Disease Outbreak News

Dengue - Global situation

30 May 2024

Situation at a glance

As of 30 April 2024, over 7.6 million dengue cases have been reported to WHO in 2024, including 3.4 million confirmed cases, over 16 000 severe cases, and over 3000 deaths. While a substantial increase in dengue cases has been reported globally in the last five years, this increase has been particularly pronounced in the Region of the Americas, where the number of cases has already exceeded seven million by the end of April 2024, surpassing the annual high of 4.6 million cases in 2023. Currently, 90 countries have known active dengue transmission in 2024, not all of which have been captured in formal reporting. In addition, many endemic countries do not have strong detection and reporting mechanisms, so the true burden of dengue globally is underestimated. In order to control transmission more effectively, real-time robust dengue surveillance is needed to address concerns about potential undetected cases, co-circulation and misdiagnosis as other arboviruses, and unrecorded travel movements. These factors could contribute to unrecognized disease spread and establish a potential risk for local transmission in non-endemic countries. Dengue virus is transmitted to humans through the bite of infected mosquitoes. Cases are most commonly asymptomatic or result in mild febrile illness. However, some cases will develop severe dengue, which may involve shock, severe bleeding or severe organ impairment. To strengthen global surveillance, and monitor temporal trends and disease incidence, WHO has established a global dengue surveillance system with monthly reporting across all WHO regions with a new dashboard now live (https://worldhealthorg.shinyapps.io/dengue_global/). The overall capacity for countries to respond to multiple, concurrent outbreaks continues to be strained due to the global lack of resources, including shortages of good quality dengue diagnostic kits for early disease detection, lack of trained clinical and vector control staff and community awareness. Emergency response mechanisms have been established, and WHO supports high-risk countries across affected regions. Given the current scale of the dengue outbreaks, the potential risk of further international spread and the complexity of factors impacting transmission, the overall risk at the global level is still assessed as High and thus dengue remains a global threat to public health.

Description of the situation

 

Global overview

Current situation

As of 30 April 2024, over 7.6 million dengue cases have been reported to WHO in 2024, including 3.4 million confirmed cases, over 16 000 severe cases, and over 3000 deaths. While a substantial increase in dengue cases has been reported globally in the last five years, this increase has been particularly pronounced in the Region of the Americas, where the number of cases has already exceeded seven million by the end of April 2024, surpassing the annual high of 4.6 million cases in 2023. Furthermore, this is three times what was reported during the same period in 2023, highlighting the acceleration of this health problem.  Dengue virus is transmitted to humans through the bite of infected mosquitoes. Cases are most commonly asymptomatic or result in mild febrile illness. However, some cases will develop severe dengue, which may involve shock, severe bleeding or severe organ impairment.

The risk of dengue is similar across regions, countries, and within countries. Factors associated with an increasing risk of dengue epidemics and spread to new countries include:

  • early start and longer duration of dengue transmission seasons in endemic areas;
  • changing distribution and increasing abundance of the vectors (Aedes aegypti and Aedes albopictus);
  • consequences of climate change and periodic weather phenomena (El Nino and La Nina events) leading to heavy precipitation, humidity, and rising temperatures favouring vector reproduction and virus transmission;
  • changes in the circulating serotypes within a country affecting population immunity;
  • fragile health systems amid political and financial instability in countries facing complex humanitarian crises and large-scale population movements impairing the public health response;
  • movement of people who are infected and goods that could carry the mosquito vectors.

Currently, 90 countries have known active dengue transmission in 2024, not all of which have been captured in formal reporting. In addition, many endemic countries do not have strong detection and reporting mechanisms, so the true burden of dengue globally is underestimated. In order to control transmission more effectively, real-time robust dengue surveillance is needed to address concerns about potential undetected cases, co-circulation and misdiagnosis as other arboviruses, and unrecorded travel movements. These factors could contribute to unrecognized disease spread and establish a potential risk for local transmission in non-endemic countries.

To strengthen global surveillance, and monitor temporal trends and disease incidence, WHO has established a global dengue surveillance system with monthly reporting across all WHO regions, which is now available as a dashboard.   This has so far captured 103 countries (Figures 1 and 2) including 28 zero reporting countries. No autochthonous or locally transmitted dengue cases have been reported in Europe so far in 2024 but these data will be added when autochthonous cases occur, which can occur when seasonal conditions permit vector activity from June to November.  

