Ask the Experts: Dengue: Disease Issues

Results (3)

Dengue is an infectious disease caused by dengue viruses (DENV) spread among people through the bite of an infected mosquito from the Aedes species (Ae. aegypti or Ae. albopictus). DENV are members of the genus Flavivirus in the family Flaviviridae.

There are four dengue virus serotypes (DENV-1, DENV-2, DENV-3, and DENV-4), all of which circulate globally. The four dengue virus serotypes are closely related but can be differentiated on serologic tests. Infection with one serotype generally produces long-lived immunity to that serotype, but only provides short-lived protection against infection with other serotypes. For this reason, a person can be infected with DENV as many as four times in their lifetime.

Symptoms of dengue range from asymptomatic or very mild (75% of cases) to severe disease complicated by shock, bleeding, or severe organ impairment. Fever is the most common symptom of dengue. Other symptoms can include sudden onset of headache, pain behind the eyes, loss of appetite, abdominal pain, nausea, vomiting, muscle aches, bone and joint pain, and flushing of the face. A generalized flat, red rash is often seen within 3–4 days of fever onset. Symptoms typically last 2–7 days, with most people recovering after about a week.

About 1 in 20 patients with dengue progress to severe dengue, typically 24-48 hours after the fever resolves. Severe dengue can become life-threatening within hours, often as a result of hypovolemic shock due to plasma leakage from the vasculature. There is no specific treatment for dengue. With proper supportive care in a hospital or intensive care unit setting, fewer than one in 100 people with severe dengue may die; fatality rates have been reported as high as 13% in the absence of adequate supportive care.

A person’s risk for progression to severe dengue varies based on several factors. Age (over 60), comorbidities (including pregnancy), host genetics, and the infecting virus strain are risk factors for severe dengue. For any individual, the second infection with a different DENV serotype is the most likely to cause severe dengue compared with the first, third, or fourth infections.

CDC has a website with additional details on the clinical presentation of dengue:
www.cdc.gov/dengue/healthcare-providers/clinical-presentation.html.

Last reviewed: February 16, 2022

Dengue is common throughout tropical and subtropical regions of the world. About half of the world’s population lives in areas suitable for DENV transmission and the main vector of dengue, the Aedes aegypti mosquito, is difficult to control and continues to expand its geographic range. Each year, up to 400 million people get infected with dengue viruses. Approximately 100 million people get sick from infection, and about 40,000 die from severe dengue.

Dengue is endemic in the United States territories and freely associated states of Puerto Rico, American Samoa, the U.S. Virgin Islands, the Federated States of Micronesia, the Republic of Marshall Islands, and the Republic of Palau. CDC classifies an area as endemic for dengue if the area has frequent or continuous dengue transmission, with evidence of more than 10 dengue cases in at least three of the previous 10 years. Dengue epidemics occur in a cyclical pattern every 3–7 years, with all four DENV serotypes reported in the Pacific Islands and the Caribbean. Limited surveillance data are available from the Federated States of Micronesia, the Republic of Marshall Islands, and the Republic of Palau.

Dengue can cause outbreaks with high numbers of cases in some years. In 2021, only 435 cases were reported in US territories, and 63 cases were reported in U.S. states. About 90% of the population at risk for dengue in US territories live in Puerto Rico. From 2010-20, approximately 95% of locally acquired dengue cases in the US occurred in Puerto Rico (29,779 cases), with the most cases and hospitalizations in Puerto Rico occurring among adolescents age 10 through 19 years (11,000 cases leading to 4,000 hospitalizations). Small convenience studies of children ages 9 through 16 conducted during vaccine trials estimated that 50% to 56% of children in this age group showed serologic evidence of past DENV infection. Dengue is not endemic in the continental United States or Hawaii; however, outbreaks and travel-associated cases have occurred in Texas, Florida, and Hawaii in recent years.

Last reviewed: February 16, 2022

Multiple complex mechanisms likely contribute to increased disease severity during a second DENV infection. The published ACIP recommendation provides a detailed description of these mechanisms at www.cdc.gov/mmwr/volumes/70/rr/pdfs/rr7006a1-H.pdf. In addition, CDC has developed simple illustrations and descriptions to explain this phenomenon at www.cdc.gov/dengue/vaccine/hcp/eligibility/index.html.

Last reviewed: February 16, 2022

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