New cases of the West Nile virus have been confirmed in several states. In Louisiana, Georgia, Florida and Mississippi, several birds and other animals have tested positive for the virus, while health officials in Louisiana are looking into what may be the first human cases this season. With spring barely underway, scientists agree that the high number of infections in birds this early in the year suggests the West Nile season will be a bad one. "We don't know what this year will bring, but this is obviously not good news that we're seeing birds at so many locations and in so many different states," says epidemiologist Mike Bunning of the Centers for Disease Control and Prevention. Researchers at Acambis hope to begin clinical trials of a genetically engineered West Nile virus vaccine for humans this summer, while wildlife centers, zoos, and horse owners are giving exotic birds and other animals an equine vaccine.