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Department of Food Science and Technology
Center for Food Safety
Ph.D., 1996, University of Arizona, Tucson, AZ
M.P.H., 2001, Johns Hopkins University, Baltimore, MD
E-mail: ortega@uga.edu
Telephone: 770-233-5587
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Research
Dr. Ortegas laboratory is focused on parasites that have been associated with food and water borne outbreaks. Because of current practices in the production and processing of food products, there is a need for studies aimed at the dynamics of disease transmission.
Detection assays that are sensitive and specific for human and animal pathogenic parasites in food products are being evaluated, as well as biological and environmental samples. We focus on the testing, development, and evaluation of methodologies for parasite inactivation in food products, and the study of risk factors associated with parasitic foodborne transmission.
Our goal is the development of safer produce and food products. The parasites currently being studied in this laboratory include Cryptosporidium parvum, Giardia lamblia, Cyclospora cayetanensis Toxoplasma gondii, and Neospora. Since the U.S. imports a large amount of fresh produce and some of this has been implicated in foodborne outbreaks, it was necessary and logical to initiate a training program where scientists from different institutions could become familiar with these parasites. For this two strategies have been initiated: 1) a training program for international scientists for 2-6 month periods and 2) informing the scientific community of the importance of food parasitology as an integral part of food safety. Additionally epidemiological studies on diarrheal illness in children in Peru are being developed, particularly looking at risk factors and environmental conditions that favor the presence and survival of these parasites.
REPRESENTATIVE PUBLICATIONS
Ortega Y.R., Sheehy R.R., Cama V.A., Oishi K.K., and Sterling C.R. 1991. Restriction fragment length polymorphism analysis of Cryptosporidium parvum isolates of bovine and human origin. Journal of Protozoology. 38(6):40S-41S.
Ortega Y.R., Sterling C.R., Gilman R.H., Cama V.A., and Diaz F. 1993. Cyclospora species: A new protozoan parasite of humans. New England Journal of Medicine. 328:1308-1312.
Yang Y.M., Ortega Y.R., Sterling C.R., and Adam R.D. 1994. Giardia lamblia trophozoites contain multiple alleles of a variant-specific surface protein gene with 105 base pair tandem repeats. Molecular and Biochemical Parasitology. 68:267-276.
Ortega Y.R., Gilman R.H., and Sterling C.R. 1994. A new coccidian parasite (Apicomplexa: Eimeriidae) from humans. Journal of Parasitology. 80(4):625-629
Ortega Y.R., Roxas C.R., Gilman R.H., Miller N.J., Cabrera L., Taquiri C., and Sterling C.R. 1997. Isolation of Cryptosporidium parvum and Cyclospora cayetanensis from vegetables collected in markets of an endemic region in Peru. The American Journal of Tropical Medicine and Hygiene. 57(6):683-686.
Ortega Y.R. Nagle R., Gilman R.H., Watanabe J., Miyagui J., Quispe H., Kanagusuku P., Roxas C., and Sterling C.R. 1997. Pathological and clinical findings in patients with cyclosporiasis and a description of intracellular parasite life cycle stages. Journal of Infectious Diseases. 176(6):1584-1589.
Sturbaum G.D., Ortega Y.R, Gilman R.H., Sterling C.R., Cabrera L., and Klein D.A. 1998. Detection of Cyclospora cayetanensis in sewage water. Applied Environmental Microbiology. 64:2284-2286.
Cama R.I., Parashar U.D., Taylor D.N., Hickey T., Figueroa D., Ortega Y.R., Romero S., Perez J., Sterling C.R., Gentsch J.R., Gilman R.H., and Glass R.I. 1999. Enteropathogens and other factors associated with severe disease in children with acute watery diarrhea in Lima, Peru. The Journal of Infectious Diseases. 119:1139-1144.
Cegielski J.P., Ortega Y.R, McKee S., Madden J.F., Gaido L., Schwartz D.A., Manji K., Jorgensen A.F., Miller S.E., Pulipaka U.P., Msengi A.E., Mwakyusa D.H., Sterling C.R., and Reller L.B. 1999. Cryptosporidium, Enterocytozoon and Cyclospora infections in pediatric and adult patients with diarrhea in Tanzania. Clinical Infectious Diseases. 28:314-321.
Adam R.D., Ortega Y.R., Gilman R.H., and Sterling C.R. 2000. ITS1 variability in Cyclospora cayetanensis. Journal of Clinical Microbiology. 38(6):2339-2343.
