COLUMBIA — So far, Boone County has not had a confirmed case of H1N1, or swine flu, though not everyone with symptoms is being tested, Columbia health officials said Thursday.
There were 29 confirmed cases in Missouri as of Thursday, according to the Missouri Department of Health and Senior Services Web site.
Genalee Alexander, a spokeswoman for the Columbia/Boone County Department of Public Health and Human Services, said none of those cases were in Boone County.
The virus is the suspected cause of death of a 44-year-old St. Louis County man on May 19. His death has not yet been officially connected to swine flu; confirmation from the Centers for Disease Control and Prevention is pending. It would be the first death in the state from swine flu.
In early May, the CDC gave the state the necessary equipment to confirm H1N1 influenza cases, Alexander said. Currently, those with flu-like symptoms are only being tested if the case is severe enough for hospitalization, or if they have had direct contact with someone who has a confirmed case, Alexander said.
“The testing has changed as it has been found that the symptoms are more mild,” she said.
Only people with acute cases are being tested, so the actual number of cases in the state is probably higher, said Michael Cooperstock, medical director of the Infection Control Department for MU Health Care. That holds true with the seasonal flu as well, he said.
“Two weeks ago, about half the tested cases were H1N1, and half were normal influenza,” Cooperstock said, speaking in general terms about the virus and not its incidence locally. “Now, about three-fourths of (tested) cases are H1N1.”
During the summer months, there is usually a decline in the number of confirmed cases of seasonal influenza.
“H1N1 appears to be more transmissible,” Cooperstock said. “We never see this kind of spread for the normal flu during the spring and summer season.”
H1N1 differs from the normal flu because it appears that much of the population has no immunity, he said. Those older than age 50 might have a slight immunity, possibly because they were exposed to a similar strain earlier in their life, he said.
According to the World Health Organization, the transmissibility of H1N1 ranges from 22 percent to 33 percent, compared with 5 percent to 15 percent for the seasonal flu.
“If it’s true that this is more contagious, there may be a huge outbreak in the Southern Hemisphere,” Cooperstock said. It is winter there now, and the air is drier, he said.
The Health Department is in communication with the CDC to take any necessary precautions, Alexander said, and has stepped up its disease surveillance.
The Associated Press contributed to this report.