While the official tally of confirmed U.S. swine flu cases topped 4,700 on Friday, experts at the Centers for Disease Control and Prevention now estimate the true number of infections at more than 100,000 nationwide. Also on Friday, health officials announced two new deaths linked to the H1N1 virus, bringing the nationwide total to five, according to a report carried today by Associated Press. "Today we had our fourth death reported from Maricopa County in Arizona," Dr. Daniel Jernigan, from CDC's Influenza Division, said during an afternoon teleconference Friday. "There are more deaths and hospitalizations that we are monitoring," he said. The Arizona patient, a woman in her late 40s with an underlying lung condition, died last week, the Associated Press reported. Also on Friday, health officials in Nueces County, Texas, announced that state's third swine flu-related death, an unidentified 33-year-old man with multiple underlying health conditions who died May 5 or 6, according to the AP. The two new fatalities come after two others in Texas and one in Washington state. All of the victims had underlying health problems besides the flu. Most cases of swine flu occurring in the United States appear to be mild, health officials said.