The state laboratory tasked with testing possible cases of dengue fever is keeping pace with its typical 24-hour turnaround time as the overall count from the Big Island outbreak continues to climb.

“There’s no backup,” said Dr. Christian Whelen, who serves as director for the lab. Lab personnel test all samples, typically 50 to 60 a day, by the following business day. The lab has tested up to 84 samples in a single day.

During a briefing of legislators earlier this month, the state epidemiologist was criticized by state Sen. Josh Green (D, Kona-Kau), a Hawaii island medical doctor, and other lawmakers who called for the state to do more, including setting up an on-island lab for dengue testing rather than wait for results from the Oahu lab.

Regarding dengue testing, Whelen said, “Some tests are easy to do, but this doesn’t fall in that category.”

The state opened up its lab in Pearl City to the media Friday for a demonstration of two kinds of testing — one for antibodies and the other for the dengue virus itself. Microbiologists demonstrated the painstakingly careful work they undertake to test samples using state-of-the-art equipment in well-contained and controlled environments.

With a dozen lab personnel now handling everything from testing to uploading requisitions and sending out information to other Health Department workers, it would be difficult to also move equipment and train staff on Hawaii island, Whelen said. “It’s not very realistic,” he said.

The number of confirmed cases Friday was 146 — up by one case from Thursday’s count, with the latest onset of symptoms ranging from Sept. 11 to Dec. 3.

Of the 146 cases, 129 involved residents and 17 visitors; 114 involved adults, and 32, children.

Another 556 suspected cases have been ruled out.

Two of the cases were determined to be imported; both involved Hawaii residents — one from Hawaii island and the other from Oahu — who had returned from Asia.

Testing has so far yielded no positive cases of West Nile virus or chikungunya, state Department of Health officials said Friday.

It takes the DOH two to three days to notify health care providers from the time it obtains a sample.

Over the past seven decades various attempts have been made to develop a dengue vaccine. On Wednesday a French pharmaceutical company announced it had received approval in Mexico for the first dengue vaccine. Claiming a 60 percent efficacy rate, the vaccine is available for persons ages 9 to 45.

Sanofi Pasteur’s spokeswoman told the Honolulu Star-Advertiser that the vaccine will first be made available to countries where the virus is endemic, such as Southeast Asia and Latin America, rather than in the United States where, despite outbreaks in Hawaii and Puerto Rico, it is not endemic.

Meanwhile, Takeda Pharmaceuticals will begin in the first half of 2016 the final phase of developing a vaccine from the dengue virus. This clinical trial phase, which could take two to four years, involves testing the vaccine in populations where the disease is endemic. Its U.S. approval may be five years away.

“A vaccine for the dengue virus has been the target of development for more than 70 years,” said Dr. John Boslego of Takeda’s Global Vaccine Business Unit in Illinois. “It’s been a difficult target to be successful at.”

He said the vaccine is being developed for all four serotypes of dengue. “The backbone virus is for the Type 2 dengue,” unlike the Sanofi Pasteur vaccine, he said.

The Sanofi Pasteur vaccine is derived from the related yellow fever virus, the Star-Advertiser confirmed with Sanofi Pasteur.

“No vaccine works 100 percent of the time, but we are striving for protection of 70 to 90 percent of individuals,” he said. When someone is inoculated, an immune response is stimulated and “basically kills the virus,” Boslego said.

“Other ways to control dengue is much more difficult,” such as keeping people from getting bitten and eliminating mosquitoes, he said.

“If you had an effective, highly protective vaccine, if we had one today, I’m certain the authorities would be anxious to utilize it on the Big Island,” Boslego said. The more people who have an immune response, the less risk of dengue spreading, he said.

Hawaii Biotech Inc. announced Dec. 3 the Army’s Small Business Innovation and Research program had awarded it a small-business contract to develop an effective dengue vaccine to protect military personnel against the disease.

Worldwide, dengue cases number 400 million, and 40 percent of the world’s population lives in a region where dengue is endemic, Boslego said. “It’s actually frightening. Perhaps, people speculate, because of global warming dengue is spreading.

“There is a huge travel market including business, tourist and U.S. military travel to places that have a lot of dengue,” such as Thailand, Vietnam and Brazil, he added.