BELFAST, Maine — State officials have issued a medium priority health advisory after confirming a cluster of three acute cases of hepatitis a in Waldo County.

All three people affected by the disease live in Waldo County, according to an advisory issued Thursday by the Maine Center for Disease Control and Prevention.

“At least one [person] attended a number of social functions in different areas of Maine while infective which included attendees from across the state,” the advisory said.

“We, therefore, believe other people may be at risk for contracting the illness and may be showing signs and symptoms of it in the coming days and weeks.”

Attempts Saturday afternoon to contact state officials for further information about the reported cases of hepatitis a were unsuccessful.

According to the advisory, hepatitis a is an “uncommon” disease in Maine, resulting in 11 cases on average in the state each year. it can result in mild illness for children, with many cases being asymptomatic, while in adults the disease can range in severity from mild to life-threatening. Less than 2 percent of people over the age of 50 who contract hepatitis a die from the disease, the advisory said.

The virus that causes hepatitis a is excreted in feces and is transmitted “by the fecal-oral route,” state officials said in the release.

“Good hand-washing is key to limiting disease transmission,” the advisory states.

A year ago, an outbreak of hepatitis a on Swan’s Island resulted in the death of one summer resident and the hospitalization of another after both had left the state. in all, six cases were identified, all of which were traced back to the same house on the Hancock County island.

At the time, state officials said they believed the house’s septic system may have been malfunctioning. in fall 2008, an outbreak of hepatitis a at Kennebunk Elementary School resulted in approximately seven people contracting the disease.

Dr. Dora Anne Mills, head of Maine CDC, said in August 2009 that the disease has a long incubation period and can lie dormant for weeks before symptoms become apparent.

Anyone exhibiting symptoms such as diarrhea, fatigue, fever or nausea should consult a doctor, she said at the time.

“If they have symptoms, they should be seen right away,” Mills said. “The sooner the better.”

More information about hepatitis a and the Waldo County cluster is available online at maine.gov/dhhs/boh/index.shtml#han.