Our laboratory uses field-based, cellular and molecular approaches to further an understanding of the immunobiology of schistosomiasis in people. We focus on immunoregulation, resistance to reinfection and how having schistosomiasis impacts immune responses to unrelated immunizations. These studies go on entirely in western Kenya, with our collaborators there, headed by Dr. Diana Karanja at the Kenya Medical Research Institute (KEMRI) in Kisumu, Kenya.
Schistosomiasis is a parasitic worm infection that people acquire by going into fresh water that contains schistosome-infected snails, the intermediate host. Globally, over 250 million people are infected with this intravascular worm. About 5%-10% of those infected may progress to suffer severe, life-threatening disease, while most of those infected experience more subtle morbidity, such as cognitive and physiologic deficits due to their schistosomiasis. It is a major public health threat in endemic areas of the world. Adult schistosome male and female worms live inside the blood vessels of people infected for several years, producing fertilized eggs that carry out the life cycle of the worm when they get into fresh water through excreta and the next stage of the life cycle infects species of fresh water or amphibious snails.
Our research seeks to understand the roles of the immune system in the regulation and resistance observed during this chronic disease, and how schistosomiasis impacts other immune responses. Our human studies of Schistosoma mansoni infections have been done in the past through extensive collaborations in the West Indies, Brazil, and Egypt. For the last 20 years these studies have been done in western Kenya, as indicated above.
In addition to my own immunologic research described above, I am the Director of the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE: http://score.uga.edu , a major program funded by the Bill & Melinda Gates Foundation to pursue operational research focused on practical efforts to control and eliminate schistosomiasis. SCORE studies are being done in more than 8 African countries, primarily through North-South partnerships funded through subawards from the UGA Research Foundation.
Immunobiology of human schistosomiasis. Immunoregulation and resistance to reinfection
Watanabe, K., Mwinzi, P.N.M., Black, C.L., Muok, E.M.O., Karanja, D.M.S., Secor, W.E., Colley, D.G. T regulatory cell levels decrease in people infected with Schistosoma mansoni upon effective treatment. Am. J. Trop. Med. Hyg., 77:676-682, 2007.
Colley, D.G. and Secor, W.E. A Schistosomiasis Research Agenda. PLoS Neglected Tropical Diseases. 1(3):e32, doi:10.1371/journal.pntd.0000032, 2007.
Mwinzi, P.N.M., Ganley-Leal, L.M., Black, C.L., Secor, W.E., Karanja, D.M.S., Colley, D.G. Circulating CD23+ B cell subset correlates with development of resistance to Schistosoma mansoni reinfection in occupationally exposed, multiply treated adults. J. Infect. Dis., 199:272-279, 2009
Gatlin, M.R., Black, C.L., Mwinzi, P.N.M., Secor, W.E., Karanja, D.M.S., Colley, D.G., Association of the gene polymorphisms IFN-γ +874, IL-13 -1055 and IL-4 -590 with patterns of reinfection with Schistosoma mansoni, PLoS NTD, 3(2):e375, 2009.
Black, C.L., Mwinzi, P.N.M., Muok, E.M.O., Abudho, B., Fitzsimmons, C.M., Dunne, D.W., Karanja, D.M.S., Secor, W.E., Colley, D.G. Influence of exposure history on the immunology and development of resistance to human schistosomiasis mansoni. PLoS NTD, 4(3):e637. Doi:10.1371/journal.pntd.0000637, 2010.
Black, C.L., Muok, E.M.O., Mwinzi, P.M.N., Carter, J.M., Karanja, D.M.S., Secor, W.E., Increases in schistosome-specific IgE and CD23+ B cells in a cohort of Kenyan children undergoing repeated treatment and reinfection with Schistosoma mansoni. J. Infect. Dis. 202(3):399-405, 2010.
Colley DG, Binder S, Campbell C, King C, Tchuem Tchuente, L-A, N’Goran E, Erko B, Karanja DMS, Kabatereine N, van Lieshout, L, Rathbun S. A five-country evaluation of a point-of-care cathodic antigen urine assay for the prevalence of Schistosoma mansoni. Am. J. Trop. Med. Hyg., 88:426-432, 2013
Colley, D.G., Bustinduy, A., Secor, W.E., and King, C.H., Human schistosomiasis, The Lancet, http://dx.doi.org/10.1016/S0140-6736(13)61949-2., 2014
Mwinzi, P, Kittur, N, Ochola, E, Cooper, PJ, Campbell, CH Jr., King, CH, Colley, DG, Additional evaluation of the point-of-contact circulating cathodic antigen assay for Schistosoma mansoni infection. Front Pubic Health, 3:48, 2015. doi: 10.3389/fpubh.2015.00048.
Kittur, N, Castleman, JD, Campbell, CH, Jr, King, CH, Colley, DG. Comparison of Schistosoma mansoni Prevalence and Intensity of Infection as Determined by the Circulating Cathodic Antigen Urine Assay or by the Kato-Katz Fecal Assay: A Systematic Review. Amer J Trop Med Hyg. 2016 (PMID: 26755565)