NASHVILLE (AP) - Tennessee inmates infected with hepatitis C have filed a federal lawsuit against state prison officials, seeking treatment for all inmates who have the potentially deadly disease.

The American Civil Liberties Union and other advocates are alleging in U.S. District Court in Nashville that Tennessee Department of Correction officials are knowingly denying inmates care for their hepatitis C.

The lawsuit alleges the department is denying care because the best available medication is too expensive, The Tennessean reported (http://tnne.ws/2aqGNVp).

"In reality, (department officials) ignore the medical needs of (inmates) and class members in order to save costs. (The department's) written policies for HCV diagnosis, assessment and treatment utilize outdated standards of care and normalize the practice of refusing treatment for unjust and medically unsound reasons," the lawsuit said.

Tennessee Department of Correction spokeswoman Neysa Taylor said in an email the department "is currently unaware of the referenced court filing but is confident the department is providing adequate medical care as determined by medical protocol."

The suit was brought by inmates Charles Graham and Russell L. Davis.

"Incarcerating people under conditions that erode their health, safety and human dignity amounts to cruel and unusual punishment, which not only has devastating long-term effects for those individuals, but which undermines the purported purpose of a rehabilitative criminal justice system," Thomas Castelli, the ACLU-TN legal director, said in a news release.

A Tennessean investigation earlier this year found that, as of March, nearly 3,500 inmates had hepatitis C while only eight were receiving treatment that could cure them.

Hepatitis C was difficult to treat until the release of new medications in late 2013. The new medications result in curing the infection in more than 90 percent of cases. But one pill can cost $1,000.

The attorneys are seeking class-action status for the case.