Symptoms range from a mild febrile illness to severe disease associated with hemorrhage and shock. Onset is usually 7-10 days after infection and symptoms include high fever, severe headache, retro-orbital pain, arthralgia and myalgias, nausea, and vomiting; some may develop a generalized rash.
The World Health Organization (WHO) classifies dengue as 1) dengue with or without warning signs for progression of disease and 2) severe dengue. Warning signs for disease progression include abdominal pain or tenderness, persistent vomiting, fluid accumulation (e.g., ascites, pericardial or pleural effusion), mucosal bleeding, restlessness, postural hypotension, liver enlargement greater than 2 cm. Severe dengue is defined as any sign of severe plasma leakage leading to shock, severe bleeding or organ failure, or fluid accumulation with respiratory distress. Management is supportive care.
Dr. Bonnie M. Word
Prevention: In the US, Dengvaxia, a live attenuated tetravalent vaccine, is approved for use in children aged 9–16 years with laboratory-confirmed previous dengue virus infection and living in areas where dengue is endemic. It is administered at 0, 6, and 12 months. It is not available for purchase on the mainland. Continued control of the vector and personal protection is necessary to prevent recurrent infections.
CHIKV
Chikungunya (CHIKV), which means “that which bends up” in the Mkonde language of Tanzania, refers to the appearance of the person with severe usually symmetric arthralgias characteristic for this infection that otherwise is often clinically confused with dengue and Zika. It too is transmitted by A. aegypti and A. albopictus and is prevalent in tropical Africa, Asia, Central and South America, and the Caribbean. Like dengue it is predominantly an urban disease. The WHO reported the first case in the Western Hemisphere in Saint Martin in December 2013. By August 2014, 31 additional territories and Caribbean or South American countries reported 576,535 suspected cases. Florida first reported locally acquired CHIKV in June 2014. By December an additional 11 cases had been identified. Texas reported one case in 2015. Diagnosis is with IgM ab or PCR. Treatment is supportive with most recovering from acute illness within 2 weeks. Data in adults indicate 40-52% may develop chronic or recurrent joint pain.
Prevention: IXCHIQ, a live attenuated vaccine, was licensed in November 2023 and recommended by the CDC in February 2024 for use in persons at least 18 years of age with travel to destinations where there is a CHIKV outbreak. It may be considered for persons traveling to a country or territory without an outbreak but with evidence of CHIKV transmission among humans within the last 5 years and those staying in endemic areas for a cumulative period of at least 6 months over a 2-year period. Specific recommendations for lab workers and persons older than 65 years were also made. This is good news for your older patients who may be participating in mission trips, volunteering, studying abroad, or just vacationing in an endemic area. Adolescent vaccine trials are ongoing and pediatric trials will soon be initiated. In addition, vector control and use of personal protective measures cannot be emphasized enough.
There are several other mosquito borne diseases, however our discussion here is limited to three. Why these three? WNV as a reminder that it is the most common neuroinvasive agent in the US. Dengue and CHIKV because they are not endemic in the US so they might not routinely be considered in febrile patients; both diseases have been reported and acquired on the mainland and your patients may travel to an endemic area and return home with an unwanted souvenir. You will be ready for them.
Dr. Word is a pediatric infectious disease specialist and director of the Houston Travel Medicine Clinic. She said she had no relevant financial disclosures.
Suggested Reading
Chikungunya. Centers for Disease Control and Prevention. 2024. https://www.cdc.gov/vaccines/acip/recommendations.html.
Fagrem AC et al. West Nile and Other Nationally Notifiable Arboviral Diseases–United States, 2021. MMWR Morb Mortal Wkly Rep. 2023 Aug 25;72(34):901-906.
Fever in Returned Travelers, Travel Medicine (Fourth Edition). 2019. doi: 10.1016/B978-0-323-54696-6.00056-2.
Paz-Baily et al. Dengue Vaccine: Recommendations of the Advisory Committee on Immunization Practices, United States, 2021 MMWR Recomm Rep. 2021 Dec 17;70(6):1-16).
Staples JE and Fischer M. Chikungunya virus in the Americas — what a vectorborne pathogen can do. N Engl J Med. 2014 Sep 4;371(10):887-9.
Mosquitoes and Diseases A-Z, Centers for Disease Control and Prevention. https://www.cdc.gov/mosquitoes/about/diseases.html.