PLoS Neglected Tropical Diseases (2020) 14 (3 - e0007719)

Ailie Robinson, Julie Bristow, Matthew V. Holl, Pateh Makalo, Wondu Alemayehu, Robin L. Bailey, David Macleod, Michael A. Birkett, John C. Caulfield, Virginia Sarah, John A. Pickett, Sarah Dewhirst, Vanessa Chen-Hussey, Christine M. Woodcock, Umberto D'Alessandro, Anna Last, Matthew J. Burton, Steve W. Lindsay and James G. Logan (2020)
Responses of the putative trachoma vector, Musca sorbens, to volatile semiochemicals from human faeces
PLoS Neglected Tropical Diseases 14 (3 - e0007719)
Abstract: The putative vector of trachoma, Musca sorbens, prefers to lay its eggs on human faeces on the ground. This study sought to determine whether M. sorbens females were attracted to volatile odours from human faeces in preference to odours from the faeces of other animals, and to determine whether specific volatile semiochemicals mediate selection of the faeces. Traps baited with the faeces of humans and local domestic animals were used to catch flies at two trachoma-endemic locations in The Gambia and one in Ethiopia. At all locations, traps baited with faeces caught more female M. sorbens than control traps baited with soil, and human faeces was the most successful bait compared with soil (mean rate ratios 44.40, 61.40, 10.50 [P<0.001]; 8.17 for child faeces [P = 0.004]). Odours from human faeces were sampled by air entrainment, then extracts of the volatiles were tested by coupled gas chromatography-electroantennography with laboratory-reared female M. sorbens. Twelve compounds were electrophysiologically active and tentatively identified by coupled mass spectrometry-gas chromatography, these included cresol, indole, 2-methylpropanoic acid, butanoic acid, pentanoic acid and hexanoic acid. It is possible that some of these volatiles govern the strong attraction of M. sorbens flies to human faeces. If so, a synthetic blend of these chemicals, at the correct ratios, may prove to be a highly attractive lure. This could be used in odour-baited traps for monitoring or control of this species in trachoma-endemic regions.
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Database assignments for author(s): Michael A. Birkett, John A. Pickett, Sarah Y. Dewhirst

Research topic(s) for pests/diseases/weeds:
pheromones/attractants/traps

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Musca sorbens		Ethiopia
	Musca sorbens		Gambia