Serological diagnosis of neosporosis in a herd of dairy cattle in southern Brazil.
Neospora caninum-specific antibodies were detected in 60 of 172 (34.8%) dairy cattle by enzyme-linked immunosorbent assay (ELISA) in a herd from Parana State, Brazil. The seropositive animals included 47 of 126 (37.3%) adult cows, 7 of 29 (24%) heifers (1-2 yr), 4 of 15 (27%) heifers (5 mo-1 yr), and 2 precolostral samples. Data collected over a 9-yr follow-up period revealed that the proportion of pregnancies ending in abortion was 20% (31/154) among ELISA seropositive cows and 8% (15/193) among seronegative cows. The farm recorded 46 abortions, of which 31 (67.3%) were from seropositive cows. All sera positive by ELISA (n = 60) and sera from cows (n = 11) that were ELISA-negative but that had aborted were tested by the indirect fluorescent antibody test (IFAT) at dilutions from 1:25 to 1:200. All sera from ELISA-positive cows (n = 47) had an IFAT titer of 1:25:35 (74%) of these sera were also seropositive at a dilution of 1:200 (IFAT). Cows seropositive by ELISA had a 4-fold increased risk of having aborted at least once, compared to ELISA-seronegative cows. This association was statistically significant (P = 0.0016). The attributable fraction for this association indicated that approximately 76% of the risk for a cow having a history of abortion was attributable to seroconversion to N. caninum.
Locatelli-Dittrich
R
R
Universidade Federal do Paraná, S.C.A., Departamento de Medicina Veterinária, Curitiba, Brazil.
Soccol
V T
VT
Richartz
R R
RR
Gasino-Joineau
M E
ME
Vinne
R
R
Pinckney
R D
RD
D000031:Abortion, Septic / Q000662:veterinary; D000034:Abortion, Veterinary / Q000209:etiology; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D001938:Brazil; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D003048:Coccidiosis / Q000175:diagnosis / Q000662:veterinary*; D003612:Dairying; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D018688:Neospora / Q000276:immunology*; D011247:Pregnancy; D012698:Serologic Tests
D000913:Antibodies, Protozoan