ATLANTA (AP) - A mysterious illness has killed 30 intravenous drug users in Scotland, Ireland and England since April, and U.S. officials are helping in the investigation.

Health officials have reported 59 people with the ailment, characterized by swelling and redness at the injection site, low blood pressure and a high white blood cell count, often followed by heart failure.

Most of the deaths came about two days after the patient was admitted to a hospital, despite treatment with antibiotics and other measures.

Tests of victims' blood and tissue have uncovered multiple organisms, but none has been identified as the culprit.

Investigators said a new illness could be to blame, but a more likely cause is a known organism behaving in an unfamiliar way.

The Centers for Disease Control and Prevention were called two weeks ago by health authorities in the United Kingdom to help investigate.

No cases have been reported in the United States, but the CDC sent letters of warning last week to state health authorities.

(From Yahoo)