Stephen A. Smith
Professor of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine
Expertise: Aquatic Medicine; Fish Health Management
Web site: http://www.vetmed.vt.edu/Organization/Research/Aquatic/
| Phone: 540-231-5131 | FAX: 540-231-6033 | e-mail: |
Research Interests:
Finfish diseases, Mycobacteriosis, Immunology, Clinical medicine, Pharmacokenetics.
Personal Information
Dr. Stephen Smith joined the faculty of the Virginia-Maryland Regional College
of Veterinary Medicine at Virginia Tech in 1991 after receiving his DVM
from The Ohio State University and Ph.D. from North Carolina State University.
As a veterinarian, his specific area of expertise is in aquatic medicine and fish health management. In addition, he has established a research and isolation laboratory for the study of fish pathogens and chemotherapeutic development. He has been associated with over one million dollars in research grants and was the 1995 recipient of the Pfizer Animal Health Award for Research Excellence. Dr. Smith is a member of the Fish Health Section of the American Fisheries Society, the International Association for Aquatic Animal Medicine, American Association of Zoo Veterinarians, American Association of Wildlife Veterinarians, and the American Veterinary Medical Association.
Since joining Virginia Tech, Dr. Smith has directed numerous research projects, including the evaluation of the immune response in striped bass; the development of hematology and blood chemistry values in striped bass and tilapia; the description of normal anatomy and histology of commonly cultured fish; and the evaluation of the effects of various environmental chemical toxicants on the immune system of fish.
He has been involved with the development of several diagnostic assays for infectious disease of cultured finfish, and has promoted the development of non-lethal assays for the evaluation and monitoring of fish health. Another area of his research focuses on mycobacteriosis in aquatic organisms and techniques to detect this potentially zoonotic bacteria premortem. He has been involved with determining the distribution of whirling disease in cultured and wild trout populations in Virginia, and is one of the initial researchers involved with the discovery of the toxic dinoflagellate Pfiesteria piscicida, which is the reported cause for many of the fish kills along the eastern U. S. coast.
Current Projects
Finfish diseases
The Aquatic Medicine Laboratory has a fully functional diagnostic laboratory
using the facilities of the VA/MD Regional College of Veterinary Medicine.
This laboratory provides diagnostic services to aquaculturists, home aquarist
and researchers using aquatic animals. With the recent increased interest
in marine aquaculture, detection and evaluation of various diseases in marine
finfish has expanded the laboratory. Primarily focused on the summer flounder
at this time, this area of research has already yielded several previously-undescribed
pathogens of marine fish.
Mycobacteriosis
Mycobacteriosis in fish is a chronic, progressive wasting disease that also
has a serious zoonotic (being passed from animal to human) potential. The
majority of this research is focused on the pathogenesis of the infection
in commercially cultured fish, such as the hybrid striped bass, tilapia
and angelfish. In addition, a rapid molecular polymerase chain reaction
(PCR) laboratory procedure has been established for the detection and speciation
of the major aquatic mycobacterial species. Various disinfectants are also
being evaluated for their ability to eliminate mycobacterial organisms
from the environment.
Immunology
The immune response of an animal is a major component that directly influences
whether an animal survives in a particular environment. The ontogeny of
the immune response and it's associated organ systems in hybrid striped
bass, tilapia and sturgeon is being examined. Information from these studies
will help determine when fish should be vaccinated, handled, graded and
moved. As part of this endeavor, an aquatic immunotoxicology program has
been established that can evaluate the immune response of fish using a
variety of immunological assays.
Clinical medicine
The laboratory has been involved with the standardization of blood collection
techniques for fish and the establishment of normal hematological and blood
chemistry values for various cultured fish species. Normal blood values
for the various hybrids of the striped bass have been determined and recent
studies completed on hybrid tilapia and summer flounder. These values will
be used in future studies to see if they can be diagnostic for various
diseases in fish. This could potentially give the producer a means of early
disease detection in aquaculture stocks.
Pharmacokenetics
Chemotherapeutics are often used in fish to combat bacterial diseases. Unfortunately,
only two drugs are legally approved for use in foodfish, and a number of
common bacterial organisms of cultured fish have resistance to both drugs.
Thus, another research focus of the laboratory is the acquisition of pharmacological
data on various potential chemotherapeutants for fish. Fish species evaluated
include: tilapia, yellow perch, and summer flounder.
Recent Publications
Papers
2007. Spotswood, T and S.A. Smith. Radiographic imaging of the horseshoe crab, (Limulus polyphemus). Veterinary Radiology and Ultrasound 48:14-20.
2006. Newman, S.J. and S.A. Smith. Marine Mammal Neoplasia: A Review. Veterinary Pathology 43(6): 865-880.
2006. Pasnik, D.J. and S.A. Smith. Protection of hybrid striped bass Morone saxitilis x M. chrysops against acute Mycobacterium marinum infection after DNA vaccination. Diseases of Aquatic Organisms 73:33-41.
2006. Knowles, S., T.C. Hrubec, S.A. Smith and R. Bakal. Hematology and plasma chemistry reference intervals for cultured shortnose sturgeon (Acipennser brevirostrum). Veterinary Clinical Pathology 35:434-440.
2006. Lowry, T.L. and S.A. Smith. Mycobacterium sp. in cultured cobia. Bulletin of the European Association of Fish Pathologists 26(2):87-92.
2006. King, R.K., G.J. Flick, Jr., S.A. Smith, M.D. Pierson, G.D. Boardman, C.W. Coale, Jr. Comparison of bacterial presence in biofilms on different materials commonly found in recirculating aquaculture systems. Journal of Applied Aquaculture 18:79-88.
