There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
Foot-and-mouth disease virus (FMDV) can be spread by a variety of mechanisms and the
rate of spread, the incubation period and the severity of disease depend on a multitude
of parameters, including the strain of virus, the dose received, the route of introduction,
the animal species and the husbandry conditions. More knowledge with regard to these
parameters is urgently needed to improve resource-efficient disease control. This
report describes detailed studies of FMDV load, excretion and transmission in pigs
infected with FMDV O UKG 2001, O TAW 1997 and C Noville virus and in cattle infected
with the O UKG 2001 virus to facilitate use of a "FMDV load framework" for the assessment
of transmission risks. Virus replicated rapidly in pigs and cattle exposed by direct
contact. The mean incubation period was around 3-4 days for cattle-to-cattle and 1-3
days for pig-to-pig transmission, depending on the intensity of contact. The results
confirmed that a strong relation exists between dose and length of incubation period.
Clinical disease was severe in pigs but relatively mild in inoculated cattle; contact
infection of cattle appeared to increase the severity of lesions. FMDV RNA was recovered
in nasal and mouth swabs from inoculated animals soon after they developed a viraemia
and probably reflected the early production and excretion of virus. FMDV RNA in nasal
and mouth swabs from contact animals could be detected several days before they showed
other signs of infection, indicating the possibility of detecting exposed animals
during the incubation period. FMDV RNA could also be detected in swab samples after
the viraemic phase. This may have represented background environmental virus that
had been trapped in the respiratory tract and mouth. Alternatively, it may have indicated
a somewhat slower clearance or half-life of viral RNA or an extended low level of
FMDV replication at these sites. The pattern of FMDV RNA concentrations in pigs was
closely similar to that in cattle, but the amounts of FMDV RNA were higher.