Pseudorabies Virus Variant in Bartha-K61–Vaccinated Pigs, China, 2012 - Vol. 19 No. 11 - November 2013 - Emerging Infectious Disease journal - CDC

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Pseudorabies Virus Variant in Bartha-K61–Vaccinated Pigs, China, 2012 - Vol. 19 No. 11 - November 2013 - Emerging Infectious Disease journal - CDC

 

Volume 19, Number 11—November 2013

Research

Pseudorabies Virus Variant in Bartha-K61–Vaccinated Pigs, China, 2012

Article Contents

• Materials and Methods
• Results
• Discussion
• Acknowledgment
• References
• Figure 1
• Figure 2
• Figure 3
• Figure 4
• Figure 5
• Table 1
• Table 2
• Table 3
• Table 4
• Suggested Citation

Tong-Qing An¹, Jin-Mei Peng¹, Zhi-Jun Tian¹, Hong-Yuan Zhao, Na Li, Yi-Min Liu, Jia-Zeng Chen, Chao-Liang Leng, Yan Sun, Dan Chang, and Guang-Zhi Tong 

Author affiliations: Chinese Academy of Agricultural Sciences, Harbin, China (T.-Q. An, J.-M. Peng, H.-Y. Zhao, N. Li, Y.-M. Liu, J.-Z. Chen, C.-L. Leng, Y. Sun, D. Chang, Z.-J. Tian, G.-Z. Tong); Chinese Academy of Agricultural Sciences, Shanghai, China (G.-Z. Tong)

Suggested citation for this article

Abstract

The widely used pseudorabies virus (PRV) Bartha-K61 vaccine has played a key role in the eradication of PRV. Since late 2011, however, a disease characterized by neurologic symptoms and a high number of deaths among newborn piglets has occurred among Bartha-K61–vaccinated pigs on many farms in China. Clinical samples from pigs on 15 farms in 6 provinces were examined. The PRV gE gene was detectable by PCR in all samples, and sequence analysis of the gE gene showed that all isolates belonged to a relatively independent cluster and contained 2 amino acid insertions. A PRV (named HeN1) was isolated and caused transitional fever in pigs. In protection assays, Bartha-K61 vaccine provided 100% protection against lethal challenge with SC (a classical PRV) but only 50% protection against 4 challenges with strain HeN1. The findings suggest that Bartha-K61 vaccine does not provide effective protection against PRV HeN1 infection.

Pseudorabies virus (PRV; family Herpesviridae, subfamily Alphaherpesvirinae, genus Varicellovirus) contains a double-stranded DNA genome with strong genetic stability. The virus has a broad host range and can infect most mammals and some avian species (1). Pigs are the natural reservoir for PRV; infection in adult pigs is called Aujeszky disease. Swine farmers with PRV-infected pigs can incur substantial economic costs from reproductive losses in sows and from weight loss in infected adults (2). PRV is especially prominent in regions of South America, Asia, and Europe with dense swine populations. There have been no reports of PRV in Norway, Finland, or Malta, and the disease has been eradicated from domestic pig populations in Germany, Austria, Sweden, Denmark, the United Kingdom, Canada, New Zealand, and the United States (3).