Sleuthing Swine Flu

Chance Test Led CDC Investigators to Link Cases in U.S., Mexico

ATLANTA Nancy Cox's phone connection to Mexico kept cutting off. Rain came down in sheets above the Centers for Disease Control and Prevention.

On the other end of the line the night of April 23, Mexican Health Ministry officials anxiously awaited results on a batch of samples they had sent to Atlanta that morning. They were trying to solve a mystery Cox's team had been wrestling with for more than a week: Was the sickness killing young Mexicans related to a strange new flu popping up in the United States?

People across the border were sick and dying, and, in the United States, a novel virus had surfaced in the San Diego area. Using samples from the California cases, the CDC was getting close to determining whether the cross-border illnesses matched.

"I could hear the cracks of thunder," recalled Cox, director of the CDC influenza division, describing the long silent minutes as she and the Mexicans waited for the results.

The answer she delivered was both satisfying and troubling to disease detectives at the CDC, the sleuths who unravel the puzzles surrounding outbreaks of illnesses in the United States and abroad. Yes, she told them, the viruses matched.

What began as a scientific anomaly in this country was now a deadly binational outbreak. And it was spreading fast. In the course of nine days, the virulent bug would jump swiftly from the Americas to Europe, New Zealand, the Middle East and Asia. It would lead to school closures across the United States, the slaughter of hundreds of thousands of pigs in Egypt, and the quarantining of 300 people in a Hong Kong hotel after the disease was diagnosed in a guest.

Although the disease detectives were operating without a health secretary in Washington or a permanent CDC director, Cox, an Iowa native with a love of science and travel, had years of intense preparation for just such an outbreak.

After hanging up the phone, she followed the pandemic playbook, notifying her bosses, who ordered the agency's Emergency Operations Center to ramp up to its highest response level. Within days, CDC would dispatch medical investigators to Mexico, ship new flu-test kits to state health laboratories in the United States and release pharmaceutical supplies from the Strategic National Stockpile to all 50 states.

Then Cox's cellphone rang again, with a call from home. There was more bad news for the soft-spoken blondvirologist who had grown the CDC's flu division from 14 people to more than 100 scientists. Her 1916 Tudor house in the Druid Hills neighborhood of Atlanta had been struck by lightning. Her husband and daughter were safe, but their lovingly restored home was burning to the ground.

A Fortuitous Test

The medical detective work that unearthed the 2009 outbreak of swine-origin influenza A (H1N1) -- more commonly known as swine flu -- began with a bit of happenstance.

On March 30, a 10-year-old boy in Southern California developed a cough and fever. Normally, doctors wouldn't have bothered testing for the flu; they would have given him medicine and sent him home.

But the Naval Health Research Center in San Diego was participating in a clinical trial of new, 30-minute flu tests, so they took a nasal swab and tested it the next day.