2005. Hurton, L., J. Berkson and S.A. Smith. Selection of a standard culture medium for primary culture of Limulus polyphemus amebocytes. In Vitro Cell. Dev. Biol. - Animal 41:325-329.
2005. McAdams, T.J., R.G. Reinhart, C.F. Fernandes, G.J. Flick, S.A. Smith, C.R. Hackney, G.S. Libey, and L. A. Granata. Incidence of pathogenic microorganisms in aquacultured rainbow trout (Oncorhynchus mykiss). Journal of Aquatic Food Product Technology. 14:95-105.
2005. Collins, M.V., G.J. Flick, S.A.Smith, R. Fayer, R. Croonenberghs, S. O'Keefe and D.S. Lindsay. The effect of high-pressure processing on infectivity of Cryptosporidium parvum oocysts recovered from experimentally exposed Eastern oysters (Crassostrea virgunica). J. Eukaryotic Microbiology 52:500-504.
2005. Collins, M.V., D.S. Lindsay, R. Fayer, and S.A.Smith and G.J. Flick. Effects of e-beam and microwave irradiation on Eastern oysters (Crassosterea virginica) experimentally infected with Cryptosporidium parvum. J. Eukaryotic Microbiology 52:484-488
2005. Mainous, M.E. and S.A. Smith. Evaluation of various disinfectants on Mycobacterium marinum. Journal of Aquatic Animal Health 17:284-288
2005. Smith, S.A. and J. Berkson. Laboratory culture and maintenance of the horseshoe crab (Limulus polyphemus). Lab Animal 34:27-34.
2005. Hurton, L., J. Berkson and S.A. Smith. Determination of total hemolymph volume in the horseshoe crab Limulus polyphemus. Marine and Freshwater Behavior and Physiology 38:139-147.
2005. Pasnik, D.J., S.A. Smith, And D.S. Lindsay. Intestinal coccidiosis in bluegill (Lepomis machrochirus). Journal of Parasitology 91:967-970.
2005. Pasnik D.J. and S.A. Smith. Immunogenic and protective effects of a DNA vaccine for Mycobacterium marinum. Veterinary Immunology and Immunopathology 103:195-206
2005. Mowry, D.E., M.H. Schwarz, K.H. Hartman, M.L. Jahncke and S.A. Smith. Efficacy of hydrogen peroxide in marine recirculating aquaculture systems holding summer flounder (Paralichthys dentatus). Journal of Applied Aquaculture 17:65-75
2004. Hrubec, T.C., D. Ward, S.A. Smith and J.L. Robertson. Age-related changes in humoral immune response of hybrid striped bass (Morone chrysops x Morone saxatilis). Veterinary Immunology and Immunopathology 101:103-108.
2004. Haskell, S.R.R., K. Carberry-Goh, M.A. Payne and S.A. Smith. Current status of aquatic species biologics. Journal of the American Veterinary Medicine Association 225:1541-1544.
2004. Hrubec, T. and S.A. Smith. Hematology and blood chemistry reference intervals for yellow perch (Perca flavescens) raised in recirculation systems. International Journal of Recirculating Aquaculture 5:29-42.
2003. Hughes, K.P. and S.A. Smith. Common and emerging diseases in commercially cultured summer flounder, Paralichthys dentatus. Journal of Applied Aquaculture 14:163-178.
2003. Pasnik, D.J., S.A. Smith and J.C.Wolf. Accidental electroshock of fish in a recirculation facility. The Veterinary Record 153:562-564
2003. Pasnik, D.J., R. Vemulapalli, S.A. Smith and G.G. Schurig. A recombinant vaccine expressing a mammalian Mycobacterium sp. antigen is immunostimulatory but not protective in striped bass. Veterinary Immunology and Immunopathology 95:43-52.
2003. Pasnik, D.J., and S.A. Smith, Development of a DNA vaccine for piscine mycobacteriosis. GAA (Global Aquaculture Alliance) Advocate. 6:24-25.
2003. Smith, S.A., K.H. Hartman, and D.J. Pasnik. New and old diseases of cultured yellow perch, Perca flavescens. GAA (Global Aquaculture Alliance) Advocate 6:10-12.
2003. Harms, C.A., K.E. Howard, J.C. Wolf, S.A. Smith and S. Kennedy-Stoskopf. Transforming growth factor-B response to mycobacterial infection in striped bass Morone saxatilis and hybrid tilapia Oreochromis spp. Veterinary Immunology and Immunopathology. 95:155-163.
2002. Tengjaroenkul, B., B.J. Smith, S.A. Smith, and U. Chatreewongsin. Ontogenic development of the intestinal enzymes of cultured Nile tilapia, Oreochromis niloticus L. Aquaculture 211:241-251.
2002. Smith, S.A., K.P. Hughes, and J. Luoma. Amoebic gill infestation in pallid sturgeon, Scaphirhynchus albus. Bull. Eur. Ass. Fish Pathol. 22(6):400-402
2002. Hughes, K.P, R.B. Duncan. and S.A. Smith. Renomegaly associated with a mycobacterial infection in summer flounder, Paralichthys dentatus. Fish Pathology 37:83-86.
2002. Walls, E.A., J. Berkson, and S.A. Smith. The Horseshoe Crab, Limulus polyphemus: 200 Million Years of Existence, 100 Years of Study. Reviews in Fisheries Science 10:39-73.
2002. Hughes, K.P., R.B. Duncan, S.A. Smith. Mass in oral cavity of cultured summer flounder, Paralichthys dentatus. Lab Animal 31:25-27.
2002. S.A. Smith. Non-lethal clinical techniques used in the diagnosis of fish diseases. Journal of the American Veterinary Medicine Association. 220:1203-1206
