BOSTON (AP) — Doctors are monitoring five patients who may have been exposed to Hepatitis B when they were treated at Boston Medical Center.

Hospital spokeswoman Jennifer Watson said Saturday that the hospital became aware that a small number of patients were potentially exposed to the hepatitis B virus and five patients are potentially at risk.

WBZ reports that the hospital says the patients may have been exposed earlier this month through dialysis equipment that was not properly cleaned.

The Massachusetts Department of Public Health says it's investigating.

Hepatitis B attacks the liver and can last a few weeks or become a long-term, life-threatening ailment. The virus is spread through bodily fluids such as blood.

Symptoms include fever, fatigue, nausea and joint pain.