Comparative dissection of the peripheral olfactory system of the Chagas disease vectors Rhodnius prolixus and Rhodnius brethesi

American trypanosomiasis or Chagas disease is thought to be transmitted by both domestic and sylvatic species of Triatominae. These haematophagous insects use sensory cues to find their vertebrate hosts. Among them, odorants have been shown to play a key role. Previous work revealed morphological differences in the sensory apparatus of sylvatic and domestic species of Triatomines, but to date a functional study of the olfactory system is not available. After examining the antennal sensilla with scanning electronic microscopy (SEM), we compared olfactory responses of the domestic Rhodnius prolixus and the sylvatic Rhodnius brethesi with an electrophysiological approach. In electroantennogram (EAG) recordings, we first show that the antenna of R. prolixus shows high responses to carboxylic acids, compounds found in their habitat and headspace of hosts. We then compared responses from olfactory sensory neurons (OSNs) housed in the grooved peg sensilla of both species as these are tuned to these compounds using single-sensillum recordings (SSR). In R. prolixus , the SSR responses revealed a narrower tuning breath than its sylvatic counterpart, with the latter showing responses to a broader range of chemical classes. Additionally, we observed significant differences between these two species in their response to particular volatiles, such as amyl acetate and butyryl chloride. In summary, the closely related, but ecologically differentiated R. prolixus and R. brethesi display distinct differences in their olfactory functions. Considering the ongoing rapid destruction of the natural habitat of sylvatic species and likely shifts towards environments shaped by humans, we expect that our results will contribute to the design of efficient vector control strategies in the future.

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Comparative dissection of the peripheral olfactory system of the Chagas disease vectors Rhodnius prolixus and Rhodnius brethesi

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009098 ◽

2021 ◽

Vol 15 (4) ◽

pp. e0009098

Author(s):

Florencia Campetella ◽

Rickard Ignell ◽

Rolf Beutel ◽

Bill S. Hansson ◽

Silke Sachse

Keyword(s):

Chagas Disease ◽

Olfactory System ◽

Control Strategies ◽

Natural Habitat ◽

Rhodnius Prolixus ◽

Functional Study ◽

Olfactory Responses ◽

Efficient Vector ◽

Vertebrate Hosts ◽

Morphological Differences

American trypanosomiasis, or Chagas disease, is transmitted by both domestic and sylvatic species of Triatominae which use sensory cues to locate their vertebrate hosts. Among them, odorants have been shown to play a key role. Previous work revealed morphological differences in the sensory apparatus of different species of Triatomines, but to date a comparative functional study of the olfactory system is lacking. After examining the antennal sensilla with scanning electronic microscopy (SEM), we compared olfactory responses of Rhodnius prolixus and the sylvatic Rhodnius brethesi using an electrophysiological approach. In electroantennogram (EAG) recordings, we first showed that the antenna of R. prolixus is highly responsive to carboxylic acids, compounds found in their habitat and the headspace of their vertebrate hosts. We then compared responses from olfactory sensory neurons (OSNs) housed in the grooved peg sensilla of both species, as these are tuned to these compounds using single-sensillum recordings (SSRs). In R. prolixus, the SSR responses revealed a narrower tuning breath than its sylvatic sibling, with the latter showing responses to a broader range of chemical classes. Additionally, we observed significant differences between these two species in their response to particular volatiles, such as amyl acetate and butyryl chloride. In summary, the closely related, but ecologically differentiated R. prolixus and R. brethesi display distinct differences in their olfactory functions. Considering the ongoing rapid destruction of the natural habitat of sylvatic species and the likely shift towards environments shaped by humans, we expect that our results will contribute to the design of efficient vector control strategies in the future.

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High-Throughput Identification of the Rhodnius prolixus Midgut Proteome Unravels a Sophisticated Hematophagic Machinery

Proteomes ◽

10.3390/proteomes8030016 ◽

2020 ◽

Vol 8 (3) ◽

pp. 16 ◽

Cited By ~ 2

Author(s):

Radouane Ouali ◽

Karen Caroline Valentim de Brito ◽

Didier Salmon ◽

Sabrina Bousbata

Keyword(s):

Digestive Tract ◽

Chagas Disease ◽

High Throughput ◽

Control Strategies ◽

Anterior Part ◽

Rhodnius Prolixus ◽

Etiologic Agent ◽

Parasitic Infections ◽

Developmental Cycle ◽

Starting Point

Chagas disease is one of the most common parasitic infections in Latin America, which is transmitted by hematophagous triatomine bugs, of which Rhodnius prolixus is the vector prototype for the study of this disease. The protozoan parasite Trypanosoma cruzi, the etiologic agent of this disease, is transmitted by the vector to humans through the bite wound or mucosa. The passage of the parasite through the digestive tract of its vector constitutes a key step in its developmental cycle. Herewith, by a using high-throughput proteomic tool in order to characterize the midgut proteome of R. prolixus, we describe a set of functional groups of proteins, as well as the biological processes in which they are involved. This is the first proteomic analysis showing an elaborated hematophagy machinery involved in the digestion of blood, among which, several families of proteases have been characterized. The evaluation of the activity of cathepsin D proteases in the anterior part of the digestive tract of the insect suggested the existence of a proteolytic activity within this compartment, suggesting that digestion occurs early in this compartment. Moreover, several heat shock proteins, blood clotting inhibitors, and a powerful antioxidant enzyme machinery against reactive oxygen species (ROS) and cell detoxification have been identified. Highlighting the complexity and importance of the digestive physiology of insects could be a starting point for the selection of new targets for innovative control strategies of Chagas disease.

