Journal of Clinical Infectious Diseases & Practice
Open Access

Dengue fever; Mosquito-borne; Viral infection; Public health; Transmission; Clinical manifestations; Prevention; Control; Vector-borne diseases

Introduction

Vector-borne diseases (VBDs) are illnesses caused by pathogens and parasites transmitted by vectors such as mosquitoes, ticks, and flies. Among these, dengue fever stands out due to its widespread prevalence and impact on global health. Dengue is primarily transmitted by Aedes aegypti and Aedes albopictus mosquitoes. With increasing urbanization, climate change, and global travel, the incidence of dengue and other VBDs has surged, necessitating a comprehensive understanding and effective control measures [1].

Epidemiology of dengue

Dengue fever is endemic in over 100 countries, predominantly in Southeast Asia, the Americas, the Western Pacific, and Africa. The World Health Organization (WHO) estimates that 390 million dengue infections occur annually, with about 96 million manifesting clinically. Epidemics are often cyclical, with outbreaks peaking every 3-5 years.

Transmission and life cycle

The dengue virus (DENV) belongs to the Flaviviridae family and has four distinct serotypes (DENV-1 to DENV-4). Transmission occurs when an infected mosquito bites a human, introducing the virus into the bloodstream. The mosquito becomes infected when it feeds on a viremic individual, allowing the virus to replicate in the mosquito’s midgut before spreading to its salivary glands [2].

Clinical manifestations

Dengue fever presents with a wide spectrum of clinical manifestations, ranging from asymptomatic infection to severe dengue (previously known as dengue hemorrhagic fever and dengue shock syndrome). Common symptoms include high fever, severe headache, retro-orbital pain, myalgia, arthralgia, rash, and mild bleeding (e.g., nose or gum bleed). Severe dengue is characterized by plasma leakage, fluid accumulation, respiratory distress, severe bleeding, or organ impairment, which can be fatal without prompt medical intervention.

Diagnosis

The diagnosis of dengue is primarily based on clinical symptoms and laboratory tests. Serological tests (e.g., detection of dengue-specific IgM and IgG antibodies) and molecular methods (e.g., reverse transcription-polymerase chain reaction [RT-PCR]) are commonly used to confirm infection [3].

Prevention and control

Effective dengue control relies on vector management strategies aimed at reducing mosquito populations and minimizing human-vector contact. Key approaches include:

Environmental Management: Elimination of mosquito breeding sites by properly disposing of solid waste, covering water storage containers, and cleaning gutters.

Biological Control: Introduction of natural predators or pathogens that target mosquito larvae.

Chemical Control: Use of insecticides for larval and adult mosquito control, with careful consideration to prevent resistance [4].

Personal Protection: Utilization of insect repellent, protective clothing, and bed nets.

Vaccination: The development of dengue vaccines, such as Dengvaxia, offers a promising tool for prevention, although challenges remain regarding efficacy and safety across different populations.

Other vector-borne diseases

In addition to dengue, several other VBDs pose significant health risks globally, including:

Malaria: Transmitted by Anopheles mosquitoes, caused by Plasmodium parasites.

Zika Virus: Also transmitted by Aedes mosquitoes, associated with congenital abnormalities.

Chikungunya: Characterized by severe joint pain, transmitted by Aedes mosquitoes.

Yellow Fever: A viral hemorrhagic disease prevented by vaccination, transmitted by Aedes and Haemagogus mosquitoes [5].

West Nile Virus: Transmitted by Culex mosquitoes, can cause severe neurological disease.

Integrated vector management

Integrated Vector Management (IVM) is a comprehensive approach that combines various control methods based on local epidemiological and entomological data. IVM promotes sustainable and cost-effective interventions, community participation, and intersectoral collaboration.

Challenges and future directions

The control of dengue and other VBDs faces several challenges, including insecticide resistance, changing environmental conditions, and socio-economic factors. Future research should focus on developing innovative tools, such as genetically modified mosquitoes, improved diagnostics, and effective vaccines. Strengthening surveillance systems and public health infrastructure is also crucial for early detection and response to outbreaks [6].

Discussion

Vector-borne diseases, transmitted by arthropods such as mosquitoes, ticks, and flies, pose a significant global health threat. Dengue, one of the most common and impactful vector-borne diseases, exemplifies this challenge.

Dengue fever: an overview

Dengue fever is caused by the dengue virus, transmitted primarily by Aedes mosquitoes, especially Aedes aegypti and Aedes albopictus. The disease is prevalent in tropical and subtropical regions, affecting millions annually. Symptoms range from mild fever to severe dengue (dengue hemorrhagic fever and dengue shock syndrome), which can be fatal without proper treatment [7].

Global burden

1. Incidence and prevalence

• Approximately 390 million dengue infections occur each year, with around 96 million manifesting clinically.
• Endemic in over 100 countries, particularly in Southeast Asia, the Americas, the Western Pacific, Africa, and the Eastern Mediterranean.

2. Economic impact

• High healthcare costs and economic burden due to illness and loss of productivity.
• Significant strain on healthcare systems in endemic countries during outbreaks.

3. Social impact

• Fear and stigma associated with outbreaks.
• Impact on travel and tourism, affecting economies reliant on these industries.

Other vector-borne diseases

Malaria: Caused by Plasmodium parasites, transmitted by Anopheles mosquitoes.

Zika Virus: Also transmitted by Aedes mosquitoes, with severe consequences such as microcephaly in newborns.

Chikungunya: Another Aedes mosquito-transmitted disease causing debilitating joint pain.

Yellow Fever: Caused by a virus transmitted by mosquitoes, preventable by vaccination [8].

Strategies for prevention and control

1. Vector control

• Environmental management

• Reducing mosquito breeding sites by eliminating standing water.
• Proper waste management and improved water storage practices.

• Biological control

• Introducing natural predators of mosquito larvae, such as certain fish species.
• Using bacteria like Wolbachia to reduce mosquito populations and virus transmission.

• Chemical control

• Insecticide-treated bed nets and indoor residual spraying.
• Use of larvicides in water bodies to kill mosquito larvae [9].

2. Vaccination

• Dengue vaccine (Dengvaxia)
• The first dengue vaccine approved for use in some endemic countries.
• Ongoing research for more effective vaccines with broader protection.

3. Surveillance and early warning systems

• Disease monitoring

• Strengthening national and regional surveillance systems for early detection of outbreaks.
• Use of geographic information systems (GIS) for tracking and predicting outbreaks.

• Public health education

• Raising awareness about prevention methods.
• Community engagement in vector control activities.

4. International collaboration

• Global health initiatives

• WHO's Global Vector Control Response (GVCR) 2017-2030 aims to reduce the burden of vector-borne diseases through coordinated action [10].
• Partnerships between countries, international organizations, and research institutions for resource sharing and collaborative research.

• Research and development

• Development of new vector control tools and strategies.
• Investment in research for effective vaccines and treatments.

Conclusion

Dengue and other vector-borne diseases continue to pose significant public health challenges globally. Effective control requires a multifaceted approach, integrating vector management, community engagement, and robust healthcare systems. Ongoing research and innovation, coupled with international cooperation, are essential to mitigate the impact of these diseases and improve global health outcomes.

Acknowledgement

None

Conflict of Interest

None

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