Some diseases are transmitted to humans by mosquitoes. These disease often cycle back and forth from mosquito to human and back so that if an uninfected mosquito bites a human who is infected with one of these particular diseases, the mosquito can become infected themselves. After a certain period of time (e.g., a week), these mosquitoes become able to infect the next humans they bite. It is usually the female mosquitoes, rather than the males, that bite, so they can lay their eggs afterward.Not all mosquitoes transmit diseases, and many diseases are only spread by certain mosquito species. For example, dengue, chikungunya, and Zika virus diseases are transmitted by the day-biting Aedes (Stegomyia) mosquitoes, which are found here in Hawaii. Specifically, Aedes albopictus may be found on all islands, while Aedes aegypti has only been found in some areas on the Big Island.
Mosquito-borne diseases may cause serious illness. You can protect yourself and your family by getting rid of mosquito breeding sites (i.e., areas with standing water) around your home and by taking steps to protect yourself from mosquito bites (like using mosquito repellent).
Mosquito-borne diseases are not felt to be an immediate threat in Hawaii-e.g., because travelers are usually vaccinated (yellow fever) or disease spread requires a sick bird to travel all the way from the mainland (West Nile virus). Some mosquito-transmitted diseases (e.g., malaria or Japanese encephalitis virus) are not likely to ever be a threat because the mosquito species needed to spread the disease are not found in Hawaii. However, it is important for travelers to be aware of these serious diseases and where they occur in the world so they may protect themselves.
For health-related information for your travel destination, visit the Centers for Disease Control and Prevention’s (CDC) “Traveler’s Health” site.
Case Counts of Mosquito-Transmitted Diseases of Direct Threat to Hawaii
Number of confirmed cases during 2025
As of July 2025 (Case counts will be updated on the first working day of the month)
| Arbovirus | Total Number of Cases |
|---|---|
| Dengue | 9 |
| Chikungunya | 0 |
| Zika | 1 |
| West Nile Virus | 0 |
| Malaria | 0 |
Number of confirmed cases in past 4 years
| Arbovirus | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|
| Dengue | 0 | 3 | 6 and 1 probable | 16 |
| Chikungunya | 0 | 0 | 0 | 0 |
| Zika | 0 | 0 | 0 | 0 |
| West Nile Virus | 0 | 0 | 0 | 1 |
| Malaria | 1 | 2 | 5 | 2 |