Novel repellents for the blood-sucking insects Rhodnius prolixus and Triatoma infestans, vectors of Chagas disease

Abstract

Background: Studying the behavioral response of blood-sucking disease-vector insects to potentially repellent volatile compounds could shed light on the development of new control strategies. Volatiles released by human facial skin microbiota play different roles in the host-seeking behavior of triatomines. We assessed the repellency effect of such compounds of bacterial origin on Triatoma infestans and Rhodnius prolixus, two important vectors of Chagas disease in Latin America. Methods: Using an exposure device, insects were presented to human odor alone (control) and in the presence of three individual test compounds (2-mercaptoethanol, dimethyl sulfide and 2-phenylethanol, the latter only tested in R. prolixus) and the gold-standard repellent NN-diethyl-3-methylbenzamide (DEET). We quantified the time the insects spent in the proximity of the host and determined if any of the compounds evaluated affected the behavior of the insects. Results: We found volatiles that significantly reduced the time spent in the proximity of the host. These were 2-phenylethanol and 2-mercaptoethanol for R. prolixus, and dimethyl sulfide and 2-mercaptoethanol for T. infestans. Such an effect was also observed in both species when DEET was presented, although only at the higher doses tested. Conclusions: The new repellents modulated the behavior of two Chagas disease vectors belonging to two different triatomine tribes, and this was achieved using a dose up to three orders of magnitude lower than that needed to evoke the same effect with DEET. Future efforts in understanding the mechanism of action of repellent compounds such as 2-mercaptoethanol, as well as an assessment of their temporal and spatial repellent properties, could lead to the development of novel control strategies for these insect vectors, refractory to DEET.

Production of Plant-Associated Volatiles by Select Model and Industrially Important Streptomyces spp.

“…[ 18 , 63 , 64 , 125 ] and by plants such as rose [ 65 ]. It has been shown to function as an insect repellent against Rhodnius prolixus (Family: Reduviidae) and Triatoma infestans (kissing bug), both of which are vectors of the Chagas disease parasite [ 77 ]. Phenylethyl alcohol also displays antifungal activity against the plant pathogen, Ceratocystis fimbriata (Family: Ceratocystidaceae) [ 63 ].…”

Diagnosis and Prevalence of Chagas Disease in an Indigenous Population of Colombia

“…), which support the breeding and living conditions of Triatomines, the CD vectors. Although only a few of the more than 130 different Triatomine species transmit the pathogen Trypanosoma cruzi ( T. cruzi ) [ 12 ], the most important ones are found in the examined zone, such as Rhodnius prolixus [ 14 ].…”

Analysis of Streptomyces Volatilomes Using Global Molecular Networking Reveals the Presence of Metabolites with Diverse Biological Activities

“…In addition, 2-octanol produced by soil bacteria (including Bacillus , Microbacterium , Stenotrophomonas , Streptomyces , and Serratia ) displays potent nematocidal activities against a free-living nematode ( Panagrellus redivivus ) and the pinewood nematode ( Bursaphelenchus xylophilus ) ( 104 ). Another compound detected was phenylethyl alcohol, which is synthesized by multiple Streptomyces species ( 19 , 105 ) and plants ( 106 ) and is known to repel certain insects ( 107 , 108 ). It also has antifungal activities against pathogens of peanuts ( 109 ) and sweet potato ( 110 ).…”