Dengue Fever Occurrence and Vector Detection by Larval Survey, Ovitrap and MosquiTRAP: A Space-Time Clusters Analysis

Abstract

The use of vector surveillance tools for preventing dengue disease requires fine assessment of risk, in order to improve vector control activities. Nevertheless, the thresholds between vector detection and dengue fever occurrence are currently not well established. In Belo Horizonte (Minas Gerais, Brazil), dengue has been endemic for several years. From January 2007 to June 2008, the dengue vector Aedes (Stegomyia) aegypti was monitored by ovitrap, the sticky-trap MosquiTRAP™ and larval surveys in an study area in Belo Horizonte. Using a space-time scan for clusters detection implemented in SaTScan software, the vector presence recorded by the different monitoring methods was evaluated. Clusters of vectors and dengue fever were detected. It was verified that ovitrap and MosquiTRAP vector detection methods predicted dengue occurrence better than larval survey, both spatially and temporally. MosquiTRAP and ovitrap presented similar results of space-time intersections to dengue fever clusters. Nevertheless ovitrap clusters presented longer duration periods than MosquiTRAP ones, less acuratelly signalizing the dengue risk areas, since the detection of vector clusters during most of the study period was not necessarily correlated to dengue fever occurrence. It was verified that ovitrap clusters occurred more than 200 days (values ranged from 97.0±35.35 to 283.0±168.4 days) before dengue fever clusters, whereas MosquiTRAP clusters preceded dengue fever clusters by approximately 80 days (values ranged from 65.5±58.7 to 94.0±14. 3 days), the former showing to be more temporally precise. Thus, in the present cluster analysis study MosquiTRAP presented superior results for signaling dengue transmission risks both geographically and temporally. Since early detection is crucial for planning and deploying effective preventions, MosquiTRAP showed to be a reliable tool and this method provides groundwork for the development of even more precise tools.

Spatio-temporal patterns of dengue in Malaysia: combining address and sub-district level

“…Thirdly, the home addresses used to allocate the dengue cases may not always be the correct ones, reflecting the mobility of patients with respect to recreation and work activities. Nevertheless, the higher probability of multiple infections in the household strengthens the home address as the main infection site (Halstead, 2008;de Melo et al, 2012). Additional illustrations of the monthly spatiotemporal clusters of dengue cases at the address level from year 2008 to 2010 can be found in the Supplement.…”

Field comparison of oviposition substrates used in ovitraps for Aedes aegypti surveillance in Salta, Argentina

“…Ovitraps are artificial oviposition sites, a tool developed for monitoring mosquito populations and to assess the control measures (Rose, 2001), that have even shown to be more sensitive and effective than the traditional larvae surveys (deMelo, Scherrer, & Eiras, 2012). Ovitraps provide several advantages over other surveillance methods because of their low cost, high sensitivity and ease of field management, which allow operation by unqualified personnel (Bellini, Carrieri, Burgio, & Bacchi, 1996;Carrieri et al, 2011).…”

Development of the Gravid <I>Aedes</I> Trap for the Capture of Adult Female Container-Exploiting Mosquitoes (Diptera: Culicidae)

“…Sampling of adult container-breeding Stegomyia to monitor mosquito densities and spatial and temporal distribution has been a great contribution in the control of dengue vectors (Barrera 2011, de Melo et al 2012. Backpack aspirators (Clark et al 1994) rely on the collection of adult mosquitoes inside and outside premises.…”

“…Various sticky trap designs have been developed and evaluated in Þeld conditions to monitor vector abundance (Ritchie et al 2003, Fávaro et al 2006, Facchinelli et al 2007, Chadee and Ritchie 2010a and to analyze the association between adult abundance and risk of dengue transmission , Eiras and Resende 2009, de Melo et al 2012. Although sticky traps have been developed in countries such as Mexico (Ordó ñ ez- Gonzalez et al 2001), Australia , Brazil (Gama et al 2007), Italy (Facchinelli et al 2007), and China (Zhang and Lei 2008), the most studied versions are the double sticky trap (Trinidad and Australia; Chadee and Ritchie 2010a) and the MosquiTRAP (Brazil; Eiras and Resende 2009).…”