The Hawaii Department of Health (DOH) has confirmed a travel-related Zika virus case on Oahu, marking the first such case in Hawaii for the current year. Another travel-related Zika case was reported on Oahu in May of the previous year.
Between 2015 and 2019, Hawaii experienced more frequent travel-associated Zika cases, peaking at 25 cases in 2017 when the virus was circulating globally. To date, there have been no documented locally acquired Zika cases in Hawaii.
Zika virus, similar to dengue, is primarily transmitted through the bite of an infected mosquito. Although Hawaii hosts the mosquito species capable of transmitting Zika, the virus is not established in the state. The Centers for Disease Control and Prevention (CDC) notes that Zika can also spread through sexual contact or from a pregnant person to their fetus. Infection during pregnancy can lead to severe birth defects and is associated with complications such as miscarriage, stillbirth, and preterm birth.
Common symptoms of Zika include fever, rash, headache, red eyes, and joint and muscle pain. However, many individuals infected with Zika may experience no symptoms or only mild ones, according to the CDC.
Separately, the DOH also confirmed an additional travel-related dengue case on Oahu, which will be recorded as Hawaii's 15th dengue case for 2025, based on symptom onset. Dengue symptoms include fever, rash, nausea, vomiting, and aches and pains, including eye pain.
The DOH confirmed that these Zika and dengue cases are unrelated, and the affected individuals were exposed while traveling in regions where these viruses are known to be active.
In response, DOH teams have been deployed to conduct outreach, inspections, and implement mosquito control measures in the affected areas. The department emphasized that controlling local mosquito populations is crucial to prevent the spread of both Zika and dengue, as both are transmitted by mosquito species present in Hawaii. The DOH will continue to monitor mosquito numbers in these areas but did not disclose specific locations on Oahu.
The CDC recommends that travelers review Zika and dengue risk information before departing. Individuals experiencing symptoms within two weeks of visiting an area with Zika or dengue risk should consult their doctor and inform them of potential exposure. Healthcare providers and anyone suspecting a Zika or dengue infection are advised to call the Disease Reporting Line at 808-586-4586.