J Vet Sci.  2014 Sep;15(3):361-367. 10.4142/jvs.2014.15.3.361.

Detection of porcine reproductive and respiratory syndrome virus in oral fluid from naturally infected pigs in a breeding herd

• Trang NT
• Hirai T
• Yamamoto T
• Matsuda M
• Okumura N
• Giang NT
• Lan NT
• Yamaguchi

• KMID: 2155619
• DOI: http://doi.org/10.4142/jvs.2014.15.3.361

Abstract

The objectives of the present study were to evaluate the anatomic localization of porcine reproductive and respiratory syndrome virus (PRRSV) in naturally infected pigs and to determine whether oral fluid could be used to detect the virus in infected animals. Two sows, seven 2-month-old grower pigs, and 70 6-month-old gilts were included in this study. PRRSV in sera and oral fluid were identified by nested reverse transcription PCR (nRT-PCR) while lung, tonsil, and tissue associated with oral cavity were subjected to nRT-PCR, immunohistochemistry, and in situ hybridization. In sows, PRRSV was identified in oral fluid and tonsils. PRRSV was also detected in oral fluid, tonsils, salivary glands, oral mucosa, and lungs of all seven grower pigs. However, viremia was observed in only two grower pigs. Double staining revealed that PRRSV was distributed in macrophages within and adjacent to the tonsillar crypt epithelium. In gilts, the North American type PRRSV field strain was detected 3 to 8 weeks after introducing these animals onto the farm. These results confirm previous findings that PRRSV primarily replicates in tonsils and is then shed into oral fluid. Therefore, oral fluid sampling may be effective for the surveillance of PRRSV in breeding herds.

Keyword

acclimatization; localization; oral fluid; porcine reproductive and respiratory syndrome virus; tonsil

MeSH Terms

Animals
Female
In Situ Hybridization/veterinary
Lung/virology
Male
Palatine Tonsil/virology
Polymerase Chain Reaction/veterinary
Porcine Reproductive and Respiratory Syndrome/*virology
Porcine respiratory and reproductive syndrome virus/*physiology
Saliva/*virology
Salivary Glands/virology
Swine/virology
Virus Replication/physiology