Hawaii health officials are looking into a stomach parasite case in someone who never left the islands, which raises the possibility of a local food or water source.

• An Oahu resident got sick at the end of July without traveling, unlike earlier cases tied to trips off-island.
• Officials say the risk to the public is low, but they are still hunting for a local source.
• The parasite spreads through food or water contaminated with feces, and past US outbreaks have been tied to fresh produce like berries, cilantro, mint, and lettuce.
• It does not spread person to person, since the parasite needs a week or two outside the body before it can infect anyone.
• Cooking produce kills it; rinsing under warm water and washing hands are the main defenses.

Outlook: Investigators will keep tracing what the patient ate, and more cases could surface if a contaminated local supply is confirmed.