Seven people in southeastern Alabama have fallen ill with similar symptoms and two have died, but it is not known if the cases are connected, according to ABC News.
"At this time, there is no epidemiological link between these patients," an Alabama health department document stated.
Other than the illness and some health factors such as smoking, COPD, and obesity, the patients had very little in common.
The patients' ages range from early 20's to late 80's. The illness started out with common flu-like symptoms like shortness of breath, coughing, and fever. The two fatalities were due to the illness developing into pneumonia.
Dr. Richard Besser, chief health and medical editor for ABC News said the patients who come down with pneumonia are rarely tested to find out the cause. This time the Centers for Disease Control and Prevention are considering looking into the cause of infection. Health officials will also look into if the patients had any common exposures and if they have ever had contact with each other.
One of the patients tested positive for H1N1, more commonly known as the "swine flu." Another patient tested positive for a strain of influenza called AH3.
It's still unclear whether swine flu or influenza played a role in the mysterious illness, or if they are connected at all.
"Temporal clustering can make something look like an outbreak," said Besser, "Good science will tell you whether it is.
According to the Huffington Post, the illness seems to be secluded to the area where the cases were reported.
"We're only aware of the Southeast, but we don't know - we haven't received reports from anywhere else," Alabama Department of Public Health spokeswoman Mary McIntyre said. "That's why we're trying to get the information out."
The health of the five surviving patients seems to be improving, but health officials are still on the lookout for more cases of the mystery illness.
