Members of the U.S. Congress - particularly those representing states along the border with Mexico and Canada - are calling on the Obama administration to do more to prevent travelers infected with swine flu from entering the United States.  They made their appeals to Homeland Security Secretary Janet Napolitano during a Senate hearing looking at the federal response to the swine flu outbreak. 

A number of lawmakers have suggested closing U.S. borders as a way to stop swine flu-infected travelers from entering the country.  Their concern was heightened by news that the first death from the virus in the United States was a 23-month-old boy from Mexico who died in Texas.

Testifying before the Homeland Security and Governmental Affairs Committee Wednesday, Homeland Security Secretary Napolitano said closing U.S. borders would cause immense trade and economic disruption and would be ineffective in controlling the spread of the disease.

"Making such a closure now has not been merited by the facts," she said. "It would have very little marginal benefit in terms of containing the outbreak of virus within our own country."

Some senators said if border closures would not be considered, the U.S. government should step up monitoring of travelers entering the United States.

Former Republican presidential candidate, Senator John McCain, is from the southern border state of Arizona.

"I really hope we would pursue vigorously better technological and scientific and closer observation of people going across the border than is presently the case," he said.

Senator Susan Collins, a Republican from the northern border state of Maine, suggested the United States could follow the example of a number of Asian nations.

"Other countries are being far more aggressive in their screening," she said. "Singapore, Thailand, Japan, Indonesia, South Korea, and the Philippines, are all using thermal scanners.  These scanners are able to detect if a passenger has a fever, and then the person could be set aside."

But Secretary Napolitano said such technology is ineffective.

"With respect to the thermal scanners, they are not always accurate," said Napolitano. "They are not as precise as what we wish.  In addition, you have travelers who actually have the flu who do not have a temperature.  So they don't really sift out travelers who are ill from those who are not."

Napolitano said border patrol officers are actively monitoring travelers who wish to enter the United States.   She said those who appear ill are interviewed about their current health status and travel history.

Napolitano said she would consider additional steps to better screen the health of migrant agricultural workers who are given temporary visas.

Meanwhile, Anne Schuchat of the U.S. Centers for Disease Control and Prevention told the panel that efforts are underway to develop a vaccine against the swine flu, and it could be ready as early as September.