This story was updated at 2:30 p.m. with additional information.
MONTGOMERY, Ala. (AP) -- Alabama health officials investigating a cluster of respiratory illnesses say the total has increased to 10, but they are closing the investigation.
State Health Officer Don Williamson said Thursday the cases are unrelated and all have reasonable explanations. He said health officials took extraordinary caution because of two new viruses -- one in China and another in the Middle East. But they found no evidence of new or unexpected viruses or bacteria in the cluster of cases in southeast Alabama.
Two have died, six remain in hospital and two have been released from hospitals. The 10 people range in age from 24 to 87.
The Centers for Disease Control and Prevention announced earlier that testing on seven of the patients found no sign that the illnesses were caused by any single germ.
Health officials say lab tests have ruled out any unusual germ as the cause of nine mysterious illnesses in Alabama.
The tests on seven of the nine patients found common cold and flu viruses. A Centers for Disease Control and Prevention official on Thursday said the agency found no sign that the illnesses were caused by any single germ.
Meanwhile, Alabama officials said they had added two more cases to the cluster, which included two earlier deaths.
The cluster was first reported earlier this week. Most of the nine were treated at Southeast Alabama Medical Center in Dothan, but one was seen at a hospital in Crenshaw County.
The nine people suffered a flu-like illness with symptoms like fever, cough and shortness of breath.