Washington (AP) The head of the Centers for Disease Control and Prevention says an outbreak of Hepatitis C at a Nevada clinic may represent “the tip of an iceberg” of safety problems at clinics around the country.

The City of Las Vegas shut down the Endoscopy center of Southern Nevada last Friday after state health officials determined that six patients had contracted Hepatitis C because of unsafe practices including clinic staff reusing syringes and vials.

Nevada health officials are trying to contact about 40,000 patients who received anesthesia by injection at the clinic between March 2004 and January 11th to urge them to get tested for Hepatitis c, Hepatitis B and Hiv.

CDC head doctor Julie Gerberding says health officials need to be more aggressive about alerting clinicians of the dangers of reusing syringes.