Another person has contracted rat lungworm disease on the Big Island.

The Hawaii State Department of Health (DOH) says an adult visitor got the disease while traveling on the west side of the island in late June. 

DOH officials couldn't pinpoint an exact source, but say the visitor ate a lot of fresh, unwashed food. 

The disease is caused by a parasitic roundworm that impacts the brain and spinal cord. 

In Hawai'i, most people get sick by accidentally eating a slug infected with the disease.  Common symptoms include headaches and a stiff neck. 

At least seven people have contracted the disease in Hawai'i this year.