Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 22, 1995
Publication Date: N/A
Interpretive Summary: The protozoan parasite, Neospora caninum causes abortion in livestock and paralysis in dogs. Its life cycle and sources of infection are unknown. Transplacental transmission is the only proven route of infection. It is not certain if the same parasite infects cattle. Scientists at the Beltsville Agricultural Research Center and the University of California, Davis have studied the small subunit ribosomal RNA of gene sequences of Neospora isolates from cattle and dogs. They found no differences among Neospora isolates suggesting that one species, N. caninum infects all species of livestock.
The nuclear small subunit ribosomal RNA (nss-rRNA) gene sequence of Neospora spp. isolated from cattle was analyzed and compared to the sequence from several closely related cyst-forming coccidial parasites. Double stranded DNa sequencing of 5 bovine Neospora spp. isolated (PBA1- 5), two Neospora caninum isolates (NC-1) and NC-3) and 3 Toxoplasma gondii isolates (RH, GT-1, CT-1) were performed and compared to each other, as well as to other sequences available in GenBank for the NC-1 isolated, Sarcocystis muris, and Cryptosporidium parvum. There were no nucleotide differences detected between the Neospora spp. isolates from cattle and dogs. Four nucleotide differences were consistently detected when sequences of Neospora spp. isolates were compared to those of the T. gondii isolates. These results indicate that Neospora spp. and T. gondii are closely related, but distinct species.