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

»» Read More

The Return Of H1N1v

 

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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

»» Read More