The first cases of locally contracted dengue fever in 10 years appear to be limited to five Pearl City residents and did not become a major outbreak.

The state Department of Health has ended its investigation of a possible dengue fever outbreak after 65 of the 83 reports of suspected dengue cases received from physicians since March 24 were ruled out or found to be negative, Environmental Health Deputy Director Gary Gill said yesterday. The department did not have results of the remaining 18 cases.

The Health Department had known of four probable cases of dengue fever since March and recently found a fifth case believed to be the person who first brought the mosquito-borne disease to Pearl City.

That fifth person, a Pearl City resident, had traveled to Asia, became infected there, then returned home, where the disease spread by mosquitoes to the other four Pearl City residents, the department said.

Gill did not know the relationship of the initial case to the four other cases, but he did say the area in which the four lived was swarming with mosquitoes. “It was a mosquito paradise,” he said.

In a 2001 outbreak in which 153 people contracted the disease, three cases were linked to a person who reported denguelike illness after traveling to French Polynesia, a 2005 study showed.

“We can’t let our guard down on diseases like dengue fever,” said Dr. Sarah Park, state epidemiologist and chief of the Disease Outbreak and Control Division. “It’s an ongoing effort that requires continued vigilance on the part of the department, physicians and the public. Although this most recent publicized investigation has been closed, my staff continues to investigate reported cases so the department can act quickly to control and prevent the possible spread of illness.”

The virus is passed from human to mosquito to human but cannot be transmitted human to human. Often travelers to tropical or subtropical regions who visit or return to Hawaii bring the disease with them.

“The problem continues as soon as someone else brings the dengue infection back to Hawaii and gets bitten by a mosquito, so it’s a constant threat,” Gill said. “That’s why we’re constantly reminding people to abate their mosquitoes.”

Dengue fever is usually characterized by high fever, pain behind the eye and muscle pain.

In February a doctor in Wisconsin suspected dengue fever in a visiting woman from Pearl City and had her blood tested for the virus. Those results were reported to Hawaii’s Department of Health. Two of the woman’s family members and a neighbor also came down with the disease. These cases were later confirmed.