Detection of Serum Antibody Responses in Cattle with Natural or Experimental Neospora Infections
Open Access
- 1 October 1993
- journal article
- research article
- Published by SAGE Publications in Journal of Veterinary Diagnostic Investigation
- Vol. 5 (4), 572-578
- https://doi.org/10.1177/104063879300500412
Abstract
Parasite-specific antibody responses were detected using an indirect fluorescent antibody (IFA) test in cattle that were naturally or experimentally infected with Neospora parasites. The test was developed using Neospora tachyzoites isolated from an aborted bovine fetus and grown in bovine cell cultures (isolate BPA1). In all cases, infections were confirmed by the identification of Neospora tachyzoites and/or bradyzoite cysts in fetal or calf tissues using an immunoperoxidase test procedure. Fifty-five naturally infected cows that aborted Neospora-infected fetuses had titers of 320-5,120 at the time of abortion. The titer of 6 cows that were serologically monitored over a prolonged period decreased to 160–640 within 150 days after they aborted infected fetuses. Two of the cows showed an increase in their Neospora titers during their subsequent pregnancy, and they gave birth to congenitally infected calves that had precolostral titers of 10,240-20,480. Postcolostral titers of these calves and of 4 other calves with congenital Neospora infections were all 25,120, whereas calves with no detectable parasites had titers ≤ 160. Two pregnant heifers that were experimentally infected with the BPA1 isolate at approximately 120 days gestation seroconverted to Neospora antigens within 9 days and developed peak titers of 5,120 and 20,480 within 32 days of infection. The fetus taken by caesarian section 32 days postinfection from 1 heifer and the full-term calf born to the other had Neospora titers of 640 and 10,240, respectively. Nine cows that aborted uninfected fetuses and 61 adult cattle maintained under pasture or feedlot conditions, where risk of exposure to Neospora was considered to be low, had titers ≤ 320. Some of the feedlot cattle tested had serologic reactivity that was restricted to antigens at the apical end of both Neospora and Toxoplasma gondii tachyzoites. This type of reactivity, which may result from serologic cross-reactivity between conserved apical complex antigens of closely related sporozoan parasites, differed from the whole parasite fluorescence that was observed with sera from Neospora-infected animals. The significance of these results and the potential application of the IFA test for the diagnosis of Neospora infections in cattle are discussed.Keywords
This publication has 21 references indexed in Scilit:
- In vitroisolation and characterization of aNeospora sp. from aborted bovine foetusesParasitology, 1993
- Neospora-Like Protozoan Infection as a Cause of Abortion in Dairy CattleJournal of Veterinary Diagnostic Investigation, 1992
- Neosporaabortion in New Zealand cattleNew Zealand Veterinary Journal, 1991
- Neospora-like Protozoal Infections Associated with Bovine AbortionsVeterinary Pathology, 1991
- Neospora-Like Encephalomyelitis in a Calf: Pathology, Ultrastructure, and ImmunoreactivityJournal of Veterinary Diagnostic Investigation, 1991
- Bovine Fetal Encephalitis and Myocarditis Associated with Protozoal InfectionsVeterinary Pathology, 1990
- Neospora Caninum- Associated Myocarditis and Encephalitis in an Aborted CalfJournal of Veterinary Diagnostic Investigation, 1990
- Congenital neosporosis in a calfPublished by Wiley ,1989
- Neosporosis-Like Abortions in a Herd of Dairy CattleJournal of Veterinary Diagnostic Investigation, 1989
- Immuno‐histochemical and ultrastructural characteristics of a cyst‐forming sporozoon associated with encephalomyelitis and myositis in dogsAPMIS, 1988