Safeguarding Public Health

Author:
Felicitas Colombo, MPA
Director of Public and Government Affairs, Americas Health Foundation

Dengue fever, a mosquito-borne viral infection, poses a significant threat to public health, particularly in tropical and subtropical regions. It is transmitted primarily by the Aedes aegypti mosquito, which breeds in stagnant water. Symptoms can range from mild flu-like signs to severe illness, including dengue hemorrhagic fever and dengue shock syndrome. 

With increasing global temperatures and urbanization, the incidence of dengue has surged, making effective regulation and management crucial. This article explores the importance of dengue regulation and its impact on public health, economic stability, and community resilience.

According to the World Health Organization (WHO), as of April of 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.”

Yet, dengue is not only present in the Americas but has become a global concern. In 2024, 90 countries reported active dengue transmission. However, many endemic countries do not have strong detection and reporting mechanisms, so the true burden of dengue globally is underestimated.

To strengthen global surveillance, and monitor trends and disease incidence, WHO has established a global dengue surveillance system with monthly reporting across all regions. (available as a dashboard)

“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,” says the WHO report.

Understanding Dengue Surveillance

Global dengue surveillance is essential in preventing outbreaks, guiding public health interventions, and protecting vulnerable populations. Dengue surveillance encompasses the systematic collection, analysis, and interpretation of data related to dengue infections. This includes monitoring mosquito populations, tracking incidence rates, and assessing environmental factors that contribute to the spread of the virus. Effective surveillance can help identify trends, predict outbreaks, and inform health responses.

Major vector control strategies focus on reducing the population of Aedes mosquitoes, the primary carriers of the virus. Key methods include:

1. Source Reduction: This involves eliminating standing water where mosquitoes breed. Actions include cleaning and disposing of containers that collect water, regularly emptying flower pots, and maintaining proper drainage in urban areas.
2. Larvicides: Applying chemical agents to water bodies to kill mosquito larvae. This can be effective in areas where standing water cannot be eliminated.
3. Insecticides: Spraying insecticides, such as fogging, can help reduce adult mosquito populations during outbreaks. This method is often used in conjunction with other control strategies.
4. Biological Control: Introducing natural predators of mosquito larvae, such as fish or certain bacteria (like Bacillus thuringiensis israelensis), can help manage mosquito populations without harmful chemicals.
5. Community Engagement: Educating communities about dengue prevention and involving them in vector control efforts. 
6. Personal Protection: Encouraging the use of insect repellent, wearing long-sleeved clothing, and installing window screens can help reduce human exposure to mosquito bites.

 Key Reasons for Global Dengue Surveillance

1. Early Detection and Response: Timely and accurate surveillance allows for the early detection of dengue cases, enabling public health authorities to respond swiftly. Rapid response measures, such as vector control and community awareness campaigns, can help contain outbreaks before they escalate.
2. Data-Driven Decision Making: Surveillance data provides critical insights that inform public health policies and resource allocation. By understanding transmission patterns and risk factors, health agencies can prioritize interventions in high-risk areas, ensuring that resources are utilized effectively.
3. Monitoring Climate and Environmental Factors: Global surveillance helps track the impact of climate change and urbanization on dengue transmission. Understanding these environmental influences is essential for developing predictive models and targeted interventions, especially in regions at risk of emerging outbreaks.
4. Supporting Vaccine Development: Surveillance data can guide research and development efforts for dengue vaccines and treatments by identifying serotypes in circulation and monitoring vaccine efficacy.
5. Enhancing International Collaboration: Dengue knows no borders; therefore, global surveillance fosters collaboration among countries and organizations. Sharing data and best practices enhances collective knowledge and strengthens regional and global efforts to control dengue transmission.

Challenges in Dengue Surveillance

While the benefits of global dengue surveillance are clear, several challenges persist. These include limited funding, inadequate infrastructure in many regions, and varying levels of technical expertise. Furthermore, surveillance systems specifically targeting endemic transmission are weak or non-existent in many countries. Addressing these challenges is crucial for establishing effective surveillance systems worldwide.

Vaccination

The WHO estimates that around 390 million dengue infections occur annually, leading to significant morbidity and mortality. It asserts that “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.” It further recommends vaccination “in children aged 6 to16 years in settings with high dengue transmission intensity.”

Economic Implications

Dengue not only affects people’s health but also has substantial economic repercussions. The costs associated with healthcare, lost productivity, and outbreak responses can strain public resources. A range of regulatory measures, that could include surveillance and vaccination, could mitigate these costs by preventing outbreaks and fostering a healthier community. As the global landscape continues to change, proactive policies will be essential in the fight against dengue fever.

Americas Health Foundation

AHF has been involved in the prevention of dengue since 2015, with projects that range from awareness campaigns, consensus conferences, expert task forces and media workshops. Through a network of diverse stakeholders and sponsors, the foundation strives to improve public health across the Americas and globally.