Health District Identifies 77 Potential Clinic-Associated Infections

LAS VEGAS – The Southern Nevada Health District has identified 77 potential clinic-associated hepatitis C infections during its continuing investigation into the outbreak associated with the Endoscopy Center of Southern Nevada. There have been a total of eight acute hepatitis C cases associated with the outbreak, seven of which can be linked directly to the Shadow Lane clinic. To date, the health district has interviewed approximately 400 people who received positive test results and were patients at the clinic between March 2004 and Jan. 11, 2008.

Since the initial patient notification Feb. 27, approximately 50,000 test panels have been ordered through local labs; however, this number represents the number of tests ordered and not the number of patients who have been tested. The health district cannot say for certain that the number of test panels represents everyone who received a notification. “Because the patient list we received was not complete, we cannot say for certain if all of the affected patients have been tested,” said Dr. Lawrence Sands, chief health officer. “The health district continues to receive a higher number of positive test results than we did before the notification in February, which means people are getting tested and that is a positive outcome.”

In the coming months, patients who underwent procedures at the end of 2007 or early 2008 will need to be tested at a later date because it can take as long as six months for a positive test result to occur. Negative test results are not reported to the Southern Nevada Health District.

Health district investigators continue to sort through positive test results to determine which patients received procedures at the clinic, what prior risk factors they have to determine potential exposure, and which results are duplicates or retests. It is possible that some patients are tested regularly as part of ongoing management of their chronic medical conditions. The evaluation of chronic hepatitis C infections involves examining a patient’s risk over the course of their lives. The evaluation of acute hepatitis C infections involves examining a patient’s risk for six months prior to the onset of symptoms.

To evaluate patients’ risk factors and to determine if their infection is related to the clinic, a set of criteria has been developed to classify cases based on whether they are chronic or acute cases. In addition, classifications about the likelihood that the patient was exposed at the clinic have also been developed to help investigators better understand patient risk factors prior to having a procedure at the clinic.

“We anticipate that this investigation is going to take many months to complete and we will likely see additional positive test results that could be associated with the clinic,” said Sands.

Approximately 4 percent of the clinic population would have been previously infected with hepatitis C and laboratory testing cannot distinguish between recent and older infections. Because many of the newly reported infections may have been acquired years previously it may not be possible to determine the source of the infection. In addition to the recommendation to get tested for hepatitis C, the health district advised patients to get tested for hepatitis B and HIV. To date, there have been no acute hepatitis B cases or an increase in HIV infection rates associated with the clinic or the outbreak. The health district routinely investigates acute hepatitis B and HIV cases, however, the risk of acquiring either of these two infections is thought to be much lower for persons possibly exposed at the clinic.

Source: Southern Nevada Health District