LSHTM Research Online

African pit latrines produce prodigious numbers of the latrine fly, Chrysomya putoria, a putative vector of diarrhoeal pathogens. We set out to develop a simple, low-cost odour-baited trap for collecting C. putoria in the field. A series of field experiments was carried out in The Gambia to assess the catching-efficiency of different trap designs. The basic trap was a transparent 3L polypropylene box baited with 50 g of fish, with a white opaque lid with circular entrance holes. We tested variations of the number, diameter, position and shape of the entrance holes, the height of the trap above ground, degree of transparency of the box, its shape, volume, colour, and the attractiveness of gridded surfaces on or under the trap. Traps were rotated between positions on different sampling occasions using a Latin Square design. The optimal trapping features were incorporated into a final trap that was tested against commercially available traps. Features of the trap that increased the number of flies caught included: larger entrance holes (compared with smaller ones, p,0.001), using conical collars inside the holes (compared with without collars, p = 0.01), entrance holes on the top of the trap (compared with the side or bottom, p,0.001), traps placed on the ground (compared with above ground, p,0.001), the box having transparent sides (compared with being opaque, p,0.001), and with no wire grids nearby (compared with those with grids, p = 0.03). This trap collected similar numbers of C. putoria to other common traps for blow flies. The optimum trap design was a transparent box, with a white plastic lid on top, perforated with 10 conical entrance holes, placed on the ground. Our simple trap provides a cheap, low-maintenance and effective method of sampling C. putoria in the field. Citation: Lindsay TC, Jawara M, D’Alessandro U, Pinder M, Lindsay SW (2012) Development of Odour-Baited Flytraps for Sampling the African Latrine Fly, Chrysomya putoria, a Putative Vector of Enteric Diseases. PLoS ONE 7(11): e50505. doi:10.1371/journal.pone.0050505 Editor: John Vontas, University of Crete, Greece Received September 6, 2012; Accepted October 22, 2012; Published November 30, 2012 Copyright: 2012 Lindsay et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The work was supported by the Bill and Melinda Gates Foundation (# OPP1034747; Grand Challenges Explorations Phase I, Round 6 Project Grant). SWL received support from the Research and Policy for Infectious Disease Dynamics (RAPIDD) Program of the Science and Technology Directory, Department of Homeland Security, and Fogarty International Center, National Institutes of Health, Medical Research Council, UK. The sponsors of the study did not have a role in the design of the study, data collection, analysis, interpretation and writing of this manuscript. SWL had full access to the data and had the final responsibility for submitting the manuscript for publication. Competing Interests: The authors have declared that no competing interests exist. * E-mail: S.W.Lindsay@durham.ac.uk