Evaluation of metaphylactic RNA interference to prevent equine herpesvirus type 1 infection in experimental herpesvirus myeloencephalopathy in horses.
OBJECTIVE
To evaluate metaphylactic RNA interference to prevent equine herpesvirus type 1 (EHV-1) infection in experimental herpesvirus myeloencephalopathy in horses and to determine whether horses infected with a neuropathogenic strain of the virus that develop equine herpesvirus myeloencephalopathy (EHM) have differences in viremia.


METHODS
13 seronegative horses.


METHODS
EHV-1 strain Ab4 was administered intranasally on day 0, and small interfering RNAs (siRNAs [EHV-1 specific siRNAs {n = 7} or an irrelevant siRNA {6}]) were administered intranasally 24 hours before and 12, 24, 36, and 48 hours after infection. Physical and neurologic examinations, nasal swab specimens, and blood samples were collected for virus isolation and quantitative PCR assay. Data from the study were combined with data from a previous study of 14 horses.


RESULTS
No significant difference was detected in clinical variables, viremia, or detection of EHV-1 in nasal swab specimens of horses treated with the EHV-1 targeted siRNAs (sigB3-siOri2) versus controls. No significant differences in viremia were detected between horses that developed EHM and those that did not.


CONCLUSIONS
Administration of siRNAs targeted against EHV-1 around the time of EHV-1 infection was not protective with this experimental design. Horses infected with the neuropathogenic EHV-1 strain Ab4 that developed EHM did not have a more pronounced viremia.
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. gap7@cornell.edu
Gillian A
GA
Perkins
Gerlinde R
GR
Van de Walle
Nicola
N
Pusterla
Hollis N
HN
Erb
Nikolaus
N
Osterrieder
D000818:Animals; D004279:DNA, Viral / Q000235:genetics; D004679:Encephalomyelitis / Q000235:genetics / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D005260:Female; D006566:Herpesviridae Infections / Q000235:genetics / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D004861:Herpesvirus 1, Equid / Q000145:classification / Q000472:pathogenicity / Q000502:physiology*; D006734:Horse Diseases / Q000235:genetics* / Q000517:prevention & control* / Q000821:virology; D006736:Horses; D008297:Male; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics / Q000627:therapeutic use*; D013997:Time Factors; D014766:Viremia / Q000821:virology*
D004279:DNA, Viral; D034741:RNA, Small Interfering