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Sensitivity and specificity of multiple technologies for the detection of confirmed persistently BVDV infected cattle from a feed yard in South Texas Lalitha Peddireddi1, Richard Hesse1, Gregg Hanzlicek1, Jeff Baxter2, Ivan Leyva-Baca2

1Kansas State Veterinary Diagnostic Laboratory, Kansas State University, 2005 Research Park Circle Manhattan, KS 66506 2Animal Health Group at Thermo Fisher Scientific, 2130 Woodward St, Austin, TX 78744, USA

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Etiology: Bovine Viral Diarrhea Virus (BVDV) Etiology: Bovine Viral Diarrhea Virus (BVDV) is an pathogen that belongs to the genus Pestivirus of

the family Flaviviridae

BVDV is an enveloped, single stranded RNA virus

Economic Relevance: Bovine Viral Diarrhea leads to major economic loss in both beef and dairy

industries estimated to be ~ $2-3 billion annually in the US alone

History: It was first reported in 1946 in Ithaca New York by researchers from Cornell University in

one-cow herd with subsequent outbreaks of the disease with morbidity 33-88% and mortality of 4-8%

Genome: Has a positive sense single stranded RNA genome (ss (+) RNA). Size of approximately

12.3 Kb. The genomic RNA has one open reading frame of about 4000 codons flanked with 2 untranslated regions (5’- and 3’-UTR)

Vet. Res. 41 (6) 44 (2010)

DOI: 10.1051/vetres/2010016

This is an Open Access article distributed under the terms of the

Creative Commons Attribution-Noncommercial License

(http://creativecommons.org/licenses/by-nc/3.0/), which permits

unrestricted use, distribution, and reproduction in any

noncommercial medium, provided the original work is properly

cited.

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Classification of BVDV

Cattle are the natural host of the BVDV but infection has

been demonstrated in other species:

• Sheep, goats, wild ruminants, pigs, bison, alpacas, mouse deer, mountain goats, and white-tailed can also be infected...

The virus is divided in to two main genotypes:

• BVDV-1, is considered the most prevalent genotype

• BVDV-2, historically is considered more virulent causing severe disease

• Most recently BVDV-3 or HoBi-like pestivirus that has been classified as an atypical pestivirus

• Other pestivirus are: Classical Swine fever, Borders Disease Virus

Note: More recent data has demonstrated that both genotypes (BVDV-1 and BVDV-2) can cause the same

damage at respiratory and reproductive level

Further classification based on isolates

• non-cytopathogenic (ncp): do not induce apoptosis and is the main source is PI cattle. NCP account for 95% of the isolated BVDV

• cytopathogenic (cp): induces apoptosis. The ncp biotype is the main frame to generate cp biotype through mutations and reconventions

Vet. Res. 41 (6) 44 (2010) DOI: 10.1051/vetres/2010016

This is an Open Access article distributed under the terms of the

Creative Commons Attribution-Noncommercial License

(http://creativecommons.org/licenses/by-nc/3.0/), which permits

unrestricted use, distribution, and reproduction in any

noncommercial medium, provided the original work is properly cited.

ncp cp

Virol J. 2011 Feb 25;8:83. doi: 10.1186/1743-422X-8-83

©Copyright Policy – open access http://openi.nlm.nih.gov/index.php

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BVDV Presence and Epidemiology

Presence:

• BVD has a world-wide presence

• Prevalence of seropositive cattle varies among countries and is influenced by vaccine use and management practices

• In USA, seropositive rates range between 40 and 90%

• Unvaccinated herd-level prevalence with unvaccinated cattle varies from 28 to 53% depending on the region

• PI prevalence is ~0.2% in the USA

Epidemiology:

• From an epidemiological point of view BVDV is very talented

• It has a combination of strategies to remain in a herd for extended periods of time

• Persistent infection provides a unique ability to BVDV to survive by inducing immune tolerance trough evasion of both innate and acquired immunity in utero

• Laboratory techniques are the best way to detect the presence of BVDV and distinguish the form of the disease

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BVDV-Persistently Infected (PI) Creation

embrionic death

return to estrus

Vet. Res. 41 (6) 44 (2010) DOI: 10.1051/vetres/2010016

This is an Open Access article distributed under the terms of the

Creative Commons Attribution-Noncommercial License

(http://creativecommons.org/licenses/by-nc/3.0/), which permits

unrestricted use, distribution, and reproduction in any noncommercial

medium, provided the original work is properly cited.

