Quantities of infectious virus and viral RNA recovered from sheep and cattle experimentally infected with foot-and-mouth disease virus O UK 2001.
The profiles of virus production and excretion have been established for sheep experimentally infected with the UK 2001 strain of foot-and-mouth disease (FMD) virus by inoculation and by direct and intensive contact. Virus replicated rapidly in the inoculated sheep, from which a peak infectivity of airborne virus of 10(4.3) TCID(50) per sheep per 24 h was recovered. Around 24 h later, contact-infected sheep excreted airborne virus maximally. Similar amounts of airborne virus were recovered from cattle. The excretion of virus by the sheep under these conditions fell into three phases. First, a highly infectious period of around 7-8 days. Second, a period of 1-3 days soon afterwards when trace amounts of viral RNA were recovered in nasal and rectal swabs. Third, at 4 weeks after exposure, the demonstration, by tests on oesophageal-pharyngeal samples, that 50% of the sheep were carriers. The implications of the results and the variable role that sheep may play in the epidemiology of FMD are discussed.
Alexandersen
S
S
Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK1.
Zhang
Z
Z
Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK1.
Reid
S M
SM
Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK1.
Hutchings
G H
GH
Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK1.
Donaldson
A I
AI
Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK1.
D000336:Aerosols; D000391:Air Microbiology; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000635:transmission / Q000821:virology*; D005536:Foot-and-Mouth Disease / Q000635:transmission / Q000821:virology*; D029544:Foot-and-Mouth Disease Virus / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity*; D009666:Nose / Q000821:virology; D012367:RNA, Viral / Q000032:analysis / Q000097:blood; D012007:Rectum / Q000821:virology; D012756:Sheep; D012757:Sheep Diseases / Q000635:transmission / Q000821:virology*; D013048:Specimen Handling / Q000662:veterinary; D017201:Virus Shedding
D000336:Aerosols; D000914:Antibodies, Viral; D012367:RNA, Viral