LA GLORIA, Mexico — Residents in this community of 3,000 believe their town is ground zero for the swine flu epidemic, even if health officials aren’t saying so.

More than 450 residents say they’re suffering from respiratory problems from contamination spread by pig waste at nearby breeding farms co-owned by U.S. company Smithfield Foods, Inc..

Officials with the company say they’ve found no sign of swine flu on its farms, and Mexican authorities haven’t determined the outbreak’s origin.

The swine flu strain is suspected in more than 150 deaths in Mexico and cases have been confirmed in at least four other countries.

As far back as late March, roughly one-sixth of the residents here in the Gulf Coast state of Veracruz began complaining of respiratory infections that they say can be traced to a farm that lies upwind five miles (8.5 kilometers) to the north, in the town of Xaltepec.

But Jose Luis Martinez, a 34-year-old resident of La Gloria, said he knew the minute he learned about the outbreak on the news and heard a description of the symptoms: fever, coughing, joint aches, severe headache and, in some cases, vomiting and diarrhea.

‘When we saw it on the television, we said to ourselves, ‘This is what we had,” he said Monday. ‘It all came from here. … The symptoms they are suffering are the same that we had here.’

On April 6, the Mexican newspaper La Jornada and journalist Andrés Timoteo Morales broke the story on respiratory illnesses in La Gloria.

Martinez and Bertha Crisostomo, a liaison between the villagers and the municipal government of Perote to which La Gloria belongs, say half of the people from the town live and work in Mexico City most of the week, and could easily have spread the swine flu in the capital, where the largest number of cases have been reported.

Granjas Carroll de Mexico, 50 percent owned by Virginia-based Smithfield has eight farms in the area. Smithfield spokeswoman Keira Ullrich said the company has found no clinical signs or symptoms of the presence of swine influenza in its swine herd or its employees working at its joint ventures anywhere in Mexico.

But in the wake of the epidemic, Smithfield stocks plummeted 12 percent on April 27. Smithfield and other pork producers have been lobbying to get the name of swine flu changed.

Residents say they have been bothered for years by the fetid smell of one the farms, which lies upwind of the community, and they suspect their water and air has been contaminated by waste.

Huge, industrial hog farms have been a growing problem for many communities, including in the United States. The smell and pollution from such large-scale operations have laid waste to whole swaths of rural areas.

When Associated Press journalists entered the farm on Monday, the cars were sprayed with water. Manager Victor Ochoa required the visitors to shower and don white overalls, rubber boots and masks before entering any of the 18 warehouses where 15,000 pigs are kept.

Ochoa showed the journalists a black plastic lid that covered a swimming pool-size cement container of pig feces to prevent exposure to the outside air.

‘All of our pigs have been adequately vaccinated and they are all taken care of according to current sanitation rules,’ Ochoa said. ‘What happened in La Gloria was an unfortunate coincidence with a big and serious problem that is happening now with this new flu virus.’

Martinez said residents have been fighting for years to force the company to improve their pig-waste management. Mexican news media reported that a municipal health official traced the source of a disease outbreak in La Gloria to a type of fly that reproduces in pig waste.

Local health officials and Federal Health Secretary Jose Angel Cordova downplayed claims that the swine flu epidemic could have started in la Gloria, noting that of 30 mucous samples taken from victims of respiratory diseases there, only one — that of 4-year-old Edgar Hernandez — came back positive. The boy later recovered.

But ABC news Nightline reported the state of Veracruz – and not neighboring Oaxaca – was emerging as the “ground zero” for the epidemic because of the large pig farms in the state.

Mexican Agriculture Department officials said Monday that its inspectors found no sign of swine flu among pigs around the farm in Veracruz, and that no infected pigs have been found yet anywhere in Mexico. But Ochoa, the farm manager, said no one from the government has inspected his farm for swine flu.

Juan Lubroth, an animal health expert at the U.N. Food and Agriculture Organization in Rome, supported officials’ assessment of the pig situation and said there is no evidence of sick or dying swine in Mexico.

Dr. Alejandro Escobar Mesa, deputy director for the control and prevention of disease for the state of Veracruz, said the epidemic in La Gloria was a combination of viral and bacterial illnesses, caused by an unusually dry climate.

‘The dust dries up the mucous membranes and facilitates environmental conditions for the transmission of illnesses,’ Escobar said.

But residents here say they are certain that Edgar Hernandez was not the only swine flu victim in their town. Concepcion Llorente, a first-grade teacher in La Gloria, says authorities still owe the town some answers.

‘They said that what we had here was an atypical flu, but if the boy tested positive for swine flu, where did he get it from?’ she said.

AP Medical Writer Margie Mason and AP writers Mark Stevenson and Lisa J. Adams in Mexico City contributed to this report.