In the context of global climate change, “extreme” changes in temperature and humidity lead to changes and abnormal increases in many dangerous infectious diseases, including vector‐borne diseases such as malaria and dengue fever with high morbidity and mortality, including in Vietnam.
With the unpredictable progression of the disease and the difficulty in controlling and containing it, the health sector and the community are also facing many challenges to prevent and eliminate these vector‐borne diseases. According to the latest information, in the first 3 months of 2024, more than 5 million cases and more than 2,000 deaths were recorded globally.
Key points about dengue fever
Dengue fever Dengue (SXHD) is one sick infectious byvi‐rus Dengue is caused by and is transmitted from person to person, primarily through the bite of infected mosquitoes. Mosquitoes of the genus Aedes major disease vectors, mainly mosquitoes Aedes aegypti. This species feeds mainly during the day with two peaks of activity in the early morning and late afternoon. About half of the world’s population is at risk of developing the disease. SXHD and annually estimateabout 100‐400 million cases globally;
SXHD found popularlive the tropical and subtropical climates of the world, common disease live the area urban and semi‐urban; There are many cases of infection. DENV is asymptomatic or causes only mild disease, in some cases DENV can cause cases sick more severe and even fatal;
Prevention workSXHDdependent on vector controldisease transmission. Because ofThere is currently no cure for the disease. sick specific, So early detection and Proper treatment will do Significant reduction in mortality from severe dengue fever cause.
Figure 1. Some major infectious diseases circulating globally 2022‐2023
Dengue fever situationDengue (SXHD) currently in the world
Dengue fever incidenceThe number of reported cases globally has increased significantly over the past two decades, posing a significant public health challenge. Between 2000 and 2019, the World Health Organization (WHO) recorded a tenfold increase in the number of reported cases globally, from 500,000 in 2000 to 5.2 million in 2019. 2019 was considered the year with the highest number of cases ever recorded, with reported cases spreading to 129 countries.
Thereafter, the number of dengue cases decreased slightly in 2020‐2022 due to the COVID‐19 pandemic. By 2023, the number of cases had increased significantly globally in both the number of cases and the scale of the outbreak, expanding to areas that had not previously been reported. Dengue transmission is cyclical and large outbreaks can occur every 3‐4 years. During the COVID‐19 pandemic, Moderate dengue transmission in some areas and low transmission in others results in many people lacking immunity to some dengue serotypes. However, data on the prevalence of dengue serotypes are limited.
Since the beginning of 2023, DHF transmission has continued to occur in many parts of the world, accompanied by a sharp increase in DHF cases with more than 5 million cases and more than 5,000 DHF‐related deaths, close to the highest recorded historical high, reported in more than 80 countries/territories in 5 regions: Africa, the Americas, Southeast Asia, the Western Pacific, and the Eastern Mediterranean globally. Nearly 80% of the cases (approximately 4.1 million cases) were reported in the Americas region. DHF is the most common arbovirus disease and causes the highest number of arbovirus cases in the Americas region, with outbreaks occurring every 3‐5 years. In addition, indigenous clusters of DHF cases have been reported in Europe. However, these data may underestimate the true burden of dengue because most infections are asymptomatic and case reporting is not mandatory in many countries.
Figure 2. El Nino‐induced weather variability in seasonal rainfall
Some factors associated with increased risk of transmissionDengue epidemics include changes in vector distribution.(mainly Aedes aegypti and Aedes albopictus), especially in countries without previous dengue outbreaks; the consequences of the 2023 El Niño event and climate change leading to increased temperatures, heavy rainfall, and high humidity; weak health systems amid the COVID‐19 pandemic, political and financial instability in countries facing complex humanitarian crises, and high population movements. These factors also challenge the ability to respond to the outbreak and risk further spread to other countries. Weaknesses in surveillance systems in many affected countries may result in delayed reporting and response as well as missed identification of symptoms, contributing to the increase in severe dengue cases.
Figure 3. Countries, territories and regions reporting local dengue cases from2022‐2023.
Nguồn: WHO, 2023
WHO has assessed the risk as high globally considering the increasing risk of transmission as well as the increase in cases and deaths.
Dengue fever in Africa
Africa is among the four regions most affected by diseases caused byArbovirusincluding yellow fever, dengue fever, chikungunya, O’nyong Nyong, Rift Valley fever and Zika. In 2023, Africa recorded 171,991 cases and 753 deaths related to dengue. Evidence of disease circulation has been detected in the local population and/or among travelers returning from more than 30 African countries.
Outbreaks of dengue have been reported in 15 of the 47 countries including Benin, Burkina Faso, Cape Verde, Chad, Côte d’Ivoire, Ethiopia, Ghana, Guinea, Mali, Mauritius, Niger, Nigeria, São Tomé and Principe, Senegal and Togo. Outbreaks in these countries all began in 2023, except in São Tomé and Príncipe, which are extensions of an outbreak that began in April 2022. As of 19 December 2023, outbreaks are still ongoing in 11 countries, while Chad, Guinea, Mauritius, São Tomé and Príncipe have declared the outbreak over.
