Thursday, March 05, 2009

Hong Kong: Wild Birds Linked To Recent Bird Flu Outbreak In Poultry

 


# 2864

 

 

Last December, for the first time in six years, Hong Kong experienced an H5N1 outbreak on a poultry farm.  Since their first experience with the virus in 1997, which claimed the lives of 6 residents,  Hong Kong has been particularly diligent in their eradication and control efforts.

 

Poultry are routinely vaccinated against the virus with an H5N1 vaccine purchased from the Netherlands.   The December outbreak raised alarms because those birds had supposedly been vaccinated, leading some scientists to worry that the virus had mutated.

 

Subsequently, scientists reported the virus had not `obviously mutated', although no explanation was offered as to how vaccinated birds contracted the virus.  

 

 

Dead chickens get H5N1 mutation all-clear


Adele Wong
Friday, December 19, 2008

The H5N1 virus found in dead chickens in a Yuen Long farm had not mutated, Undersecretary for Food and Health Gabriel Leung told the Legislative Council's panel on food safety and environmental hygiene yesterday.

 

The genetic sequencing of the bird flu virus detected in the farm on December 9 did not contain obvious differences from previous viruses, Leung told the panel.

 

Leung also said more tests were needed to find out how the chickens contracted the virus.

 

 

Today, Hong Kong officials are addressing the other unknown about this outbreak. 

 

Just how did the virus get into the poultry farm?  One that supposedly practices sophisticated biosecurity?

 

Early on there was speculation that it was introduced through the smuggling of infected eggs from mainland China, but that was reportedly investigated and ruled out.

 

The investigation has settled on wild birds as being the most likely vector, although they admit that the evidence is circumstantial, and that `other sources of the virus, such as rodents or contaminated clothing of farm staff, could not be ruled out.'

 

This report from Radio Australia News.

 

 

 

Hong Kong birdflu outbreak blamed on wild birds

At least 250 people have died of bird flu since it emerged in Asia in 2003. Outbreaks of the disease have forced the culling of millions of poultry in the region. [Reuters]

PHOTO

At least 250 people have died of bird flu since it emerged in Asia in 2003. Outbreaks of the disease have forced the culling of millions of poultry in the region. [Reuters]

 

An outbreak of the deadly H5N1 bird flu virus at a Hong Kong farm last year which led to the slaughter of 90,000 chickens was most likely spread by wild birds.


A team of government scientists has been investigating the outbreak near the border with China last December, which was the first at a Hong Kong poultry farm in six years.


"As with many epidemiological studies of this nature, it is difficult to determine the exact cause of the outbreak," leading scientist Thomas Sit said.


But he said the virus was "most likely to have been introduced to the farm by wild birds", playing down concerns the outbreak might have represented a mutation in the virus.


He said dust and dirt near the entrance of an affected chicken shed could have been contaminated by droppings from infected wild birds and blown into the shed area by a gust of wind.


However the scientists say other sources of the virus, such as rodents or contaminated clothing of farm staff, could not be ruled out.