Dengue Epidemics in Brazil: Lessons Learned
by Dr. Giovanini Coelho
In its efforts to share first-hand testimonials from dengue-endemic countries, the Dengue Vaccine Initiative (DVI) asked Dr. Giovanini Coelho, Coordinator of the National Program for Dengue Control in Brazil and a member of its Dengue Prevention Board, to describe his experience with dengue outbreaks. The article, originally published by DVI, captures the challenges of controlling dengue in Brazil and the efforts of its Ministry of Health.
The reintroduction of the dengue virus in Brazil during the 1980s led to the transmission of the disease in the country for the past 28 years. Aspects related to climatic conditions and the infrastructure of the cities, such as irregular garbage collection and water supply, associated with the absence of effective control measures for the vector, Aedes aegypti, have all contributed to the current hyperendemic/epidemic scenario now observed in Brazil.
Between 2000 and 2012, dengue became one of the biggest public health challenges in Brazil. Currently the population is exposed to four serotypes which are circulating in all regions of the country. During this time period, we observed significant changes in the disease epidemiology, highlighted by a higher number of hospitalizations with shifts in disease severity towards children and the elderly. Because of this, improved prevention and control measures, and the development of state and municipality capacity for response during dengue epidemics, became a priority to the Ministry of Health.
The National Dengue Control Program (PNCD), instituted in 2002, has been promoting diverse initiatives aimed at strengthening epidemiologic surveillance, vector control strategies, patient’s management and population’s communication and mobilization. All these components are part of the contingency plans developed by the Public Health System (SUS) management of Brazil.
Dengue is a mandatory notifiable disease and the surveillance system is present in all 5,570 municipalities of the country. Among its characteristics, we highlight the use of standardized instruments for data collection with a common information system and a wide laboratory network for diagnostics and identification of circulating serotypes of the virus. This system has fostered increased knowledge of the disease’s epidemiological aspects such as the detection of epidemic processes, identification of changes in the pattern of affected people’s age groups and the description of the seasonality of the transmission between different geographic regions.
The Aedes aegypti Infestation Index Rapid Survey (LIRAa) was also developed in order to strengthen Brazil’s vector control activities. This methodology is able to quickly identify areas with the highest indices of residential mosquito infestation and the predominant breeding sites in a representative sample of the municipalities. This information allows the Ministry of Health to implement control measures in the most critical areas.
The reduction of mortality due to dengue is the main goal of PNCD. During epidemic periods, the health facilities experience an overwhelming increase in the number of patients searching for care. Strategies to increase the patients’ access to care are numerous, including the adoption of extended working hours of health units and the utilization of tents for intravenous fluid therapy to prevent hypovolemic shock. The training of health professionals, doctors and nurses is also a strategic component that has evolved in its methodology, focusing on the spread of knowledge through a number of means such as distance learning supported by universities and the Ministry of Health.
Brazil’s community mobilization campaigns have evolved to focus on the differences observed in the epidemiology and characteristics of the public among the different regions of the country. This allowed informing each particular target group (health professionals, managers, etc.) and geographic areas according to its entomological singularities.
Due to the absence of effective dengue control measures, the Ministry of Health has supported additional research on alternative vector and disease control methods. Specifically, the Ministry has focused on the Wolbachia bacteria effectiveness evaluation studies on the prevention of dengue, the use of traps for the development of a new entomological index, large scale use of screens impregnated with insecticides in households, and preparation studies for the introduction of dengue vaccines in the future.
In all these efforts, the Ministry of Health has searched for partnerships with international organizations such as the World Health Organization (WHO/OMS) and Dengue Vaccine Initiative (DVI).