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May 2008 marks the 13th anniversary of Hepatitis wareness Month in the United States. May 19 is World depatitis Day, which recognizes the importance of gloal commitments to prevent liver disease and cancer aused by viral hepatitis. This issue of MMWR includes report on an outbreak of acute hepatitis C associated ith unsafe injection practices at an endoscopy clinic nd a report on hepatitis C virus (HCV) infections among oung injection-drug users. Both reports highlight the ole of viral hepatitis surveillance in detecting outbreaks nd populations at risk. Development of effective state nd local surveillance for acute and chronic viral hepatis is a public health priority.

HCV infection is the most common bloodborne illness, e leading cause of chronic liver disease, and the primary dication for liver transplantation in the United States. ICV is spread primarily through exposure to infectious lood; injection-drug use is the major contributor to HCV ansmission in the United States. Although HCV infecon can result in acute illness, most of its effects on the ver, including cirrhosis and liver cancer, are not apparent ntil years after exposure. Many of the estimated 3.2 milon persons living with chronic HCV infection in the nited States are unaware of their infection status.

CDC recommends HCV testing for persons at risk (1). ersons with HCV infection also should be assessed regurly for severity of liver disease, onset of liver cancer, and e need for treatment. Additional information about ral hepatitis is available at http://www.cdc.gov/hepatitis.

On January 2, 2008, the Nevada State Health Division (NSHD) contacted CDC concerning surveillance reports received by the Southern Nevada Health District (SNHD) regarding two persons recently diagnosed with acute hepatitis C. A third person with acute hepatitis C was reported the following day. This raised concerns about an outbreak because SNHD typically confirms four or fewer cases of acute hepatitis C per year. Initial inquiries found that all three persons with acute hepatitis C underwent procedures at the same endoscopy clinic (clinic A) within 35-90 days of illness onset. A joint investigation by SNHD, NSHD, and CDC was initiated on January 9, 2008. The epidemiologic and laboratory investigation revealed that hepatitis C virus (HCV) transmission likely resulted from reuse of syringes on individual patients and use of single-use medication vials on multiple patients at the clinic. Health officials advised clinic A to stop unsafe injection practices immediately, and approximately 40,000 patients of the clinic were notified about their potential risk for exposure to HCV and other bloodborne pathogens. This report

The MMWR series of publications is published by the Coordinating Center for Health Information and Service, Centers for Disease Control and Prevention (CDC), U.S. Department of Health and Human Services, Atlanta, GA 30333.

Suggested Citation: Centers for Disease Control and Prevention. [Article title]. MMWR 2008;57:[inclusive page numbers].

Centers for Disease Control and Prevention
Julie L. Gerberding, MD, MPH
Director

Tanja Popovic, MD, PhD Chief Science Officer James W. Stephens, PhD Associate Director for Science

Steven L. Solomon, MD

Director, Coordinating Center for Health Information and Service
Jay M. Bernhardt, PhD, MPH

Director, National Center for Health Marketing
Katherine L. Daniel, PhD

Deputy Director, National Center for Health Marketing
Editorial and Production Staff

Frederic E. Shaw, MD, JD
Editor, MMWR Series
Teresa F. Rutledge

(Acting) Managing Editor, MMWR Series
Douglas W. Weatherwax
Lead Technical Writer-Editor
Donald G. Meadows, MA
Jude C. Rutledge
Writers-Editors
Peter M. Jenkins

(Acting) Lead Visual Information Specialist Lynda G. Cupell

Malbea A. LaPete

Visual Information Specialists Quang M. Doan, MBA

Erica R. Shaver

Information Technology Specialists

Editorial Board

William L. Roper, MD, MPH, Chapel Hill, NC, Chairman
Virginia A. Caine, MD, Indianapolis, IN
David W. Fleming, MD, Seattle, WA

William E. Halperin, MD, DrPH, MPH, Newark, NJ
Margaret A. Hamburg, MD, Washington, DC
King K. Holmes, MD, PhD, Seattle, WA
Deborah Holtzman, PhD, Atlanta, GA
John K. Iglehart, Bethesda, MD
Dennis G. Maki, MD, Madison, WI
Sue Mallonee, MPH, Oklahoma City, OK
Stanley A. Plotkin, MD, Doylestown, PA
Patricia Quinlisk, MD, MPH, Des Moines, IA
Patrick L. Remington, MD, MPH, Madison, WI
Barbara K. Rimer, DrPH, Chapel Hill, NC
John V. Rullan, MD, MPH, San Juan, PR
Anne Schuchat, MD, Atlanta, GA

Dixie E. Snider, MD, MPH, Atlanta, GA
John W. Ward, MD, Atlanta, GA

focuses on the six cases of acute hepatitis C identified cr ing the initial investigation, which is ongoing; addition cases of acute hepatitis C associated with exposures at dir A might be identified. Comprehensive measures involving viral hepatitis surveillance, health-care provider education. public awareness, professional oversight, licensing, and inprovements in medical devices can help detect and prever transmission of HCV and other bloodborne pathogens in health-care settings.

