| 
 Daniel
K. Howe, PhD
Maxwell H. Gluck Equine Research Center
Department of Veterinary Science
University of Kentucky Lexington, Kentucky 40546-0099
My research interests are focused on molecular studies of
the Coccidia, which are a very significant group of protozoan
pathogens that includes the human parasite Toxoplasma gondii
and the domestic animal parasites Neospora spp., Eimeria spp.,
and Sarcocystis spp. Our particular emphasis is on Sarcocystis
neurona, the primary causative agent of equine protozoal myeloencephalitis
(EPM).
EPM is one of the most common neurologic diseases of horses
in North America. It is also one of the more enigmatic equine
disorders that continues to be difficult to accurately diagnose,
prevent, and treat. A primary objective for my research program
is to resolve deficiencies in molecular data on S. neurona,
and to utilize this information to improve our ability to
understand and control EPM.
To help define the molecular composition of S. neurona, we
have conducted an expressed sequence tag (EST) sequencing
project that has produced over 15,000 partial gene sequences
from two different EPM isolates of S. neurona. An additional
6000+ sequences have been generated from the closely-related
parasite Sarcocystis falcatula. The S. neurona sequence data
can be accessed at the URL http://compbio.dfci.harvard.edu/tgi/cgi-bin/tgi/gimain.pl?gudb=s_neurona.
We are currently exploring the sequence information produced
by the S. neurona EST project to discover important parasite
genes. Thus far, this approach has allowed us to identify
and characterize a gene family of major parasite surface antigens,
which we designated as SnSAGs, and several parasite secretory
antigens. We are now investigating the biological characteristics
of these proteins to gain insight into their role as parasite
virulence factors.
Additionally, we have designed enzyme-linked immunosorbent
assays (ELISAs) based on the S. neurona surface antigens.
These SnSAG ELISAs will accurately detect S. neurona antibodies
in equine serum and cerebrospinal fluid, thereby providing
tests that reliably identify animals exposed to S. neurona.
Additionally, these assays are being used as research tools
to assess equine immune responses during parasite infections
and the progression to neurologic disease.
|
