Friday, February 13, 2015

ECDC: Rapid Risk Assessment On LPAI H7N7

image

# 9707

 

Up until two years ago, human infection with H7 avian viruses were both rare, and almost always mild.  Often little more than mild `flu-like’ symptoms and/or conjunctivitis. 

 

The one notable exception occurred in 2003 when a largest known outbreak of H7N7 infected 89 people, one of whom died (see Eurosurveillance Journal Human-to-human transmission of avian influenza A/H7N7, The Netherlands, 2003).


When H7N9 showed up unexpectedly in China two years ago, it was the first time we’d seen a highly pathogenic (in humans, yet LPAI in birds) H7 virus, sporting an impressive mortality rate. 

 

Suddenly H7 avian viruses were due a lot more respect.

 

But, except for the Asian H7N9 virus, the remainder of the avian H7 viruses appear to pose only a minor human health threat at this time.  Viruses can change over time, hence the need for a qualifier.


With the recent outbreak of H7N9 in UK poultry, the ECDC has produced an updated Rapid Risk Assessment on the human health risks for Europe.  First their brief summary, followed by a link to the full document, and some excerpts:

Low risk to public health in the EU from low pathogenic avian influenza A(H7N7) viruses

13 Feb 2015

On 2 February 2015, British authorities reported an outbreak of low pathogenic avian influenza virus A(H7N7) on a chicken farm in Hampshire in the United Kingdom. Culling of the birds in the affected holding has started, with restriction and surveillance zones established, and investigations into how the birds became infected have been initiated.

Three persons who had been exposed to the flock reported an influenza-like illness or conjunctivitis, however no human infections with A(H7N7) or other respiratory viruses were identified.

Groups at risk for infection include people with occupational exposure to infected poultry, e.g. during the culling and destruction process when there are outbreaks on poultry farms. However, the risk for zoonotic transmission to the general public in EU/EEA countries is considered to be extremely low.

Outbreaks in poultry holdings caused by low pathogenic avian influenza A(H7N7) viruses have been reported previously in Europe, causing infections in humans occupationally exposed to infected poultry . Such infections caused mild disease with influenza-like symptoms or conjunctivitis.

Read the risk assessment

Main conclusions and recommendations


On 2 February 2015, British authorities reported an outbreak of low pathogenic avian influenza virus A(H7N7) on a chicken farm in Hampshire in the United Kingdom. Culling of the birds in the affected holding has started, with a restriction zone established, and investigations into how the birds became infected have been initiated. The virus has been analysed genetically and does not contain key mutations associated with increased risk for zoonotic infection.


Outbreaks in poultry holdings caused by low pathogenic or high pathogenic avian influenza A(H7N7) viruses have been reported previously in Europe, as well as human infections with low pathogenic avian influenza virus  A(H7N7). Such infections generally cause mild disease with influenza-like symptoms or conjunctivitis.


The group at risk for infection includes people with occupational exposure to poultry. This group should be made aware of the clinical features of infection, and advised to alert authorities and healthcare providers about  any relevant exposure if they develop influenza-like illness or other symptoms.


There is a low risk of zoonotic transmission to people who are directly exposed to infected birds during the culling and destruction process when there are outbreaks in poultry farms. The risk can be minimised if the exercise is performed under the safety measures recommended in Directive 2005/94/EC. Persons with direct contact to infected poultry before or during culling and disposal should be monitored for symptoms, and postexposure antiviral prophylaxis should be considered.


The risk for zoonotic transmission to the general public in EU/EEA countries is considered to be extremely low.

image

No comments: