FluView Week 17: Fatal Swine Variant (H1N1v) Case In Ohio

Credit Wikipedia

 

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I confess to being a little chagrined that – with our regular flu season essentially over – I didn’t check last week’s FluView report (week 17), else I’d have seen the following notice (h/t Camster on FluTrackers) summarizing the second  swine variant (H1N1v) infection recorded for 2015 (see FluView Wk 3 for 1st report) . 

 

A bit surprisingly, it was not listed in last week’s MMWR table of Notifiable diseases (which I did check).  First the report, then I’ll return with a bit more on swine variant viruses.

 

Novel Influenza A Virus:

One human infection with a novel influenza A virus was reported by the state of Ohio. The person was infected with an influenza A (H1N1) variant (H1N1v) virus and died from complications as a result of the infection. The patient worked at a livestock facility that housed swine but no direct contact with swine was reported in the week prior to illness onset. No ongoing human-to-human transmission has been identified.

Early identification and investigation of human infections with novel influenza A viruses are critical in order to evaluate the extent of the outbreak and possible human-to-human transmission. Additional information on influenza in swine, variant influenza infection in humans, and strategies to interact safely with swine can be found at http://www.cdc.gov/flu/swineflu/index.htm.

 

The CDC describes Swine Variant viruses in their Key Facts FAQ.

 

What is a variant influenza virus?

When an influenza virus that normally circulates in swine (but not people) is detected in a person, it is called a “variant influenza virus.” For example, if a swine origin influenza A H3N2 virus is detected in a person, that virus will be called an “H3N2 variant” virus or “H3N2v” virus.

 

Over the past few years we’ve watched as several swine variant influenza viruses (H1N1v, H1N2v or H3N2v) have made tentative jumps into the human population (see Keeping Our Eyes On The Prize Pig) and each summer the CDC has issued advice on preventing infection at county and state fairs (see Measures to Minimize Influenza Transmission at Swine Exhibitions, 2014).

Of the 374 Swine variant infections detected over the past decade (undoubtedly an undercount given the limited testing), the the vast majority have been of the H3N2v subtype.  Only 18 (5%) were H1N1v, and even less (5) were of the H1N2v variety.

We’ve not seen many reported cases the past couple of years, but during the summer of 2012 more than 300 cases were detected, with Indiana and Ohio accounting for more than 3/4ths of the cases. 

 

Illnesses were usually mild or moderate ( only 1 fatality until now), and infection usually occurred in the summer and fall - associated with attendance of local and state fairs where pigs were being shown.  Of course, some people have contact with swine all year round, and so while uncommon, it isn’t terribly surprising that someone would contract a swine variant virus `out of season’.

 

These swine viruses are important because – unlike many of the avian strains – they belong to the H1, H2, and H3 HA types that have led to all of the known pandemics of the past 130 years.  

 

The progression of human influenza pandemics over the past 130 years has been a fairly unoriginal H2, H3, H1, H2, H3, H1, H1 sequence.

 

While that doesn’t prove that an H5 or an H7 virus couldn’t adapt to humans (or hasn’t in the past), it has led some researchers to wonder whether a non H1, H2, or H3 virus has the `right stuff’ to spark a pandemic (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?).

 
So – while not all that unusual, typically poorly transmitted by humans, and generally producing only mild to moderate illness – we keep a special eye on any swine origin virus that manages to jump to humans. 

 

Two weeks ago, in Waiting For The Next Flu To Drop, we looked at some of these `novel flu contenders’, and with county and state fair season kicking off in some areas next month, I’m sure we’ll be talking about biosecurity measures both for the swine and poultry exhibits frequently over the summer.

Keeping Our Eyes On The Prize Pig

Credit Wikipedia

 

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To give you an idea of how rapidly things change in the world of emerging infectious diseases, two summers ago (June 2012), no one had ever heard of the MERS coronavirus, the H7N9 avian flu virus was still 8 months away from breaking out in China, and avian H5N8, H10N8, H6N1 and H5N6 weren’t on anyone’s radar screen.

 

Aside from the perennial concerns over change in transmissibility of H5N1 virus, our primary emerging disease concerns that summer lay in a major outbreak of West Nile Virus (see DVBID: 2012 Record Number Of West Nile Fatalities), and an outbreak of human infection with variant influenza  contracted from show pigs displayed at county and state fairs. 