Bern C., Ortega Y.R., Checkley W., Roberts J.M., Lescano A.G., Cabrera L., Verastegui M., Black R.E., Sterling C.R., and Gilman R.H. 2002. Epidemiologic differences between cyclosporiasis and cryptosporidiosis in a cohort of Peruvian children. Emerging Infectious Diseases. 8(6):581-585.
Sathyanarayanan L. and Ortega Y.R. 2004. Effects of pesticides on sporulation of Cyclospora cayetanensis and viability Cryptosporidium parvum. Journal of Food Protection. 67(5):1044-49.
Huamanchay O., Genzlinger L., Iglesias M. and Ortega Y.R. 2004. Ingestion of Cryptosporidium oocysts by Caenorhabditis elegans. J. Parasitol. 90(5):1176-1178.
Saavedra, G.M. and Ortega Y.R. 2004. Seroprevalence of Toxoplasma gondii in swine and cattle from slaughter houses in Lima, Peru and Georgia, United States of America. J. Parasitol. 90(4):902-4.
Sathyanarayanan, L. and Ortega, Y. R. 2006. Effects of temperature and different food matrices on sporulation and viability of Cyclospora cayetanensis. Journal of Parasitology. 92: 218-222.
Cama V., Gilman, R. H., Vivar, A, Ticona, A., Ortega, Y., Bern C., and Xiao, L. 2006. Frequent mixed Cryptosporidium infections and HIV. Emerging Infectious Diseases. 12:1025-1028.
Ortega, Y.R. and Liao, J. 2006. Efficacy of microwave heating to inactivate Cyclospora cayetanensis and Cryptosporidium parvum oocysts. Journal of Food Protection. 68:1957-1960.
Torres, M. P. and Ortega, Y. R.. 2006. Neospora caninum antibodies in commercial fetal bovine serum. Veterinary Parasitology.140: 352-355.
Erickson, M. and Ortega, Y. 2006. Inactivation of protozoan parasites in food, water, and environmental systems. Journal of Food Protection. 69(11):2786-2808.
Cama, V., Arrowood, M., Ortega, Y., and Xiao, L. 2006. Molecular characterization of the Cryptosporidium parvum Iowa isolate kept in different laboratories. Journal Eukaryotic Microbiology. 53: S40-2.
Feng, Y., Ortega, Y., He, G., Das, P., Zhang, X., Fayer, R., Gatei, W., Cama, V., and Xiao, L. 2007. The wide occurrence of Cryptosporidium bovis and the deer-like genotype in bovines. Veterinary Parasitology. 144:1-9.
Ortega, Y., Torres, P., and Mena, K. 2007. Determination of the prevalence of Neospora in dairy cattle using milk. Veterinary Parasitology. 144:353-5.
Ortega, Y.R., Torres, M.P., Van Excel, S., Moss, L. and Cama, V. 2007.Efficacy of disinfectants and sanitizers on viability of Encephalitozoon intestinalis. Journal of Food Protection. 70:681-684.
Cama V., Ross J., Crawford S., Kawai V., Chavez-Valdez R., Vargas D., Vivar A., Ticona E., Ñavincopa M., Williamson J., Ortega Y.R., Gilman R.H., Bern C., and Xiao L. 2007. Difference sin clinical manifestations among Cryptosporidium species and subtypes in HIV-infected persons. The Journal of Infectious Diseases. 196:684-691.
Xiao, L., Cama, V.A., Cabrera, L., Ortega, Y.R., Pearson, J., and Gilman, R.H. 2007.Possible transmission of Cryptosporidium canis between children and a dog in a household. Journal of Clinical Microbiology. 45:2014-2016.
Cama V.A., Pearson, J., Cabrera, J., Pacheco, L., Gilman, R., Meyer, S., Ortega, Y., Xiao, L. 2007. Transmission of Enterocytozoon bieneusi between a child and guinea pig. Journal of Clinical Microbiology. 45(8): 2708-2710.
BOOK CHAPTERS
Ortega Y.R., Sterling C. and Gilman R. 1998. Cyclospora cayetanensis in Opportunistic Protozoa in Humans. Vol 40. In Advances in Parasitology. Opportunistic Protozoa in Humans. (Eds.: Jr. Baker, R. Muller and D. Rollinson. Guest Ed: Saul Tzipori) Academic Press Limited, London, U.K., pp: 400-418.
Ortega Y.R. Cyclospora 1999. In Waterborne Pathogens Manual. 1st Edition. (Eds.: D. Talley, M. Malgrande and S. Nakauchi-Hawn) American Water Works Association. Denver, CO., pp: 163-166.
Ortega Y.R. 1999. Cryptosporidium, Cyclospora and Isospora. In Manual of Clinical Microbiology, 7th Edition. (Ed in chief: Patrick R. Murray) ASM Press, Washington, D.C., pp: 1406-1412.
