A cat found dead in April had been infected with the virulent strain of the bird flu influenza, the government confirmed Monday.

The National Veterinary Research and Quarantine Service (NVRQS) said tests conducted by Chungnam National University showed the cat, found in Gimje located 262 kilometers south of Seoul, died of the H5N1 virus that swept through the country from early April to mid-May.

Gimje, North Jeolla Province, was one of the first regions hit by this year's avian influenza that resulted in a record 8.46 million birds being culled at the cost of 264.1 billion won ($262 million).

``Since the cat died of the bird flu, it probably had eaten a sick bird or came in very close contact with chickens or ducks,'' a quarantine inspector was quoted as saying by Yonhap News. He added that because there has been no reported case of a cat spreading the bird flu, there was no risk to human health.

Cats and dogs are usually not susceptible to the avian influenza, so quarantine officials only check animals that have regular contact with birds.

In contrast, pigs are checked thoroughly because they are more likely to contract the disease. Under existing operating procedures, the movement of pigs is banned during an outbreak.

The NVRQS, which is under the Agriculture Ministry, said earlier in the month that samples from the latest outbreak sent to the U.S. Center for Disease Control and Prevention were confirmed to be from the virulent strain of bird flu. However, it said the particular sub-strain has no prior history of actually causing people to get sick.

South Korea has been hit three times with the bird flu, but humans have not caught the disease.