 

The CDC describes Swine Variant viruses in their Key Facts FAQ.

What is a variant influenza virus?

When an influenza virus that normally circulates in swine (but not people) is detected in a person, it is called a “variant influenza virus.” For example, if a swine origin influenza A H3N2 virus is detected in a person, that virus will be called an “H3N2 variant” virus or “H3N2v” virus.

Although the actual number of human variant flu infections that occur each year is unknown, the CDC has reported 1 or 2 cases each year since 2005. In 2010, that number jumped to 8, and in 2011, to 12. During the summer of 2012 more than 300 cases were recorded across the United States, and nearly all were linked to contract with pigs displayed at county and state fairs that summer.

 

Last year we only saw a handful of cases, but with state and county fair season once again upon us (it runs June-November around the nation) the potential exists for seeing cases again this summer and fall. 

 

While fairs have instituted inspections for any signs of illness in livestock – as we’ve discussed previously (see Asymptomatic Pigs: Revisited) - pigs can carry this virus without showing any outward signs of infection.

 

Swine are highly susceptible to a variety of flu viruses (human, swine, avian) - and can serve as `mixing vessels’, allowing viruses to reassort into new hybrid strains, a topic well covered by Helen Branswell a few years ago in a SciAm article called called Flu Factories.

 

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Some of my earlier blogs on swine variant influenza include: H3N2v: When Pigs Flu , You Say You Want An Evolution? & The (Swine) Influenza Reassortment Puzzle.

 

These swine variant strains are – like the 2009 H1N1 pandemic virus – reassortants, that continue to circulate (and evolve) in swine herds.  Starting in 2011, the H1N1v virus was found to have acquired the M (matrix) gene from the 2009 H1N1 pandemic virus. Since then, this M gene has been showing up regularly in all three swine variant viruses (H1N1v, H1N2v, H3N2v).

 

The CDC has speculated that `This M gene may confer increased transmissibility to and among humans, compared to other variant influenza viruses.’

 

The concern with these variant swine flu infections, as it is with any animal flu that jumps to humans, is that it gives the virus another opportunity to better adapt to human physiology. While humans have a long history of exposure to seasonal H3N2 flu viruses, research has shown only limited community immunity to these variant strains (see CIDRAP: Children & Middle-Aged Most Susceptible To H3N2v).

 

The good news is that while some limited community transmission of these variant flu strains appears to have occurred during the summer of 2101, sustained and efficient human-to-human transmission did not, and for the most part, the virus only caused mild to moderate illness.

 

But as we’ve seen so often in the past, things can change quickly in the world of infectious diseases.

 

So while Chikungunya, West Nile Virus and MERS will be getting the bulk of the headlines this summer,  public health officials will also be on the lookout for any new swine variant infections - and more importantly - for any signs that the behavior of the virus has changed.

 

In the meantime, the CDC offers this advice for those planning to visit the fair this year:

 

Exhibitors of swine, and those in charge of the venue, will want to consult  Guidance Associated with Fairs.

Arkansas Reports Two H1N1v Infections

 

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The most common swine flu viruses are H1N1, H1N2, H3N1, H3N2, and H2N3. These viruses, when they jump to humans, are called variant viruses (e.g. H3N2v, H1N2v, H1N1v).  While the public health risk posed by these variant flu viruses appears low right now, emerging flu viruses can abruptly change, and so the CDC keeps a close watch on these variant flu strains.

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So far – out of nearly 370 cases reported since 2005 - most illnesses have been moderate-to-mild, few patients have required hospitalization, and only 1 death has been attributed to these variant viruses.

 

Over the past several years, H3N2v has – by far – been the most commonly reported variant strain reported in the United States, making up more than 90% of the reported cases.  This summer, we’ve seen 18 H3N2v cases reported, from Indiana, Illinois, and Michigan.  Since 2005, H1N2v is the least common (n=5), while H1N1v had accounted for 14 cases.  

Today, from the Arkansas Department of Health, we learn of two new H1N1v cases.

 

Friday, Sep 13, 2013

Swine Flu Variant in Arkansas

Little Rock -- Two people in Arkansas have been infected with a strain of influenza (flu) known as H1N1(v) after contact with swine (pigs). These cases have been confirmed by the Centers for Disease Control and Prevention (CDC).