Given the current scale of the dengue outbreaks, the potential risk of further international spread and the complexity of factors impacting transmission, the overall risk at the global level is still assessed as High and thus dengue remains a global threat to public health.

Figure 1. Epidemic curve of dengue cases and deaths as reported to WHO from January to April 2024*

* Note: includes 103 countries so far integrated in the WHO global surveillance system, 28 of which have submitted zero reports to date

Figure 2: Geographical distribution of dengue cases as reported to WHO from January to April 2024*

*Note: only 103 countries integrated in the WHO global dengue surveillance system so far are shown 

Co-circulation of dengue, chikungunya and Zika viruses

There is considerable overlap in the geographic distribution of dengue, chikungunya, and Zika viruses, which are all transmitted by Aedes mosquitoes and share some clinical features that can result in misdiagnoses and misreporting in the absence of differential laboratory testing. Surveillance data during large outbreaks of ‘suspected dengue’ may erroneously include cases of one or both of the other diseases. For instance, in one study in Brazil (Ribas Freitas AR, et al., 2024), in the state of Minas Gerais in 2023, ‘suspected dengue’ accounted for 84.4% of cases of the 828 654 cases of ‘suspected arboviruses’, and ‘suspected chikungunya’ only accounted for 15.6%. The true proportion of the two diseases amongst laboratory-confirmed cases was 65.9% chikungunya and only 34.1% dengue.

Surveillance systems specifically targeting endemic transmission of chikungunya or Zika are weak or non-existent in many countries. Misdiagnosis between diseases is a surveillance concern because skewed surveillance can misinform policy decisions. As dengue, chikungunya, and Zika viruses share the same Aedes mosquito vectors and co-circulate in the same geographic areas, they also share many prevention strategies, such as differential diagnosis, mosquito control and public awareness campaigns. However, there are important differences between these diseases that affect risk populations, patient management and use of health care resources. For instance, Zika is particularly dangerous for pregnant women due to its association with Congenital Zika Syndrome. Consequently, expanding surveillance to simultaneously monitor for all three viruses can help public health authorities accurately determine the true burden of each disease, refine risk assessments, and optimize clinical management and resource allocation for more effective public health interventions.

So far in 2024, more than 250 000 cases of chikungunya have been reported to WHO and almost 7000 cases of Zika virus disease. Figure 3 shows countries/territories/areas with evidence of current or previous circulation of at least two of the three viruses.

Figure 3: Countries, territories or areas with previous or current local mosquito-borne transmission of more than one Aedes-borne virus (dengue, chikungunya and Zika) as of 30 April 2024

Regional overview

African Region

The African region is strongly affected by arboviruses, although the exact burden is not well understood due to challenges with laboratory capacity. There is evidence of current or prior dengue circulation in local populations and/or among travellers returning from approximately 30 African countries. In 2023, outbreaks were reported in 15 countries in the WHO African Region: Benin, Burkina Faso, Cabo Verde, Chad, Côte d'Ivoire, Ethiopia, Ghana, Guinea, Mali, Mauritius, Niger, Nigeria, São Tomé and Principe, Senegal, and Togo. 

In 2024, from 1 January to 28 April, 13 countries are known to have ongoing active transmission of the dengue virus — Benin, Burkina Faso, Cape Verde, Côte d’Ivoire, Ethiopia, Kenya, Mali, Mauritania, Mauritius, Niger, São Tomé and Principe, Senegal, and the Seychelles. A total of 32 925 dengue cases (14 095 confirmed; 1051 severe cases) and 57 deaths have been reported from these 13 countries and an additional 16 countries have reported zero cases through their respective routine surveillance mechanisms. Circulation of three of the four dengue serotypes of the dengue virus (DENV-1, DENV-2, DENV-3) has been identified in the WHO African region. The current priority countries based on dengue burden are Burkina Faso, Mauritius and Mali. Burkina Faso reported 72% of all cases and 89% of all deaths in the region from the beginning of 2023 to 28 April 2024, and remains the country with the largest dengue burden, reporting 17 098 cases (52%) and 38 deaths (67%) in 2024. Mauritius reported 7177 dengue cases and 15 deaths during the first 17 weeks of 2024, with only DENV-2 serotype being detected to date. In Mali between 1 January and 28 April 2024, a total of 3231 dengue cases and three deaths have been reported, with two serotypes (DENV-1, DENV-3) currently circulating. The main challenges in addressing dengue in the affected countries include funding constraints that hinder preparedness and response, shortages of rapid diagnostic tests, vector control specialists, lab technicians, and entomologists.

