Demonstration of sheep-associated malignant catarrhal fever virions in sheep nasal secretions.
Ovine herpesvirus-2 (OvHV-2) is the causative agent for sheep-associated malignant catarrhal fever, which has never been propagated in vitro. Previous studies from this laboratory demonstrated significantly high levels of OvHV-2 DNA in sheep nasal secretions, suggesting a likely avenue of transmission. In the present study, real-time PCR was used to identify sheep experiencing an episode of intense OvHV-2 DNA shedding in their nasal secretions. A nuclease-resistance assay was used to examine the secretions for the presence of intact cell-free enveloped OvHV-2 virions. The results revealed that all nasal secretion samples from five selected individuals experiencing intensive shedding events contained cell-free OvHV-2 virions. Virions could not be identified in secretion samples from 11 OvHV-2 infected sheep that were not experiencing a shedding event. This is the first unequivocal demonstration of cell-free OvHV-2 virions. These results suggest that OvHV-2 lytic infection occurs in the epithelium of certain tissues in the upper respiratory tract of the natural host.
Kim
Okjin
O
United States Department of Agriculture-Agricultural Research Service, Washington State University, 3003 ADBF, Pullman, WA 99164, USA.
Li
Hong
H
Crawford
Timothy B
TB
D000818:Animals; D018142:Gammaherpesvirinae / Q000235:genetics / Q000302:isolation & purification*; D006566:Herpesviridae Infections / Q000662:veterinary*; D008304:Malignant Catarrh / Q000635:transmission / Q000821:virology*; D009297:Nasal Mucosa / Q000378:metabolism / Q000821:virology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000635:transmission / Q000821:virology*; D014412:Tumor Virus Infections / Q000821:virology*; D014771:Virion / Q000502:physiology; D017201:Virus Shedding