The state Department of Health reported Wednesday that the number of confirmed dengue fever cases is now 176 on Hawaii island, up by nine cases since Monday.

The most recent date of illness onset was Dec. 17. The first known date of illness onset was Sept. 11.

Those sickened in 18 of the cases were visitors to Hawaii, while the remaining 158 were Hawaii island residents who have been confirmed with having had the virus.

Dengue fever is spread by infected mosquitoes, and officials are encouraging residents of Hawaii island to take measures to prevent being bitten by possibly infected mosquitoes.

As for potential cases excluded by testing or not meeting case criteria, there have been 687 such occurrences.

Symptoms include high fever, headache, nausea, red rash, muscle aches, and bone and joint pain.

Anyone who suspects having dengue fever is urged to seek medical care as some cases can become severe.

All testing is done by a state laboratory and is free to the patient.