Health officials are investigating a never-before-seen form of the flu that combines pig, bird and human viruses and which has infected people in the U.S. and Mexico.
As of Monday night, there are no confirmed cases of swine flu in Chicago or anywhere in Illinois, and at least one doctor hopes steps taken to combat bird flu have paid off.
"I hope it's a good fire drill and not a fire," said Dr. John Flaherty, an infectious disease specialist at Northwestern University.
Flaherty confirmed Monday evening that a male patient in his 30s who just returned from Mexico ill with flu-like symptoms did not test positive for the swine flu virus. The patient returned to Chicago on Wednesday was sick for a couple of days before going to a doctor Saturday. The man was given Tamiflu and told to go home while doctors ran tests.
The patient is one of four to be subjected to testing. He and another patient have been cleared while two others are still being tested.
"I think there is a lesson there that this is a fairly non-specific presentation, that a lot of things can look like the swine flu and, so far, we haven't found it yet," Flaherty said.
He described the virus as a "mosaic," and having elements of pig, avian and human flu strains. Still, he said that the cases that have appeared in the United States seem to be mild and treatable with the medicines available.
"We don't quite understand the difference there, and are we seeing a different illness, or what exactly is happening," Flaherty said, adding that when the virus does arrive locally, it should come and go "over a period of maybe three weeks."
Over the weekend, Chicago Department of Public Health commissioner Dr. Terry Mason said it's not a question of if the state will see swine flu, but when cases will surface.
President Barack Obama on Monday said his administration was closely monitoring swine flu cases, and the Department of Health and Human Services had declared a public health emergency as a precaution.
"I’m getting regular updates on the situation from the responsible agencies, and the Department of Health and Human Services as well as the Centers for Disease Control will be offering regular updates to the American people so that they know what steps are being taken and what steps they may need to take," Obama said in a speech before the National Academy of Sciences.
On Sunday, the U.S. declared a public health emergency to deal with the swine flu, reporting 20 domestic cases of the disease in five states, including California, Ohio, Texas, New York and Kansas. In Mexico, the disease has killed up to 86 people and likely sickened up to 1,400 since April 13.
"People who have recently traveled to impacted areas and have flu symptoms need to see a doctor and be tested so we can determine if swine flu is present in Illinois sooner rather than later," said Dr. Damon Arnold, the state public health department's director. "Aside from seeking medical attention, these people should stay home if sick."
Arnold suggested travelers returning from Mexico pay close attention to their health for around a week, and he recommended they see a doctor if they develop a fever, cough, sore throat or have trouble breathing.
"Many people travel from, to and through Illinois and it is imperative to take precautions and protect against illness," Arnold said.
Public health officials at the same news conference said the Centers for Disease Control's permanent quarantine station at O'Hare International Airport was activated and engaged.
A spokesman for Chicago's Department of Aviation, which oversees O'Hare and Midway International Airport, declined to comment further.
On Sunday, multiple airlines, including Chicago-based United Airlines, waived change fees for passengers flying through Mexico because of the outbreak. According to its Web site, United said passengers who purchased tickets on or before Saturday, April 26 for travel through April 30 may change their plans without incurring a penalty.
Chicago Public Schools CEO Ron Huberman said that the nation's third largest school district would ask parents basic health questions when they call their children in sick. He said that information would be shared with the public health department.
One CPS school, Orozco Community Academy, is forbidding its students from shaking hands. Orozco is in the largely Hispanic Pilsen neighborhood, and the school principal said students often travel to and from Mexico with their families.
On Saturday, Deerfield, Ill.-based drug maker Baxter International Inc. said it had asked the World Health Organization for a sample of the flu strain so it could work to develop a vaccine.
The company has patented technology that allows development of vaccines in half the time it usually takes -- about 13 weeks instead of 26, Baxter spokesman Christopher Bona said.
Pink markers are suspect
Purple markers are confirmed
Deaths lack a dot in marker
Yellow markers are negative