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

10.1101/789602 ◽

2019 ◽

Author(s):

Melanie Ramírez ◽

Mario I. Ortiz ◽

Pablo Guerenstein ◽

Jorge Molina

Keyword(s):

Chagas Disease ◽

Dimethyl Sulfide ◽

Control Strategies ◽

Statistical Tests ◽

Positive Control ◽

Negative Control ◽

Rhodnius Prolixus ◽

Triatoma Infestans ◽

Host Seeking ◽

Blood Sucking

AbstractBackgroundStudying 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.MethodsUsing an exposure device, insects were presented to human odor alone (negative control) and in the presence of three individual tested compounds (2-mercaptoethanol, dimethyl sulfide and 2-phenylethanol, which was only tested in R. prolixus) and the gold-standard repellent NN-diethyl-3-methylbenzamide–DEET (positive control). We quantified the time the insects spent in the proximity of the host and performed nonparametric statistical tests to determine if any of the compounds evaluated affected the behavior of the insect.ResultsWe 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.ConclusionsThe 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 deeply 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 insect vectors refractory to DEET.

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Silencing the odorant receptor co-receptor RproOrco affects the physiology and behavior of the Chagas disease vector Rhodnius prolixus

Insect Biochemistry and Molecular Biology ◽

10.1016/j.ibmb.2015.02.012 ◽

2016 ◽

Vol 69 ◽

pp. 82-90 ◽

Cited By ~ 27

Author(s):

Thiago A. Franco ◽

Daniele S. Oliveira ◽

Monica F. Moreira ◽

Walter S. Leal ◽

Ana C.A. Melo

Keyword(s):

Chagas Disease ◽

Odorant Receptor ◽

Rhodnius Prolixus ◽

Disease Vector ◽

And Behavior

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Identification and characterization of the SIFamide receptor in the hemimetabolous Chagas disease vector, Rhodnius prolixus Stål, 1859, (Hemiptera, Reduviidae, Triatominae)

Peptides ◽

10.1016/j.peptides.2021.170600 ◽

2021 ◽

pp. 170600

Author(s):

Mahnoor Ayub ◽

Angela B. Lange ◽

Ian Orchard

Keyword(s):

Chagas Disease ◽

Rhodnius Prolixus ◽

Disease Vector ◽

Identification And Characterization

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Rhodnius prolixus smells repellents: Behavioural evidence and test of present and potential compounds inducing repellency in Chagas disease vectors

Journal of Insect Physiology ◽

10.1016/j.jinsphys.2015.07.012 ◽

2015 ◽

Vol 81 ◽

pp. 137-144 ◽

Cited By ~ 14

Author(s):

Paula F. Zermoglio ◽

Hadrien Martin-Herrou ◽

Yohan Bignon ◽

Claudio R. Lazzari

Keyword(s):

Chagas Disease ◽

Rhodnius Prolixus ◽

Disease Vectors ◽

Chagas Disease Vectors ◽

Behavioural Evidence

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Transformation of Rhodococcus rhodnii, a symbiont of the Chagas disease vector Rhodnius prolixus, with integrative elements of the L1 mycobacteriophage

Infection Genetics and Evolution ◽

10.1016/s1567-1348(03)00002-9 ◽

2003 ◽

Vol 3 (2) ◽

pp. 103-109 ◽

Cited By ~ 24

Author(s):

Ellen M Dotson ◽

Bonnie Plikaytis ◽

Thomas M Shinnick ◽

Ravi V Durvasula ◽

Charles B Beard

Keyword(s):

Chagas Disease ◽

Rhodnius Prolixus ◽

Disease Vector

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Distribution and aggregation of engorging ticks on body parts of small rodent hosts

Systematic and Applied Acarology ◽

10.11158/saa.25.11.8 ◽

2020 ◽

Vol 25 (11) ◽

pp. 2018-2032

Author(s):

László Egyed ◽

Zsolt Lang

Keyword(s):

Control Strategies ◽

Natural Habitat ◽

Neck Region ◽

The Body ◽

Rodent Species ◽

Small Rodent ◽

Body Parts ◽

Lactating Females ◽

Tick Survival ◽

Disease Risks

Small rodent species are the most important blood source of tick larvae, their role is crucial for tick survival, maintainance and spread in nature. From data of 1409 ticks collected from 282 individuals of three small rodent species live-trapped at a natural habitat, we drew conclusions about aggregation of ticks, the anatomical sites most frequently used for engorgement, different susceptibility of host species to tick infestation. We studied data of various age and sex groups of hosts, individuals of different reproductive status and recaptured rodents. The tick load of A. agrarius and A. flavicollis differed significantly, accumulation of ticks was shown on the auricles of both Apodemus species, and on the throat-neck region of A. agrarius. Old rodents carried more, lactating females less ticks, than the average. Data of recaptured hosts showed, that ticks invade the body via the toes and nose and they are aiming for the auricles. Voles were significantly more heavily infested with nymphs which fed in the auditory tracts, which were free of ticks in mice. The phenomenon of aggregation is important for understanding the ecology of tick-borne diseases, as only a minority of the hosts are responsible for disease risks, and it is particularly important for control strategies that apply acaricides to reservoir hosts.

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