“A few times a year an animal variant of the influenza virus is identified in humans” said Dr. Dirk Haselow, State Epidemiologist. “Viruses of this type typically cause only mild illness in those affected and, in contrast to seasonal flu, are not easily transmitted from person to person” added Haselow. ADH has carefully monitored the patient contacts for several days without evidence of any human to human spread. Both patients identified to date have recovered fully.

When an influenza virus that normally circulates in swine is detected in a person, it is called a variant influenza virus and is labeled with a ‘v’. Influenza viruses such as H1N1(v) and other related variants are not unusual in swine and can be directly transmitted from swine to people and from people to swine. When humans are in close proximity to live swine, such as in barns and livestock exhibits at fairs, movement of these viruses can occur back and forth between humans and animals.

“We are not currently aware of any additional human influenza cases caused by H1N1(v) and do not anticipate making any new public health recommendations regarding human exposure to swine. However, we will continue to assess the situation and conduct aggressive surveillance for additional influenza cases” Haselow emphasized.

Influenza has not been shown to be transmitted by eating properly handled and prepared pork or other products derived from pigs.

"ADH has been carefully following all suspected cases of influenza. We have also worked closely with our veterinary colleagues and the Arkansas Livestock and Poultry Commission to remain informed about potential infections in swine. It is because of this careful surveillance that these cases have come to our attention,” said Haselow.

Case investigations have indicated that the illnesses resulting from H1N1(v) infection have been similar to seasonal influenza. Symptoms include fever, muscle aches, decreased energy, coughing, runny nose, and sore throat. Contact your health care provider if you are experiencing flu-like symptoms and inform the doctor if you have had contact with swine.

To prevent the spread of other infections you can get from animals, the following precautions are recommended:

• Wash your hands often with soap and running water. Particularly after contact with animals. If soap and water are not available, use an alcohol-based hand rub.
• Never eat, drink or put things in your mouth in areas where animals are present, and don’t take food or drink into areas where animals are housed.
• Never take toys, pacifiers, spill-proof cups, baby bottles, strollers or similar items into areas with animals.
• Avoid close contact with animals that look or act ill.
• Children younger than 5 years, people 65 years and older, pregnant women, and people with certain chronic medical conditions (like asthma, diabetes, heart disease, weakened immune and nervous systems) are at higher risk for serious complications of infections. These people should consider avoiding exposure to pigs and other animals at petting zoos and barns during fair season.

 

 

Although it is likely (see CID Journal: Estimates Of Human Infection From H3N2v (Jul 2011-Apr 2012)) that the number of confirmed cases (this year, and in previous years) under-represents the total number of variant flu infections that occur each year - for now, the threat to the public from these swine variant viruses appears low.

 

The CDC, in a statement on June 28th of 2013, offered this assessment on H3N2v:

CDC will continue to watch this virus closely to make sure there are no changes in the epidemiology of related human infections. That means watching for any changes in the severity of illness caused by infection with this virus and any signs that the virus is becoming more adept at spreading from person-to-person. Like all influenza viruses, it’s possible that mutations could occur that would allow this virus to become more severe or to spread more easily between people.

The risk of this virus triggering a full-blown pandemic is considered relatively low, however, because serology studies have suggested that significant numbers of adults have some existing immunity against this virus. Children younger than about 10 years old, however, have little to no immunity against H3N2v virus. Given this, a more likely scenario if H3N2v were to become more transmissible among people would be localized outbreaks in pockets of the population that do not have immunity against this virus, for example, in day care or school settings.

 

Recent  blogs on Swine variant influenza include:

 

Study: Novel & Variant Swine Influenzas In Korean Pigs

CDC Updates H3N2v County & State Fair Advice

CDC HAN Advisory On H3N2v

 

For more information, you may wish to visit the CDC’s Variant (Swine Origin) Influenza Viruses in Humans webpage, or visit these related links.

 

• Key Facts about Human Infections with Variant Viruses (Swine Origin Influenza Viruses in Humans)
• Reported Infections with Variant Influenza Viruses in the United States since 2005
• Influenza A (H3N2) Variant Virus
• What People Who Raise Pigs Need To Know About Influenza (Flu)
• Reports of Human Infections with Variant Viruses

A Variant Swine Flu Review

Credit Wikipedia

 

 

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Last summer, before anyone had ever heard of MERS-CoV (initially dubbed novel coronavirus or nCoV) and the H7N9 avian flu virus, public health officials across the nation were facing large outbreaks from two emerging disease threats; West Nile Virus (WNV) and Swine Variant Influenza.

 

We’ve discussed WNV several times recently (see Texas: First West Nile Case Of 2013, DVBID: 2012 Record Number Of West Nile Fatalities), but swine variant influenza has been pretty much crowded out of the headlines since late last fall.

 

With state and county fair season once again upon us (it runs June-November around the nation) – tens of thousands of fairgoers will once again be coming into relatively close contact with farm animals – providing fresh opportunities for swine variant flu viruses to make the jump to humans.

 

The CDC describes Swine Variant viruses in their Key Facts FAQ. 

 

What is a variant influenza virus?

When an influenza virus that normally circulates in swine (but not people) is detected in a person, it is called a “variant influenza virus.” For example, if a swine origin influenza A H3N2 virus is detected in a person, that virus will be called an “H3N2 variant” virus or “H3N2v” virus.

 

Although the actual number of human variant flu infections that occur each year is unknown, the CDC has reported 1 or 2 cases each year since 2005.

 

In 2010, that number jumped to 8, and in 2011, to 12.

 

These cases were generally mild, and have primarily involved children under the age of 10.  They have generated enough concern, however, that in late 2011 the CDC announced their intention to work on a candidate vaccine (see H3N2v Vaccine Trials).

 

Last summer the floodgates opened, with more than 300 confirmed cases, nearly all linked to county or state fair attendance.

 

Indiana reported the most cases (n=138), followed by Ohio (n=106).

 

While the H3N2v virus was by far the most commonly reported strain, H1N1v and H1N2v were also detected.

 

 

As to why these swine variant viruses suddenly began jumping to humans with vigor last year? 

 

Starting in 2011, the H1N1v virus was found to have acquired the M (matrix) gene from the 2009 H1N1 pandemic virus. Since then, this M gene has been showing up regularly in all three swine variant viruses (H1N1v, H1N2v, H3N2v).

 

The CDC has speculated that `This M gene may confer increased transmissibility to and among humans, compared to other variant influenza viruses.’

 

In September of last year, the CDC published MMWR: H3N2v Related Hospitalizations In Ohio – Summer 2012 that provided an overview of 11 patients from Ohio that required hospitalization, including the nation’s only H3N2v related fatality.

 

The MMWR report provides a summary of the findings, which reads:

 

What is already known on this topic?

Beginning in the summer of 2012, CDC reported increases in numbers of cases of human infections with influenza A (H3N2) variant (H3N2v) viruses associated with swine exposure at agricultural fairs. Nationwide, 305 cases, 16 hospitalizations, and one death across 10 states have been reported since July 2012.

What is added by this report?

Of 16 patients hospitalized with confirmed H3N2v virus infection, 11 were Ohio residents, including the only H3N2v-associated fatality to date. All but one of the Ohio patients were children, and six were considered high-risk for complications of influenza because they were aged <5 years or had underlying medical conditions; four high-risk persons became ill after indirect contact with pigs. These findings support current CDC recommendations that persons at high risk for complications of influenza should avoid exposure to swine at agricultural fairs this fall.

What are the implications for public health practice?

County and state fairs in the United States continue to occur through the month of October, highlighting the potential for continued cases of H3N2v virus infection. Persons at high risk for complications of influenza should avoid exposure to swine at agricultural fairs. Patients with suspected influenza, including H3N2v, who are hospitalized or at increased risk for influenza complications, should receive antiviral treatment with oral oseltamivir or inhaled zanamivir as soon as possible. Antiviral treatment also is encouraged for outpatients with suspected H3N2v who are not at increased risk for influenza complications.

 

 

While fairs have instituted inspections for any signs of illness in livestock – as we discussed last October (see Asymptomatic Pigs: Revisited) - pigs can carry this virus without showing any outward signs of infection.

 

The CDC offers the following advice for fairgoers and exhibitors.

 

Preventive Actions

CDC Recommendations For People At High Risk:

• If you are at high risk of serious flu complications and are going to a fair where pigs will be present, avoid pigs and swine barns at the fair this year. This includes children younger than 5 years, people 65 years and older, pregnant women, and people with certain long-term health conditions (like asthma, diabetes, heart disease, weakened immune systems, and neurological or neurodevelopmental conditions).

