Highly contagious classical swine fever (CSF) remains a major trade and health problem in the pig industry, resulting in large economic losses worldwide. In CSF-endemic countries, attenuated CSF virus (CSFV) vaccines have been routinely used to control the disease. However, eradication of CSFV in a geographical area would require permanent reduction to zero presence of the virus. It is therefore of paramount importance to develop a safe, potent, and non-infectious CSF vaccine. We have previously reported on a cost-effective CSF E2 subunit vaccine, KNB-E2, which can protect against CSF symptoms in a single dose containing 75 µg of recombinant CSFV glycoprotein E2. In this study, we report on a series of animal studies undertaken to elucidate further the efficacy of KNB-E2. We found that pigs vaccinated with a single KNB-E2 dose containing 25 µg of recombinant CSFV glycoprotein E2 were protected from clinical symptoms of CSF. In addition, KNB-E2-mediated reduction of CSF symptoms was observed at two weeks post-vaccination and the vaccinated pigs continued to exhibit reduced CSF clinical signs when virus challenged at two months and four months post-vaccination. These results suggest that KNB-E2 effectively reduces CSF clinical signs, indicating the potential of this vaccine for safely minimizing CSF-related losses.
Animals ; Classical Swine Fever ; Glycoproteins ; Swine ; Vaccines

Objective:To investigate the clinical efficacy of pancreaticoduodenectomy (PD) for periampullary diseases.Methods:The retrospective cohort study was conducted. The clinico-pathological data of 2 019 patients with periampullary diseases who underwent PD in the First Affiliated Hospital of Nanjing Medical University from January 2016 to December 2020 were collected. There were 1 193 males and 826 females, aged 63(15) years. Observation indicators: (1) surgical situations; (2) postoperative conditions; (3) postoperative pathological examinations; (4) prognosis of patients with periampullary carcinoma. Regular follow-up was conducted by telephone interview and outpatient examination once every 3 months within the postoperative first year and once every 6 months thereafter to detect the survival of patients with periampullary carcinoma. The follow-up was up to December 2021. Measurement data with skewed distribution were represented as M(IQR) or M(range), and comparison between groups was analyzed using the rank sum test. Count data were described as absolute numbers and (or) percentages, and comparison between groups was analyzed by the chi-square test or Fisher exact probability. Kaplan-Meier method was used to draw survival curves and calculate survival rates, and Log-Rank test was used to conduct survival analysis. Results:(1) Surgical situations: of 2 019 patients, 1 116 cases were admitted from 2016-2018 and 903 cases were admitted from 2019-2020. There were 1 866 cases undergoing open PD and 153 cases undergoing laparoscopic or robot-assisted PD. There were 1 049 cases under-going standard PD and 970 cases undergoing pylorus-preserved PD. There were 215 cases combined with portal mesenteric vein resection, 3 cases combined with arterial resection. The operation time of 2 019 patients was 255(104)minutes and the volume of intraoperative blood loss was 250(200)mL. The intraoperative blood transfusion rate was 31.401%(623/1 984), with the blood transfusion data of 35 cases missing. The proportions of pylorus-preservation, combination with portal mesenteric vein resection, intraoperative blood transfusion were 585 cases(52.419%), 97cases(8.692%), 384 cases(34.941%) for patients admitted in 2016-2018, versus 385 cases(42.636%), 118 cases(13.068%), 239 cases(27.006%) for patients admitted in 2019-2020, showing significant differences between them ( χ2=19.14,10.05,14.33, P<0.05). (2) Postoperative conditions: the duration of postoperative hospital stay of 2 019 patients was 13 (10) days. One of 2 019 patients lacked the data of postopera-tive complications. The overall postoperative complication rate was 45.292%(914/2 018), of which the incidence rate of grade B or C pancreatic fistula was 23.439%(473/2 018), the rate of grade B or C hemorrhage was 8.127%(164/2 018), the rate of grade B or C delayed gastric emptying was 15.312%(309/2 018), the rate of biliary fistula was 2.428%(49/2 018) and the rate of abdominal infection was 12.884%(260/2 018). The reoperation rate of 2 019 patients was 1.932%(39/2 019), the in-hospital mortality was 0.644%(13/2 019), the postoperative 30-day mortality was 1.238%(25/2 019), and the postoperative 90-day mortality was 2.675%(54/2 019). There were 541 cases(48.477%) with overall postoperative complications, 109 cases(9.767%) with grade B or C hemorr-hage, 208 cases(18.638%) with grade B or C delayed gastric emptying , 172 cases(15.412%) with abdominal infection, 39 cases(3.495%) with postoperative 90-day mortality of 1 116 patients admitted in 2016-2018. The above indicators were 373 cases(41.353%), 55 cases(6.098%), 101 cases(11.197%), 