The objectives of the investigation were to conduct cas finding and review health histories of infected persons. determine the source of transmission and implement control measures, to identify other patients at risk for exposure, and to assist in development of recommendations t. prevent HCV transmission in health-care settings. Person with acute hepatitis C were interviewed, and blood samples were obtained after these persons gave oral consent. Blood samples were sent to CDC for testing for HCV genotype the NS5b region and phylogenetic relatedness at t. hypervariable 1 region (HVR1) to help determine whethe a common source of transmission existed (1). Specimen also were tested for other bloodborne infections (hepatitis B virus [HBV]) and human immunodeficiency virus [HIV]). Case-finding activities included SNHD's review of acute hepatitis C surveillance records, cross-matching of local HCV laboratory records with clinic A procedure log review of medical records for patients who underwent pro cedures at clinic A on the same day as HCV-infected per sons, and serologic HCV, HBV, and HIV testing of staf An extensive review of the clinic practices and procedure also was conducted, including observation of several end scopic procedures and endoscopic reprocessing, observation of anesthesia practices, and interviews with staff members regarding their infection-control practices.

For this investigation, a person was defined as having health-care-associated acute hepatitis C if he or she 1) hac symptoms of acute hepatitis within 6 months of having a procedure performed at clinic A during July-Decembe 2007; 2) had laboratory-confirmed HCV infectio (antibodies to HCV [anti-HCV]) by enzyme immuno say (EIA) and recombinant immunoblot assay (RIBA of EIA with an appropriate signal-to-cutoff ratio for a given assay, or presence of HCV RNA by polymerase chain rea tion (PCR) in the absence of acute hepatitis A virus (HAV) and 3) did not have other risks for HCV infection.

In addition to the three persons identified initially, thre other persons were determined to have health-care associated acute hepatitis C, for a total of six cases diag nosed during July-December 2007. One of the three cases was identified by review of surveillance records, another

ss-matching local laboratory records with procedure ords at clinic A, and the third by physician report after ::start of the investigation. The six persons ranged in age n 37 to 72 years; four were female. All had signs and ptoms of acute hepatitis, including jaundice, abdomidiscomfort, and laboratory evidence of liver inflamman with alanine aminotransferase (ALT) levels of -1,165 units/L.* Four of the six persons required hoslization as a result of their HCV infection.

he six persons with acute hepatitis C had onset of sympis in late October 2007 and November 2007, 35-90 s after undergoing procedures at clinic A (Figure 1) and hin the typical incubation period of 15-160 days. None significant risk factors for HCV infection and none had er common exposures. One of the procedures was perned in July 2007; the other five were performed on the e day in September 2007. Five persons (four with proures on the same day) for whom blood specimens were ilable at the time of this report had HCV genotype la. four who had procedures on the same day had viral uences with 99%-100% genetic similarity at HVR1, nting to a common source of infection. The viral uence from the HCV-infected person who had the proure in July 2007 was not genetically related to the other ster, suggesting a separate transmission incident. During the 2 days in which persons with health-careociated hepatitis C had procedures at clinic A, 120 itional persons had procedures at the clinic. HCV test ults for those persons are pending. Thirty-eight staff mbers at the clinic involved in direct patient care were ilable for testing during the investigation, and none had lence of previous or current HCV infection. None of the sons with health-care-associated acute hepatitis C and e of the staff tested positive for HBV or HIV infections. appropriate reuse of syringes on individual persons and of medication vials intended for single-person use on Itiple persons was identified through direct observation nfection-control practices at clinic A (Figure 2). Specifiy, a clean needle and syringe were used to draw medica1 from a single-use vial of propofol, a short-acting avenous anesthetic agent. The medication was injected ctly through an intravenous catheter into the patient's 1. If a patient required more sedation, the needle was oved from the syringe and replaced with a new needle; new needle with the old syringe was used to draw more lication. Backflow from the patient's intravenous cathor from needle removal might have contaminated the

: normal ALT range varies according to age, sex, and other factors. An upper it of 28-55 units/L is generally considered normal.

syringe with HCV and subsequently contaminated the vial. Medication remaining in the vial was used to sedate the next patient.

As soon as improper injection practices were observed, health officials advised clinic A to stop these practices and educated staff about the risks. Clinic A is a free-standing private endoscopy clinic in southern Nevada that primarily performed upper endoscopies and colonoscopies (approximately 50-60 procedures a day, 5 days a week). For at least the 4 years that clinic A occupied its existing location, the unsafe injection practices had been commonly used among some staff members who administered anesthesia, according to those who were interviewed. On February 27, 2008, SNHD began notifying approximately 40,000 persons who underwent procedures requiring anesthesia at the clinic from March 1, 2004, through January 11, 2008, via mail and through the media, to undergo screening for HCV, HBV, and HIV infections. Results of this screening are pending.

Reported by: B Labus, MPH, L Sands, DO, P Rowley, Southern Nevada Health District, Las Vegas; IA Azzam, MD, Nevada State Dept of Health and Human Svcs. SD Holmberg, MD, Div of Viral Hepatitis, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention; JF Perz, DrPH, PR Patel, MD, Div of Healthcare Quality Promotion, National Center for Preparedness, Detection, and Control of Infectious Diseases; GE Fischer, MD, M Schaefer, MD, EIS officers, CDC.

Editorial Note: Although case-control studies have not indicated an increased risk for acquiring HCV from medical, surgical, or dental procedures in the United States (2), outbreaks of HCV in health-care settings have long been recognized (3). These outbreaks have been identified primarily through clusters of temporally related cases detected by routine viral hepatitis surveillance, a method that likely