An outbreak of abortion affecting multiparous cows was associated with Hobi-like pestivirus infection. Viral RNA and antigens were detected in the tissues of two aborted fetuses. Molecular assays for other common abortogenic agents tested negative. At the genetic level, the Hobi-like pestivirus displayed the closest relatedness to Italian, Australian, and South American viruses, whereas it diverged from the prototype Thai isolate. These findings may have important implications for the pestivirus control/ eradication programs in cattle herds.
Bovine viral diarrhea viruses (BVDVs) are members of the genus Pestivirus (family Flaviviridae), responsible for a number of clinical signs, including subclinical infections, immunosuppression, acute diarrhea, respiratory disease, reproductive failures, and mucosal disease in persistently infected calves. Reproductive disorders caused by BVDVs vary according to the fetal age and include embryo death, abortion, mummification, congenital abnormalities, or stillbirths (2). Thus far, two different BVDV species have been recognized, BVDV-1 and BVDV-2, that cocirculate in cattle herds worldwide (20). In 2004, an atypical pestivirus, strain D32/00_Hobi, was isolated from a contaminated batch of fetal calf serum (FCS) (19). The virus was distantly related to BVDV-1/BVDV-2, and it was proposed as a prototype of a new pestivirus species (14, 15). Hobi-like sequences have been repeatedly detected in commercial FCS batches (17,22,23), whereas there are few reports on natural infections (4, 5, 21, 23) and clinical outbreaks (5). The virus has been recently detected in aborted bovine fetuses in Brazil, thus suggesting direct clinical implications (4).Here, we report the isolation and genetic characterization of a Hobi-like strain detected from aborted fetuses in southern Italy. The abortion outbreak occurred in June 2011 in a cattle herd where a Hobi-like pestivirus-associated respiratory disease had been recently described (5). Abortion was observed in eight multiparous cows in a group of 270 lactating Holstein cows and occurred between the fourth and sixth months of pregnancy. The animals neither showed prodromal signs nor presented postabortion complications. Two aborted fetuses (280/11-A, 280/11-B) were sent to our laboratory, and tissue samples were collected from lungs, spleens, livers, kidneys, and placentas for diagnostic investigations. Nucleic acids were purified using the DNeasy tissue kit (Qiagen) and QIAamp RNeasy minikit (Qiagen). Reverse transcription (RT)-PCR and PCR assays were performed using SuperScript one-step RT-PCR for long templates (Life Technologies) and LA PCR kit version 2.1 (TaKaRa Bio Inc.), respectively. Positive and negative controls were processed in parallel to the screened samples. The samples tested negative by PCR for Chlamydophila spp. 3, 8). Conversely, the pestivirus genome was detected with two different 24), and the virus was characterized as Hobi-like by a species-specific nested PCR (7) (Fig. 1A). Viral titers, quantified by a TaqMan-based real...