Academic
Publications
Transmission of classical swine fever virus depends on the clinical course of infection which is associated with high and low levels of virus excretion

Transmission of classical swine fever virus depends on the clinical course of infection which is associated with high and low levels of virus excretio

Transmission of classical swine fever virus depends on the clinical course of infection which is associated with high and low levels of virus excretion   (Citations: 2)
BibTex | RIS | RefWorks Download
Infection with moderately virulent strains of classical swine fever virus (CSFV) can lead to different courses of disease: either (sub)acute, resulting in death or recovery, or chronic disease. The virus excretion dynamics between these courses are quite dissimilar, but it is not known if this also results in differences in virus transmission. In this study, the excretion and transmission dynamics of the moderately virulent Paderborn strain were studied in 15 one-to-one experiments. In these experiments, a single inoculated pig was housed with a single susceptible contact pig from day 1 post-inoculation (p.i.). Each contact pig that became infected was removed and replaced by a new contact pig at day 17 p.i. and day 26 p.i. Infection of contact pigs was monitored by reverse transcription quantitative real-time PCR on oropharyngeal fluid samples. Five of the inoculated pigs developed the chronic form or died during the acute phase (high excreting pigs), while 10 pigs recovered from the infection (low excreting pigs). In the first contact period, there was no significant difference in virus excretion between the high and low excreting pigs, while in the second and third contact period, high excreting pigs excreted significantly higher quantities of virus. Over the entire study period, the reproduction ratio differed significantly between the high (143 [56.3–373]) and low excreting pigs (23.1 [11.5–45.0]). This indicates the importance of high excreting pigs in transmission of CSFV. Furthermore, this study showed the rate of CSFV infections from a contaminated environment.
Journal: Veterinary Microbiology - VET MICROBIOL , vol. 147, no. 3, pp. 262-273, 2011
Cumulative Annual
View Publication
The following links allow you to view full publications. These links are maintained by other sources not affiliated with Microsoft Academic Search.
    • ...The extent of protection, particularly against virus transmission, induced by C-strain vaccination at times earlier than 5 days post-vaccination has not been described in detail. For an emergency vaccination, the rapidity with which an intervention will prevent spread of virus is of utmost importance. This knowledge is crucial for making decisions on use of emergency vaccination strategies compared to a pre-emptive slaughter policy. These investigations indicate that by 3 days post-vaccination, the majority of animals were substantially protected from clinical disease and viraemia and the amount of virus present in nasal secretions was markedly reduced. The difference between the fates of the in contact animals in the groups vaccinated 3 days prior to challenge in the two experiments was, almost certainly, due to the presence of one animal with underlying health issues in the UK2000/7.1 challenge experiment that was unable to control the disease. This animal had a high level of virus in nasal secretions that was sufficient to result in infection of the in-contact animals. The lower level of virus present in nasal swabs of other animals in this pen, at a time when they were no longer viraemic, is likely to originate from environmental contamination derived from this one animal rather than secretion from the other animals themselves. Interestingly, although one animal vaccinated 3 days prior to challenge with CBR/93 had an intermediate level of virus in the blood, vaccination provided sufficient protection to prevent nasal secretion and infection of the in-contact animals. Even as early as one day post-vaccination a proportion of the animals were protected to some degree. Although, this was insufficient to prevent infection of animals in direct contact, there was a reduction in the overall level of virus excreted into the environment. As virus transmission is affected by the amount of virus excreted ...

    Simon P. Grahamet al. Challenge of Pigs with Classical Swine Fever Viruses after C-Strain Va...

Sort by: