Bad Bentheim, Germany
#18,164
Following yesterday's announcement of an H7 outbreak on a German poultry farm on the border with the Netherlands we learned overnight that the virus has been sub-typed as HPAI H7N5. While we've seen reports of LPAI H7N5 in wild birds in the past, this is - as far as I can tell - the first detection of an HPAI version.
So far, much of the information we are seeing is coming from the Netherlands, which suffered a historic outbreak of H7N7 in 2003, which resulted in at least 1,000 (mostly mild) human infections, and the loss of 30 million birds.
The following is the translated text of a letter sent from the Dutch Minister of Agriculture to their House of Representatives.
Date 4 July 2024
Our feature
DGA-DAD/63213730
Subject Information about the bird flu outbreak in Germany on July 2, 2024
Dear Chairman,
With this letter I inform the House of Representatives about the outbreak of highly pathogenic bird flu at a laying farm in Bad Bentheim, Germany, just across the border with the Netherlands.
It was quiet for a long time regarding the number of bird flu outbreaks in Europe. In the Netherlands, the last outbreak was on December 2, 2023. Unfortunately, on July 2, the Chief Veterinary Officer of Germany reported that a bird flu infection had been detected at a laying hen farm in Bad Bentheim, Germany.
The location is close to the Dutch border. This time it concerns a different serotype than the H5N1 variant that has led to many outbreaks in recent years. This company in Germany concerns a highly pathogenic serotype H7N5, which has not previously led to outbreaks in Europe.
Following this outbreak, Germany must establish a 10 km restriction zone set, as prescribed by European Regulation (EU) 2020/687. Because part of that zone falls on Dutch territory, I established a restriction zone in the Netherlands on July 2. The regulations for this and the press release were published on that day (Bird flu detected in border area Germany | News item | Rijksoverheid.nl).
The two poultry farms located in the 3 km zone were, in accordance with current policy, examined for bird flu by the NVWA on July 3. The regular measures apply in the 10 km restriction zone, including transport restrictions for poultry and poultry products.
Commercially kept poultry in the 10 km zone must be caged. The area will remain intact for at least 30 days. The German authorities will conduct a tracing investigation. The source of the infection and the route of infection are now unknown, but I consider wild birds the most likely source of infection. It is known that many serotypes, mostly of a low pathogenic variety, circulate in wild birds. A low pathogenic variant of the H7 type may have led to infection of poultry on the farm, where it subsequently mutated into a highly pathogenic variant.
Such a scenario occurred in the Netherlands in 2003 with another H7 variant (H7N7), which led to a large number of outbreaks. The German tracing research into the infection may provide more information about the situation, the source of the infection and the virus characteristics.
No dead wild birds with HPAI have recently been found in the Netherlands, and monitoring of living wild birds in June showed no evidence of virus circulation of an H7 serotype. I have decided to ask the animal diseases expert group to conduct a risk assessment of the situation in the Netherlands.
I will use their assessment to determine whether additional measures are necessary in the Netherlands to reduce the risk of an outbreak. I will inform the House of Representatives about this.
In January this year, my predecessor informed the House of Representatives about the progress regarding the Intensification Plan for Bird Flu Prevention (Parliamentary Paper 28807, no. 296). In May this year, the House of Representatives was informed about the progress of the vaccination process (Parliamentary Paper 28807, no. 300).
This step-by-step plan and the actions in it are about vaccination against the H5N1 serotype. No vaccine is authorized against an H7 serotype in the European Union. I will bring the outbreak in Germany to the attention of the vaccine manufacturers.
I will inform the House of Representatives about new developments.
Yours faithfully,
Femke Marije Wiersma
Minister of Agriculture, Fisheries, Food Security and Nature
The presumed origins of this outbreak was the introduction of an LPAI H7N5 virus - which can spread benignly through wild birds - into a poultry flock, where it mutated into an HPAI virus. While the exact process isn't fully understood, this in a known phenomenon (see graphic below), and is the reason why LPAI H5 and H7 viruses are treated as such a serious threat by WOAH/OIE.
While China's H7N9 virus proved exceptionally deadly for humans (killing roughly 40% of those hospitalized between 2013-2018), H7 outbreaks elsewhere in the world have tended to produce relatively mild symptoms in humans.
A few examples include:
- NYC's 016 dramatic H7N2 outbreak in cats, and spillover into animal shelter workers (see J Infect Dis: Serological Evidence Of H7N2 Infection Among Animal Shelter Workers, NYC 2016)
- 3 mild cases of LPAI H7N7 in Italy in 2013 (see ECDC Update & Assessment: Human Infection By Avian H7N7 In Italy).
- In 2006 1 person in the UK was confirmed to have contracted H7N3, and the following year, 4 people tested positive for H7N2 – both following local outbreaks in poultry.
- The Fraser Valley H7N3 outbreak of 2004 resulted in at least two human infections, as reported in this EID Journal report: Human Illness from Avian Influenza H7N3, British Columbia.
In 2018 a woman in Jiangsu Province, China was seriously infected by an H7N4 virus (see WHO Update & Risk Assessment On Avian H7N4), spending 21 days in the hospital.
A 7th CVV - for the H7N4 virus - is currently in development.
For now, the big concern with this outbreak is the close proximity of a large number of poultry farms, and the next few days should tell us whether this is a one-off outbreak, or the start of something bigger.
Stay tuned.