Detection of EHV-1 and EHV-4 DNA in unweaned Thoroughbred foals from vaccinated mares on a large stud farm.
BACKGROUND
A silent cycle of equine herpesvirus 1 infection has been described following epidemiological studies in unvaccinated mares and foals. In 1997, an inactivated whole virus EHV-1 and EHV-4 vaccine was released commercially in Australia and used on many stud farms. However, it was not known what effect vaccination might have on the cycle of infection of EHV-1.


OBJECTIVE
To investigate whether EHV-1 and EHV-4 could be detected in young foals from vaccinated mares.


METHODS
Nasal and blood samples were tested by PCR and ELISA after collection from 237 unvaccinated, unweaned foals and vaccinated and nonvaccinated mares during the breeding season of 2000.


RESULTS
EHV-1 and EHV-4 DNA was detected in nasal swab samples from foals as young as age 11 days.


CONCLUSIONS
These results confirm that EHV-1 and EHV-4 circulate in vaccinated populations of mares and their unweaned, unvaccinated foals.


CONCLUSIONS
The evidence that the cycle of EHV-1 and EHV-4 infection is continuing and that very young foals are becoming infected should assist stud farms in their management of the threat posed by these viruses.
Foote
C E
CE
Department of Biological Sciences, Macquarie University, Sydney 2109, Australia.
Love
D N
DN
Gilkerson
J R
JR
Whalley
J M
JM
D000818:Animals; D000833:Animals, Suckling; D000914:Antibodies, Viral / Q000097:blood; D001315:Australia / Q000453:epidemiology; D004279:DNA, Viral / Q000302:isolation & purification; D004197:Disease Reservoirs / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D006566:Herpesviridae Infections / Q000276:immunology / Q000635:transmission / Q000662:veterinary*; D004861:Herpesvirus 1, Equid / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D023141:Herpesvirus 4, Equid / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D022283:Herpesvirus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006734:Horse Diseases / Q000097:blood / Q000276:immunology / Q000635:transmission*; D006736:Horses; D018445:Infectious Disease Transmission, Vertical / Q000662:veterinary*; D008297:Male; D009297:Nasal Mucosa / Q000821:virology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D016036:Seroepidemiologic Studies; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology
D000914:Antibodies, Viral; D004279:DNA, Viral; D022283:Herpesvirus Vaccines; D015164:Vaccines, Inactivated