China is now dealing with another disease outbreak — this one mostly affecting animals, but also potentially deadly among people. The Ministry of Agriculture said late Saturday that a fresh outbreak of a lethal form of influenza had been found in poultry in the southern province of Hunan, and that officials had ordered the slaughter of 17,828 chickens. China has previously dealt with several bird flu outbreaks. In the new case, the H5N1 bird flu virus was found at a farm in the city of Shaoyang. The farm had 7,850 chickens, and more than half have died from the bird flu, the ministry said. It called the strain “highly pathogenic.” Although bird flu poses more of a danger to poultry than humans — it is not easily transmissible among people — the World Health Organization has called on countries to be on guard. China is also grappling with an African swine fever epidemic that has infected tens of thousands of pigs and could stoke worries about the food supply.