Region of the Americas

Dengue is the most widespread arbovirus and causes the highest number of arboviral disease cases in the Region of the Americas, with cyclical epidemics every 3 to 5 years. The Ae. aegypti, the first vector mosquito for dengue, is established in all countries in the Americas except Canada, which has also reported no prior autochthonous dengue cases. Previously, the highest burden of dengue was reported in 2023 with 4 600 086 suspected cases, including 2 048 048 laboratory-confirmed cases being recorded. However, in 2024 as of the end of April, there have already been 7 517 060 suspected dengue cases (3 528 635 laboratory-confirmed), 7374 (0.10%) severe dengue, and 3504 deaths (Case Fatality Ratio (CFR) 0.05%) reported. There are three times more suspected cases in 2024 to date than over the same period in 2023. Several countries in the northern hemisphere are also reporting a significant number of suspected dengue cases even though they have not yet entered their period of high transmission, which typically occurs in the second half of the year. 

In 2024, Brazil is the country with the highest number of cases, with 6 296 795 suspected dengue cases (3 040 736 laboratory-confirmed), followed by Argentina (420 867 suspected cases), Paraguay (257 667 suspected cases), and Peru (199 659 suspected cases).  All four dengue serotypes have been detected across the region and in 2024; six countries (Brazil, Costa Rica, Guatemala, Honduras, Mexico, and Panama) have already reported the simultaneous circulation of all dengue serotypes.   

Eastern Mediterranean Region

Dengue outbreaks continue to be reported in both fragile, conflict-affected, and/or vulnerable countries in the region that have weakened healthcare systems as well as countries with stronger healthcare systems that have been affected by unusual rains due to climate change. Ae. aegypti and some Ae. Albopictus mosquitoes have been identified in most of the countries in the region. In areas affected by armed conflict, the lack of detailed and timely information complicates a coordinated dengue response. Additionally, timely data sharing also remains a challenge for other countries in the region for reasons such as the potential impact in the tourism, economy and other sectors. 

European Region

Dengue is not endemic in the WHO European Region and reported cases are mainly travel-related. However, there have been sporadic autochthonous dengue cases and few dengue outbreaks reported in the region since 2010 with evidence of dengue transmission from five countries: Croatia, France, Italy, Portugal (Madeira), and Spain. In 2023, autochthonous cases were reported in three countries: Italy (82), France (45) and Spain (3). No autochthonous dengue cases have been reported in Europe so far in 2024, though the summer has not yet started when mosquito vector activity commences. Testing capacity for dengue is limited in many Member States in the WHO European Region, especially outside the European Union, and most cases likely are first-time infections and therefore mild and do not present for care, the actual numbers of dengue cases may be underestimated. 

Strong public health systems, good clinical care including access to early diagnosis, case referral, and management of severe cases, relatively short vector season, and relatively unsuitable conditions for disease transmission all contribute to reduced severe health impact and further disease spread for both imported and autochthonous cases. The region is preparing for, likely limited, local transmission in the upcoming summer and early autumn months.

The competent vector, Aedes albopictus, has been establishing itself further north and west in the European region over the past ten years. Additionally, Aedes aegypti has already been established in Cyprus, and Madeira, Portugal. While cold winters in the majority of the region do not allow for year-round transmission, the climatic suitability for transmission of dengue infections in the European region may increase with changes in climate, including potential higher temperatures and milder winters, increase in the geographical range of the competent vectors, and temperature suitability for virus transmission.  Changes in humidity and precipitation (followed by floods and stagnant water pools) may also create more favourable conditions for the vector population and therefore increased suitability for transmission of dengue virus.   