Adams A. and Ortega Y.R. 1999. Cyclospora. In Encyclopedia of Food Microbiology. (Eds: Robinson, R.K., Batt, C.A. and P.D. Patel). Academic Press Limited, London, U.K. pp: 502-513.
Ortega Y.R. 2001. Protozoan Parasites. In Food Microbiology: Fundamentals and Frontiers (Eds. M. Doyle, L. Beuchat and T. Montville) 2nd. Edition. ASM Press, Washington, D.C., pp: 549-564.
Ortega Y.R. and Cama V.A. 2002. Cyclospora. In Encyclopedia of Environmental Microbiology, 6 Volume Set (Ed. Gabriel Bitton) John Wiley & Sons, Inc. New York, N.Y., pp: 995-1001.
Ortega Y.R. 2003. From animal to man (Reservoirs and ways of transmission) Cryptosporidiosis, Microsporidiosis, Isosporiasis, Cyclosporiasis, Leishmaniasis, Pneumocystosis and Toxoplasmosis. In Atlas of Intestinal Infections in AIDS (Ed. Daniele Dionisio) Springer-Verlag Italia Srl. Milano, Italy., pp. 79-87.
Ortega Y.R. and Arrowood M. 2003. Cryptosporidium, Cyclospora and Isospora. In Manual of Clinical Microbiology, 8th Edition (Ed in chief: Patrick R. Murray) ASM Press, Washington, D.C., pp: 1406-1412.
Sterling C. and Ortega Y.R. 2004. Cyclospora cayetanensis: An emergent and still perplexing coccidian parasite. Pathogenic Enteric Protozoa: Giardia, Cryptosporidium, Cyclospora, and Entamoeba. In World Class Parasites. (Eds: Sterling and Adam) Kluwer Academic Publishers. Hingham, MA. pp 43-57.
Ortega, Y. and Sterling C.R. 2004. Cryptosporidium, Isospora, Cyclospora, Microsporidia and Dientamoeba. In Infectious Diseases. 3rd Edition (Eds. Gorbach, Blacklow and Barlet). Lippincott, Williams & Wilkins. Baltimore, MD. pp 2341-2350
Ortega Y and Sterling CR. 2005. Outbreaks Associated with Cyclospora and Cryptosporidium. In The Microbiology of Fruits and Vegetables (Ed. J. Sapers) CRC Press LLC, Boca Raton, FL. pp267-280.
Ortega, Y.R. 2005. Food and waterborne protozoan parasites. In Foodborne Pathogens: Microbiology and Molecular Biology, (Eds. P.M. Fratamico and A.K. Bhunia ) Horizon Scientific Press Ltd., Norfolk, U.K., pp: 145-161.
Ortega, Y.R. 2005. Molecular tools for the identification of foodborne parasites. In PCR Methods in Food, (Ed. J. Maurer) Springer, New York City, N.Y., pp: 119-145.
Ortega Y.R. 2006. Amoeba and ciliates. In Foodborne Parasites, (Ed. Y. Ortega) Springer Science and Business Media, Inc. New York, N.Y., pp: 1-14.
Ortega, Y.R. 2006. Toxoplasmosis. In Foodborne Parasites, (Ed. Y. Ortega) Springer Science and Business Media, Inc. New York, N.Y., pp: 109-134.
Ortega, Y.R. 2006. Cyclospora. In Waterborne Pathogens Manual of Water Supply Practices, 2nd Edition. (Ed. B. Behner) American Water Works Association, Denver, CO., pp: 199-202.
Arrowood M. J., Ortega Y. R., Xiao L., and Fayer R. (2006) Emerging Food- and Waterborne Protozoan Diseases. In: Emerging Infections 7 (Eds. W.M. Scheld , D. C. Hooper , and J.M. Hughes) American Society for Microbiology, Washington, DC, 283-308.
Ortega Y.R. 2006. Protozoan parasites. In Food Microbiology: Fundamentals and Frontiers, 3rd Edition. (Eds. M. Doyle and L. Beuchat) ASM Press, Washington, DC, 663-681.
Ortega, Y. R. and Eberhard, M. 2007. Protozoan diseases: Cryptosporidiosis, giardiasis and other intestinal protozoan diseases. In Encyclopedia of Public Health, (Ed. K. Heggenhougen) Elsevier, Burlington, MA. In press.
Ortega, Y.R. and Cama V.A. 2007. Foodborne transmission. In Cryptosporidium and cryptosporidiosis, (Eds. R. Fayer and L. Xiao) CRC Press, Boca Raton, FL. In press.