6

The Impact of BVDV PI Animals on BRD

• Although the prevalence of PI-BVDV

cattle in the USA is very low, the

presence of only one PI-BVDV

animal is well documented (Hay et

al, 2016) to be a risk factor in feed

yards for an increased rate of BRD,

cost of vaccination, antibiotic therapy

and mortality of unresolved BRD

infections

• BVDV-PI cattle are more likely to

become chronically ill or die than

non-BVDV-PI cattle. Also, the

probability for initial treatment with

respiratory disease was 43% greater

for cattle exposed to BVDV-PI cattle

in the same pen or an adjoining pen.

Loneragan; Journal of the American

Veterinary Medical Association, 2005

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• Biosecurity

• Vaccinations

• Diagnostics

BVD: Control and Management

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Study Rationale & Objectives

Rationale: There was a request from the Kansas Farm Bureau in South East Kansas to regulate

BVDV in their region by making it a reportable disease. SNAP BVDV Antigen Test was getting

some discrepant results when compared to testing in VDLs

• The application of highly sensitive and specific diagnostic technologies is fundamental to

accurately identify those low prevalent PI-BVDV animals for implementation of control strategies

Objective: To compare the sensitivity and specificity performance of:

BVDV Test Methods

Immunochromatographic strip

Antigen Capture ELISA

Applied Biosystems RT-PCR VetMAXTM Gold BVDV PI Detection Kit

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Materials and Methods

• Two samplings with three weeks apart of previously confirmed PI-BVDV (n=37) and BVDV-negative (n=20) cattle were performed from a feed yard located in South Texas, USA holding 24,000 cattle and keeping PI-BVDV in a single pen until slaughter time (~n=48)

• During the first sampling five ear notches from each animal were collected in a single day shipped out overnight to the Kansas State Veterinary Diagnostic Laboratory (KSVDL) in order to be processed immediately after arrival with the following diagnostic technologies:

• Two weeks later, resampling of the same set of animals (n=57) was carried out to be tested with IHC and BVDV RNA sequencing as the gold standard methods

• True positive or true negative based on the combined results from at least 1 out of the 2 methods was implemented

Ear Notch No. 1 2 3 4 5

Testing Method

VetMAX™Gold

BVDV PI

Detec t ion Kit

SNAP BVDV Antigen Test

ACE BVDV Kit

IHC/BVDV RNA

Sequencing

Sample Prep AM1836

MagMAXTM-96 Viral Isolation Kit

- - - -

Testing Location

KSVDL, Manhattan, KS

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Results

• VetMAX-Gold BVDV PI Detection Kit is more sensitive than the other methods.

• Missing some of the PI-BVDV animals when utilizing technologies with low sensitivity will

generate false-negative results, allowing PI-BVDV cattle to be undetected and continue

comingling with BVDV-negative cattle which is very detrimental for the health status of a herd

Diagnstic technology P/P P/N N/P N/N

Total

count Se Sp

SNAP 33 3 0 21 57 91.67 100.00

ACE 34 2 0 21 57 94.44 100.00

VetMAX-Gold BVDV PI Detection Kit 36 0 0 21 57 100.00 100.00

Table 1. Result of the real-time PCR testing, SNAP test and Antigen Capture ELISA

Gold standard/Tested technology

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Discussion and Conclusions

• All of the diagnostic technologies tested in this study offered a good but different level of sensitivity and equal level of specificity

• However, the real-time PCR technology tested was more sensitive than the antibody-based methods

• The practical implication of using diagnostic technologies with low sensitivity e.g. (91.67% and 94.44%) with a disease of very low prevalence (0.2%-0.4%) such as PI-BVDV in the US is of significant importance

SNAP Test ACE VetMAXTM Gold BVDV PI Detection Kit

• The current study reveals substantial practical differences in diagnostic methods that can be used as management tools in controlling BVDV and ultimately reducing the incidence of BRD.

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Acknowledgments

• KSVDL

• South Texas Feed Yard

• Thermo Fisher Scientific

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