IE 11 is not supported. For an optimal experience visit our site on another browser.

Virus Panic: Expect More Ebola False Alarms, CDC Says

Federal officials have stepped up screening for travelers who might have Ebola, and they expect their tighter net to produce false alarms.

Federal officials have stepped up screening at U.S. airports for travelers who might be infected with Ebola, and they fully expect their tighter net to produce many more false alarms.

That, combined with heightened nervousness after the first U.S. Ebola death, will make for many alerts, Centers for Disease Control and Prevention Director Dr. Thomas Frieden says.

And some probably will be real Ebola cases, he predicts.

“We have been very clear that as long as Ebola continues to spread in Africa, we can't make the risk zero here,” Frieden told reporters Wednesday. “We wish we could, we wish there was some way we could make it zero.”

But so long as the epidemic spreads in Liberia, Sierra Leone and Guinea, the whole world risks getting some cases. The World Health Organization said Wednesday that more than 8,000 people have been infected, and close to half of them have died. It’s certainly an underestimate, WHO says, predicting 20,000 or more cases by November.

“We expect that as people are more concerned, as there is a higher index of suspicion, people will be scared, there will be rumors and concerns and potential cases, and that is how it should be,” Frieden said.

“One of things we are working hard on is to ensure that doctors, nurses, health care workers think Ebola."

The heightened awareness may be useful in catching the next case.

“One of things we are working hard on is to ensure that doctors, nurses, health care workers think Ebola,” Frieden said. Anyone who has a fever should be asked about travel to West Africa. “That is really important because that will help us ensure that if there is another patient that arrives, they will be rapidly identified and isolated for their own sake promptly,” Frieden said.

So far, airport screening at departure zones has caught 77 people with fevers and none had Ebola, Frieden said. “About one out of 500 travelers boarding a plane in west Africa has had a fever. Most of them have malaria.”

So with more screening, expect more false alarms.

There were several alerts about possible U.S. cases on Wednesday, hours after officials announced the death of Thomas Eric Duncan, the Liberian citizen diagnosed with Ebola in Dallas. One came from a sheriff’s deputy who had been inside Duncan’s Dallas apartment and mistakenly feared he had been exposed to the virus.

Simply being inside a room where a patient has been does not constitute exposure. To be infected, people must have close personal contact with a patient with active symptoms or with bodily fluids such as blood, vomit or diarrhea.

The people who need to be careful are the 10 close contacts — seven healthcare workers and three people, including his girlfriend, who were with Duncan when he was sick. They’ll need to take their temperatures daily to watch for fever until about October 19, which marks 21 days since their last close contact with Duncan.

“We are actually at the peak of eight to 10 days, so it is a time we are anxious and carefully assessing,” Frieden said.

Frieden says it’s tragic that Duncan died, but not unexpected. “Ebola, even with the best of treatment, is a terrible disease and is fatal in a high proportion of cases,” he said. “We encourage rapid and early diagnosis, but the earlier someone is diagnosed, the more likely they will be able to survive.”

Duncan first felt ill on Sept. 24. He went to the hospital on Sept. 26 and was mistakenly sent home with antibiotics. Texas Health Presbyterian Hospital in Dallas says doctors failed to ask him about his travel from Liberia, which should have set off alarms. Duncan returned to the hospital two days later in an ambulance and died Wednesday.

Dr. Philip Smith of the University of Nebraska’s biocontainment treatment unit, who’s treating NBC News freelance camera operator Ashoka Mukpo for Ebola, says such a delay could make an important difference.

“It can,” he said, adding that each case is different. Patients can look and feel very well and suddenly develop very severe diarrhea and vomiting that can deplete fluids and important minerals called electrolytes that are important for organ functioning.

“Then the disease can move fairly quickly. So time is theoretically important,” Smith said.

“We're not going to see a dramatic response in a couple of hours.”

Loss of electrolytes through diarrhea and vomiting can damage the heart and even stop it.

Duncan was receiving dialysis for his failing kidneys — a serious stage of disease that makes any treatment, even the last-ditch use of an experimental drug, less likely to work, Smith said.

Mukpo is sick but stable and receiving experimental antiviral pills and a transfusion of blood from Ebola survivor Dr. Kent Brantly. The plasma, in theory, contains antibodies to kick-start Mukpo's immune reponse.

“This is not like giving penicillin for pneumonia," Smith cautioned. “We're not going to see a dramatic response in a couple of hours.”

Correspondent Kate Snow and Producer Jane Derenowski contributed to this story