Triatomine bugs, commonly known as kissing bugs, vinchuca, chipo, barbeiro, are blood-sucking insects, vectors of the protozoan parasite Trypanosoma cruzi, the causative agent of Chagas Disease. This Disease is endemic in Mexico, Central and South America and affects about 11-13 million people. Control of Chagas Disease depends mainly on the elimination of vectors through use of residual insecticides and screening of blood banks for infection with T. cruzi. Interruption of vectorial transmission of Chagas Disease requires continuous entomological surveillance even in countries where the domestic vectors are in the process of being eliminated or have been eliminated because many wild animals act as reservoir hosts and many species of triatominae that could become domiciliated transmit the parasite. Surveillance could be effectively achieved by methods that actively detect the presence of insects, e.g. using odor-baited traps. Such methods would allow efficient monitoring of houses for the presence of the insects prior to application of intervention measures. In addition, the use of traps could contribute to control efforts under certain circumstances (e.g., under conditions of low insect population density), thus reducing the use of undesirable insecticides. Triatomine insects rely mainly on olfactory cues to find their hosts. Studies of the physiology and role of the olfactory system of these insects will provide knowledge that could be used to develop odor-baited traps. An initial step to develop these surveillance and control tools is to identify the chemical constituents of the attractive animal odors. We will use gas chromatography (GC) coupled to electrophysiological recording from olfactory receptor cells (ORCs) to characterize the chemical constituents of natural host odors that are detected by the olfactory system of Rhodnius prolixus, one of the main vectors of Chagas Disease. Moreover, we will couple this technique to multi-channel electrophysiological recordings from neurons in the antennal lobe (AL;the insect's primary olfactory center). This state-of-the-art technique (which we have been using successfully in our laboratory) will allow us to probe how odor information is represented in the AL. Moreover, because neural responses to odors at this central level of olfactory processing are highly sensitive owing to the high degree of convergence of ORCs into AL neurons, AL recordings will allow us to detect active constituents of natural odors efficiently and with high sensitivity. We will identify the active compounds using GC coupled to mass spectrometry (GC-MS), a technique also established in our laboratory. After identifying bioactive odors, we will develop attractive blends of synthetic odorants. To accomplish this, the efficiency of different blends will be evaluated by means of electrophysiological recordings of AL neurons and behavioral assays using dual-choice olfactometers. The use of recordings from brain neurons coupled to analytical chemical techniques to identify efficient attractant blends is novel and is being developed in our laboratory. Ultimately, efficient chemical attractants could serve as lures in traps for sensitive detection and trapping of triatomines in or around houses.
Triatomine bugs are blood-sucking vectors of Chagas Disease, a parasitic infection that affects more than 11 million people in the Americas. Complete and continuous interruption of disease transmission by these insects requires improvement of entomological surveillance, which could be effectively achieved by methods (e.g. odor-baited traps) that use natural attractants (e.g. host-odors) actively to detect the presence of the insects. We propose to use neurophysiological, analytical chemical, and behavioral methods to identify odor attractants used by Rhodnius prolixus, one of the main vectors of the disease, to find its hosts and that can be used as trap lures.
| Reisenman, Carolina E (2014) Hunger is the best spice: effects of starvation in the antennal responses of the blood-sucking bug Rhodnius prolixus. J Insect Physiol 71:8-13 |
| Reisenman, Carolina E; Lee, Yan; Gregory, Teresa et al. (2013) Effects of starvation on the olfactory responses of the blood-sucking bug Rhodnius prolixus. J Insect Physiol 59:717-21 |
