The H1N1 (swine) flu strain that has infected almost 4,300 people in 33 countries did not come from hogs at a Smithfield Foods operation in Mexico, according to Mexico’s agriculture department.

Test results released May 14 by the Mexican Ministry of Agriculture, Ranching, Rural Development, Fisheries and Food confirmed that the H1N1 influenza A virus was not found in pigs at the Granjas Carroll de Mexico farm in Veracruz. The pigs also tested negative for other viruses.

National Pork Producers Council (NPPC) welcomed the news, but said the damage to the U.S. pork industry by wrongfully labeling the strain “swine” flu has already been done.

“Before the flu outbreak, pork producers were losing money, but things were looking up because we were heading into the grilling season,” reports NPPC CEO Neil Dierks. “When this flu was misnamed, things went south, and producers’ losses nearly doubled.”

On April 24, the first day the flu coverage received media attention, pork producers were losing $10.91/pig. Two weeks of coverage on “swine” flu dramatically dropped pork prices, with producers losing an average of $20.60/pig or nearly $8.4 million a day.

Pork price drops were attributable to a slump in domestic demand as well as import bans by several U.S. pork importers, including China and Russia. Russia’s ban now is limited to 11 states, most of which are not major pork producers. At least a dozen countries that banned or announced bans of U.S. pork have now reversed those decisions.

“Speculation on the H1N1 flu’s connections to the Mexican farm specifically, and to hog farms generally, would be irresponsible and would only bring injury and pain to pork producers for something that was not of their making,” Dierks says.