Dengue Outbreaks

Authored by

Last reviewed

September 26, 2023

Fact checked by Holly Lutmer PharmD
Fact checked by Robert Carlson, MD

Content Overview

Dengue outbreaks in Asia, Brazil, Caribbean, Costa Rica, Florida, France, India, Mexico, Peru, Puerto Rico, Spain, Thailand in 2023.

Dengue Outbreaks September 2023

According to the U.S. Centers for Disease Control and Prevention (CDC), Dengue is a vaccine-preventable, vectorborne infectious disease caused by four dengue viruses (DENV) and is endemic in about 125 countries. Dengue is present in Asia, the Pacific Islands, the Americas, and Africa. The CDC recently issued Travel Health Notices regarding dengue outbreaks in the Americas (September 25, 2023), Africa/Middle East (July 21, 2023), Costa Rica, and Asia/Pacific Islands (July 25, 2023). In addition, the Pan American Health Organization (PAHO) and the World Health Organization (WHO) issued various dengue travel advisories in 2023. The European Centre for Disease Prevention and Control (ECDC) confirmed as of August 23, 2023, over 3.7 million cases and 2,000 dengue-related deaths have been reported globally.

On June 30, 2023, a study concluded higher environmental temperature shortens the DENV extrinsic incubation period in mosquitoes, increases human transmission, and plays a critical role in dengue outbreak dynamics. Dr. Easwaran Sreekumar, who led the research team, commented, "The body temperature of mosquitoes is not constant as in higher animals, and it increases or decreases as temperatures change. The Annals of Internal Medicine published results from a study on June 20, 2023, which found most dengue patients acquired the disease in the Caribbean (31%) and Southeast Asia (24%). A recent study published by the Royal Society indicates that dengue-carrying mosquitoes are expanding their range by an average of 6.5 meters of elevation and have moved polewards by 4.7 km annually.

Dengue Africa

The U.S. CDC stated on July 21, 2023, that Dengue is an ongoing risk in many parts of Africa, such as Egypt, São Tomé and Príncipe, Somalia, and Sudan. And Ethiopia has had nearly annual dengue outbreaks since 2013. In addition, there has been an ongoing dengue fever outbreak in the Afar region in northeastern Ethiopia since April 2023. The World Health Organization Africa Region reported on May 29, 2023, a total of 1,638 suspected and confirmed dengue cases and nine associated deaths (case fatality ratio 0.5%) in Logia and Mille districts in the Region from April 4 through May 10, 2023. The U.S. CDC issued a Travel Health Notice on July 21, 2023, confirming Dengue is an ongoing risk in Mauritius.

Dengue in the Americas

As of September 2023, the WHO assessed the risk of dengue outbreaks as high at the regional level due to the widespread distribution of the Aedes spp. Mosquitoes in the Region of the Americas. The total number of dengue cases reported until September 19, 2023, was 3,407,921. The highest number of dengue cases were reported in Brazil, with 2,569,746 cases, followed by Peru. With regard to the severe dengue cases reported in 2023, the highest number of cases were reported in Brazil, with 1,396 severe cases, followed by Colombia, Peru, Bolivia, and Mexico. Countries with severe dengue cases included Cuba, Honduras, Colombia, Panama, Paraguay, the Dominican Republic, Guatemala, Grenada, Puerto Rico, the U.S. Virgin Islands and British Virgin Islands (9.09%). Additionally, the case fatality rate [CFR] is 0.047%). The WHO reported 2.8 million dengue cases from 46 countries in the Region of the Americas in 2022.

According to the Republic of Costa Rica Health Surveillance Directorate, for epidemiological week 36, 10,286 dengue cases were reported, with the Huetar Caribe and Central Sur regions presenting the most cases. As of August 4, 2023, all four dengue serotypes were registered.

Dengue has been reported in 28 of 32 Mexico states in 2023. Quintana Roo (Cancun) is the leading state reporting Dengue cases in 2023. In 2022, the PAHO reported 36,926 cases throughout Mexico and 53 dengue deaths (Sonora confirmed 14 deaths, Oaxaca 13 deaths). In addition, dengue transmission has been documented in Yucatan, Mexico (Cancun) since 1979. The recent increase in dengue cases in Mexico has been partly attributed to the genetic diversification of DENV serotypes and the emergence of new genotypes across Latin America (Hernández-García et al., 2020).

