The number of confirmed swine flu cases in the United States jumped Sunday to 245 in 35 states, but officials said that's largely from catching up on a backlog of lab tests rather than a sudden spurt in new infections. Dr. Anne Schuchat of the Centers for Disease Control and Prevention (CDC) in Atlanta told reporters that she expects “ the numbers to jump quite a bit in the next couple days.” The new number also reflects that “we do think this virus is fairly widespread,” she said. “Virtually all of the United States probably has this virus circulating now. That doesn't mean that everybody's infected, but within the communities, the virus has arrived.” Early Sunday, the CDC updated its number to 226 cases in 30 states, up from 160 in 21 states. Later, five more states reported confirmed cases, and new illnesses elsewhere were added to the tally. Mexico's health secretary said Sunday that his country's outbreak is “now in its declining phase,” but Schuchat noted that the United States got off to a later start. “We believe we are just in the upswing here,” she said. Scientists are still gathering information on how severe the nation's 30 hospitalized cases are, she said. They are mostly older children and young adults, in contrast to ordinary flu, which tends to send the elderly and very young to the hospital, Schuchat said. The only swine flu death in the U.S. is that of a Mexican toddler who was visiting Texas.