The lesions observed were smaller in size in comparison to those seen in the non-vaccinated infected animals. No tongue lesions were observed in these two unprotected vaccinated animals. Foot lesions in two of the non-vaccinated
buffalo were observed at 7 dpc, whereas foot lesions in the other four non-vaccinated buffalo were observed at 11 dpc. Only one non-vaccinated buffalo developed a tongue find protocol lesion, which was observed at 7 dpc. Five non-vaccinated cattle showed foot lesions at 10 dpc and one showed a foot lesion at 11 dpc. Four of these six unprotected cattle showed tongue or dental pad lesions at 10 dpc, one showed at 7 dpc and the 6th one did not show any tongue or dental pad lesion. Pyrexia (≥39.0 °C to 40.2 °C) was recorded at the same time as the appearance of vesicles, but was less evident in the vaccinated KU-57788 clinical trial unprotected animals in comparison to the unprotected non-vaccinated animals. A neutralizing antibody titre to FMDV O/IND/R2/75 was detected as early
as 14 dpv and peak antibody titres were obtained at 28 dpv in vaccinated buffalo and cattle. The mean antibody titre in vaccinated buffalo and cattle were 101.2 (95% confidence interval (CI): 100.8–101.7) and 101.5 (95% CI: 101.2–101.8), respectively, at the time of exposure. Two vaccinated buffalo that showed clinical signs had low serum neutralizing antibody titres (100.9; 101.1) whereas a third vaccinated buffalo with low neutralizing antibodies (101.1) at the time of exposure was protected. Following the challenge exposure, the serum neutralising antibody titres were observed in the range of 101.2 to 101.8 up to 32–39 days post challenge in vaccinated buffalo and cattle (Fig. 2). In non-vaccinated control buffalo and cattle a rapid 3-mercaptopyruvate sulfurtransferase seroconversion was evident following exposure
to challenge and the antibody titres (101.0 to 101.4) were detected up to 32–39 dpc (Fig. 2). Both vaccinated buffalo and cattle had significantly higher neutralising antibody titres than non-vaccinated control buffalo and cattle at all time points post exposure, but there was no significant difference in serum neutralising antibody titres between vaccinated buffalo and cattle at any time point post exposure. NSP antibodies appeared at 9 dpc in three non-vaccinated buffalo and four non-vaccinated cattle, at 14 dpc in two non-vaccinated buffalo and two non-vaccinated cattle and at 19 dpc in one non-vaccinated buffalo. NSP antibodies were detected at 14 dpc in three vaccinated buffalo and two vaccinated cattle while two vaccinated buffalo and one vaccinated cattle showed NSP antibodies at 32 dpc. One vaccinated buffalo and two vaccinated cattle were not positive for NSP antibodies. Virus replication occurred earlier in non-vaccinated control animals than in the vaccinated animals as was evident from antibody responses against NSP (Fig. 3).