First came the notifications, now come the phone calls.
The Southern Nevada Health District as early as Friday will begin the next phase of its investigation into whether any additional cases of hepatits C can be traced to the Endoscopy Center of Southern Nevada by contacting people who have recently tested positive for the disease.
Patients who tested positive -- and who were also among the 40,000 to receive a letter from the agency notifying them of the health alert -- will be asked a series of questions to try to more precisely determine the source of infection.
The process will take months, maybe years, health officials say.
"This is a marathon, not a sprint,'' said Brian Labus, senior epidemiologist for the health district. "It is really going to take some time."
Some people, Labus said, may have had their medical procedures in January and, because of the six-month incubation period, would need to be retested in July, even if they received recent negative test results.
The earliest the district could have complete results is July, Labus said. "But I suspect we'll have some preliminary numbers before then.''
The next phase involves prying into the medical history of patients as well as a host of risk factors, including intravenous drug use.
Six people with acute hepatitis C have already been linked to the Endoscopy Center on Shadow Lane. A seventh person with the disease has been linked to an affiliated clinic, the Desert Shadow Endoscopy Center at 4275 S. Burnham Ave.
In recent weeks, the health district has received hundreds of positive hepatitis C results from labs such as LabCorp and Quest Diagnostics. But it's too early to tell how many of those cases are linked to the Endoscopy Center because, under normal circumstances, the health district receives 20 to 30 reports of hepatitis C a day. Those chronic cases are different from the Shadow Lane facility's cluster of six, which are acute.
Also, the number of positive cases being reported could be skewed by the fact that people who did not receive letters and did not visit the Endoscopy Center are getting tested. Labus said that's because of fear stemming from reports of similar unsafe practices observed at other ambulatory surgery centers not necessarily linked to the Shadow Lane facility.
The names of the 40,000 known patients of the clinic were acquired by the health district during its initial investigation of the facility back in January.
Once names are matched with positive test results, health officials will call those patients and pose a series of questions based on a questionnaire created by Labus and his staff. The questionnaire is available to other health departments where patients might be living, he said.
The federal Medical Reserve Corps, a group of about 200 local volunteer health care professionals, will assist in asking the questions, said Paula Martel, program coordinator. The volunteer organization assists local health authorities during medical emergencies, she said.
The questionnaire will be used to verify a patient's name, place and date of procedure and whether they were given Propofol, an injectable form of anesthesia.
"Obviously, if the person didn't have a procedure at the clinic, that is pretty much the end of the interview,'' Labus said.
Those who did have procedures at the clinic will be asked about their symptoms -- whether they're acute or chronic.
"It's a lot easier to work with acute cases than chronic because, at most, there is a six month incubation period for acute hepatitis C,'' Labus said. "You only have to look at risk factors within six months in that person's life. With chronic hepatitis C, you could have contracted it at any point in your life.''
Still, Labus said, the risk factors are identical for both types of hepatitis C cases. So anyone who has tested positive will be asked additional questions.
Those include whether patients have used illicit intravenous drugs, had an organ transplant or blood transfusion prior to 1992, or are receiving hemodialysis for kidney failure. Patients will be asked if they have relatives who have the disease and whether transmission could have occurred within the home.
Health care workers will be asked whether they could have been exposed to infected blood, and patients who are diabetic will be asked if they have ever shared blood glucose monitors with someone else.
The number of sexual partners is also on the list of questions as will be a question about tattoos, Labus said.
Once questionnaires have been completed, disease investigators will then sift through the data and classify patients based on their risk for exposure at the clinic.
"The question we will be asking is 'How likely is it this person was infected at the clinic as opposed to some other source,' '' Labus said. "Most people will end up in an intermediate category in which we can't rule it out, but we can't say that the clinic is the source either. People with chronic hepatitis C could have been exposed decades ago and that is going to be frustrating to people.''
Health officials believe the six known hepatitis C cases occurred when nurse anesthetists reused syringes on infected patients, contaminating vials of medication that were shared by multiple patients.
Five of the six patients underwent procedures at the clinic on Sept. 21. The other had a procedure on July 25.
The health district has linked 117 patients to those days when infection probably was spread at the facility. They are being contacted and are currently undergoing interviews and blood testing, Labus said.
As of Monday, Labus said he didn't know if any of the 117 have tested positive. However, the health district is just beginning to test those patients.
"We know of some of them who will be coming in positive,'' Labus said. " But we want to retest everyone, even if we know they have hepatitis C.''
That's because the health district needs the blood of any of those 117 who test positive to do genetic coding. That way, officials can tell if someone is a source that might have led to transmission of disease to other patients.
The health district is also trying to determine if patients of the Desert Shadow Endoscopy Center should be notified about testing, Labus said. In that regard, he said, the agency is still awaiting access to medical records which are in the possession of Las Vegas police.
Contact reporter Annette Wells at email@example.com or (702) 383-0283.