Presented in Spanish, the webinar “Crisis Sanitaria por Dengue en Latino América y el Caribe” (Dengue Public Health Crisis in Latin America and the Caribbean was held on July 30, drawing over 300 participants. The event, part of the Emerging Topics in Global Public Health Distinguished Speaker series, focused on the region’s rapidly worsening dengue fever epidemic. 

Co-sponsored by the AIDS Healthcare Foundation (AHF) Global Public Health Institute, the National Institute of Public Health of Mexico, Cayetano Heredia University in Peru, and the Public Health Policy Lab from the University of Miami Miller School of Medicine's Department of Public Health Sciences, the webinar brought together experts from diverse countries to assess the scale of the dengue outbreak and explore potential solutions.

Jorge Saavedra, M.D., M.P.H., M.Sc., executive director of the AHF Global Public Health Institute at the University of Miami, moderated the discussion, emphasizing the unprecedented nature of the dengue epidemic. Dr. Saavedra highlighted the need for collaboration among international experts to develop comprehensive strategies to combat the escalating health crisis.

Michael Johansson, Ph.D., a research biologist from the U.S. Centers for Disease Control and Prevention (CDC), highlighted Puerto Rico's alarming surge in dengue cases, which had already surpassed historical epidemic thresholds early in 2024. By March, Puerto Rico declared an official dengue epidemic, experiencing its highest case count since 2013. Dr. Johansson noted a shift in the viral landscape, with dengue serotype 3 emerging as predominant, complicating outbreak management.

Warm and humid conditions in Puerto Rico create an ideal environment for mosquito breeding and survival, allowing the mosquitoes to thrive year-round. This makes it difficult to control the mosquito population effectively, as interventions like vector control must be ongoing and aggressive to have any impact.

The region’s susceptibility to tropical storms and hurricanes exacerbates the problem. These events often lead to increased standing water, which provides more breeding sites for mosquitoes, further complicating efforts to control the spread of dengue.

Dr. Johansson emphasized that predictive models, which incorporate data on environmental factors such as climate change, population growth, and human mobility, are key to forecasting dengue outbreaks. These models help identify new hotspots and enable public health officials to implement targeted interventions, such as vector control, at optimal times to mitigate the spread of the disease.

These models could help anticipate and prepare for future dengue outbreaks in Puerto Rico and other regions with similar climatic conditions. 

Brazil faces one of its most severe dengue epidemics, with over six million cases recorded in 2023 alone, and nearly 5,000 confirmed deaths. Dr. Libia Carla Vinhal Frutuoso, General Coordinator for Arbovirus Surveillance at Brazil’s Ministry of Health, described the magnitude of the outbreak, noting that it had surpassed previous records both in terms of cases and fatalities. 

Challenges persist in controlling Aedes aegypti, the mosquito responsible for transmitting dengue, which has spread to previously unaffected areas. Dr. Vinhal Frutuoso highlighted environmental and social factors such as rapid urbanization, inadequate water sanitation, stagnant water accumulation, and climate change as contributors to the mosquito's expansion, particularly in regions where they had been protected by cooler weather.

To help combat the epidemic, Brazil introduced the dengue vaccine, targeting adolescents between 10 and 14 years old. However, the limitations of the vaccine, such as its need for multiple doses and reduced effectiveness in individuals without prior exposure to dengue, were acknowledged by Dr. Vinhal Frutuoso. She emphasized that while the vaccine represents a valuable tool, it must be part of a broader, integrated dengue control strategy.

Alejandro Llanos, M.D., Ph.D., M.Sc., professor emeritus at the Cayetano Heredia University in Peru, discussed the numerous barriers that impede dengue control efforts in Peru. “One of the most significant challenges is the persistent lack of funding for research, which has hindered the development of more effective prevention and treatment strategies,” he said. 

