Researchers say a new influenza virus found in Chinese pigs has become more infectious to human beings. They said that the new virus needs to be watched closely should it ever leave China and develop into a possible “pandemic virus.” Health experts said the flu virus does not present an immediate threat to humans, however. A team of Chinese researchers studied pigs from 10 provinces and in a veterinary hospital. The team studied tests of the animals and said they found a total of 179 swine flu viruses. The researchers expressed concern about a virus they called “G4.” It is a version of H1N1, the virus that caused a pandemic in 2009.