Dengue Asia

Dengue is an ongoing risk in many parts of Asia, such as Bangladesh, Cambodia, India, Laos, Malaysia, Maldives, Myanmar (Burma), Pakistan, Sri Lanka, Thailand, and Vietnam, as of September 2023. Dengue cases have steadily increased in the last 50 years - East Asian countries such as India. Dengue is endemic in India with an overall seroprevalence of 48·7 % (95 % CI 43·5–54·0). Over a hundred thousand dengue cases are diagnosed in India annually, and about half of the country's population carries dengue virus-specific antibodies. Since 2000, genotype III of DENV-1, the cosmopolitan genotype of DENV-2, genotype III of DENV-3, and genotype I of DENV-4 have dominated India. Moreover, the DENV-4-Id is drifting towards DENV-1 and DENV-3 clades, suggesting the role of cross-reactive antibodies in its evolution. As of June 11, 2023, Mumbai has reported 386 dengue cases, accounting for 31% of all registered cases in 2023.

The WHO published Dengue Situation Report # 1 on August 28, 2023, confirming Dengue is endemic in Bangladesh, with yearly increases and peaks reported around the monsoon season. According to Bangladesh's Directorate General of Health Services, the dengue cases recorded as of August 11, 2023, exceed 78,000 and at least 364 deaths. Of these, 63% of patients and 62% of deaths were reported in July 2023. The WHO reported from January to August 7, 2023, the case fatality rate (CFR) of 0.47%. As of December 2022, a total of 274 related fatalities (CFR 0.44%) were reported by the Ministry of Health & Family Welfare of Bangladesh in 2022. According to a Bangladesh Sangbad Sangstha report in 2019, 179 deaths were reported.

Dengue Europe

The European CDC reported in July and August 2023 that six autochthonous/non-travel-associated dengue cases have been reported in Europe, from France (2) and Italy (4). Six cases from 2022 were reported retrospectively in Spain in 2023. Ibiza, Spain, health officials issued a dengue warning in March 2023. "One of the potential vectors of dengue is the Aedes albopictus mosquito, present throughout the area, the Spanish Mediterranean and the Balearic Islands and also in some areas of the interior and north of the country," a spokesperson for the Spanish Ministry of Health said, according to EuroNews. From May through December 9, 2022, Public Health France reported metropolitan France confirmed 272 imported cases of dengue fever.

Dengue United States

Provisional data published by the U.S. CDC as of September 13, 2023, indicates 44 jurisdictions have reported about 880 dengue cases in 2023. In addition, the CDC says Dengue is endemic in the U.S. territories 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.

As of September 23, 2023, the Florida Health Department reported that there had been 316 travel-associated dengue cases (Miami-Dade) and 31 locally acquired dengue cases confirmed as week #38 in 2023. Both Miami-Dade and Broward Counties remain under a mosquito-borne illness alert. In 2022, 903 travel-associated and 68 locally-acquired dengue cases were reported. In 2022, the Florida Department of Health in Miami-Dade County confirmed (DENV-3) cases.

As of July 27, 2023, Puerto Rico's Department of Health Arboviral Disease Week #34 report indicates about 525 probable dengue cases in 2023. In 2022, 929 confirmed dengue cases and three related fatalities were reported. From 2010 to 2020, approximately 95% of locally acquired dengue cases in the U.S. (n = 31,289) occurred near San Juan, Puerto Rico (n = 29,779). The estimated dengue seroprevalence among persons nine years of age was approximately 40%. During 2010–2020, Puerto Rico reported the highest number of dengue cases (29,862 [96.6%]), followed by American Samoa (660), USVI (353), and Guam (28). A recent CDC study stated that dengue vaccinations' cost-effectiveness in PR depends on the seroprevalence, which is lower for younger age groups.

Dengue Western Pacific Region

Dengue is an ongoing risk in many parts of the Pacific Islands, such as the Philippines and Taiwan, as of July 25, 2023. The WHO published Update #664 on the Dengue situation in the Western Pacific Region. As of August 2023, countries like Vietnam, Singapore, the Philippines, Thailand, and Malaysia experienced dengue outbreaks. Thailand's Bureau of Epidemiology, Department of Disease Control reported through epidemiology week #20 there have been 16,650 dengue cases, including 14 deaths in 2023. The Dengvaxia and Qdenga vaccines are commercially available in Thailand in 2023.