J Bacteriol Virol.  2010 Mar;40(1):39-47. 10.4167/jbv.2010.40.1.39.

Selection of a Less Pathogenic BVDV Strain for the Construction of Avirulent Chimeric Pestivirus

• Kim J
• Lim SI
• Tark DS
• Song JY
• Kim B

• KMID: 1456252
• DOI: http://doi.org/10.4167/jbv.2010.40.1.39

Abstract

To select a less pathogenic bovine viral diarrhea virus (BVDV) strain for the construction of chimeric pestivirus harboring classical swine fever virus (CSFV) E2 gene, five Korean BVDV isolates (four type 1 isolates and a type 2 isolate) were evaluated for their pathological and biological properties with respect to porcine infection. Each of five groups of 100-day-old pigs was inoculated intranasally with one of the five BVDV isolates. No clinical sign or leukopenia was observed in any pig throughout the duration of the experiment, but viruses were detected in blood, nasal discharges and postmortem samples using RT-PCR. These results indicated that although the five BVD viruses could infect pigs, they did not cause clinically apparent symptoms. Because of its proper infection dynamics shown in this preliminary animal study and its fast growth rate and quick CPE in cell culture, one isolate (KD26-1) was chosen among the five isolates to test its virulence and immunogenic properties in 40-day-old piglets. Neither clinical sign nor pathological lesion was observed in 40-day-old piglets during the course of infection of isolate KD26-1. The first neutralizing antibodies were detectable 14 days post-inoculation (PI) and increased to 1:128~1:256 28 days PI. A BVDV specific gene was detectable by RT-PCR in tonsil, spleen, inguinal lymph node and brain until 14 days PI. According to this study, it can be concluded that isolate KD26-1 has little pathological effect in pigs and is a candidate for construction of chimeric pestivirus harboring CSFV E2 gene.

Keyword

Bovine viral diarrhea virus; Classical swine fever virus; Animal study; Pigs; Pathological effect

MeSH Terms

Animals
Antibodies, Neutralizing
Brain
Cell Culture Techniques
Classical swine fever virus
Diarrhea
Leukopenia
Lymph Nodes
Palatine Tonsil
Pestivirus
Spleen
Sprains and Strains
Swine
Viruses
Antibodies, Neutralizing

Figure

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  Figure 1. Leukocyte counts (103 cells/mm3) during the course of intranasal infection in the first animal study. Mean leukocyte counts in pigs inoculated with isolates KD26-1, 32669, 95589, 32527 and 95002 and those of contact pigs are given. Standard deviations are shown as error bars.

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  Figure 2. Leukocyte counts (103/mm3) of pigs after intramuscular inoculation with KD26-1 (107.5 TCID50/head). Mean leukocyte counts in pigs inoculated with isolates KD26-1 and those of contact pigs are given. Standard deviations are shown as error bars.

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  Figure 3. Virus neutralization titers of sera from pigs after intramuscular inoculation with KD26-1 (107.5 TCID50/head). Mean virus neutralization titers in pigs inoculated with isolates KD26-1 and those of contact pigs are given. Standard deviations are shown as error bars.

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