Submitted to: Molecular and Biochemical Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 27, 1995
Publication Date: N/A
Interpretive Summary: Neospora caninum is a recently described protozoan which causes neurological disease in dogs. Neospora parasites also cause abortion and neonatal morbidity and mortality in several other domestic animal species, and neosporosis has recently been recognized as an important cause of abortion in dairy cattle in the USA. The design of effective control strategies against neosporosis is dependent on further investigation into the disease, and this is currently hindered by the lack of a sensitive and specific test for the diagnosis of neosporosis. This paper describes the cloning and sequencing of a N. caninum gene. The gene sequence was used to design primers which can be used in a polymerase chain reaction (PCR) assay to detect N. caninum DNA. The test appears to be specific for N. caninum, since it does not detect DNA of several closely related parasites. The results suggest that this test may be useful for the diagnosis of neosporosis, and may also be useful in studies aimed at identifying the definitive host of the parasite.
Technical Abstract: Neospora caninum is a recently described apicomplexan parasite which causes neuromuscular disease in dogs, and abortion and neonatal morbidity in cattle, sheep and horses. Morphological similarities and serological cross reactivity between N. caninum and the closely related parasite Toxoplasma gondii, have resulted in the frequent misdiagnosis of neorsporosis as toxoplasmosis. This report describes the isolation and characterization o a N. caninum cDNA clone encoding a 14-3-3 protein homologue. The 14-3-3 proteins are a class of proteins which show a high degree of amino acid sequence conservation across several eukaryotic taxa. Using less conserved regions of the N. caninum cDNA clone, nested primers were designed for the amplification of a 614p N. caninum DNA fragment by the polymerase chain reaction (PCR). The DNA fragment was amplified from N. caninum genomic DNA, but not from T. gondii, Sarcocystis muris, Sarcocystis tenella, or Sarcocystis cruzi genomic DNA. Additionally, the fragment was amplified from DNA prepared from the brains of N. caninum-infected mice, but not from the brain of a mouse infected with T. gondii. These results suggest that this PCR assay may be useful for the diagnosis of neosporosis.