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United States Department of Agriculture

Agricultural Research Service

Title: A Deletion at the Ul/ir Junction Reduces Pseudorabies Virus Neurovirulence

Authors
item Dean Hansi J,
item Cheung, Andrew

Submitted to: Journal of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 17, 1994
Publication Date: N/A

Interpretive Summary: Pseudorabies virus (PRV) is a virus of swine which causes significant economic losses to the swine industry. PRV infects the upper respiratory tract and spreads to the central nervous system. We have genetically engineered a mutant strain of PRV, termed LLTBd2. Pigs inoculated with LLTBd2 showed significantly reduced mortality compared to pigs inoculated with the parental strain of virus. In addition, LLTBd2-infected pigs did not demonstrate neurological signs typical of PRV infection. LLTBd2 was not impaired in replication in tissue culture, replication in the upper respiratory tract, or spread to the central nervous system. Instead, the reduced virulence of LLTBd2 was due to reduced ability of the virus to replicate in the central nervous system. B = beta; d = delta.

Technical Abstract: Pseudorabies virus (PRV) is a neurotropic alphaherpesvirus of swine which is genetically similar to herpes simplex virus. A recombinant PRV, termed LLTBd2, was constructed which contains a 3 kilobase pair deletion spanning the junction of the unique long (UL) and internal repeat (IR) sequences. Compared to the parental strain and a virus rescued for the deleted sequences, LLTBd2 exhibited similar replication characteristics in tissue culture. When inoculated intranasally in 4-week-old or 4-day-old pigs, LLTBd2 was significantly reduced in virulence and did not produce neurological signs characteristic of PRV infection. LLTBd2 replicated efficiently at the site of inoculation and in peripheral nervous tissues, but replication was restricted in the central nervous system. These results identify a PRV neurovirulence determinant mapping to the UL/IR junction. B = beta; d = delta.

Last Modified: 8/22/2014
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