Molecular survey of latent pseudorabies virus infection in nervous tissues of slaughtered pigs by nested and real-time PCR.
In this study, the prevalence and quantity of a latent pseudorabies virus (PrV) infection in the nervous tissues of randomly selected pigs was determined via nested and real-time PCR. The nervous tissues, including the trigeminal ganglion (TG), olfactory bulb (OB), and brain stem (BS), were collected from the heads of 40 randomly selected pigs. The majority of the nervous tissues from the selected pigs evidenced a positively amplified band on nested PCR. In particular, nested PCR targeted to the PrV glycoprotein B (gB) gene yielded positive results in all of the BS samples. Nested PCR for either the gE or gG gene produced positive bands in a less number of nervous tissues (57.5% and 42.5%, respectively). Real-time PCR revealed that the examined tissues harbored large copy numbers of latent PrV DNA, ranging between 10(0.1) and 10(7.2) (1-1.58 x 10(7)) copies per 1 microg of genomic DNA. Real-time PCR targeted to the PrV gE gene exhibited an accumulated fluorescence of reporter dye at levels above threshold, thereby indicating a higher prevalence than was observed on the nested PCR (100% for BS, 92% for OB, and 85% for TG). These results indicate that a large number of farm-grown pigs are latently infected with a field PrV strain with a variety of copy numbers. This result is similar to what was found in association with the human herpes virus.
Yoon
Hyun A
HA
Laboratory of Microbiology, College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Jeonju 561-756, Republic of Korea.
Eo
Seong Kug
SK
Aleyas
Abi George
AG
Park
Seong Ok
SO
Lee
John Hwa
JH
Chae
Joon Seok
JS
Cho
Jeong Gon
JG
Song
Hee Jong
HJ
D000003:Abattoirs; D000818:Animals; D017931:DNA Primers; D004279:DNA, Viral / Q000032:analysis / Q000302:isolation & purification; D011558:Herpesvirus 1, Suid / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D009420:Nervous System / Q000821:virology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011557:Pseudorabies / Q000821:virology*; D013552:Swine; D013553:Swine Diseases / Q000821:virology*; D017735:Virus Latency
D017931:DNA Primers; D004279:DNA, Viral