If you are not at high risk, take these precautions:

• Don’t take food or drink into pig areas; don’t eat, drink or put anything in your mouth in pig areas.
• Don’t take toys, pacifiers, cups, baby bottles, strollers, or similar items into pig areas.
• Wash your hands often with soap and running water before and after exposure to pigs. If soap and water are not available, use an alcohol-based hand rub.
• Avoid close contact with pigs that look or act ill.
• Take protective measures if you must come in contact with pigs that are known or suspected to be sick. This includes minimizing contact with pigs and wearing personal protective equipment like protective clothing, gloves and masks that cover your mouth and nose when contact is required.
• To further reduce the risk of infection, minimize contact with pigs and swine barns.

 

Swine are highly susceptible to flu viruses - can serve as `mixing vessels’, allowing viruses to reassort into new hybrid strains – and were the originating host of the 2009 H1N1 pandemic virus.

 

 

The variant viruses that now carry the M gene from the 2009 H1N1 virus are reassortants as well.

 

The concern with these variant swine flu infections, as it is with any novel flu, is that it gives the virus another opportunity to better adapt to human physiology.

 

While humans have a long history of exposure to seasonal H3N2 flu viruses, research has shown only limited community immunity to these variant strains (see CIDRAP: Children & Middle-Aged Most Susceptible To H3N2v).

 

The good news is that while some limited community transmission of these variant flu strains appears to have occurred last summer, sustained and efficient human-to-human transmission did not.

 

Public health officials will no doubt be alert for any new cases -  and more importantly, for any signs that the behavior of the virus has changed - over the coming months.

 

For more on the flu risks from swine reassortments, I’d heartily recommend Helen Branswell’s terrific piece in SciAm  from late 2010 called Flu Factories.

Flu Factories

The next pandemic virus may be circulating on U.S. pig farms, but health officials are struggling to see past the front gate

By Helen Branswell  | December 27, 2010 |

 

And for some of my earlier looks at swine influenza, you may wish to revisit:

 

H3N2v: When Pigs Flu

You Say You Want An Evolution?

The (Swine) Influenza Reassortment Puzzle

Ontario Confirms H1N1v Case

 

Credit Wikipedia

 

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While details are somewhat scant this morning, the Province of Ontario, Canada has announced that they have detected a single of case of H1N1v flu infection in a person who had contact with pigs.

 

First the press release, then I’ll return with a bit more:

 

 

Case of Influenza A H1N1 Variant Detected in Ontario

September 25, 2012 8:00 AM

Today, Dr. Arlene King, Ontario's Chief Medical Officer of Health, issued the following statement on a case of influenza A H1N1 variant detected in Ontario:

 

"An Ontario resident has been confirmed as having been infected with an H1N1 variant (H1N1v) influenza virus. An influenza virus that normally circulates in animals is referred to as a variant virus when it infects humans.

 

This adult male patient became ill after close contact with pigs. He is being treated and closely monitored in a hospital in southwestern Ontario.

 

I would like to reassure Ontarians that this variant influenza virus rarely spreads from animals to humans. Subsequent human-to-human transmission is also rare. I would also like to stress that this is not a food safety issue; the consumption of properly cooked pork continues to be safe.  Proper cooking of meats, including pork, kills all bacteria and viruses.

 

Ontarians should remember that hand washing is the single best infection prevention and control measure against respiratory illnesses such as influenza. Individuals should wash their hands often with soap and running water, or use an alcohol-based hand rub if soap and water are not available.

 

I also would like to remind Ontarians that it is important to get immunized every year with the seasonal flu vaccine when it becomes available each fall. This will protect you against seasonal influenza viruses that are expected to circulate. Everyone six months of age and older should get the seasonal flu vaccine each year.

 

The identification of this case is the result of the strength of our current surveillance system here in Ontario. It is not an unexpected occurrence and there have been a number of human infections with variant influenza viruses in the United States over the past year.

 

I would like to thank health officials in Ontario who displayed the utmost vigilance in identifying, treating and closely investigating this case. Protecting the health of Ontarians is a priority and we will continue to monitor the situation."

 

 

H1N1v is one of the `viral contenders’ I wrote about several weeks ago in An Increasingly Complex Flu Field, and until just over a year ago, was the most commonly reported variant swine flu virus detected in humans since 2005.

