Sustained Reduction of the Dengue Vector Population Resulting from an Integrated Control Strategy Applied in Two Brazilian Cities

Abstract

Aedes aegypti has developed evolution-driven adaptations for surviving in the domestic human habitat. Several trap models have been designed considering these strategies and tested for monitoring this efficient vector of Dengue. Here, we report a real-scale evaluation of a system for monitoring and controlling mosquito populations based on egg sampling coupled with geographic information systems technology. The SMCP-Aedes, a system based on open technology and open data standards, was set up from March/2008 to October/2011 as a pilot trial in two sites of Pernambuco -Brazil: Ipojuca (10,000 residents) and Santa Cruz (83,000), in a joint effort of health authorities and staff, and a network of scientists providing scientific support. A widespread infestation by Aedes was found in both sites in 2008–2009, with 96.8%–100% trap positivity. Egg densities were markedly higher in SCC than in Ipojuca. A 90% decrease in egg density was recorded in SCC after two years of sustained control pressure imposed by suppression of >7,500,000 eggs and >3,200 adults, plus larval control by adding fishes to cisterns. In Ipojuca, 1.1 million mosquito eggs were suppressed and a 77% reduction in egg density was achieved. This study aimed at assessing the applicability of a system using GIS and spatial statistic analysis tools for quantitative assessment of mosquito populations. It also provided useful information on the requirements for reducing well-established mosquito populations. Results from two cities led us to conclude that the success in markedly reducing an Aedes population required the appropriate choice of control measures for sustained mass elimination guided by a user-friendly mosquito surveillance system. The system was able to support interventional decisions and to assess the program’s success. Additionally, it created a stimulating environment for health staff and residents, which had a positive impact on their commitment to the dengue control program.

The State of the Art of Lethal Oviposition Trap-Based Mass Interventions for Arboviral Control

“…This was first addressed in a study performed by Regis et al [54] during which 8400 small (2 L) ovitraps were deployed over a two-year intervention period, during which five ovitraps were placed at each participating residence. Unlike the mechanical suppression of adults in Lok et al [29], control in the Regis et al [54] trap intervention relied on the physical collection and destruction of eggs or treatment of containers with Bacillus thuringiensis israelensis (Bti) to kill any larvae that developed. The decision not to rely on insecticide treated ovistrips was most likely based on the presence of insecticide resistance in local Ae.…”

Dengue virus detection inAedes aegyptilarvae from southeastern Brazil

“…With the ongoing search for an efficient vaccine and an antiviral drug, prevention is still the best way to control the disease, which is possible through vector control in several forms (Bäck and Lundkvist , Resende et al , Resende et al ). Various trap models to capture and measure the density of the vector have been designed, and their use in many countries has shown them to be a better strategy than classical surveillance methods for monitoring (Regis et al , Regis et al ).…”

The susceptibility of Aedes aegypti populations displaying temephos resistance to Bacillus thuringiensis israelensis: a basis for management

“…Bti has also been used in oviposition and adult traps to prevent the development of larvae in these devices when they are used for monitoring, or on a massive scale, to reduce mosquito populations [24-26]. Another factor that supports the increasing use of Bti is the worldwide Ae .…”