CARSON CITY, Nev. (AP) - Better surveillance, education and oversight is needed to prevent another hepatitis C outbreak in Nevada, according to a federal Centers for Disease Control and Prevention report released Thursday.

The report follows recent word from public health administrators that more than 80 people treated at the now-closed Endoscopy Center of Southern Nevada tested positive for the potentially deadly virus and had no risk factors other than their treatments.

They're among about 400 former patients of the center who tested positive. Officials have determined the other patients could have contracted the virus through other means, including intravenous drug use, blood transfusions, organ transplants or kidney dialysis, receiving blood clotting agents before 1987, or sexual contact with a person with hepatitis C.

While hospitals regularly evaluate infection-control practices, the CDC report says that may not be the case for outpatient clinics, adding, "As use of these settings grows, appropriate methods will be needed to provide similar oversight" of those facilities.

Public health officials in Las Vegas have said local labs have reported handling about 50,000 hepatitis virus tests following a call for former patients at the Endoscopy Center to get tested for hepatitis strains C, B, and HIV, the virus that causes AIDS.

No cases of hepatitis strain B or HIV have been linked to the outbreak.

The Endoscopy Center and several other clinics were headed by doctors Dipak Desai and Eladio Carrera, whose Nevada medical licenses have been suspended pending state Board of Medical Examiners hearings.

Authorities have said at least 50,000 patients may have been exposed to unsafe injection practices by clinic staff who reused syringes and single-use vials of medication during anesthesia.

Las Vegas police have seized medical records from the clinics, and the FBI, the Nevada state attorney general and the Clark County district attorney are involved in a criminal investigation. The owners of the clinics have surrendered business licenses and paid $500,000 in fines.

The CDC will release a more detailed report to the state soon, but Gov. Jim Gibbons said Thursday's report, which has an accounting of what the CDC found during its inspections, has "essential" information that people need to see.

(Copyright 2008 by The Associated Press. All Rights Reserved.)