Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 3, 1997
Publication Date: N/A
Interpretive Summary: Neospora caninum, a single celled parasite, causes abortion in livestock and paralysis in companion animals. Its source of infection and life cycle are unknown. Transplacental transmission is the only recognized mode of transmission in nature. The diagnosis of abortion due to neosporosis is difficult and is based mainly on the identification of the organism in fetal tissues by histology which is an insensitive method to diagnose the cause of abortion. Scientists at the Beltsville Agricultural Research Center and the Department of Agriculture, Drachten, The Netherlands describe the detection of antibodies to N. caninum in bovine fluid obtained from aborted fetuses. Antibodies to N. caninum were detected in 65% of infected fetuses. Because detection of antibodies is much faster and inexpensive than histology, it could be used to supplement histologic examination for the diagnosis of bovine neosporosis abortion. The results will be useful to veterinary diagnosticians.
To evaluate the efficacy of fetal serology in the diagnosis of bovine neosporosis abortion, sera from 48 fetuses with immunohistochemically confirmed neosporosis and 42 fetuses without demonstrable Neospora caninum were examined in the indirect fluorescent antibody test (IFAT). Fetal sera were diluted two-fold starting at a 1:25 dilution. Antibodies to N. caninum were detected in 31 of 48 (65%) fetuses with confirmed neosporosis; the IFAT antibody titers were 1:25 (5 fetuses), 1:50 (17 fetuses), 1:200 (6 fetuses) and ò1:800 (3 fetuses). Neospora caninum antibodies were found in 3 of 42 fetuses without demonstrable protozoa; in all 3 cases a high titer was found suggesting undiagnosed congenital neosporosis. A recombinant antigen ELISA was not useful for the detection of fetal antibodies to N. caninum.