In Mexico, an Unusual Flu Season Was a Sign of Something Ominous
Sunday, May 3, 2009
MEXICO CITY, May 2 -- For seven tense days, the nation's top epidemiologist, Miguel Ángel Lezana, waited for the answer to a deadly mystery. When the news finally came April 23, it was as bad as he had feared.
That afternoon, Lezana learned in a conference call with his counterparts in the United States and Canada that 26 of the roughly 50 saliva swabs and lung samples sent to Winnipeg, Manitoba, had tested positive for a previously unknown swine flu virus.
"At that moment, we learned that we have this new strain in Mexico," said Lezana, director of the National Center for Epidemiology and Disease Control. "We started to move ahead immediately. I'm talking about hours. The response was immediate."
The positive test for swine flu launched a public health emergency in Mexico that has led to the shutdown of all nonessential government and commerce as the nation struggles to contain the outbreak.
But the first confusing signs that something was very wrong in Mexico stretched back weeks.
Evidence was mounting in the spring that this was no ordinary flu season. There were 3,000 more cases of serious flu than usual in Mexico this season, and the number of "outbreak clusters" was more than double. Previously healthy adults were dying from severe cases of pneumonia from San Luis Potosi to Oaxaca.
By March 10, authorities first heard reports of a mysterious influenza-like illness in the desert village of La Gloria, a dust-blown settlement in hog-farming country a three-hour drive east of Mexico City. Although the flu season usually should have ended, residents were beginning to feel feverish and achy at an alarming rate. By the end of the outbreak on April 10, 616 people -- nearly 30 percent of the village -- were sick.
"That was a very high attack rate," Lezana said. "Very high."
Teams of health care workers entered the village in early April to investigate. They took nasal and throat swab samples from 50 of the ill. Other medical teams distributed medicine and fumigated the entire village.
The health workers sent the samples to state and federal public health labs. Weeks later, a single patient in La Gloria, 5-year-old Édgar Enrique Hernández, tested positive for swine flu.
One reason for the delay in understanding the outbreak was the fact that the national testing laboratory in Mexico City was unable to identify the new strain found in La Gloria.
As medical researchers were trying to understand the situation in La Gloria, they received information about another outbreak, this time in the southern city of Oaxaca, where a cluster of patients was showing severe respiratory distress.