Vaccination of ewes for prevention of vertical transmission of Neospora caninum
To evaluate the immunologic response of a killed tachyzoite vaccine against Neospora caninum and its effectiveness in preventing vertical transmission of N caninum in sheep. 40 Dorset ewes seronegative for N caninum. Group-A ewes (n = 20) were vaccinated on days 1 and 126 with a killed N caninum tac...
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Veröffentlicht in: | American journal of veterinary research 2003-04, Vol.64 (4), p.449-452 |
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Zusammenfassung: | To evaluate the immunologic response of a killed tachyzoite vaccine against Neospora caninum and its effectiveness in preventing vertical transmission of N caninum in sheep.
40 Dorset ewes seronegative for N caninum.
Group-A ewes (n = 20) were vaccinated on days 1 and 126 with a killed N caninum tachyzoite preparation in a commercially available adjuvant. Group-B ewes (n = 20) were sham vaccinated. Blood samples were collected from ewes every 2 weeks and a recombinant ELISA (rELISA) was used to determine serum antibody titers against N caninum. During pregnancy, ewes were challenged with live N caninum tachyzoites. Precolostral serum was collected from lambs and tested for antibodies against N caninum by use of an indirect fluorescence antibody test and the rELISA. Tissue specimens from stillborn lambs or lambs that died within 2 weeks of birth were collected and examined for N caninum antigen and DNA by use of immunohistochemistry and polymerase chain reaction assay, respectively.
Serum antibody titers against N caninum were significantly higher in group-A ewes, compared with group B ewes, following vaccination. Serum antibodies against N caninum were detected in 100% (33/33) of group-B lambs and 75% (18/24) of group-A lambs. In tissue specimens, N caninum DNA was detected in 9 of 11 group-B lambs and 0 of 10 group-A lambs. Histologically, N caninum tachyzoites were observed in 4 group-A lambs and 3 group-B lambs.
The killed tachyzoite vaccine against N caninum stimulated a humoral immune response in sheep and provided partial protection against vertical transmission. |
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ISSN: | 0002-9645 1943-5681 |
DOI: | 10.2460/ajvr.2003.64.449 |