Dr. Llanos noted that while dengue continues to afflict vulnerable populations in Peru and across Latin America, there remain critical gaps in understanding the disease’s vectors and reservoirs. These gaps impede the ability of health officials to develop precise interventions aimed at curbing the spread of the virus. He also pointed out that current vaccines are limited in their effectiveness, particularly for individuals who have not previously been exposed to the virus.

In addition to vaccines, Dr. Llanos defended the potential of alternative vector control strategies, such as introducing Wolbachia bacteria into mosquito populations. According to Dr. Llanos, this method, which has shown promise in reducing mosquito lifespans and their ability to transmit dengue, could be a game-changer in regions where traditional methods like insecticides have become less effective due to growing mosquito resistance.

Beyond scientific advancements, Dr. Llanos expressed concern over the resilience of dengue vectors, particularly Aedes aegypti, and the challenges in diagnosing and managing dengue amidst the presence of other co-circulating arboviruses, such as Zika and Chikungunya. This co-circulation complicates both diagnosis and treatment, as symptoms overlap, making it difficult for healthcare providers to accurately identify the cause of infection and administer appropriate care.

Celso Ramos, M.D., Ph.D., M.Sc., a researcher at the National Institute of Public Health of Mexico, echoed Dr. Llanos’ sentiment –– the urgent need for stronger vector control programs.

He shared details of a national initiative led by the Mexican government, which mobilized schools and healthcare units across 32 states to create dengue-free environments. The initiative focused on reducing mosquito habitats in educational institutions and medical facilities, while also investing in the training of healthcare professionals. Dr. Ramos emphasized the pivotal role of community participation, noting that public health campaigns must prioritize education and local engagement to effectively curb the virus's spread.

Both Dr. Ramos and Martha Torales, head of the National Vector-Borne Diseases Program in Paraguay, emphasized the crucial role of community involvement in dengue prevention.

Dr. Ramos pointed to initiatives like neighborhood clean-up campaigns as critical for reducing mosquito breeding grounds but noted that consistent education and resources are necessary to maintain these efforts over time. Similarly, Dr. Torales warned that without ongoing public cooperation, even the most well-designed vector control programs would struggle to succeed. She advocated for governments and health officials to build long-term partnerships with communities, ensuring continued adherence to preventive measures such as proper water storage and eliminating stagnant water.

The webinar underlined the importance of collective action and interdisciplinary collaboration. Experts from various fields agreed on the need for comprehensive strategies, combining cutting-edge research, predictive models, and public health interventions to mitigate the impact of dengue across Latin America and the Caribbean.

Key solutions discussed included:

• Enhanced Surveillance Systems: Developing real-time monitoring systems to track dengue cases and hotspots.
• Predictive Modeling: Utilizing models to forecast outbreaks and optimize resource distribution.
• Vaccination Programs: Promoting the use of dengue vaccines, while continuing research to improve their effectiveness.
• Vector Control: Strengthening mosquito control through new insecticides, genetic modifications, and Wolbachia bacteria.
• Community Engagement: Encouraging active community participation in eliminating mosquito breeding grounds and raising public awareness.
• Health System Preparedness: Equipping healthcare systems with the training and resources needed to manage large-scale outbreaks.
• Environmental Management: Addressing urbanization and poor water sanitation to eliminate mosquito breeding sites.
• Technological Innovation: Using drones and geographic information systems (GIS) to identify and manage mosquito habitats.
• Legislative Support: Advocating for stronger public health policies to enforce dengue prevention and control measures.

“The strides in reducing dengue mortality through improved clinical management are notable, but the disease's overall burden continues to climb,” remarked Gamaliel Gutiérrez, M.D., M.Sc., technical officer, Surveillance of Arboviral Diseases at the Pan American Health Organization (PAHO). While significant progress has been made in certain areas, the experts concur that a sustained, multi-faceted effort is required to curb the spread of dengue and protect vulnerable populations throughout the Latin America and Caribbean region.

Written by Deycha Torres Hernández, published on August 19, 2024.