Generation of Calves Persistently Infected with HoBi-Like Pestivirus and Comparison of Methods for Detection of These Persistent Infections

Authors

• F. V. Bauermann, USDA, Agricultural Research ServiceFollow
• S. M. Falkenberg, Elanco Animal Health
• B. Vander Ley, University of MissouriFollow
• N. Decaro, University of Bari
• Bruce W. Brodersen, University of Nebraska - LincolnFollow
• A. Harmon, Novartis Animal Health US, Inc
• B. Hessman, Haskell County Animal Hospital
• E. F. Flores, Federal University of Santa Maria
• J. F. Ridpath, USDA, Agricultural Research Service

Document Type

Article

Date of this Version

2014

Citation

Journal of Clinical Microbiology November 2014 Volume 52 Number 11

Comments

Copyright © 2014, American Society for Microbiology

doi:10.1128/JCM.01563-14

Abstract

The identification and elimination of persistently infected (PI) cattle are the most effective measures for controlling bovine pestiviruses, including bovine viral diarrhea virus (BVDV) and the emerging HoBi-like viruses. Here, colostrum-deprived calves persistently infected with HoBi-like pestivirus (HoBi-like PI calves) were generated and sampled (serum, buffy coat, and ear notches) on the day of birth (DOB) and weekly for 5 consecutive weeks. The samples were subjected to diagnostic tests for BVDV—two reverse transcriptase PCR (RT-PCR) assays, two commercial real-time RT quantitative PCR (RT-qPCR), two antigen capture enzyme-linked immunosorbent assays (ACE), and immunohistochemistry (IHC)—and to HoBi-like virus-specific RT-PCR and RT-qPCR assays. The rate of false negatives varied among the calves. The HoBi-like virus-specific RT-PCR detected HoBi-like virus in 83%, 75%, and 87% of the serum, buffy coat, and ear notch samples, respectively, while the HoBi-like RT-qPCR detected the virus in 83%, 96%, and 62%, respectively. In comparison, the BVDVRT-PCR test had a higher rate of false negatives in all tissue types, especially for the ear notch samples (missing detection in at least 68% of the samples). The commercial BVDVRT-qPCRs and IHC detected 100% of the ear notch samples as positive. While ACE based on the BVDV glycoprotein E^rns detected infection in at least 87% of ear notches, no infections were detected using NS3-based ACE. The BVDVRT-qPCR, ACE, and IHC yielded higher levels of detection than the HoBi-like virus-specific assays, although the lack of differentiation between BVDV and HoBi-like viruses would make these tests of limited use for the control and/or surveillance of persistent HoBi-like virus infection. An improvement in HoBi-like virus tests is required before a reliable HoBi-like PI surveillance program can be designed.