A hepatitis C outbreak affecting more than 80 people and exposing tens of thousands more was caused by workers reusing syringes at a Las Vegas clinic, federal health officials said Friday.
The Centers for Disease Control and Prevention report bolsters earlier conclusions by state and county officials, which led to the biggest public health notification operation in U.S. history.
State health officials contacted the CDC on Jan. 2 after two people treated at the now-closed Endoscopy Center of Southern Nevada were diagnosed with acute hepatitis C.
The practice of reusing syringes with the sedative propofol "was observed, and interviews suggested it was a common practice," the CDC investigators said in a report to the Nevada State Health Division.
"This was considered the most likely mode of transmission," the report said.
Officials have linked 84 cases of the potentially deadly liver disease to the clinic and have notified 50,000 patients that they may be at risk. Another case was linked to a sister clinic.
The 85 are 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.
Hepatitis C results in the swelling of the liver and can cause stomach pain, fatigue and jaundice. It may eventually result in liver failure. Even when no symptoms occur, the virus can slowly damage the liver.
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.
Las Vegas police have seized medical records from the clinics, and the FBI, the 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.
Former patients at the Endoscopy Center are being 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.
Since 1999, the CDC counts 14 hepatitis outbreaks in the U.S. linked to bad injection practices.
The largest outbreak occurred in Fremont, Neb., where 99 cancer patients were infected at an oncology center from 2001 to 2002. At least one died.