Virus titers (plaque-forming units (pfu) mL-1) were determined on

Virus titers (plaque-forming units (pfu) mL-1) were determined on BHK-21, as described elsewhere [48]. Animal experiments Nine 2-month-old pigs and six 1-year-old bovines see more were divided into three groups, each consisting of three pigs and two bovines. All animals were seronegative for FMDV non-structural protein (NSP) antibodies prior to experimental infection.

Two non-RGD recombinant viruses and Asia1/JSp1c8 virus with a titer of 1.6 × 107 pfu mL-1, 1.3 × 107 pfu mL-1, and 1.0 × 107 pfu mL-1, respectively, were used to separately inoculate animals. Each pig was inoculated with 2 mL inoculum via the intramuscular route, each bovine received 1 mL intramuscularly and 1 mL via the tongue. Following inoculation, animals were carefully scored for appearance of lesions at inoculation sites and at other sites. Lesion scores were based on the number of sites affected that were distinct from actual Lumacaftor price injection sites. Scores were calculated as described

by Rieder et al [28]. The viral load in the blood was assessed by real-time quantitative RT-PCR using the RNA Master SYBR green I kit (Roche), as specified by the manufacturer. Quantification was relative to a standard curve obtained with known amounts of FMDV O/CHA/99 RNA, using a procedure that has been described previously [49], except that the primers (patent pending) targeted the 3D non-structural protein were altered. The viral RNA was extracted from vesicular fluid (collected on selected days), selleck reverse transcribed, and sequenced through the entire VP1 region as described above. All animal

studies were approved by the Review Board of Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences (Permission number: SYXK-GAN-2004-0005). All animals used in this study were humanely bred during the experiment and euthanasia was carried out at the end of the experiment to reduce suffering. Statistical analysis Changes in viral titer over time for the in vitro passage experiments were modeled using linear models with virus and time since infection (treated as a factor) as fixed effects. Model selection proceeded by stepwise deletion of non-significant terms (as judged by F-tests) starting from a model including virus, time since infection and an interaction between these factors. Lesion scores over time were modeled using linear mixed models with virus and species as fixed effects and animal identification number as a random effect. Model selection proceeded by stepwise deletion of non-significant terms (as judged by the Akaike information criterion; AIC) starting from a model including virus, species and an interaction between these factors.

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