title: Neosporosis in naturally infected pregnant dairy cattle.
abstract: Neosporosis caused by caused by the apicomplexan parasite Neospora caninum is one of the major causes of infectious abortion in bovines worldwide. A long-term prospective study was performed in a dairy herd endemic for N. caninum in order to analyze the impact of neosporosis on the proportion of aborting cows. A total of 1078 pregnant cows were tested for presence of antibodies and the proportion of abortions was calculated. The overall seroprevalence of N. caninum found in the herd was 35.5%. The percentage of abortions in seropositive cows was 3 times higher than in their seronegative counterparts (21.6 and 7.3%, respectively). No statistically significant association was found between the antibody level of positive during pregnancy and the proportion of aborting cows. However, 41.2% of the dams with antibody titers of 1:12,800 aborted. The risk of abortion for such dams was 2.7 times higher than for other seropositive cows which had lower titers of antibodies (p=0.0072). In the follow-up examinations of the seropositive cows during several pregnancies, the overall percent of abortions observed was significantly higher than in seronegative individuals (49.3 and 16.9%, respectively; p<0.0001). Moreover, the proportion of repetitive abortion observed was 5 to 1 (17.4 and 3.5%) in seropositive and seronegative dams, respectively (p<0.001). The rate of vertical transmission in positive dams was 61.0% and it appeared to be directly associated with antibody levels: the higher the titer in the dams during pregnancy, the higher the percentage of sero-positivity in their calves. Increased proportion of abortions was observed in seropositive cows both in summer and winter in comparison with spring and autumn. It was found that in seropositive cows, an increased number of pregnancies, which was directly related to the age of the dam, has been associated with an increased number of abortions.
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, Bet Dagan 50250, Israel; Department of Microbiology and Molecular Genetics, Kuvin Centre for the Study of Infectious and Tropical Diseases, Hebrew University of Jerusalem, Jerusalem, Israel. Electronic address: monica@int.gov.il.
authors.forename: Monica L
authors.initials: ML
authors.lastname: Mazuz
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, Bet Dagan 50250, Israel.
authors.forename: Leah
authors.initials: L
authors.lastname: Fish
authors.affiliation: Mutual Society for Insurance and Veterinary Services, Hachaklait, Caesarea, Israel.
authors.forename: Dror
authors.initials: D
authors.lastname: Reznikov
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, Bet Dagan 50250, Israel.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Wolkomirsky
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, Bet Dagan 50250, Israel.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Leibovitz
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, Bet Dagan 50250, Israel.
authors.forename: Igor
authors.initials: I
authors.lastname: Savitzky
authors.affiliation: Department of Microbiology and Molecular Genetics, Kuvin Centre for the Study of Infectious and Tropical Diseases, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Jacob
authors.initials: J
authors.lastname: Golenser
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, Bet Dagan 50250, Israel.
authors.forename: Varda
authors.initials: V
authors.lastname: Shkap
mesh_terms: D000034:Abortion, Veterinary / Q000469:parasitology; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology* / Q000473:pathology; D003048:Coccidiosis / Q000469:parasitology / Q000473:pathology / Q000662:veterinary*; D005260:Female; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000473:pathology / Q000662:veterinary*
keywords: Abortion; Dairy cattle; Natural infection; Neosporosis