Hong Kong health officials slaughtered nearly 20,000 birds after they discovered a dead bird in a poultry market was infected with the virus that causes bird flu, according to Bloomberg News.
The culling is one of a series of precautionary steps the government announced. Authorities also tested birds from the city's 30 chicken farms, and so far, no other birds tested positive for the virus, known as H5N1.
The city will also close the market where the infected chicken carcass was found until Jan. 12, and there is currently a ban on importing live poultry. They are also testing people who may have come into contact with the birds.
In addition, there is a ban on the sale and import of live poultry for three weeks.
Despite the safety measures, a bird flu expert at the University of Hong Kong stressed that while there is a need to be cautious, there is no need to panic.
The first recorded cases of H5N1 in humans came from Hong Kong in 1997, and in response the government ordered the slaughter of all poultry in the city.
H5N1 is a potentially lethal virus and has the capacity to become a global pandemic, says the U.S. Centers for Disease Control and Prevention. H5N1 does not normally infect humans unless they are in close contact with birds that have it, but according to statistics from the World Health Organization, there have been more than 500 human cases of bird flu and more than 300 deaths.
After the outbreak in Hong Kong in 1997, the virus didn't re-emerge until 2003, when it began to spread across Asia, Europe and Africa. Millions of birds have been infected and have either died or been killed in an effort to stop the spread of the virus.