"We don't think asking a 70-year-old woman about her previous sexual partners is relevant,'' said Nia Killebrew, an attorney who represents about 50 former patients who have tested positive for hepatitis C.

The health district's goal was to learn how many patients acquired blood-borne diseases during procedures at the Endoscopy Center of Southern Nevada between March 2004 and Jan. 11 of this year.

But getting those questions answered, and thereby getting a handle on what the district calls the "big picture," might never be achieved.

Many patients have not responded to telephone questionnaires. Nor are they enrolling in the district's Hepatitis C Exposure Registry.

Killebrew has advised her clients not to respond to the health district in any capacity.

"I don't think the registry is appropriate,'' Killebrew said.

Billie-Marie Morrison, an attorney representing about 1,500 former endoscopy center patients as well as 72 who have tested positive for one of the three blood-borne diseases, says her office "kick-started" the campaign to not respond to the health district.

She said a person's drug or sexual history is none of the district's business. Also, she said, it is up to a doctor to report if a patient has hepatitis C, not the patient.

"All they (health district officials) need to know is 'Did you have a procedure, and where?''' Morrison said.

Morrison said her office sent a letter to clients telling them not to answer health district questions. A letter was also sent to the health district explaining this approach and some concerns about the registry.

The district's registry, developed in late June, was designed to assist disease investigators in identifying patients who had procedures at either clinic, including those who are infected with the hepatitis C virus. The health district classifies patients who tested positive depending on the answers they give.

Case classification is based on patient responses to certain risk-factor questions. There are four case classification categories: clinic associated, possible clinic associated, clearly unrelated, or indeterminate.

Originally the health district, as well as volunteers from the federal Medical Reserve Corps, conducted interviews by telephone to determine classification. The health district developed the registry after some patients refused to respond.

Patients were asked about the location of their procedures and dates of procedures, and whether Propofol, a form of anesthesia, was administered. They were also asked whether they'd had any blood transfusions or organ transplants before 1992, or whether they have been on long-term hemodialysis.

They were also asked if they have had sexual contact with a known hepatitis C carrier.

The district and the federal Centers for Disease and Control and Prevention decided on the questions, said Brian Labus, health district epidemiologist. "These questions are based on known major risk factors for infections of hepatitis C.''

Failure to obtain information "will have a negative impact on any investigation we are doing,'' Labus said.

Labus admitted the health district doesn't have the authority to require anyone to answer questions or to respond to the registry. But in order for the health district to better understand just how many people acquired a blood-borne disease at the 700 Shadow Lane facility, the district would need to hear from patients.

Out of 60,000 letters sent to patients over the past seven months, the health district has received 7,000 responses.

Labus said last month that his office is currently in the process of analyzing the data collected from those responses. He expects to have a full report on that analysis completed within the next few months.

"It's not a nice statistical sample of the clinic's population, but it will give us some indication of what the numbers mean,'' he said.

Dr. Nicola Thompson, an epidemiologist with the CDC's division of viral hepatitis, said a patient's medical history is the cornerstone of any public health investigation.

"This information helps investigators identify past exposures or risks for a specific disease or illness and is used to determine the role that a given exposure or risk may have played in the development of the disease under investigation,'' Thompson said. "Collection of a medical history must consider the timing and nature of infections. Because an individual with hepatitis C virus can be asymptomatic and unknowingly infected for a period of 20 to 30 years, knowing the lifetime risk for an exposure to a pathogen is very important.''

Patients were put at risk, health officials say, when a syringe would be reused on an infected patient and then used to draw anesthesia from vials intended for just one patient. The vials would then be used on other patients, potentially spreading disease.

"My big thing with the registry is, if you look at the last page, our clients are asked to sign a release," Morrison said. "What that release says is that the health district can release that information to anyone the health district wants. This is very private and personal information. ... This information could be turned over to law enforcement for their investigation or turned over to the defense.''

Morrison said the defense, meaning attorneys for Dr. Dipak Desai and his clinics, are attempting to obtain information from the health district about the hepatitis C cases, especially the information contained in the registry.

Attorneys for patients are trying to block them from getting this information, she said.

Desai is the majority owner of the 700 Shadow Lane facility, where eight transmissions of hepatitis C have been linked. One case has been linked to a facility on Burnham Avenue.

The health district has confirmed that 400 former patients have tested positive for hepatitis C, but only 77 of them are classified as having "possible" links to the Shadow Lane clinic.

Morrison said her office has turned over the names of individuals who have tested positive for hepatitis C to the health district. Whether those individuals are included in the district's figures is unknown, she said.

Jean Sternlight, professor of law at UNLV's Boyd School of Law, said it's not uncommon for plaintiffs' attorneys to encourage their clients not to speak with anyone other than the attorney during civil cases.

"The reason is likely that they are afraid their clients would say something to the health district which would misconstrue or misrepresent what has happened,'' she said. "Attorneys don't want their clients to say something that might come back and haunt them. This is the same reason attorneys tell their clients not to speak with insurance companies.''

But Will Kemp, another Las Vegas attorney representing former endoscopy center patients, said he is allowing his clients to participate in the health district's registry.

Kemp said his office has taken the position that it will act in the best interest of the public.

"As an attorney, though, there's always concerns clients will give inconsistent answers" when giving depositions, he said.

Kemp said he knows of attorneys who have directed their clients not to speak with health officials because of that fear. But, he said, the majority of attorneys are cooperating with law enforcement and the health district.

Travis Bennington, a Nebraska attorney, said if attorneys are telling clients not to divulge information to health officials, they are probably trying to protect them from embarrassment.

Bennington represented 19 patients who acquired hepatitis C at a Nebraska cancer center in 2002. In all, 89 lawsuits were filed by former patients of the cancer center.

That incident, considered the largest hepatitis C outbreak in U.S. history, also came as a result of unsafe injection practices.

The CDC, along with Nebraska health officials, identified 99 people who had acquired hepatitis C at the cancer center. The lawsuits ended after more than four years of litigation, Bennington said.

"Attorneys defending these types of lawsuits use that sort of information against the victims of malpractice,'' he said. "It is usually a great source of embarrassment, particularly for elderly women.''

Contact reporter Annette Wells at awells @reviewjournal.com or 702-383-0283.