South- East Asia Region

In the South-East Asia Region, all Member States have the environmental conditions for dengue endemic transmission, and all have systematically reported dengue cases, except the Democratic People’s Republic of Korea. There are clear seasonal patterns in dengue incidence, associated with the climate patterns in respective countries. 

In 2024, Indonesia is experiencing a surge in dengue incidence, with 88 593 confirmed cases and 621 deaths as of    30 April 2024 – approximately three times higher than the same period in 2023. In 2024 Bangladesh, Nepal, and Thailand have reported a higher number of cases compared to the same period of 2023. From January to April 2024, the CFR varied from 0% in Nepal to 1.09% in Bangladesh. However, interpreting these values requires caution since the case definition used varies across countries with some countries reporting only (lab confirmed) hospitalized cases (compared to others reporting probable cases from communities), hence leading to higher case fatality rate among those hospitalized or severe dengue cases.    

The surge in dengue incidence is likely triggered by various factors, including shifts in the circulating serotype and climate change. At least five countries (Bangladesh, India, Myanmar, Nepal and Thailand) are currently grappling with the initiation of monsoon season, which creates suitable conditions for Aedes mosquito breeding and survival. Additionally, urbanization and population movements have played a pivotal role in the increasing burden in the region. Changes in the predominant circulating serotype increase not only the incidence but also the population risk of subsequent exposure to a heterologous DENV serotype, which in turn increases the risk of higher rates of severe dengue and deaths.

Western Pacific Region

The Western Pacific Region continues to face a high burden of mosquito-borne arboviral diseases, particularly dengue, which is endemic in twenty-three countries in the region. In 2024, seven countries including Australia, Cambodia, China, Lao People’s Democratic Republic, Malaysia, Singapore, and Viet Nam have reported dengue cases; Malaysia and Viet Nam are the most affected as of 22 April, reporting 50 650 cases and 39 deaths (CFR 0.07%) and 16 111 cases and one death (CFR 0.01%) respectively. Factors such as climate change, underdevelopment of infrastructure, cross-border population movements, and the resurgence of global travel following the COVID-19 pandemic, increase the risk of further international spread. The number of cases is expected to continue increasing once the rainy season begins in June. 

There have not been any large outbreaks reported from Pacific Island countries/territories (PICs) in several years however in 2024, outbreaks have been reported in Fiji (3841 cases), Samoa (261 cases), Tokelau (130 cases as of 23 January 2024) and French Polynesia (43 cases). With ongoing travel between the PICs and the presence of competent Aedes mosquitoes, there is a risk of outbreaks occurring because of introduction from areas with active transmission.

Member States in the region with endemic transmission continue to report longer seasonal dengue epidemics with increasing magnitude and geographic spread. However, disease burden estimation is less reliable due to the underreporting of cases, particularly in the PICs, based on their current syndromic reporting of dengue as dengue-like illness (DLI). Further, the reported number of deaths due to severe dengue is heterogenous across countries. As such, country-level and sub-national CFRs may appear inconsistent.  

A subset of the region requires additional support for dengue to address operational gaps in clinical management, surveillance, laboratory support, risk communication and community engagement, and operational management. There is also a need to improve adherence to the existing WHO “Framework for National Surveillance and Control Plans for Aedes vectors” for non-endemic countries in the Pacific Region, particularly establishing a comprehensive Early Warning System that integrates climate, disease, viral/serological, and entomological surveillance. 

 

Epidemiology

Dengue virus is transmitted to humans through the bite of infected mosquitoes typically in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban areas. The primary vectors that transmit the disease are Aedes aegypti and, to a lesser extent, Aedes albopictus mosquitoes, though in some regions such as Europe and North America, this latter vector is more widespread.

DENV has four serotypes (DENV-1, DENV-2, DENV-3, DENV-4). Infection with one serotype provides long-term immunity to the same serotype and only transient immunity to the other serotypes, after which secondary infections with a different serotype increase the risk for severe dengue. Dengue cases are most commonly asymptomatic or result in mild febrile illness. However, some cases will develop severe dengue, which may involve shock, severe bleeding or severe organ impairment. This stage often starts after the fever has gone away and it is preceded by warning signs such as intense abdominal pain, persistent vomiting, bleeding gums, fluid accumulation, lethargy or restlessness, and liver enlargement. 

