Lettuce grows on a farm near Salinas, Calif. A multistate outbreak was linked to iceberg lettuce processed by Taylor Farms de Mexico, which on July 17 recalled all iceberg lettuce sourced from central Mexico.

The Hawaii Department of Health on Wednesday said it is investigating a sixth case of cyclosporiasis in the islands. This time, the case is not travel-related.

Health officials said an Oahu resident became ill at the end of July, and did not travel outside of Hawaii during the period when they were likely exposed, which is usually in the previous two weeks.

DOH investigators are reviewing how the infection may have been acquired locally, either through food or other potential exposures. They have not yet identified a suspected contaminated food source, officials said.

“A single locally acquired case does not change the overall risk assessment for the general public, which remains low,” health officials said in a news release. “DOH will continue to update the public on investigation findings as they become available.”

The five cases previously reported in Hawaii involved individuals who had traveled outside of the state during their likely exposure periods. The first case in July involved a nonresident visitor whose infection was acquired outside of Hawaii, officials said.

The second and third cases involved Hawaii residents from the same household who traveled internationally. The fourth and fifth cases involved separate military members based in Hawaii who had traveled internationally before becoming ill.

The latest discovery comes as the number of cyclosporiasis cases nationally surpassed 17,000, according to the U.S. Centers for Disease Control and Prevention. As of Monday, the CDC had confirmed 17,180 cases across 48 stats plus the District of Columbia, with 922 hospitalizations and two deaths.

More than 11,000 additional cases require further investigation and analysis, officials said.

The number includes a multistate outbreak that was linked to iceberg lettuce processed by Taylor Farms de Mexico, which on July 17 recalled all iceberg lettuce sourced from central Mexico.