Our work over the past few years has focussed particularly on the medically-important bug, Rhodnius prolixus. This bug takes enormous blood meals from humans, and during the subsequent excretion of excess salts and water (diuresis), the parasite, Trypanosoma cruzi, is transmitted to the human host where it causes Chagas disease. We are examining a variety of short term events which occur following the natural stimulus of a blood meal, including the neurohormonal control of diuresis, and also the cessation of diuresis. In particular, we are defining the precise input associated with feeding which results in elevations in haemolymph serotonin and diuretic peptide hormones (identified by us), describing the location and physiological properties of the neurosecretory cells which release these diuretic and anti-diuretic hormones, and their target sites (e.g. salivary glands, midgut, hindgut, Malpighian tubules, heart and epidermal cells). Blood gorging is also the stimulus for growth, development and reproduction, and so we are also studying these longer term events, and the involvement of similar families of neuropeptides.
Progress in this area has been facilitated and enhanced because of the Rhodnius genome project, and we have been successful in cloning, for the first time in Rhodnius, the genes for neuropeptides and GPCRs, synthesising the neuropeptides and examining their physiological effects.
This research also lays the foundation for pest control strategies, targeting neuropeptides as lead compounds. Since the parasite is transmitted during diuresis, one can argue that diuretic hormones actually control the transmission of Chagas disease. Interfering with this process should interfere with the transmission of Chagas disease. Our discovery of the diuretic and possibly more relevant antidiuretic hormones, is of some considerable importance.
Some honors and awards:
Research Excellence Award, University of Toronto Mississauga:https://www.utm.utoronto.ca/main-news/research-excellence-award-winner-shares-his-findings-kissing-bug
NASCE Fellow: https://www.nasce-snaec.com/ian-orchard.html
Paul W. Fox Award, University of Toronto Mississauga:https://www.utm.utoronto.ca/main-news/utm-honour-former-principal-ian-orchard-other-noteworthy-campus-champions-alumni-awards
Contributions to Research; For up to date publications please see the following research profile databases https://www.researchgate.net/profile/Ian_Orchard/contributions, https://loop.frontiersin.org/people/20992/overview, and https://scholar.google.com/citations?hl=en&tzom=300&user=Y7b_bJoAAAAJ