Sampling Host-Seeking Anthropophilic Mosquito Vectors in West Africa: Comparisons of an Active Human-Baited Tent-Trap Against Gold Standard Methods

Krajacich, Benjamin J; Slade, Jeremiah; Mulligan, Robert F.; Labrecque, Brendan; Alout, Haoués; Grubaugh, Nathan D.; Meyers, Jacob I.; Fakoli, Lawrence; Bolay, Fatorma K.; Brackney, Doug E.; Burton, Timothy A.; Seaman, Jonathan A.; Diclaro, Joseph W.; Dabiré, Roch K.; Foy, Brian D.

doi:10.4269/ajtmh.14-0303

Cited by 12 publications

(9 citation statements)

References 25 publications

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“…However, the current "gold standard" for anthropophilic vector capture, HLC, although effective and an essential parameter for the calculation of entomological indices, such as biting rate, anthropophilic degree and human exposure, puts participants at risk for vector-borne diseases [27]. …”

Section: Discussionmentioning

confidence: 99%

A new methodology for sampling blackflies for the entomological surveillance of onchocerciasis in Brazil

et al. 2017

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The effectiveness of the MosqTent® trap was evaluated in endemic area to onchocerciasis in Brazil. This study seeks to provide subsidies for the monitoring of the onchocerciasis transmission in the country. The study was carried out at the Homoxi and Thirei villages, located in the Yanomami Indigenous Land, in the state of Roraima. This area presents hyperendemicity, high blackflies densities, large population migrations and mining activities. The Homoxi and Thirei villages are assisted by the Brazilian Ministry of Health. To conduct the present study, the village leader, health leaders and the Brazilian Ethics Committee were consulted. Blackflies captures were carried out simultaneously at the Homoxi and Thirei, using systematized methods to allow for comparisons between the traditional Human Landing Catch (HLC) and HLC protected by the MosqTent®. The female blackflies were captured at two equidistant capture stations per locality, by two collectors per station, for five consecutive days. Individuals captured by interval/station/day were counted, identified and maintained at -20°C. The underlying probability distributions and the differences between the methods for the independent sample data were verified in a comparative statistical analysis between the use of the MosqTent® and the HLC. A total of 10,855 antropophilic blackflies were captured by both methodologies. A total of 7,367 (67.87%) blackflies belonging to seven species were captured by MosqTent® —Simulium incrustatum s.l (99.06%); S. guianense s.l (0.74%), S. oyapockense s.l (0.01%), S. exiguum (0.10%), S. metallicum (0.05%), S. ochraceum (0.03%) and S. minusculum s.l (0.01%). Moreover, 3,488 (32.14%) blackflies belonging to four species were captured by HLC—S. incrustatum s.l (98.33%); S. guianense s.l (1.38%), S. oyapockense s.l (0.26%) and S. metallicum (0.03%). The MosqTent® was more effective and efficient when compared to HLC. When comparing total blackflies captured/day, the MosqTent® was more efficient than HLC (p = 0.031) with a means of 799.4 blackflies/day versus 217.6 blackflies/day by HLC. The results demonstrated improved performance and high reliability of the MosqTent® compared to the traditional HLC method.

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Section: Discussionmentioning

confidence: 99%

A new methodology for sampling blackflies for the entomological surveillance of onchocerciasis in Brazil

et al. 2017

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“…), and all aspirated mosquitoes were identified as An. gambiae sensu stricto as previously described [24]. Forceps clutching the thorax were used to hold blood fed mosquitoes in place while the contents of the abdomen were pressed onto 96-well format FTA cards (one blood meal per "well") using sterile pipet tips (S1E Fig.).…”

Section: Field Collection Of Indoor Resting Blood Fed Mosquitoesmentioning

confidence: 99%

Xenosurveillance: A Novel Mosquito-Based Approach for Examining the Human-Pathogen Landscape