There is no specific treatment for dengue, but the timely diagnosis of dengue cases, identification of warning signs for severe dengue, and appropriate clinical management are key elements of care to prevent the progression to severe dengue and deaths. 

Public health response

The overall capacity for countries to respond to multiple, concurrent outbreaks continues to be strained due to the global lack of resources, including shortages of good quality dengue diagnostic kits for early disease detection, lack of trained clinical and vector control staff and community awareness. Emergency response mechanisms have been established, and WHO supports high-risk countries across affected regions; however, the needs continue to outweigh the available resources. Coordination with partners, including UNICEF, has led to the development and implementation of common analyses and priority-setting tools. Nevertheless, it is imperative to sustain and enhance partner collaboration.  

Countries are encouraged to learn and adopt successful examples of effective case management, prevention, and control of dengue and other arboviruses through heightened research projects, which is also aimed at limiting the vectors reducing their ability to spread across the urban context. WHO should closely review local interventions and under the best evidence to accept and recommend them for public health programmes, facilitating early adaptation to reduce the growing health impact of dengue.  

Other response activities within WHO to support countries in their ongoing response activities include:  

WHO Leadership and Coordination 

  • Establishment of Joint WHO Health Emergencies Programme/Neglected Tropical Diseases (NTD) Incident Management System Team to coordinate the global response
  • Integrated response to address dengue, chikungunya, and Zika viruses aligned with the Global Arbovirus Initiative   
  • Current global response strategy contributing to the WHO Global NTD roadmap by 2030 and the Global Vector Control Response 2017-2030
  • Release of Global Contingency Fund for Emergencies (CFE) USD 5.5 million on 7 March 2024 to support urgent response to global dengue outbreaks
  • Development of regional operational plans for dengue response, aiming to boost regional and national resource mobilization  
  • Inclusion of dengue in the WHO flash appeal for health emergencies in 2024 
  • Development of the Strategic Preparedness, Readiness and Response Plan (SPRRP) for dengue and other arboviruses, set to launch end of May 2024  
  • Resource mobilization activities and donors' briefing to be organized.
  • Preventing and Responding to Sexual Exploitation, Abuse and Harassment (PRSEAH) interventions to be integrated in dengue operational response according to Emergency Response Framework (ERF) requirements. Interventions will depend on the type and phase of the response (active response or readiness/preparedness mode), context, location and scale of the response
  • Collaboration with key One Health partners to coordinate supply and ensure optimal access to supplies
  • Operational Support and Logistics (OSL) contacting suppliers to secure dengue kits and maintaining a pipeline for bulk items   
  • Provision of technical support to all ongoing outbreaks, including epidemiology, laboratory, case management, risk communication and community engagement (RCCE), and vector control
  • Support deployment through the Global Outbreak Alert and Response Network (GOARN) and Standby Partners
  • Advocacy for research initiatives

WHO Health Operations Support 

Clinical Management:   

  • Systematic review for the updated arbovirus clinical guidance in progress, to be completed by May 2024  
  • Meeting of the Guideline Development Group (GDG) scheduled for July 2024 to discuss dengue and other arbovirus clinical management recommendations  
  • Work on standardized forms to support clinical management in hospitalized patients and outpatients, aimed at reducing CFR
  • Expansion of the clinical data platform for COVID-19 to include dengue and other infectious diseases outbreaks  
  • Development of online training courses in OpenWHO 
  • In the South East Asian Region facilitation of dengue case management training and TOT by Regional experts to countries
  • Expansion of WHO “Virtual Patient” training initiative to include dengue and other vector borne diseases.