In 2023, Burkina Faso is the most affected country in the region with a significant increase in cases compared to 2021 and 2022. As of 18 December 2023, the cumulative number of cases is 146,878 including 68,346 positive rapid diagnostic tests and 688 deaths among suspected cases with a case fatality rate of 0.5%.
The burden of dengue in Africa is poorly understood due to: (i) Non‐specific clinical symptoms of the disease compared to malaria and other tropical febrile diseases; (ii) Limited laboratory capacity to detect and confirm cases promptly, which is critical for detecting and reporting cases and preventing the spread of the disease; (iii) Inadequate surveillance and limited case reporting, especially for dengue.
Efforts are underway to better understand the transmission mechanisms of dengue and other arboviral diseases in the region. The WHO Regional Office for Africa has endorsed the integrated framework for the control, elimination and eradication of tropical and vector‐borne diseases in Africa 2022‐2030. In addition, the Regional Office has drafted a framework for the implementation of the Global Arboviral Initiative by Member States in the African region.
Dengue fever in the Americas
From 1 January 2023 to 11 December 2023, a total of 4.1 million suspected dengue cases (cumulative incidence of 419 cases per 100,000 population), including 6,710 severe dengue cases (0.16% of suspected cases) and 2,049 deaths (CFR 0.05%) were reported from 42 countries and territories in the Americas region, with 15 countries reporting active outbreaks. Of the total dengue cases as of 12 November 2023 (week 48 2023), 1,895,122 (45%) were laboratory‐confirmed.
Currently, 46 countries and territories systematically report, through the Americas Health Information Network, weekly total cases, incidence, severe cases, deaths, and fatalities due to dengue as well as entomological surveillance data. As of week 48, Brazil reported the highest number of suspected cases in the region (n=2,909,404; 1,359 cases per 100,000 population), followed by Peru (n=271,279; 813 cases per 100,000 population) and Mexico (n=235,616; 179 cases per 100,000 population). Regarding severe dengue, Colombia reported the most cases (1504; 1.35% of cases), followed by Brazil (1474; 0.05% of cases), Mexico (1272; 0.54% of cases), Peru (1065; 0.39% of cases), and Bolivia (640; 0.44% of cases).
Although dengue is endemic in most countries of South America, Mexico, Central America, and the Caribbean, the second half of 2023 saw an alarming increase in cases, with cumulative cases exceeding previous annual totals and cases in some countries moving beyond previously affected transmission areas. Dengue cases have increased in the Americas over the past four decades, from 1.5 million cases between 1980 and 1989 to 17.5 million cases in 2010‐2019. Prior to 2023, the highest number of dengue cases on record was in 2019, with more than 3.18 million cases, 28,208 severe cases, and 1,823 deaths (CFR 0.06).
Dengue virus (DENV) is the most common arbovirus and causes the highest number of arbovirus cases in the Americas, with outbreaks occurring every 3 to 5 years. Approximately 500 million people in the region are currently at risk of dengue infection. Mosquito Ae. aegypti is vectortransmitting dengue fever, widely distributed in the Americas, with only Canada being the only country that is dengue‐free and has no vectors. Uruguay, where Ae. Aegypti Limited local transmission was last reported in 2016 and since then only oral transmission has been reported.
All 04 tuDENV serotypes (DENV‐1, DENV‐2, DENV‐3 and DENV‐4) are currently circulating in the Americas. Previously, cases were mainly due to uDENV‐1 and DENV‐2, while in 2023, DENV‐3 and DENV‐4 were detected more frequently. However, 9 countries reported the presence of all 4 viruses at the same time. userum polymorphism. The simultaneous circulation of all serotypes. uýpThis serotype has been detected in Brazil, Colombia, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua, Panama, and Venezuela. The Arbovirus Diagnostic Laboratory Network of the Americas has been strengthened to respond to the emergence of new DHF serotypes and the re‐emergence of other arboviruses, such as Chikungunya, Zika virus, and West Nile virus, all of which are currently circulating in the region alongside DHF. The primary objective of the laboratory network is to ensure effective surveillance and rapid response to disease outbreaks.
Dengue fever in Europe
DHF is not endemic in Europe and cases are mainly travel‐related; however, since 2010, indigenous cases have been reported in several countries in the region including Croatia, France, Israel, Italy, Portugal and Spain. In 2018, the year for which comprehensive data are available, a total of 2,500 DHF cases were reported to WHO through the annual regional surveillance data collection mechanism with Germany, France and the UK contributing the majority of cases. The majority of these cases were imported. However, it should be noted that the completeness of the data remains challenging.
From 1 January to 5 December 2023, cases and sporadic local outbreaks were reported in three countries: Italy (n = 82), France (n = 43), and Spain (n = 3). Routine dengue testing in the European Region member states is not common unless there is a travel history and suspected cases, so the actual number of dengue cases in 2023 may be underestimated. One death associated with an imported traveler was reported in Italy; no additional deaths have been reported in European countries in 2023 to date.