et al. 2015

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BackgroundGlobally, regions at the highest risk for emerging infectious diseases are often the ones with the fewest resources. As a result, implementing sustainable infectious disease surveillance systems in these regions is challenging. The cost of these programs and difficulties associated with collecting, storing and transporting relevant samples have hindered them in the regions where they are most needed. Therefore, we tested the sensitivity and feasibility of a novel surveillance technique called xenosurveillance. This approach utilizes the host feeding preferences and behaviors of Anopheles gambiae, which are highly anthropophilic and rest indoors after feeding, to sample viruses in human beings. We hypothesized that mosquito bloodmeals could be used to detect vertebrate viral pathogens within realistic field collection timeframes and clinically relevant concentrations.Methodology/Principal FindingsTo validate this approach, we examined variables influencing virus detection such as the duration between mosquito blood feeding and mosquito processing, the pathogen nucleic acid stability in the mosquito gut and the pathogen load present in the host’s blood at the time of bloodmeal ingestion using our laboratory model. Our findings revealed that viral nucleic acids, at clinically relevant concentrations, could be detected from engorged mosquitoes for up to 24 hours post feeding by qRT-PCR. Subsequently, we tested this approach in the field by examining blood from engorged mosquitoes from two field sites in Liberia. Using next-generation sequencing and PCR we were able to detect the genetic signatures of multiple viral pathogens including Epstein-Barr virus and canine distemper virus.Conclusions/SignificanceTogether, these data demonstrate the feasibility of xenosurveillance and in doing so validated a simple and non-invasive surveillance tool that could be used to complement current biosurveillance efforts.

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“…gambiae were used for independent test sets. These numbers were chosen to roughly keep classes the same size, with the sporozoite positive samples being the limiting sample set (due to a 1.5–5.1% sporozoite positive rate in samples tested) [ 58 ]. Of these, 28/40 of the nulliparous are non-blood-fed, 27/39 of parous are non-blood-fed, and 8/40 of the sporozoite positive are non-blood-fed (Additional file 5 : Table S4).…”

Section: Resultsmentioning

confidence: 99%

“…Independent test sets 2 and 3 (ITS2, ITS3) were comprised of adult mosquitoes caught via indoor aspiration or by a human baited tent-trap and were noted for blood-fed status, scanned, parity dissected (see below), and stored in individual 1.5-ml tubes containing t.h.e. 100% indicating silica gel desiccant beads (#EM-DX0017–1, EMD Millipore, Billerica, MA, USA) for sporozoite analysis (see below) [ 57 , 58 ]. ITS3 consisted of the nulliparous compared to the parous mosquitoes, while ITS2 consisted of the nulliparous mosquitoes compared to the sporozoite positive mosquitoes.…”

Section: Methodsmentioning

confidence: 99%

Analysis of near infrared spectra for age-grading of wild populations of Anopheles gambiae

et al. 2017

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BackgroundUnderstanding the age-structure of mosquito populations, especially malaria vectors such as Anopheles gambiae, is important for assessing the risk of infectious mosquitoes, and how vector control interventions may impact this risk. The use of near-infrared spectroscopy (NIRS) for age-grading has been demonstrated previously on laboratory and semi-field mosquitoes, but to date has not been utilized on wild-caught mosquitoes whose age is externally validated via parity status or parasite infection stage. In this study, we developed regression and classification models using NIRS on datasets of wild An. gambiae (s.l.) reared from larvae collected from the field in Burkina Faso, and two laboratory strains. We compared the accuracy of these models for predicting the ages of wild-caught mosquitoes that had been scored for their parity status as well as for positivity for Plasmodium sporozoites.ResultsRegression models utilizing variable selection increased predictive accuracy over the more common full-spectrum partial least squares (PLS) approach for cross-validation of the datasets, validation, and independent test sets. Models produced from datasets that included the greatest range of mosquito samples (i.e. different sampling locations and times) had the highest predictive accuracy on independent testing sets, though overall accuracy on these samples was low. For classification, we found that intramodel accuracy ranged between 73.5–97.0% for grouping of mosquitoes into “early” and “late” age classes, with the highest prediction accuracy found in laboratory colonized mosquitoes. However, this accuracy was decreased on test sets, with the highest classification of an independent set of wild-caught larvae reared to set ages being 69.6%.ConclusionsVariation in NIRS data, likely from dietary, genetic, and other factors limits the accuracy of this technique with wild-caught mosquitoes. Alternative algorithms may help improve prediction accuracy, but care should be taken to either maximize variety in models or minimize confounders.Electronic supplementary materialThe online version of this article (10.1186/s13071-017-2501-1) contains supplementary material, which is available to authorized users.

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Sampling Host-Seeking Anthropophilic Mosquito Vectors in West Africa: Comparisons of an Active Human-Baited Tent-Trap Against Gold Standard Methods

Cited by 12 publications

References 25 publications

A new methodology for sampling blackflies for the entomological surveillance of onchocerciasis in Brazil

A new methodology for sampling blackflies for the entomological surveillance of onchocerciasis in Brazil

Xenosurveillance: A Novel Mosquito-Based Approach for Examining the Human-Pathogen Landscape

Analysis of near infrared spectra for age-grading of wild populations of Anopheles gambiae

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