In 2024, Orange County has already identified 25 cases of dengue virus infection. This exceeds the number of county residents identified with dengue virus infection in any year over the last 10 years. All of these cases have been among international travelers and no locally acquired dengue virus infections have been identified in Orange County to date.

In June, the CDC released a Health Alert: Increased Risk of Dengue Virus Infections in the United States. While cases of dengue virus infection in the Americas have declined over the last several weeks based on data from the Pan American Health Organization (PAHO), counts remain above the 5 year average. Dengue also remains endemic in many parts of Asia and Africa.

The Aedes aegypti mosquito is the primary vector for dengue virus. Aedes aegypti are widespread in Orange County. Their presence, along with increasing numbers of travel-associated dengue virus infection, increase the risk for local transmission of dengue.  

• Maintain a high suspicion for dengue among patients with fever and recent travel (within 14 days before illness onset) to areas with frequent or continuous dengue transmission.

• Consider locally acquired dengue among patients who have signs and symptoms highly compatible with dengue (e.g., fever, thrombocytopenia, leukopenia, aches, pains, rash).

• Order appropriate FDA-approved dengue tests (RT-PCR and IgM antibody tests, or NS1 and IgM antibody tests); do not delay appropriate care waiting for test results to confirm dengue.

• Know the warning signs for progression to severe dengue, which include abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleeding, lethargy or restlessness, and liver enlargement.

• For people with suspected dengue who do not have warning signs and are not part of a population at high risk for severe dengue, consider outpatient management with close follow-up.

• While there is no specific treatment for dengue virus infection, providers should review CDC’s Clinical Care of Dengue including CDC’s recently released Dengue Clinical Management Pocket Guide.

• Providers should inform patients planning to travel of the importance of Preventing Mosquito Bites While Traveling and that they should continue these measures even upon return to help prevent locally transmission of disease.

• Providers should remember other vector borne diseases such as chikungunya, Zika, malaria and Oropouche have similar initial clinical presentations as dengue. They may be circulating in the same regions that your patients have traveled and consequently should be considered in the differential of febrile illness in a returning traveler.

CDC Dengue - https://www.cdc.gov/dengue/index.html

CDC Vector-borne Diseases - https://www.cdc.gov/vector-borne-diseases/index.html

CDPH Dengue - https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Dengue.aspx

For questions or concerns, providers can contact the OCHCA Communicable Disease Control Division at 714-834-8180.