Research Interests
My main research focus is in ecology and evolution of avian parasitic diseases. Since 1999 I have been developing a research program that addresses the evolution and ecology of host-parasite interactions, with a primary emphasis on avian blood parasites. The field encompasses many aspects of biology including ecology, evolution, parasitology and conservation genetics. In collaboration with researchers at the Center for Tropical Research at UCLA, JPL/NASA, UC Davis, and the Institute of Ecology at Vilnius University, Lithuania, I study the effects of deforestation on the spread of infectious diseases in African rainforest birds. Over the past 13 years, a unique set of more than 4000 individual blood samples has been collected from over 200 rainforest bird species in a variety of habitats across Cameroon, the Ivory Coast, Equatorial Guinea and Uganda. Significantly, the samples were collected from sites both before and after habitat degradation, permitting a unique examination into the direct effects of human induced habitat alterations. Using complementary techniques of blood smear analysis, and molecular biology, samples are assayed for the pathogens that cause malaria, trypanosomiasis, filiariasis and tuberculosis. These diseases in birds, have very similar pathologies to their human counterparts, making the study of birds an excellent model system. In addition, we use satellite imagery data to predict how changes in forest composition may affect the spread of diseases in the future. The field of conservation genetics with regard to infectious diseases is in its infancy, and with a synthesis of traditional and modern methodologies I plan to make strides in answering fundamental questions that will impact conservation policy.
Publications
Bonneaud, C., I. Sepil, B. Mila, W. Buermann, J. Pollinger, R. Sehgal, G. Valkiūnas, T. Iezhova, S. Saatchi and T. B. Smith. 2009. The prevalence of avian Plasmodium is higher in undisturbed tropical forests of Cameroon. Journal of Tropical Ecology. 25: 439-447.
G. Valkiūnas, T. A. Iezhova, C. Loiseau, T. B. Smith and R. Sehgal. 2009. New species of haemosporidian parasites (Haemosporida) from African rainforest birds, with remarks on their classification. Parasitology Research. 104:1061-1077.
G. Valkiūnas, T. A. Iezhova, C. Loiseau, A. Chasar, T. B. Smith and R. Sehgal. 2008. New species of haemosporidian parasites (Haemosporida) from African rainforest birds, with remarks on their classification. Parasitology Research. 103(5): 1213-28.
G. Valkiūnas , T. A. Iezhova, A. Krizanauskiene, V. Palinauskas, R. Sehgal, S. Bensch. 2008. A comparative analysis of microscopy and pcr-based detection methods for blood parasites. Journal of Parasitology. Mar. 20:1
H. D. Ishak, J. P. Dumbacher, N. L. Anderson, J. J. Keane, G. Valkiūnas, S. M. Haig, L. A. Tell and R. Sehgal. 2008. Blood parasites in owls with conservation implications for the Spotted Owl (Strix occidentalis). PLoS One. 3(5): e2304.
G. Valkiūnas, C. T. Atkinson, S. Bensch, R. Sehgal and R. E. Ricklefs. 2008. Parasite misidentifications in GenBank: how to minimize their number? Trends in Parasitology. 24(6): 247-248.
L. M. E. Svensson, K. C. Ruegg, C. H. Sekercioglu, and R. Sehgal. 2007. Widespread and structured distributions of blood parasite haplotypes across a migratory divide of the Swainson's thrush (Catharus ustulatus). Journal of Parasitology. 93(6): 1488-1495.
R. Sehgal, G. Valkiūnas, T. A. Iezhova and T. B. Smith. 2006. Blood parasites of chickens in Uganda and Cameroon with molecular descriptions of Leucocytozoon schoutedeni and Trypanosoma gallinarum. Journal of Parasitology. 92(6): 1336-1343.
J. Masello, R. Gustavo Choconi, R. Sehgal, L. A. Tell and P Quillfeldt. Blood and intestinal parasites in wild Psittaciformes: A case study of Burrowing parrots (Cyanoliseus patagonus). Ornotología Neotropical. 17: 515-529.
R. Sehgal, A. C. Hull, N. Anderson, G. Valkiūnas, M. J. Markovets, S. Kawamura* and L. A. Tell. 2006. Evidence for cryptic speciation of Leucocytozoon spp. (Haemosporida, Leucocytozoidae) in diurnal raptors. Journal of Parasitology. 92(2): 375-379.
R. Sehgal, H. I. Jones, and T. B. Smith. 2005. Molecular evidence for host-specificity of parasitic nematode microfilariae in some African rainforest birds. Molecular Ecology.
G. Valkiūnas, R. Sehgal, T. A. Iezhova, and T. B. Smith. 2005. Further observations on the blood parasites of birds in Uganda. Journal of Wildlife Diseases. 41(3).
R. Sehgal, H. I. Jones, and T. B. Smith. 2005. Blood parasites of some West African birds. Journal of Veterinary Medical Sciences. 67(3): 295-301.
H. I. Jones, R. Sehgal and T. B. Smith. 2005. Leucocytozoon (Apicomplexa: Leucocytozoidae) from West African birds, with descriptions of two species. Journal of Parasitology. 91(2): 397-401.
R. Sehgal and I. J. Lovette. 2003. Molecular evolution of three avian neurotrophin genes: implications for proregion functional constraints. Journal of Molecular Evolution. 57: 335-342.
F. A. Richard, R. Sehgal, H. I. Jones, and T. B. Smith. 2002. A comparative analysis of PCR-based detection methods for avian malaria. Journal of Parasitology. 88(4): 819-822
R. Sehgal, Hugh Jones, and Thomas B. Smith. 2001. Host Specificity and incidence of Trypanosoma in some African rainforest birds: a molecular approach. Molecular Ecology 10(9): 2319-2328.
R. Sehgal, B. Gumbiner, and L. F. Reichardt. 1997. Antagonism of Cell Adhesion by a Mutant of Alpha-Catenin, and antagonism of the Wnt-Signaling Pathway by Alpha-Catenin in Xenopus embryos. Journal of Cell Biology. 139(4): 1033-1046.
T. Svensson, M. Rydén, F. H. Schilling, C. Dominici, R. Sehgal, C. F. Ibañez, and P. Kogner. 1997. Coexpression of mRNA for the full-length neurotrophin receptor trk-C and trk-A in favourable neuroblastoma. European Journal of Cancer. 33(12): 2058-2063.
M. Rydén, R. Sehgal, C. Dominici, F. H. Schilling, C. F. Ibañez, and P. Kogner. 1996. Expression of mRNA for the neurotrophin receptor trk-C in neuroblastomas with favourable tumour stage and good prognosis. British Journal of Cancer. 74(5): 773-779.
Y. S. Choi, R. Sehgal, P. McCrea, and B. Gumbiner. 1990. A Cadherin-like Protein in Eggs and Cleaving Embryos of Xenopus laevis is Expressed in Oocytes in Response to Progesterone. Journal of Cell Biology. Vol 110: 1575-158.