Quantification of bovine viral diarrhoea virus ribonucleic acid in serum of infected animals by one-step reverse transcriptase quantitative real-time polymerase chain reaction

Věra Fichtelová,Kamil Kovařčík

doi:10.2754/avb201988040361

Abstract

Bovine viral diarrhoea virus (BVDV) can cause either acute transient or persistent infection. Identification and removal of persistently infected animals from infected herds is a crucial component to control BVDV infection. Only limited data on serum virus concentration in infected animals are available to date. Using one-step reverse transcriptase quantitative real-time polymerase chain reaction, we quantified the serum viral load in 40 BVDV infected animals. To control nucleic acid extraction, complementary DNA synthesis and polymerase chain reaction amplification, each serum sample was spiked with a known small amount of reference canine coronavirus. Detected ribonucleic acid copy number ranged from 2.2 × 106to 7.4 × 108per 1 ml of serum of persistently infected animals and from 6.6 × 104to 3.3 × 107of transiently infected animals. These findings support the idea that it is impossible to accurately distinguish between transiently and persistently infected animals just from a single blood sample. To use this testing as a means of declining costs of BVDV control programmes cannot be recommended and paired serum samples have to be investigated to confirm persistent infection.

Highlights

Bovine viral diarrhoea virus (BVDV) can cause either acute transient or persistent infection
Sera of young animals aged between 6–12 months were collected, each animal was sampled twice during the time period ranging from 21 days up to 2 months to confirm PI
Serum load levels of 3.3 × 107, 1.8 × 107, and 6.6 × 104 RNA copy number of BVDV were detected in acutely infected animals 37, 38, and 39, respectively (Table 1)

Summary

Introduction

Bovine viral diarrhoea virus (BVDV) can cause either acute transient or persistent infection. Detected ribonucleic acid copy number ranged from 2.2 × 106 to 7.4 × 108 per 1 ml of serum of persistently infected animals and from 6.6 × 104 to 3.3 × 107 of transiently infected animals These findings support the idea that it is impossible to accurately distinguish between transiently and persistently infected animals just from a single blood sample. Bovine viral diarrhoea virus causes either acute transient (TI) or persistent (PI) infection (Baker 1995). Persistent infection develops when foetuses are exposed to ncp biotype of BVDV before they are immuno-competent on day 120 of gestation This leads to a lack of recognition of viral antigens by the host immune system, persistent viraemia and replication of the virus to high titres in all tissues and organs (Ohmann 1988). Pooled serum samples are investigated by PCR to reduce the costs of identification of PI individuals (Munoz-Zanzi et al 2000; Mars and van Maanen 2005; Laureyns et al 2010)

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