From 1999 through 2008, nine patients treated at a hemodialysis unit in New York City were found to be infected with hepatitis C virus, according to a report published Thursday.

For four of the cases, patient-to-patient transmission of hepatitis C virus was documented. For the remaining five patients, no source was identified.

The cases illustrate how hepatitis C virus and other pathogens can be transmitted in healthcare settings when infection control procedures are not followed, Dr. R. Hallack, from the New York State Department of Health, and colleagues note in the Morbidity and Mortality Weekly Report, published by the Centers for Disease Control and Prevention (CDC).

Contaminated healthcare worker hands and treatment surfaces were among the breaches in infection control protocol identified at the hemodialysis unit, which was shut down in August 2008 after the Department of Health ordered the unit to transfer all patients to other facilities.

The hepatitis outbreak is just one of several that have occurred recently in healthcare settings. The CDC recommends routine screening for infection-causing microbes at hemodialysis centers to rapidly identify and stop potential transmission.

For their part, patients should ask their health care providers if they have been tested for hepatitis C virus infection, the CDC adds. Concerns about infection should be discussed with their provider.

The release of the report coincides with National Kidney Month in the US and World Kidney Day on March 12.