Ae. albopictus is the transmission vector‐rus Dengue is endemic in Europe, found in some southern European countries. Mosquito Ae. albopictus has been detected further north and west in the past decade and is capable of hibernating in winter. In 2023, the mosquito was identified in 13 countries in the region, up from eight in 2013. While cold winters prevent year‐round transmission of mosquito‐borne diseases, the climate is conducive to transmission. DENV in Europe is increasing, leading to flooding, stagnant water pools. These factors create more favorable conditions for vector populations to have the capacity to reproduce, develop and transmit the disease.
Ae. aegypti (the main vector of dengue in most countries) does not survive the winter but has also been present in Cyprus and Madeira, Portugal since 2022. These trends are likely to lead to an increase in dengue cases and possible deaths. Quality public health systems in many countriesincluding access to early diagnosis, case identification and management of severe cases, contributing to reducing severe health impacts and also reducing disease transmission for both imported and locally acquired cases.
Dengue fever in Southeast Asia
Southeast Asia region, 10 out of 11 member countries are known to be where the behavior is prevalent.‐rus Dengue. In 2023, several countries, including Bangladesh and Thailand, reported a significant increase in dengue cases compared to previous years. In particular, India, Indonesia, Myanmar, Sri Lanka, and Thailand are among the 30 countries with the highest endemicity in the world.
Compared to the same period in 2022, in 2023, Bangladesh and Thailand recorded the number of dengue fever casesmore. By November 2023, Bangladesh had seen a significant increase in cases to 308,167 compared to the 62,382 reported in all of 2022. Thailand saw a rise in cases of more than 300%, with 46,678 cases in 2022 rising to 136,655 in 2023 (as of 22 November 2023). During the same period, deaths in Bangladesh increased from 281 (CFR 0.45%) to 1598 (CFR 0.52%), while in Thailand, they increased from 34 (CFR 0.07%) to 147 (CFR 0.11%). In other countries, case fatality rates (CFRs) range from 0.04% in Nepal to 0.72% in Indonesia. It is important to interpret these values with caution due to differences in case definitions used between countries, with some systems focusing primarily on reporting severe or hospitalized cases of DHF.
Additionally, spatial and temporal shifts in DHF patterns were observed in 2022 and continued in 2023. Nepal and Bangladesh saw an earlier than usual spike in cases. Cases in Nepal shifted from the Kathmandu Valley in 2022 to the southeastern Terai region and hill districts in Gandaki province in 2023. In 2023, India saw an increase in DHF cases in Kerala and the northeastern states bordering Bangladesh compared to the previous year.
Dengue fever in the Western Pacific region
The Western Pacific region continues to face a high burden of diseasehighwith mosquito‐borne arbovirus diseases, especially dengue fever. These diseases This arbovirus causes significant morbidity and mortality in the region, especially among those without access to quality primary health care services.
Figure 5. Global climate change 2023‐2024 is a concern that could cause outbreaks of infectious diseases and severe shortages of shared water resources
From January 1, 2023 to December 7, 2023, there are more than 500,000 cases and 750 deaths related toDHF has been reported from 8 countries/territories in the region: Australia, Cambodia, China, Laos, Malaysia, Philippines, Singapore and Vietnam. The most severely affected countries are the Philippines (167,355 cases and 575 deaths, CFR: 0.34%) and Vietnam with 149,557 cases and 36 deaths (CFR: 0.02%). DHF is endemic in countries such as Cambodia, Laos, Philippines and Vietnam.
In Pacific Island countries/territories (n = 21), in 2023, dengue‐like illness was reported from 9 Pacific countries/territories with a total of 13,339 cases as of 30 November 2023, an increase of 28% compared to the same period in 2022. Among the most affected countries was Fiji with 8,418 cases in 2022 and 11,522 cases in 2023, an increase of 37% compared to 2022.
Endemic Member States continue to report seasonal, more prolonged dengue outbreaks with increasing intensity and geographic spread. However, disease incidence is less reliable due to low case reporting, particularly in Pacific Island States and territories that rely on existing syndromic surveillance for dengue, such as the dengue‐like illness reporting system. In addition, the number of deaths reported from severe dengue varies widely. As a result, case fatality rates (CFRs) at national and subnational levels may be inconsistent.
Given the endemicity of dengue and its public health burden in the Western Pacific Region, in 2008, the Regional Committee for the Western Pacific adopted the Dengue Strategic Plan for Asia and the Pacific 2008‐2015 (Resolution WPR/RC59.R6), which serves as a roadmap for implementation. By 2016, assess the increasing trends in dengue morbidity and mortality in the Region.
The Western Pacific Regional Action Plan for Dengue Prevention, Control and Control has been developed. This plan recommends a shift in strategy from disease containment to reducing the impact of dengue on communities, with opportunities for Pacific countries/territories to improve compliance with the “National Vector Surveillance and Control Framework”. Aede ssp.” for non‐endemic countries in the Pacific region. Due to the impact of climate change on the transmission and circulation of diseases caused by Arbovirus, nên việc thiết lập Hệ thống cảnh báo sớm toàn diện (EWS) tích hợp giám sát khí hậu, bệnh tật, vi ‐rus /serum and insect are very important. Such an early warning system has the potential to predict future risks in vulnerable communities..
