HILO >> Two more cases of rat lungworm disease have been confirmed in the state, bringing the total up to 13, Hawaii health officials said.

The patients in two new cases are from the Big Island and are separate from kava elixir-related cases reported earlier this week, said State Health department officials, who made the announcement Friday.

One of patients is being treated at a local hospital after tests for the disease came back positive Wednesday. The other was at a hospital on the mainland and tested positive a month ago.

Rat lungworm disease is caused by a parasite found in rodents, which can pass the parasite to snails, slugs, crabs and other critters. It can cause damage to the brain and spinal cord and bring nausea, severe pain and temporary paralysis.

The sources of the new patients’ exposure have not been determined, according to the department. Officials are not calling this year’s outbreak an epidemic. Last year, there were 11 rat lungworm disease cases reported.

This year’s cases have been linked to the Big Island and Maui.