Detection methods and characterization of bovine viral diarrhea virus in aborted fetuses and neonatal calves over a 22-year period

MAXIMILIANO J. SPETTER; ENRIQUE L. LOUGE URIARTE; JOAQUÍN I. ARMENDANO; ELEONORA L. MORRELL; GERMÁN J. CANTÓN; ANDREA E. VERNA; MATÍAS A. DORSCH; SUSANA B. PEREYRA; ANSELMO C. ODEON; JEREMIAH T. SALIKI; ERIKA A. GONZÁLEZ ALTAMIRANDA

BRAZILIAN JOURNAL OF MICROBIOLOGY

SOC BRASILEIRA MICROBIOLOGIA

Año: 2020

1517-8382

Detection of bovine viral diarrhea virus (BVDV) in aborted fetus samples is often difficult due to tissue autolysis and inappropriatesampling. Studies assessing different methods for BVDV identification in fetal specimens are scarce. The present studyevaluated the agreement between different diagnostic techniques to detect BVDVinfections in specimens from a large number ofbovine aborted fetuses and neonatal deaths over a period of 22 years. Additionally, genetic, serological, and pathological analyseswere conducted in order to characterize BVDV strains of fetal origin. Samples from 95 selected cases from 1997 to 2018 wereanalyzed by antigen-capture ELISA (AgELISA), nested RT-PCR (RT-nPCR), and real-time RT-PCR (RT-qPCR). In addition,amplification and sequencing of the 5′UTR region were performed for phylogenetic purposes. Virus neutralization tests againstthe BVDV-1a, BVDV-1b, and BVDV-2b subtypes were conducted on 60 fetal fluids of the selected cases. Furthermore, thefrequency and severity of histopathological lesions were evaluated in BVDV-positive cases. This study demonstrated that RTnPCRand RT-qPCR were more suitable than AgELISA for BVDV detection in fetal specimens. However, the agreementbetween the two RT-PCR methods was moderate. The BVDV-1b subtype was more frequently detected than the BVDV-1aand BVDV-2b subtypes. Neutralizing antibodies to any of the three subtypes evaluated were present in 94% of the fetal fluids.Microscopically, half of the BVDV-positive cases showed a mild non-suppurative inflammatory response. These results emphasizethe need to consider different methods for a diagnostic approach of BVDVassociated to reproductive losses.