King County reached a new 30-year high for tuberculosis in 2007, with 161 people diagnosed with active cases.

The 11 percent increase from 2006 was among new findings in the county’s latest annual report on tuberculosis (TB).

The infectious disease, caused by the bacterium Mycobacterium tuberculosis, usually involves the lungs (pulmonary TB) but can affect almost any organ in the body.

TB is almost always curable with antibiotics, but controlling it “is an ongoing challenge,” said Dr. Masa Narita, TB control officer for Seattle-King County Public Health Department.

About 100,000 people living in the county have dormant tuberculosis and aren’t contagious, “but are potentially future active TB cases,” Narita said.

Controlling the spread of TB helps prevent drug-resistant forms of the disease that cost about $250,000 per person to cure, officials said.