April 28 (Bloomberg) -- The influenza strain linked to 152 deaths in Mexico should be called “swine flu,” the World Health Organization said, rejecting calls from pork producers and an animal-health group to rename the virus.

The flu strain that has sickened people in Mexico, the U.S., Canada, Spain, New Zealand and Scotland hasn’t been observed in pigs and appears to advance through human-to-human transmission, Bernard Vallat, the head of the World Organization for Animal Health, said in an interview yesterday.

The nominal link to pigs has prompted Russia and China to ban pork imports from Mexico and parts of the U.S., while Indonesia plans to destroy imported pork and other swine products. Thailand has told officials to call the strain “Mexican flu.” At the World Health Organization, the malady is called “swine flu” because the virus is of the type that affects pigs, said Keiji Fukuda, the WHO’s assistant director general for health security and environment.

“This episode started basically with that name, and the virus that is identified is a swine influenza virus,” Fukuda said on a conference call today. “We don’t have any plans to try to introduce any new names for this disease.”

Pork producers say the “swine flu” tag is hurting their business.

‘Not Justified’

The name “is jeopardizing and may cause serious losses to swine producers all over the world,” wrote Pedro de Camargo Neto, president of the Sao Paulo-based Brazilian pork exporters association, in a letter today to WHO director general Margaret Chan.

As there is no evidence that the virus is transmitted by food, and the virus hasn’t been isolated in any animal, “it is not justified to name this disease swine influenza,” he wrote.

The United Nations’ Food and Agriculture Organization says there is no evidence the influenza strain has entered the human population directly from pigs.

“We’re calling it the ‘swine flu,’” Gregory Hartl, a spokesman for the Geneva-based WHO, said today at a press conference, after being asked whether the illness should be renamed “Mexican influenza.”

The World Organization for Animal Health, a Paris-based intergovernmental group with 174 member countries, has said there is no evidence the virus is able to circulate in animals, and suggests the strain be renamed “North-American influenza.”

“We have not seen any transmission from pigs,” said Hartl of the WHO. “There is no danger from eating pork. All transmissions so far have been human-to-human transmission.”

The Mexican virus has genetic material from swine, bird and human influenza strains, according to Vallat of the animal- health group.

Classic swine flu, common in pigs, isn’t considered serious and transmission from pigs to humans is “exceptional,” Vallat said in an interview yesterday.

Pork is safe to eat and direct contact with pigs isn’t the source of the hybrid influenza, the U.S. National Pork Producers Council said in a statement yesterday.

Smithfield Speaks

Smithfield Foods Inc., the world’s largest pork processor, said yesterday it had found no clinical signs or symptoms of the flu strain in its swine herds or employees at joint ventures in Mexico.

“Based on available recent information, Smithfield has no reason to believe that the virus is in any way connected to its operations in Mexico,” the Smithfield, Virginia-based company said in a statement.

To contact the reporter on this story: Rudy Ruitenberg in Paris at rruitenberg@bloomberg.net.

Last Updated: April 28, 2009 11:56 EDT