Netherlands: LPAI H7 Bird Flu Identified In Turkeys

 

Photo Credit – FAO

 

UPDATE:  The OIE REPORT filed for this incident now identifies this as an H5N2 (not H7 as previously reported) avian influenza strain. (Link)

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Although this news broke yesterday, I was away from my desk most of the day, and was unable to blog it.  Early reports had suggested an H5 strain, but the most recent reporting (via Reuters) is that a low pathogenic H7 avian influenza virus is the culprit.

My thanks to the reader who forwarded this Reuters story to me. I’ll return with a little background on the H7 avian viruses.

 

 

Dutch cull 42,700 turkeys after bird flu found

Reuters

12:06 p.m. CDT, March 19, 2012

AMSTERDAM (Reuters) - Dutch authorities said 42,700 turkeys have been culled at a farm in the south of the country after a mild variant of the H7 bird flu strain was reported over the weekend.

(Continue . . . )

 

 

While we pay greatest attention to the H5N1 virus due to its observed high mortality in the roughly 600 human cases we’ve identified, there are other – less deadly -avian influenza strains that have been known to infect humans.

 

Currently, H5s and H7s are both reportable diseases in poultry, due to their ability to mutate from a low pathogenic virus to highly pathogenic virus.

 

 

Below you’ll find a chart lifted and edited from CIDRAP’s excellent overview Avian Influenza (Bird Flu): Implications for Human Disease  showing non-H5N1 avian flu infections in humans over the past decade.

 

 

Perhaps the most notorious outbreak of H7 in humans occurred in 2003 in the Netherlands.  It  produced (mostly mild) symptoms in at least 89 people, but did cause 1 fatality. 

 

CIDRAP describes it this way:

During an outbreak of H7N7 avian influenza in poultry, infection spread to poultry workers and their families in the area (see References: Fouchier 2004, Koopmans 2004, Stegeman 2004). Most patients had conjunctivitis, and several complained of influenza-like illness. The death occurred in a 57-year-old veterinarian. Subsequent serologic testing demonstrated that additional case-patients had asymptomatic infection.

 

In 2006 and 2007 there were a small number of human infections in Great Britain caused by H7N3 (n=1)  and H7N2 (n=4), again producing mild symptoms.

 

Since surveillance is – at best - haphazard (or even non-existent) in many parts of the world,  how often this really happens is unknown.

 

For now, H7 avian influenzas pose only a minor public health threat. 

 

Since the H7 viruses generally produce mild symptoms in humans, you may be wondering why all the fuss over an outbreak of H7?

 

First, eradicating the virus can be time consuming, and horrendously expensive.  In 2003 outbreak in the Netherlands mentioned above required the culling of 30 million birds.

 

And second, the H7s, like all influenza viruses, are constantly mutating and evolving.

  

While considered mild today, there are no guarantees that the virus won’t pick up virulence over time, or reassort with another `humanized’ virus and spark a pandemic.

 

In fact, four years ago we saw a PNAS article that suggested that some `humanization’ of the virus was occurring.

 

Contemporary North American influenza H7 viruses possess human receptor specificity: Implications for virus transmissibility

 

As we all know, the last pandemic came out of left field; from a region of the world (North America), host species (swine), and influenza strain (H1N1) considered unlikely to spark a global epidemic.

 

Which is why even relatively benign avian strains are regarded as potential threats, and dealt with swiftly.

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Australia Finds LPAI H5 On Two Duck Farms

 

 

Victoria, Australia – Credit Wikipedia

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Overnight the wire services have been abuzz with news of the discovery of a low pathogenic form of of avian influenza (LPAI) on a couple of duck farms in Victoria, Australia.  

 

A few samples of the media coverage include:

 

Chicken safe to eat, despite Victorian bird flu

 

Bird flu detected in ducks near Melbourne

 

Bird flu outbreak sparks duck cull

 

While all of the stories (rightfully) point out that this is a low-path strain - and not considered to be a serious health hazard to humans – noticeably absent from any of the above reports is any identification of the strain of avian flu detected.