 

In the past twelve months, it has primarily been the H3N2v flu virus that we’ve seen jumping from pigs to humans (300+ cases).  But 2 weeks ago, we saw a single case of H1N1v was reported out of Missouri (see The Return Of H1N1v).

 

This was only the second H1N1v case reported in a year, and it was also the second time that the H1N1v virus had been found to carry the M (matrix) gene from the 2009 H1N1 pandemic virus. 

 

This M gene  has been showing up regularly in swine variant viruses (H1N1v, H1N2v, H3N2v) for more than a year. The CDC has previously stated that `This M gene may confer increased transmissibility to and among humans, compared to other variant influenza viruses.’

 

A couple of cases of H1N1v, hundreds of miles apart, while of concern  .  .  .  does not a pandemic make. 

 

But this is further evidence that these variant viruses (H1N1v, H1N2v, H3N2v) continue to evolve, and spread widely in swine, and on occasion manage to make the jump to humans.

 

The concern is that over time one of these viruses may become a more human adapted virus, and begin to spread more easily among the population.

 

So we watch reports such as this with more than a little bit of interest.

 

For more on the flu risks from swine reassortments, I  heartily recommend Helen Branswell’s terrific piece in SciAm  from late 2010 called Flu Factories.

Flu Factories

The next pandemic virus may be circulating on U.S. pig farms, but health officials are struggling to see past the front gate

By Helen Branswell  | December 27, 2010 |

 

And for some of my earlier looks at swine influenza, you may wish to revisit:

 

H3N2v: When Pigs Flu

You Say You Want An Evolution?

The (Swine) Influenza Reassortment Puzzle

The Return Of H1N1v

 

(click to enlarge)

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Yesterday’s FluView report, in addition to updating the number of new H3N2v cases, announced the detection of a single H1N1v flu infection in a person living in Missouri. That patient has fully recovered.

 

H1N1v is one of the `viral contenders’ I mentioned two weeks ago in An Increasingly Complex Flu Field, and until just over a year ago, was the most commonly reported variant swine flu virus detected in humans since 2005.

 

 

This week’s announced case brings to 14 the total number of H1N1v cases reported since 2005.  The last reported case of H1N1v infection came from Wisconsin in December of 2011.

 

Of particular interest, this week’s detection is the second time that the H1N1v virus has been found to contain the M (matrix) gene from the 2009 H1N1 pandemic virus. 

 

Here is how this week’s FluView describes it:

 

Confirmatory testing at CDC identified H1N1v with the matrix (M) gene from the 2009 H1N1 influenza virus in specimens collected from this patient. Cases of H1N1v have been detected previously, and the current case marks the second report of H1N1v with the M gene from the 2009 H1N1 virus.

 

This M gene  has been showing up regularly in swine variant viruses (H1N1v, H1N2v, H3N2v) for more than a year. The CDC has previously stated that `This M gene may confer increased transmissibility to and among humans, compared to other variant influenza viruses.’

 

The $64 question is, what to make of all of this? 

 

Since the outbreak of H3N2v began in earnest in mid July, the CDC and local health departments have stepped up testing for novel or variant flu viruses.

 

And as one might expect, the harder you look, the more you are likely to find.

 

Given the limits of surveillance, testing, and reporting – we really don’t know what the normal `background rate’ of these types of infections are in humans. The smattering of reports since 2005 indicate they are fairly rare, but certainly not unheard of.

 

For now, the H3N2v virus – due to roughly 300 human infections across the Midwest - has captured the bulk of our attention.

 

But these other cases serve to remind us that nature continues to churn out and test new viral variations, and that the next public health threat could come out of left field.

 

The CDC’s assessment on the H3N2v virus reads:

 

It's possible that sporadic infections and even localized outbreaks among people with this virus will continue to occur. While there is no evidence at this time that sustained human-to-human transmission is occurring, all influenza viruses have the capacity to change and it's possible that this virus may become widespread.

So far, the severity of illnesses associated with this virus in people has been similar to the severity of illnesses associated with seasonal flu virus infections. Limited serologic studies indicate that adults may have some pre-existing immunity to this virus while children do not.

CDC is closely monitoring human infections with all novel influenza viruses, including H3N2v viruses, and will provide more information as it becomes available.

 

 

For more on all of this, Robert Roos of CIDRAP NEWS, has an excellent report from last night.

 

Latest variant flu cases include rare H1N1 strain

Robert Roos News Editor