“Vertical transmission is lacking, but infected material on an egg shell could spread the virus under the right conditions. But a comprehensive program of quarantine that regulates movement will also include destroying both poultry and eggs and sanitizing areas within the quarantine zone,” he added.

Ficken says the greatest threat is to the poultry industry because highly pathogenic strains of influenza A can spread rapidly and destroy a great number of birds. But he says safeguards at Texas poultry facilities are ever diligent as routine testing and observation is ongoing. In Texas, substantial poultry facilities are located in Gonzales, Waco, Amarillo, and scattered through other areas of the state.  

According to the latest update from Mexico’s animal health officials, based on the latest test results, authorities are sampling birds at about 60 poultry farms near the outbreak area, and quarantine measures are under way in the region, which has about 500 production units. Full gene sequencing and an epidemiologic investigation to determine the source of the virus are also in progress according to Mexican health officials.

Jalisco state, in western Mexico, is the country's top egg producer. Officials have also limited poultry movements near the outbreak area and are testing birds at commercial farms, backyard flocks, and poultry markets. According to the latest OIE update, they are also assessing biosecurity practices and overseeing depopulation efforts at the affected farms.

Officials at OIE said that in some parts of Mexico, large populations of backyard poultry, live poultry markets, and commercial farms exist within close proximity, making inspection and control more difficult during times of disease outbreak.

Ficken said U.S. poultry producers, especially those in Texas, are always cautious about the potential for disease introduction from indirect contact with Mexican poultry.

“The level of security goes up when new virus outbreaks surface,” Ficken said.

John Glisson, DVM, PhD, director of research programs for the U.S. Poultry and Egg Association, said in a recent statement that "the US poultry industry would strongly agree with the idea that the disease should be dealt with quickly and that quarantine of these farms and elimination of infected flocks would be a prudent measure."

Nearly 20 million birds were destroyed in Canada in 2004 when highly pathogenic H7N3 outbreaks in British Columbia’s Fraser Valley occurred, leading to the culling of nearly 20 million birds. In addition, two related human infections were confirmed when poultry workers, both men, had been exposed to infected poultry on the farms. They were the first known H7N3 infections in humans. Both had conjunctivitis with mild flu-like symptoms and recovered without major incident.