Evidence of vertical transmission of Neospora sp infection in dairy cattle.
OBJECTIVE
To determine whether heifers with naturally acquired congenital exposure to Neospora sp would transmit the infection to their offspring during gestation.


METHODS
Prospective cohort study.


METHODS
Neonatal heifers on a dairy with a history of Neospora sp infections were selected for the study on the basis of their serum titers to Neospora sp, as determined by the use of indirect fluorescent antibody testing. Seropositive heifers (n = 25) had titers > or = 1:5,120 and seronegative heifers (25) had titers < or = 1:80. All heifers were raised and bred on the dairy, and samples were obtained from heifers and their calves at the time of calving.


METHODS
Blood samples were tested for Neospora sp antibodies. Histologic evaluations, Neospora sp immunohistochemical examinations, and protozoal culturing were performed on samples obtained from selected offspring (second-generation calves).


RESULTS
Seropositive heifers gave birth to calves with titers > or = 1:1,280 to Neospora sp. All offspring from seropositive heifers that were necropsied had evidence of Neospora sp infection. All seronegative heifers and their offspring had titers < 1:80 to Neospora sp.


CONCLUSIONS
Congenitally acquired Neospora sp infection can persist in clinically normal heifers and be transmitted transplacentally to their offspring. Vertical transmission can be a way by which neosporosis is maintained in herds.
Anderson
M L
ML
California Veterinary Diagnostic Laboratory, School of Veterinary Medicine, University of California, Davis 95617-1770, USA.
Reynolds
J P
JP
Rowe
J D
JD
Sverlow
K W
KW
Packham
A E
AE
Barr
B C
BC
Conrad
P A
PA
D000818:Animals; D000831:Animals, Newborn; D000913:Antibodies, Protozoan / Q000097:blood; D001921:Brain / Q000469:parasitology / Q000473:pathology; D002417:Cattle; D002418:Cattle Diseases / Q000151:congenital / Q000635:transmission*; D003048:Coccidiosis / Q000151:congenital / Q000635:transmission / Q000662:veterinary*; D015331:Cohort Studies; D005260:Female; D007150:Immunohistochemistry; D018445:Infectious Disease Transmission, Vertical / Q000662:veterinary*; D018688:Neospora / Q000276:immunology; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000662:veterinary*; D011446:Prospective Studies; D013116:Spinal Cord / Q000469:parasitology / Q000473:pathology
D000913:Antibodies, Protozoan