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)

# 6336

 

 

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.

»» Read More

Netherlands: H7 Bird Flu Detected

 

 

# 5445

 

 

Due to its high mortality rate, H5N1 gets most of the world’s attention when it comes to bird flu.  While human infections remain rare, among those diagnosed, roughly 60% succumb to the virus.

 

But H5 isn’t the only avian flu strain we worry about.

 

There are other – less deadly strains – including the H7s, H9s and H11s that have demonstrated the potential to jump to 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.

 

Today, we’ve news of an outbreak of bird flu on a poultry farm near Kapelle, in the Netherlands.  The virus has been identified as H7, but the exact subtype has not yet been established.

 

 

 

First a translation of the statement from the Dutch Ministry of Economic Affairs, Agriculture and Innovation, after which I’ll return with more.

 

 

Bird flu in Zeeland

News item | 03/25/2011

In Zeeland Schore, Chapel congregation is a poultry farm with 127,500 laying hens found bird flu. The H7 is a variant.

 

Because a low pathogenic H7 variant can mutate into highly pathogenic (highly contagious and lethal for chickens variant), the company both a low and a highly pathogenic variant in accordance with European regulations are removed. The new Food Safety Authority to carry out culling on March 25. In the afternoon of March 25 is known whether a low or a highly pathogenic variant,.

 

As of March 25, 2011, is 8.00 hours in an area of ​​one kilometer around the company a ban on transporting poultry, eggs, poultry and poultry manure and litter.

 

The infection probably comes from wild birds excrete the virus in their faeces.

 

 

 

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?

 

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.

 

Three years ago, we saw a study in PNAS that indicated that the H7 virus might be moving more towards adapting to humans.

 

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

 

You can read more about this in a couple of blogs from 2008, H7's Coming Out Party and H7 Study Available Online At PNAS.

 

For more on pandemic threats beyond H5N1 you may wish to revisit:

 

It Isn’t Just Swine Flu

»» Read More

Q-Fever In The Netherlands

 

 

# 4149

 

 

The slightly alarming, if not exactly accurate headline yesterday coming from the Novinite New agency of Sofia read:

 

Killer Goat Flu Appears in Netherlands

There have been press reports of an alarming new epidemic that has struck the Netherlands. Following bird flu, then swine flu, now goat flu is causing panic.

 

According to online news sources, up to 2 300 people have succumbed to goat flu in the country, and six people have died.

 

During a time when tens of thousands of deaths have been attributed to swine flu, a `killer goat flu’ makes for pretty good news copy. But this isn’t a `flu’ at all, and this outbreak isn’t `an alarming new epidemic’ -  it’s been going on now for more than two years.

 

But other than that . . .

 

What this article is referring to in an ongoing zoonotic outbreak of Q-Fever in the Netherlands.   Since Q-Fever isn’t something that a lot of my readers may be familiar with, a little background is in order.

 

Q-Fever is spread by a bacteria Coxiella burnetii (not a virus), often found in Cattle, sheep, and goats, but also found in other livestock and even domestic pets (cats, dogs).  C. Burnetii doesn’t generally cause illness in these animals, although abortions in goats & sheep have been linked to the bacterial infection.

 

The bacteria are excreted in the milk, urine and feces of infected animals, and most abundantly in the amniotic fluid released during birthing.   The bacteria are extremely hardy, and resistant to heat, drying, and many disinfectants.

 

Humans most often contract the bacteria through inhalation of contaminated barnyard dust.   Many infections are subclinical, but some may be very serious; causing severe pneumonia and rarely hepatitis and a form of endocarditis.

 

While treatment with antibiotics generally resolves the infection, some victims develop a chronic (and more dangerous) form of the disease.

 

Q-Fever has been a notifiable disease in the US since 1999, but reporting is not required in many other countries. The disease, therefore is underreported, and its true extent globally is unknown.

 

 

This `alarming new epidemic’ was first noticed in the Netherlands (there have been outbreaks in other countries) in May of 2007, when a local doctor in a rural village in the south of that country reported an unusual cluster of pneumonia cases.

 

At first they were suspected to have due to Mycoplasma pneumoniae, but further testing revealed acute  Coxiella burnetii infection. 

 

As you can see from the graph above, the number of human infections in the Netherlands has grown each year since 2007. 

 

In a normal year (2000-2006) the Netherlands might expect to see 5 to 20 infections with the bacteria.  Currently, they are diagnosing more than 2,000 cases a year.

 

While goats are traditionally considered to be the prime source of this disease, other reservoirs have been identified as well. 

 

For goats, mating generally occurs in the fall (gestation is about 5 months), and so kidding season falls in the spring.

In an attempt to curb the further spread of this disease, the RIVN [Dutch National Institute for Public Health and the Environment] is advising the Health Ministry to order the destruction of all pregnant goats from farms infected with Q-fever.

 

ProMed Mail  has been following the outbreak of Q-fever in the Netherlands since 2007, and has more than one dozen updates on file.   The latest was on December 9th of this year:

 

Archive Number     20091209.4198
Published Date     09-DEC-2009
Subject     PRO/AH/EDR> Q fever - Netherlands (13): control measures

Q FEVER - NETHERLANDS (13): CONTROL MEASURES

Minister of Health Ab Klink and Minister of Agriculture Gerda Verburg  have agreed that on infected farms where animals have not been  vaccinated, all pregnant animals must be slaughtered, whether or not they have the virus [sic; the agent is a bacterium].

 

Q-fever is caused by bacteria (_Coxiella burnetii_) released when pregnant goats or sheep have spontaneous abortions. The disease is prevalent in areas in the southern Netherlands with large-scale goat farms and a relatively dense population. This year [2009] alone, 2200 [in fact, 2293 cases as of 25 Nov 2009] people have contracted it, most of them in the southern rural province of Brabant. At least 6 people have died.

 

While these control methods are hoped to reduce the spread of this bacterial disease, the editors of ProMed Mail remind their readers that goats may not be the only source of infection:

 

While small ruminants, namely goats and sheep are traditionally regarded as the main potential source of human infection, other animals, such as cattle, dogs and cats, are not to be disregarded. In urban areas, littering cats have been seriously suspected as a significant source of human infection.

 

In the Dutch context, the earlier (1997) review "Q fever in Europe" is of interest. It included the following text: "In some human cases, no relation with "classical" sources can be found, and possible new sources must be sought. In a serological study of dogs and cats [in central Netherlands, 1992], 13.2 percent (91/688) of dogs and 10.4 percent (46/441) of cats were found to be positive for specific antibodies against _C. burnetii_. This implies that cats and dogs may be a source of infection.

 

It should be noted that Q-fever can also be spread by ticks, although human infection via that route is considered rare.   Since most cases of Q-fever result in mild or sub-clinical infections, the true extent of the spread of the disease is unknown.

While concerning, the potential for the spread of this disease is very low compared to influenza.  According to the University of Wisconsin’s VetMed page on Q-Fever:

 

Reports of human-to-human transmission are extremely rare, but C. burnetii has been isolated from human milk and human placental tissues, and there are reports of transmission to physicians during abortion procedures and autopsies.

 

So the good news in all of this is, Q-fever doesn’t have pandemic potential, even if it can present serious localized problems.  

 

For more on Q-Fever you may wish to check these resources:

 

Backgrounder: Q Fever

Emedicine Overview of Q-Fever

 

CDC Q-Fever Information

»» Read More