Larry Copeland

USA TODAY

When a person is diagnosed with Ebola, as happened last week with Thomas Eric Duncan in Dallas, the Centers for Disease Control and Prevention aids local health officials in quickly launching a process called contact tracing to determine who had physical contact with the patient or his bodily fluids while he had symptoms of the deadly disease.

Kelsey Mirkovic, an Epidemic Intelligence Service officer with the CDC, is very familiar with that process: She has been deployed to Africa to work on contact tracing twice during the current outbreak. She went to Guinea earlier this year, and she returned late last month from Senegal.

"It was a case very similar to the case here in Texas," she says. "A Guinean (man) had traveled from Guinea to Senegal. He had no symptoms, but he became ill while in Senegal. The CDC was contacted by Senegalese officials to assist with contact tracing and patient management."

It was Senegal's first confirmed case of Ebola: Aug. 29, 2014.

CDC staffers worked with the World Health Organization and Doctors Without Borders to assist the Senegalese Ministry of Health, Mirkovic says.

The first step: Establish a patient timeline.

That includes when the 21-year-old patient arrived in Dakar, Senegal; whether he was sick or not when he arrived; where he stayed, in one place or several; and anyone he visited. It was determined that the man, who had arrived in Dakar in a seven-person taxi around Aug. 14, had begun experiencing fever, diarrhea and vomiting on Aug. 16. He had made several visits to a neighborhood clinic in Senegal from Aug. 18 though25, receiving intravenous fluids and other treatments. On Aug. 26, he was admitted to University Hospital Fann in Dakar.

He did not disclose a history of contacts with any other Ebola patients. It was later determined that the patient's brother had died of Ebola on Aug. 10, and that the patient had helped prepare the body for burial.

The team's next step was to make sure that a list of contacts developed by the Ministry of Health was complete, Mirkovic says. "You want to establish it as quickly as possible. You use the timeline to make that list," she says. "You're only looking for people the patient had contact with while the patient was symptomatic."

The major contacts include everyone in the household where the patient was staying. "Then you make sure you get the contacts he saw while seeking medical care," Mirkovic says. "Anybody who came in physical contact with him or his bodily fluids while at the clinic. That would include someone who maybe has processed a blood sample, if they were not using proper protective equipment.

"If somebody came to the house and cleaned up his vomit, you would want to include that person," she says. "You only want people who had contact with that person or his bodily fluids. If they shook hands, we would want to contact them. That's probably a low risk, but we would include them."

In addition, the team interviewed family members, friends and neighbors. "We frequently go to the market to try to get information," Mirkovic says. "You wouldn't go to the market in the U.S., but maybe a church the person attended. In Africa, you would want to talk with neighbors who came and helped care for the patient."

The team came up with 67 contacts for the patient in Senegal -- 67 people who had had physical contact with him or his bodily fluids while he was displaying symptoms of Ebola. The contacts included 34 residents of the home where the patient stayed and 33 health care workers.

The team followed those contacts for 21 days. The contacts are monitored twice daily, in person, for signs of Ebola, especially for fever. "In some cases, it's just asking if they feel feverish, because there aren't enough thermometers to take everybody's temperature," Mirkovic says. "In America, I would imagine each person has a thermometer."

The contacts were asked daily if they'd had headaches, diarrhea, vomiting or muscle pains -- a list of Ebola symptoms. "If the contact developed fever, they would be promptly isolated and treated for Ebola. They would be isolated as soon as they showed symptoms," Mirkovic says.

The CDC does not recommend quarantining contacts, but the Senegalese Ministry of Health asked the contacts to stay home and voluntarily quarantine themselves, which most did. "That may make community members feel better, but it's not really necessary," Mirkovic says, adding that Senegalese officials might have been concerned for the safety of the contacts.

Four of the contacts developed symptoms. They were isolated and tested immediately. Medical staff drew their blood and it was tested, with the results available in less than 24 hours. They all tested negative for Ebola and were retested 48 hours later. Those tests also were negative. If anyone had tested positive, they would have remained in isolation while being treated.

The 21-year-old patient recovered and was released from isolation on Sept. 19.

In a paper she co-authored for the CDC's Morbidity and Mortality Weekly Report, Mirkovic said prompt notification of health personnel in Senegal by health personnel in Guinea, along with early preparations by the Senegal Ministry of Health and its partners, resulted in "a rapid containment response."

Mirkovic says the relief on the faces of contacts is palpable once the 21-day monitoring period passes and they're cleared.

"I feel a lot of compassion for the contacts," she says. "I imagine it's very, very scary to have a loved one contract Ebola. Ebola is a very fatal disease. It would be scary to know that could happen to you if you're a contact."

But she says she was never frightened on either trip to West Africa, where the World Health Organization reported 6,574 cases of Ebola with 3,091 deaths as of Sept. 23.

"No, I was never afraid," she says. "We know how to protect ourselves.

"To me, Ebola is less scary than respiratory illnesses like the flu, because the flu can be caught through the air. It's pretty easy not to handle someone's bodily fluids."