviral drug like Tamiflu, which can make your infection less severe and shorter, Dr. Schaffner says. But those are at their most effective when taken in the first 48 hours of the infection, so don’t hesitate to get medical attention if you’re at risk.