Health Information Management: 

  •  WHO global dengue surveillance system is capturing data on cases, confirmed cases, severe cases, deaths and circulating serotypes where available, with countries reporting monthly. Note, not all countries’ data are available yet and the system will continue to develop and add these as they become available
  • Data from the WHO European Region will be included when autochthonous cases are reported. Member States in EURO are being notified of heightened surveillance that will begin from 1 June to 1 December, with requests to submit via IHR mechanisms any autochthonous cases of dengue
  • A Global Dengue Surveillance Dashboard has been launched. And regional level dashboards are planned to include more granular data (sub-national, age, gender)
  • Member States will be supported to improve their surveillance and reporting systems including joint case definitions and case classifications and enhancing community-based reporting and integration of vector surveillance data for hot spot mapping

Risk Communication and Community Engagement (RCCE):   

  • Development and piloting of an RCCE toolkit
  • Adaptation of Community Conversation Kits with Dengue Topic Sheets 
  • Testing of key dengue messages for health promotion  

Laboratory:  

  • Development of an interim diagnostic laboratory testing guide for timely and accurate confirmation of dengue   
  • Planned product evaluation by the WHO NTD-WHE Expert Review Panel dengue for Diagnostic tests
  • Together with OSL working to guarantee the provision of critical supplies for laboratory and diagnostics

Vector Control:   

  • Systematic review for updated dengue vector control guidance in progress, to be completed by August 2024
  • A n operational manual for novel vector control tools is planned
  • A position paper on Water, Sanitation, and Hygiene (WASH) and vector-borne diseases was published. Link
  • Provision of technical support to Mauritius for field operations
  • Reporting of insecticide resistance monitoring at the global level by July 2024 
  • Development of online training courses in OpenWHO 
  • Information on dengue for travellers published. Link

International Health Regulations and Border Health (Vector Control):   

  • Evidence review for the disinsection of conveyances to prevent or reduce the spread of mosquito vectors via international travel
  • Development of OpenWHO online course for vector surveillance and control at PoE including aircraft disinsection

 

WHO risk assessment

Dengue is a mosquito-borne viral disease caused by the dengue virus, with the potential to cause a serious public health impact. Dengue infections are the most common vector-borne viral infections worldwide, particularly impacting tropical and subtropical countries.  DENV has the potential to cause epidemics resulting in high morbidity and mortality. The virus is primarily transmitted through the bite of infected Aedes mosquitoes, most commonly Aedes aegypti and Aedes albopictus. The proliferation and propagation of mosquitoes depend on climatic factors such as temperature, humidity and rainfall. The arbovirus can be carried by infected travellers (imported cases) and may establish new areas of local transmission in the presence of vectors and a susceptible population. As they are arboviruses, all populations living in areas with the presence of Aedes aegypti are at risk, however, their impact largely affects the most vulnerable people, in which the arboviral disease programs do not have enough resources to respond to outbreaks.  

Infection with one of the dengue serotypes (1-4) does not provide cross-protective immunity to the others, so persons living in a dengue endemic area can have four dengue infections during their lifetimes. Changes in the predominant circulating serotype increase the population risk of subsequent exposure to a heterologous DENV serotype, which increases the risk of higher rates of severe dengue and deaths.  Severe dengue is characterized by vascular leakage, hemorrhagic manifestations, thrombocytopenia, and hypotensive shock, which can lead to organ failure and death. Age, interval between infections, antibody characteristics, viral factors, and host-specific genetics are contributing factors.

Monitoring of the global dengue situation to date has shown that several factors are associated with an increasing risk of dengue epidemics becoming more extensive and less predictable, and these include;   

  • Changing distribution of the Aedes aegypti vector;
  • Urbanization and human activities fostering conducive environments for vector-host interaction;
  • Climate change-induced shifts in weather patterns;
  • Fragile healthcare systems amidst political and financial instabilities;
  • Changes in the predominant circulating serotypes and co-circulation of multiple dengue serotypes;
  • Challenges in clinical diagnosis particularly in areas with co-circulation of other arboviruses;
  • Inadequate laboratory and testing capacity; Prolonged ongoing concurrent outbreaks, including COVID-19;
  • Insufficient preparedness for the scale of the epidemic, and low capacity for dengue patient clinical management;
  • Lack of specific treatment for dengue;
  • Lack of engagement and mobilization of local communities in vector control activities; Insufficient vector surveillance and control capacities;
  • Lack of coordination among stakeholders, chronic underfunding, and low donor interest;
  • Lack of involvement of government sectors responsible for addressing social determinants e.g. implementation of policies aimed at improving conditions related to the risk of transmission, such as urban planning, water and sanitation provision, solid waste management, housing improvement, etc.
  • Lack of engagement and mobilization of local communities in vector control activities.