 

There are, of course, a great many LPAI strains out there, but only the H5s and H7s are required to be reported to the OIE because of their potential to evolve into a more pathogenic strain.

 

For a good background on avian influenza in agriculture I would invite you to visit CIDRAP’s  Avian Influenza (Bird Flu): Agricultural and Wildlife Considerations - Last updated January 21, 2012

 

 

A visit to Victoria’s Department of Primary Industries website solves the subtype mystery (stated to be H5), which is included in the following statement by Victoria’s Chief Veterinary Officer, Dr Andrew Cameron.

 

 

Chief Veterinary Officer’s Avian Influenza Update

27 January 2012

The Department of Primary Industries (DPI) has quarantined a commercial duck farm in two locations north-west of Melbourne after birds there tested positive to Low Pathogenic Avian Influenza (LPAI).

 

DPI Chief Veterinary Officer, Dr Andrew Cameron said analytical tests carried out at the Australian Animal Health Laboratory at Geelong, Victoria, had given a positive response to low pathogenic H5 subtype avian influenza virus, prompting authorities to act immediately.

 

This low pathogenic subtype of avian influenza is not the highly pathogenic H5N1 virus affecting poultry and humans throughout much of Asia. The wider community is not at risk from this incident.”

 

Dr Cameron has said, “The virus is relatively harmless now, but we do not want to take the risk it could linger in bird populations and mutate to a more virulent strain.”

 

The farm has been placed under strict quarantine and no birds, eggs, meat or associated equipment can be taken off the property.

 

The Consultative Committee for Emergency Animal Diseases (CCEAD) will meet on Friday 27 January, to discuss containment, surveillance and next steps.

 

Victoria’s Acting Chief Health Officer Dr Rosemary Lester reinforced the assurances that the public is not at risk. “Our poultry meat and eggs continue to be safe under normal food handling and cooking arrangements” she said.

 

For further information about Avian Influenza review the links below or call 1300 135559.

 

In Victoria, strict biosecurity guidelines apply to all poultry farms to prevent poultry, feed and water from mixing with wild birds. This minimises the risk of disease. It is a good practice to protect the food and water used for your pet birds and to ensure wild birds cannot come into contact with them. Finally, it is important for all of us to follow good hygiene practices to minimise the risk of any disease, such as washing hands after contact with animals and birds and, in particular, not handling sick or dead birds. These are sensible precautions that will prevent many diseases, not just AI.

Dr Andrew Cameron
Chief Veterinary Officer, Victoria

 

You’ll find another press release on this site, providing greater detail on the steps that are being taken to eradicate this virus.

 

Media release: Swift Action to Contain Avian Influenza

27 January 12

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South Korea: LPAI Detected

 

 

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Chuncheon, Gangwon Province

 

We’ve very little information right now, other than this report from the Chosun Ilbo.    It doesn’t even tell us what strain of avian influenza virus was detected, only that it was low path.

Assuming that it is an H5 or an H7 virus, the OIE should receive notification in the next couple of days.

 

 

Fresh Bird Flu Outbreak Worries Health Officials

The resurgence of bird flu in Chuncheon, Gangwon Province is causing concerns to health authorities as the H1N1 flu scare continues. A low pathogenic bird-flu virus was found in excrement of migratory birds in a reservoir in Chuncheon.

 

Despite the low infectiousness, health authorities claim they cannot rule out danger to humans or mutation and pledged to stay alert.

 

The worst-case scenario is that patients infected with the H1N1 virus could additionally contract bird flu, leading to a mutation that gives rise to a new supervirus. "But that doesn't necessarily mean that a new form of virus will be formed when the bird flu virus appears amid the spread of H1N1 virus," a health official said. "But if that did actually happen, the situation we've seen so far would be a mere shadow of what lies ahead. That's why we have to take preventive measures."

 

Disease prevention headquarters on Tuesday said it will vaccinate some 40,000 fowl breeders from the third week of this month instead of December as originally planned.

 Nov. 11, 2009 11:43 KST

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