88 cases(9.756%), 15 cases(1.661%) of 902 patients admitted in 2019-2020, respectively. There were significant differences in the above indicators between them( χ2=10.22, 9.00, 21.30, 14.22, 6.45 , P<0.05). The in-hospital mortality occurred to 11 patients(0.986%) of 1 116 patients admitted in 2016-2018 and to 2 cases(0.221%) of 903 patients admitted in 2019-2020, showing a significant difference between them ( P<0.05). (3) Postoperative pathological examinations. Disease area of 2 019 patients reported in postoperative pathological examinations: there were 1 346 cases(66.667%) with lesions in pancreas, including 1 023 cases of carcinoma (76.003%) and 323 cases(23.997%) of benign diseases or low potential malignancy. There were 250 cases(12.382%) with lesions in duodenal papilla, including 225 cases of carcinoma (90.000%) and 25 cases(10.000%) of benign diseases or low potential malignancy. There were 174 cases(8.618%) with lesions in bile duct, including 156 cases of carcinoma (89.655%) and 18 cases(10.345%) of benign diseases or low potential malignancy. There were 140 cases(6.934%) with lesions in ampulla, including 134 cases of carcinoma (95.714%) and 6 cases(4.286%) of benign diseases or low potential malignancy. There were 91 cases(4.507%) with lesions in duodenum, including 52 cases of carcinoma (57.143%) and 39 cases(42.857%) of benign diseases or low potential malignancy. There were 18 cases(0.892%) with carcinoma in other sites. Postoperative pathological examination showed carcinoma in 1 608 cases(79.643%), benign diseases or low potential malignancy in 411 cases(20.357%). The histological types of 1 608 patients with carcinoma included adenocarcinoma in 1 447 cases (89.988%), intra-ductal papillary mucinous carcinoma in 37 cases(2.301%), adenosquamous carcinoma in 35 cases(2.177%), adenocarcinoma with other cancerous components in 29 cases(1.803%), neuroendocrine carcinoma in 18 cases(1.119%), squamous carcinoma in 1 case (0.062%), and other histological malignancies in 41 cases(2.550%). The histological types of 411 patients with benign or low poten-tial malignancy included intraductal papillary mucinous neoplasm in 107 cases (26.034%), chronic or autoimmune inflammatory disease in 62 cases(15.085%), neuroendocrine tumor in 58 cases(14.112%), pancreatic serous cystadenoma in 52 cases(12.652%), pancreatic solid pseudopapillary tumor in 36 cases(8.759%), gastrointestinal stromal tumor in 29 cases(7.056%), villous ductal adenoma in 20 cases(4.866%), pancreatic mucinous cystadenoma in 2 cases(0.487%), pancreatic or duodenal trauma in 2 cases(0.487%) and other histological types in 43 cases(10.462%). (4) Prognosis of patients with periampullary carcinoma. Results of survival analysis of 1 590 patients with main locations of periampullary carcinoma showed that of 1 023 patients with pancreatic cancer, 969 cases were followed up for 3.0-69.6 months, with a median follow-up time of 30.9 months. The median overall survival time, 1-year, 3-year and 5-year survival rates of pancreatic cancer patients were 19.5 months [95% confidence interval ( CI) as 18.0-21.2 months], 74.28%, 29.22% and 17.92%. Of 225 patients with duodenal papillary cancer, 185 cases were followed up for 3.0-68.9 months, with a median follow-up time of 36.7 months. The median overall survival time, 1-year, 3-year and 5-year survival rates were unreached, 94.92%, 78.87% and 66.94%. Of 156 patients with distal bile duct cancer, 110 cases were followed up for 3.0-69.5 months, with a median follow-up time of 25.9 months. The median overall survival time, 1-year, 3-year and 5-year survival rates were 50.6 months (95% CI as 31.4 to not reached), 90.37%, 56.11% and 48.84%. Of 134 patients with ampullary cancer, 100 cases were followed up for 3.0-67.8 months, with a median follow-up time of 28.1 months. The median overall survival time, 1-year, 3-year and 5-year survival rates were 62.4 months (95% CI as 37.8 months to not reached), 90.57%, 64.98% and 62.22%. Of 52 patients with duodenal cancer, 38 cases were followed up for 3.0-69.5 months, with a median follow-up time of 26.2 months. The median overall survival time, 1-year, 3-year and 5-year survival rates were 52.0 months (95% CI as 30.6 months to not reached), 93.75%, 62.24% and 40.01%.There was a significant difference in overall survival after PD between patients with different locations of periampullary malignancies ( χ2=163.76, P<0.05). Conclusions:PD is safe and feasible in a high-volume pancreas center, but the incidence of overall postoperative complications remains high. With the increase of PD volume, the incidence of overall postoperative complications has significantly decreased. There is a significant difference in overall survival time after PD among patients with different locations of periampullary malignancies. The 5-year survival rate after PD for duodenal papillary cancer, ampullary cancer, duodenal cancer and distal bile duct cancer is relatively high, whereas for pancreatic cancer is low.