By DR. SWATI SHROFF, ABC News Medical Unit

The number of reported cases of a variant flu strain has jumped from 29 to 145 in less than a week, federal health officials reported Thursday.

According to surveillance statistics from the U.S. Centers for Disease Control and Prevention, Indiana accounts for 113 of the confirmed cases of the influenza A strain known as H3N2v, while Ohio has reported 30. Hawaii and Illinois have so far reported one case each.

In a Thursday teleconference, Dr. Joseph Bresee of the CDC's Influenza Division said he believed that over 90 percent of these cases are in children. There have been two hospitalizations so far this year. Both patients, whose identities have not been released, have recovered. There have been no deaths so far.

Bresee said the dramatic increase in the number of cases could be attributed both to more cases being reported, and actual spread of the disease.

Bresee said that those who are infected likely got sick from contact with pigs - a pattern of spread that is not unheard of, since viruses harbored by these animals have been known to infect humans. According to the CDC, this virus probably spreads through the air - not through eating the meat of an infected animal.

So far this year, there has not been any evidence of human-to-human spread, Bresee said, but he added that he anticipates that such cases may arise in the days and weeks to come.

For the time being, he said, people should not panic. "I don't think it's necessary at this point to cancel swine shows," he said.

Rather, the CDC recommends that people practice routine precautions when dealing with animals - in other words, frequent hand washing after being exposed to animals and not eating in areas near where the animals are kept. Bresse said that children, pregnant women and the elderly should try to avoid pigs altogether.

Currently here are two FDA-approved drugs to treat the virus, and they are most effective when started as soon as possible after the illness. Rapid flu tests may not detect the virus, so if you think you may be infected, you should get testing at a state health department.

Bresee said that while the regular flu vaccine probably won't protect people against this variant, "Everybody should get their flu vaccine."