MATERNAL FACTORS ASSOCIATED WITH PRENATAL TRANSMISSION OF OVINE LENTIVIRUS

Prenatal transmission of ovine lentivirus (OvLV) was studied in 85 ewe s and their offspring. The animals were from a flock with endemic OvLV infection and 49 (58%) had serum antibodies to OvLV. Blood was collec ted from all lambs before they nursed. Using the polymerase chain reac tion (PCR), OvLV DNA was detected in peripheral blood mononuclear cell s of 13 (11%) of 117 lambs, including two sets of twins. Mothers with OvLV-infected lambs (n = 11) were younger (mean, 2.5 years) and had fe wer pregnancies (mean, 2.4) than seropositive ewes (3.2 years and 3.2 pregnancies; P < .05). Of mothers with OvLV-positive lambs, 4 had plas ma antigenemia (mean, 31.3 +/- 2.1 ng/mL OvLV) in conjunction with ind eterminate antiviral antibody responses by immunoblotting. These resul ts suggest that maternal factors (age and parity) and host-virus inter actions (antiviral antibody and antigenemia) are important risk factor s in prenatal transmission of OvLV.