WHO assessed the global risk of dengue as high on 30 November 2023, and subsequently assigned a WHO internal emergency response grade of G3 at the global level on 1 December 2023. Given the current scale of the dengue outbreaks, the potential risk of further international spread and the complexity of factors impacting transmission, the overall risk at the global level is still assessed as high and thus dengue remains a global threat to public health.

WHO advice

Dengue is primarily an urban disease of the tropics and the viruses that cause it are maintained in a cycle that involves humans and Aedes aegypti mosquitoes. The same mosquitoes transmit chikungunya and Zika viruses. The proximity of mosquito vector breeding sites to human habitation is a significant risk factor for dengue virus infection. Aedes species mosquitoes can become infected with the virus after biting individuals infected with DENV and then transmit the virus to others in the vicinity. This cycle, therefore, makes the infective mosquito capable of spreading the dengue virus within households and in the neighbourhoods of cases, leading to clusters.

Effective vector control interventions are key to the prevention and control of dengue. Vector control activities should target all areas where there is a risk of human-vector contact, such as residences, workplaces, schools, and hospitals. WHO promotes Integrated Vector Management (IVM) to control Aedes species. IVM should include removing potential breeding sites, reducing vector populations, and minimizing individual exposure. This should involve vector control strategies for larvae and adults (i.e., environmental management and source reduction), especially monitoring water storage practices, draining and cleaning household water storage containers weekly, larvicide in non-potable water using WHO-prequalified larvicides at correct dosages, distribution of insecticide-treated nets (ITNs) for fever/dengue inpatients to contain spread of the virus from health facilities. Indoor space spraying for rapidly containing dengue-infected mosquitoes may be challenging to deliver in densely populated areas.

Personal protective measures during outdoor activities include topical repellents to exposed skin or the treatment of clothing and using long-sleeved shirts and pants. Additionally, indoor protection can include the use of household insecticide aerosol products, or mosquito coils during the day; window and door screens can reduce the chances of mosquitoes entering the house and insecticide-treated nets offer good protection to people against mosquito bites while sleeping during the day. Personal protective measures are recommended from dawn to dusk due to the diurnal Aedes aegypti. These measures and mosquito control should also cover workplaces and schools since the vectors are day-biting mosquitoes. Entomological surveillance should be undertaken to assess the breeding potential of Aedes mosquitoes in containers to target vector control activities and monitor insecticide resistance to help select the most effective insecticide-based interventions.

There is no specific treatment for dengue infection. However, early detection and access to appropriate healthcare for case management reduces mortality, as can rapid detection of dengue cases with warning signs and timely referrals of severe cases to tertiary healthcare facilities. Case surveillance should continue to be enhanced in all affected countries and globally. Where feasible, resources should be allocated for the strengthening of case referral mechanisms and for the confirmation and serotyping of the dengue viruses.

Vaccination against dengue should be viewed as part of an integrated strategy to control the disease, including vector control, proper case management, community education, and community engagement. WHO recommends the use of TAK-003 (only available vaccine) in children aged 6–16 years in settings with high dengue transmission intensity.

Countries are encouraged to learn and adopt successful examples of effective case management, prevention, and control of dengue and other arboviruses through heightened research projects, particularly given the recent WHO recommendations on clinical trials. Implementing clinical surveillance and case and death report forms for dengue could be particularly useful in understanding the disease better and also form a basis for developing clinical trials for new therapies or quality improvement initiatives.

WHO should closely review local interventions and under the best evidence to accept and recommend them for public health programmes, facilitating early adaptation to reduce the growing health impact of dengue.  

Ministries of Health and partners should closely review local interventions to accept and recommend them for public health programmes for early adaptation to reduce the growing health impact of dengue.  

WHO does not recommend that any general travel or trade restrictions be applied to countries based on the available information.

Further information

Citable reference: World Health Organization (30 May 2024). Disease Outbreak News; Dengue – Global Situation Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON518