Two people were hospitalized in isolation units at D.C. area hospitals on Friday with possible cases of Ebola, hospital officials confirmed; one of the cases turned out to be malaria.

One of the patients was being treated at D.C.’s Howard University Hospital, while the other was was admitted at Shady Grove Adventist Hospital in Montgomery County, Md.

The Howard patient, who had just returned to the U.S. after visiting Nigeria, was listed in stable condition with “symptoms that could be associated with Ebola,” a hospital statement said.

The Shady Grove patient had “flu-like symptoms and a travel history that matches criteria for possible Ebola,” officials there said in statement. But they added the individual was “showing signs of improvement” over the past 24 hours. Shady Grove Adventist Hospital released a statement Friday night saying its patient had malaria, not Ebola.

Federal health privacy laws prevented the hospitals from providing further details about the two individuals.

Both hospitals said the Centers for Disease Control and local health departments had been notified of the potential cases and were working with them on “appropriate infection control protocols.”
D.C. Department of Health officials were quick to emphasize, “At this time, there are no confirmed cases of Ebola in the District of Columbia.” Montgomery County health officials said similar.
Though the scares have put some on edge, the cases are not unique. After issuing an alert to hospitals and medical providers in July, the CDC has looked into approximately 100 Ebola scares in 33 states, as of Oct. 1, the agency said.

Among those, the CDC has tested the blood of 15 possible Ebola patients and found only one patient who tested positive, according to Dr. Beth Bell, director of the National Center for Emerging and Zoonotic Infectious Diseases. That patient is Thomas Eric Duncan, the Liberian man diagnosed in Texas. (He flew there via Dulles International Airport in northern Virginia.)

Diagnosing the deadly virus can be difficult. The early symptoms of the Ebola virus, including fever chills and abdominal pain, are similar to many other diseases and can be difficult to diagnose correctly.  After a hospital or state lab identifies a possible Ebola case based on both travel history and symptoms, they notify the CDC. CDC officials then talk to someone familiar with the patient’s history to determine whether blood testing for the virus is necessary.

CDC officials discuss symptoms and determine whether the patient may have been exposed to the virus. A person can easily be exposed to the virus if they buried the body of an Ebola patient, lived in the same home as an Ebola patient or was a health care worker.  Dr. William Schaffner, an infectious disease expert from Vanderbilt University Department of Medicine in Tennessee, said it is not surprising that only a small percentage of the patients investigated had a blood test to check for Ebola.

There are diseases that can appear similar to Ebola, but are far more common in the West African countries of Liberia, Guinea and Sierra Leone where the Ebola outbreak started, Schaffner noted. Doctors might end up contacting the CDC before finding out a patient actually has fever due to tuberculosis.

“You have to be mindful this could be malaria or typhoid fever. That’s your job to sort all those things out,” said Schaffner. “Your threshold for getting a blood specimen is dependent on the answers to those questions. You kind of have a decision algorithm in your head.”

Schaffner said he would not be surprised if there are a rash of new calls to the CDC from hospitals or state labs in the next few days and weeks in light of the intense media coverage of the first Ebola patient diagnosed in the U.S.   “Having all those inquiries come into the CDC are very, very indicative of the fact that the medical care community are on the alert and thinking about Ebola,” Schaffner said. “It keeps all of us on our toes.”