sciencehabit writes: A new, deadly H5N8 strain of avian influenza penetrated the biosecurity defenses of a National Institute of Animal Science (NIAS) campus near Seoul, prompting authorities to cull all of the facility's 11,000 hens and 5000 ducks. The incident highlights the difficulty of protecting poultry farms from circulating avian influenza viruses. “We are taking this situation very seriously," said Lee Jun-Won, deputy agriculture minister, at a press conference yesterday in Seoul. He noted that NIAS has the country’s most secure facilities and most vigilant staff. Lee said they were looking at three possible routes the virus could have taken onto campus: wild birds, NIAS vehicles, and supply deliveries. "We will determine the reason for the infection, and we are going to hold those responsible accountable," he said.