Investigation into the protective ability of monovalent and bivalent A Malaysia 97 and A22 Iraq 64 vaccine strains against infection with an A/Asia/SEA-97 variant in pigs

Figures

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  Figure 1. Lesion scores and rectal temperatures. (A) Maximum lesion scores in pigs challenged with A/Asia/SEA-97 variant virus post-vaccination. Horizontal lines indicate the group mean scores. (B) Average rectal temperatures in pigs vaccinated and challenged during the experiment. Temperatures >40°C were considered Horpyrexia (red dotted line).

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  Figure 2. Kaplan-Meier survival plots for protection against A/TAI/15/2013 virus in pigs vaccinated with A May 97 and A22 Iraq 64 vaccines in monovalent or combination formulations. The x-axis represents time in days, and the y-axis shows the probability of surviving or the proportion of pigs surviving the virus challenge post-vaccination in different vaccine groups. The lines represent survival curves of the seven vaccine groups (Vaccine = 1: A May V21; Vaccine = 2: A22 V21; Vaccine = 3: Combo V21; Vaccine = 4: A May V7; Vaccine = 5: A22 V7; Vaccine = 6: Combo V7; Vaccine = 7: UVC). A vertical drop in the curves indicates an event (pigs showing clinical signs of FMD). The vertical tick mark on the curves means that a pig was censored at this time.

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  Figure 3. Antibody responses to FMDV structural protein based on a solid-phase competition ELISA. Per cent Inhibition values are shown in the y-axis and day post-challenge (dpc) in the x-axis. The error bars represent the standard deviation of mean PI values. The horizontal dashed line indicates the cut-off level for a sample to have a positive response to vaccination. V21 and V7 indicate the day the vaccines were administered prior to the challenge.

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  Figure 4. Mean viral loads as (A) Log10 FMDV RNA copies/ml in serum indicative of viraemia and Log10 FMDV RNA copies/swab indicative of virus shedding in (B) oral swabs and (C) nasal swabs. The error bars show the standard deviation of the mean. Since many pigs were euthanised due to the appearance of lesions and attaining humane endpoints, the numbers in the day post-challenge differ with different groups.

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  Figure 5. Box plot showing median and mean AUC of virus load in the blood (A,B), oral fluids (C,D) and nasal secretions (E,F). The boxplots show the interquartile range (median represented as the thick horizontal line within the box, and the first and third quartile of the data) and the minimum and maximum values for each group connected to the boxes with the vertical line. Groups with subscripts differ significantly. a = p < 0.1; b = p < 0.05; c = p < 0.01 and d = p < 0.001.