You can tour Yellowstone National Park and happily call an American bison a buffalo and no one will gore you for it. Even though, technically, you'd be wrong.

And, you can certainly refer to the 2009 H1N1 flu virus as "swine flu." Few will correct you. Even though, technically, you'd be wrong.

Yet there are sticklers, whose ranks can include medical experts, scientists, the Centers for Disease Control and Prevention, a few nitpicking journalists, the secretary of the U.S. Department of Agriculture and pork producers.

Especially pork producers.

Still, as of Monday, the Associated Press' style mavens were sticking stubbornly with swine flu.

Dr. Thomas Kerkering is infectious diseases section chief for Carilion Clinic and a professor for the new Virginia Tech Carilion School of Medicine.

Kerkering commented wryly on the AP's stance.

"That is why they are journalists and not scientists," he said. "The accurate name is actually 2009 H1N1. It is not swine flu."

Tom Skinner, a senior public affairs officer for the CDC, weighed in on the debate. "If we had our say, it would be that people would refer to it as 2009 H1N1," Skinner said. "We understand that there is confusion out there about the name."

Pork noise complaints

And that confusion has hurt domestic pork producers, according to Cindy Cunningham, a spokeswoman for the National Pork Board, because buyers, both nationally and internationally, have mistakenly concluded they could contract the H1N1 virus by eating pork.

"It has had a tremendous impact on pork producers and the pork industry," Cunningham said.

And the industry has been making noise about the misunderstanding.

She said research suggests that actual and projected revenue reductions for pork producers from April 24 -- when the new flu strain was first identified -- to the end of the year now stands at about $2.07 billion.

According to the CDC, "H1N1 viruses are not spread by food. You cannot get infected with novel HIN1 virus from eating pork or pork products. Eating properly handled and cooked pork products is safe."

So, why have pigs and hogs taken a bad rap across the snout?

Originally, the virus was referred to as swine flu "because laboratory testing showed that many of the genes in this new virus were very similar to influenza viruses that normally occur in pigs (swine) in North America," the CDC reports.

But further study revealed that the new virus differs significantly "from what normally circulates in North American pigs," the CDC says. Instead, the H1N1 virus has two genes from flu viruses that normally circulate in pigs in Europe and Asia as well as bird (avian) genes and human genes.

But why 2009 H1N1?

Viruses cause influenza.

The H1N1 is an influenza A virus and all such viruses contain the proteins hemagglutinin, the "H", and neuraminidase, the "N." These proteins occupy the outer coats of flu viruses. Both have several known varieties.

Hemagglutinin enables the virus to attach and infect a cell in the respiratory system. Neuraminidase enables the virus' progeny to escape the host cell and infect new cells.

For H1N1, the numbers refer to a specific form of each protein and the 2009 H1N1 is a new variety. Because it is new, most people have no immunity -- which is why H1N1 can be highly contagious.

Other variations of H1N1 flu viruses, including the so-called Spanish Flu of 1918 and 1919, have been deadly. The H1N1 virus, though highly contagious, has tended toward causing comparatively mild illness, although there are especially vulnerable groups.

For definition of terms associated with flu, go to: www.flu.gov/glossary/index.html