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Current Research Progam

My research focuses on the transmission of disease-causing organisms by insect vectors, and more specifically we look at the insect immune response to these parasites. The insect immune response is a germ-line encoded response that results in the production of an arsenal of immune peptides. This innate immune response is not based on antibody:antigen responses, but is more similar to the acute phase immune response in vertebrates. We work with two insect vectors, mosquitoes and kissing bugs

We study a malaria model using Aedes aegypti, the yellow fever mosquito, and Plasmodium gallinaceum, the causal agent for avian malaria, and Brugia malayi, the causal agent for human lymphatic filanasis. We have isolated several immune peptides from this insect that are used to protect the insect from harmful pathogens. The question arises as to why these peptides are not expressed in response to the presence of the parasite especially as these parasites migrate through several host tissues during their development. When we feed immune-activated insects on an infectious bloodmeal, the vast majority of parasites are killed. One goal is to characterize several of these peptides and determine if the lack of the immune response is due to a function of not being able to recognize 'non-self', or whether the immune response is being inactivated by the parasite.

Another model we use is the kissing bug, Rhodnius prolixus, the vector for Chagas disease in Latin America. Unlike the mosquito system the parasites, Trypanosoma cruzi, never leave the insect gut. Instead as the insect feeds it defecates and fecal material containing parasites gets rubbed into the feeding site. This is an inefficient- but effectivemeans of transmission. We propose that this system has developed because the parasite is susceptible to the insect immune peptides and this mode of transmission avoids contact with host immune responses.

Much of the work is laboratory related but opportunities exist for work in the field. We have had collaborations with researchers in Cairo, Egypt, to look at the transmission of Lymphatic filanasis in the Nile Delta. We have a continuing collaboration with Dr. Maria Wolff at the University of Antioquia in MedellIn Colombia looking at the response of R. prolixus to T. cruzi infections. We also have collaborations in France, specifically with the Institut de Biologie Moleculaire et Cellulaire in Strasbourg, and the Laboratoire de neuroimmunologie des annelids in Lille.