By Jon Herskovitz and and Lisa Maria Garza
DALLAS (Reuters) - The first Ebola patient diagnosed in the United States took a turn for the worse on Saturday, slipping from serious to critical condition in a Dallas hospital, as health officials reported tracking scores of possible cases around the country that proved to be false alarms.
The case of Thomas Eric Duncan, who arrived in Dallas from Liberia two weeks ago, has heightened concerns that the worst epidemic of Ebola on record could spread from West Africa where it began in March and has taken more than 3,400 lives.
Dr. Thomas Frieden, director of the U.S. Centers for Disease Control and Prevention in Atlanta, said hospitals nationwide have become more vigilant in checking incoming patients for potential risks, particularly among those traveling recently from West Africa.
In the meantime, the CDC has narrowed down the number of individuals in Dallas at greatest risk of infection from Duncan, identifying nine people who had direct contact with him.
Another 40 were being monitored as potential contacts, out of a group of 114 people initially evaluated for exposure risks, though none from either group has shown symptoms, Frieden said.
Ebola, which can cause fever, vomiting and diarrhea, spreads through contact with bodily fluids such as blood or saliva.
Frieden also told a Saturday news conference that U.S. health authorities have responded to inquiries regarding well over 100 potential cases since Duncan tested positive earlier this week, but no new cases of the disease have been confirmed.
A hospital patient in Sarasota, Florida, was being monitored and treated for possible symptoms in isolation as a precaution because he, too, had traveled recently to West Africa, Governor Rick Scott said on Saturday.
But a patient admitted under similar circumstances to Howard University Hospital in Washington, D.C., after a recent trip to Nigeria was ruled out as an Ebola victim earlier in the day.
In New Jersey on Saturday, CDC agents in biohazard suits removed a sick passenger and his daughter from a United Airlines jet from Belgium that landed at Newark Liberty International Airport. But the health agency later said Ebola was ruled out as a concern once the man, who had traveled from West Africa, was fully evaluated at a hospital.
Duncan, now being treated at Texas Health Presbyterian Hospital, was sent home after his first visit to the emergency room, despite telling a nurse there that he had just been to Liberia.
The hospital said in a terse statement on Saturday that he was in critical condition, a worsening from the "serious condition" he was listed in the previous two days. The hospital declined to elaborate.
TEN PEOPLE REMAIN IN ISOLATION
On Friday, officials said 10 people with the highest risk of exposure from Duncan had been placed under isolation in Dallas and all were cooperating with public health authorities by staying in quarantine voluntarily.
"There's no one under orders. There's no one that we perceive that needs to be under orders," Judge Clay Jenkins, Dallas County's top elected official, told a news conference late on Friday.
Separately, five public school children who had possibly been exposed to the Ebola patient had been kept home from class in recent days while being monitored as a precaution, though none had shown any symptoms, said Mike Miles, superintendent of the Dallas Independent School District.
Authorities have said the individuals placed in isolation included the four members of a single family whose apartment Duncan was staying in when he fell ill after traveling to Dallas from Liberia on Sept. 19. The six others are healthcare workers, including those who transported Duncan by ambulance on his second trip to the hospital on Sept. 28.
Duncan became ill on the night of Sept. 25 and visited the emergency room at Presbyterian Hospital, but was sent home without being screened for Ebola, despite telling a nurse there that he had just been to Liberia.
The hospital issued a statement on Friday saying that Duncan's travel history was "documented and available to the full care team," including doctors, through electronic records, contrary to the hospital's earlier assertions that all staff were not made aware of his recent presence in West Africa.
The hospital offered no explanation of why its medical staff apparently failed to act on the information it had.
Just days before flying to Texas via Brussels and Washington, Duncan had helped a pregnant woman who later died of Ebola in Liberia, a fact that he concealed from airport authorities in Liberia before boarding the plane.
Dallas County District Attorney Craig Watkins told a Dallas NBC News affiliate his office was considering whether to pursue a possible criminal case against Duncan, though he did not specify on what basis Duncan might be charged.
The woman he was staying with, publicly referred to by city officials by her first name only but identified in the media as Louise Troh, was later ordered to stay inside her apartment with her 13-year-old son and two adult nephews who lived there with her.
On Friday, the family agreed to move voluntarily to an isolated four-bedroom house in a gated community in an undisclosed location somewhere within city limits, Jenkins said.
(Additional reporting by Sharon Begley and Michele Gershberg in New York; Writing by Steve Gorman; Editing by Kevin Liffey and Tom Brown)