A Multi-species Bait for Chagas Disease Vectors

Abstract

BackgroundTriatomine bugs are the insect vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. These insects are known to aggregate inside shelters during daylight hours and it has been demonstrated that within shelters, the aggregation is induced by volatiles emitted from bug feces. These signals promote inter-species aggregation among most species studied, but the chemical composition is unknown.Methodology/Principal FindingsIn the present work, feces from larvae of the three species were obtained and volatile compounds were identified by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). We identified five compounds, all present in feces of all of the three species: Triatoma infestans, Panstrongylus megistus and Triatoma brasiliensis. These substances were tested for attractivity and ability to recruit insects into shelters. Behaviorally active doses of the five substances were obtained for all three triatomine species. The bugs were significantly attracted to shelters baited with blends of 160 ng or 1.6 µg of each substance.Conclusions/SignificanceCommon compounds were found in the feces of vectors of Chagas disease that actively recruited insects into shelters, which suggests that this blend of compounds could be used for the development of baits for early detection of reinfestation with triatomine bugs.

Compounds released by disturbed adults of the haematophagous bug Triatoma infestans (Hemiptera: Reduviidae): behavioural effects of single compounds and binary mixtures

“…Although isobutyric acid can evoke an escape response when it is released from the Brindley's glands of disturbed adults, this compound can also assume a different function and act as a cue for the location of the food source related to host odours (Ward, ; Guerenstein & Guerin, ). This may also occur with butyric and acetic acids because they are present in host odours (Barrozo & Lazzari, ) and in the aggregation pheromones present in triatomine faeces (acetic acid) (Mota et al , ), and they also evoke an escape response in the larvae of T. infestans , as observed in the present study.…”

Behavioural and electrophysiological responses of Triatoma dimidiata nymphs to conspecific faecal volatiles

“…Attraction to Triatoma infestans (Klug) faeces lasts for 3 h after they have been deposited, but may extend to 10 days or longer, if the faeces remain humid (Lorenzo Figueiras & Lazzari, ). Few studies have analysed the chemical basis for attraction or aggregation to faeces, despite behavioural evidence for faecal attraction in several triatomine species (Cruz‐López & Morgan, ; Taneja & Guerin, ; Mota et al ., ). As triatomine nymphs have limited mobility and must acquire key symbionts from conspecific faeces immediately following eclosion (Beard et al ., ), attraction and aggregation to these components are important for their population dynamics, which may also affect infection with T. cruzi .…”

“…Many triatomine species are attracted to and aggregate around conspecific as well as heterospecific faeces in laboratory experiments, highlighting the effect of dry faeces on the attraction and aggregation of nymphs and adults (Schofield & Patterson, ; Cruz‐López et al ., ; Lorenzo Figueiras et al ., ; Lorenzo & Lazzari, ; Lorenzo Figueiras & Lazzari, ; Pires et al ., ; Vitta et al ., , ). Although volatile composition may shift over time (Lorenzo Figueiras & Lazzari, ; Mota et al ., ), fresh faeces are reported to have a repellent effect on triatomine bugs (Lorenzo Figueiras et al ., ). Attraction to Triatoma infestans (Klug) faeces lasts for 3 h after they have been deposited, but may extend to 10 days or longer, if the faeces remain humid (Lorenzo Figueiras & Lazzari, ).…”

The molecular sensory machinery of a Chagas disease vector: expression changes through imaginal moult and sexually dimorphic features

“…Numerous neuroethological studies have improved our understanding of diverse aspects of triatomine olfactory-mediated behaviours, such as host searching6, mating7, and aggregation responses8. Aspects of triatomine sensory ecology such as the use of thermal9 and humidity10 cues, as well as vibratory signals11, have also been studied.…”