| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2452395 | Preventive Veterinary Medicine | 2015 | 4 Pages |
•Vaccination of pregnant naturally infected dams during pregnancy was performed.•Inoculation with live tachyzoites of the Israeli isolate NcIs491 was safe in cattle.•Reduced abortion rate was recorded in vaccinated seropositive pregnant dams.•Following vaccination of naturally infected dams vertical transmission was not prevented.
Neosporosis, caused by the intracellular protozoan Neospora caninum, is a major cause of abortion and reproductive failure in cattle worldwide. The principal route of transmission of neosporosis is via in utero infection of the offspring. There is no effective prophylactic treatment or vaccine available against bovine neosporosis. A N. caninum NcIs491 isolate was examined for its ability to immunize and reduce abortions in naturally infected dairy cows under field conditions. N. caninum-seropositive pregnant dams were inoculated with 108 live tachyzoites during mid-term pregnancy. A total of 520 N. caninum seropositive dams were included in this study, of these, 146 were immunized and 374 cows served as a non-vaccinated control group. A significantly lower incidence of abortion was observed in vaccinated compared to non-vaccinated cows, 16 and 26% respectively (P = 0.01), with a vaccine efficacy of 39%. However, the number of seropositive offspring remained similar in both groups. Overall, this field trial suggests that vaccination with live N. caninum tachyzoites should be considered as an effective measure to reduce abortions caused by neosporosis in naturally infected cows.
