WHO spokesman Dick Thompson said the agriculture industry and the U.N. food agency had expressed concerns that the term "swine flu" was misleading consumers and needlessly causing countries to ban pork products and order the slaughter of pigs.
"Rather than calling this swine flu ... we're going to stick with the technical scientific name H1N1 influenza A," Thompson said.
Egypt began slaughtering its roughly 300,000 pigs Wednesday even though experts said swine flu is not linked to pigs and not spread by eating pork. Angry farmers protested the government decree.
In Paris, the World Organization for Animal Health said Thursday "there is no evidence of infection in pigs, nor of humans acquiring infection directly from pigs."
Killing pigs "will not help to guard against public or animal health risks" presented by the virus and "is inappropriate," the group said in a statement.
China, Russia, Ukraine and other nations have banned pork exports from Mexico and parts of the United States, blaming swine flu fears.
Most in the Muslim world consider pigs unclean animals and do not eat pork because of religious restrictions. The farmers in Egypt raise the pigs for consumption by the country's Christian minority.
WHO also reported the number of confirmed swine flu cases rose to 257 worldwide Thursday, with cases in Mexico rising to 97 from 26, with seven deaths. The WHO confirmed tally from the United States now stands at 109, with one death.
Other confirmed cases include 19 in Canada, 13 in Spain, eight in Britain, three each in Germany and New Zealand, two in Israel and one each in Austria, Switzerland and the Netherlands.
Thompson told reporters in Geneva that at least one of the Spanish cases involved a person who had not traveled to Mexico. Spanish officials said that was a man who apparently got the virus from his girlfriend, who recently returned from Mexico.
WHO raised the pandemic flu alert to phase 5 on Wednesday, one step away from the highest level indicating a global outbreak. WHO flu chief Keiji Fukuda said Thursday there were no indications in the past day that would prompt the U.N. body to raise the alert further.
To move from pandemic alert level 5 to level 6 means that WHO believes there is evidence of big outbreaks in at least two world regions and a pandemic is under way.
Fukuda said the jump in confirmed cases from Mexico was probably the result of scientists working their way through a backlog of untested samples from suspected cases.
"They are going through several thousands of laboratory specimens right now," he said.
WHO has started distributing its stockpile of 2 million courses of the antiviral drug Tamiflu to regional offices, which will decide where to send them next.
Many of those drugs will go to developing countries that don't have stockpiles of their own and some will be sent to Mexico, Fukuda said, without providing figures.