PMID- 31500966 OWN - NLM STAT- MEDLINE DCOM- 20200925 LR - 20200925 IS - 1873-2518 (Electronic) IS - 0264-410X (Linking) VI - 37 IP - 43 DP - 2019 Oct 8 TI - The impact of porcine circovirus associated diseases on live attenuated classical swine fever vaccine in field farm applications. PG - 6535-6542 LID - S0264-410X(19)31103-X [pii] LID - 10.1016/j.vaccine.2019.08.039 [doi] AB - Porcine circovirus associated diseases (PCVADs) are among the most important diseases affecting the worldwide swine industry. Vaccination against porcine circovirus type 2 (PCV2) infection has been utilized for disease control and effectively reduces clinical signs of PCVADs. To evaluate the efficacy of the PCV2 vaccine in field farms, we conducted a trial using conventional pigs immunized with the subunit PCV2 vaccine followed by PCV2 challenge. Immunized pigs demonstrated lower serum viral loads, less viral antigen staining in lymph nodes, and higher average daily weight gain, confirming the protective efficacy of the vaccine. However, low levels of PCV2 infection were still detected in vaccinated pigs after challenge, suggesting that the PCV2 vaccine was unable to eradicate the virus, which could lead to asymptomatic PCV2 subclinical infection (PCV2-SI) in pig farms. Additionally, PCV2 infection is a risk factor for impaired pig immune response development during the weaning to growth stages, which is a crucial period to receive vaccines against classical swine fever (CSF). Therefore, the impact of PCV2-SI or PCV2-systemic disease (PCV2-SD) on live attenuated CSF vaccine was investigated. After PCV2 challenge, there was no difference in levels of classical swine fever virus (CSFV) neutralizing antibodies (NA) between pigs with PCV2-SD and PCV2-SI, suggesting that the efficacy of CSF vaccine was compromised. Moreover, results of long-term monitoring of CSFV NA titers in PCV2-SI pigs with minimized interference by maternally-derived antibodies suggested that serum PCV2 viral loads greater than 10(2) copies/mL may compromise the efficacy of CSF vaccine. Overall, a conventional pig model was established to demonstrate the impaired efficacy of the subunit PCV2 vaccine and its impact on the CSF vaccine in vaccination-challenge trials. Additionally, the impaired efficacy of the PCV2 vaccine resulted in increased PCV2-SI, eventually leading to compromised the live attenuated CSF vaccine induced NA response in field farm applications. CI - Copyright (c) 2019 Elsevier Ltd. All rights reserved. FAU - Chen, Jing-Yuan AU - Chen JY AD - Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan, Republic of China. FAU - Wu, Chi-Ming AU - Wu CM AD - Research Center for Animal Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan, Republic of China. FAU - Liao, Chih-Ming AU - Liao CM AD - Research Center for Animal Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan, Republic of China. FAU - Chen, Kun-Chao AU - Chen KC AD - Research Center for Animal Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan, Republic of China. FAU - You, Chia-Chin AU - You CC AD - Research Center for Animal Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan, Republic of China. FAU - Wang, Yu-Wen AU - Wang YW AD - Research Center for Animal Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan, Republic of China. FAU - Huang, Chienjin AU - Huang C AD - Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan, Republic of China. Electronic address: cjhuang@dragon.nchu.edu.tw. FAU - Chien, Maw-Sheng AU - Chien MS AD - Graduate Institute of Veterinary Pathobiology, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan, Republic of China; Research Center for Animal Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan, Republic of China. Electronic address: mschien@dragon.nchu.edu.tw. LA - eng PT - Clinical Trial, Veterinary PT - Journal Article PT - Observational Study, Veterinary DEP - 20190906 PL - Netherlands TA - Vaccine JT - Vaccine JID - 8406899 RN - 0 (Antibodies, Neutralizing) RN - 0 (Vaccines, Attenuated) RN - 0 (Viral Vaccines) SB - IM MH - Animals MH - Antibodies, Neutralizing/blood MH - Circoviridae Infections/*veterinary MH - Classical Swine Fever/immunology/*prevention & control MH - Cross-Sectional Studies MH - Farms MH - Female MH - Swine MH - Swine Diseases/*virology MH - Vaccines, Attenuated/immunology/*pharmacology MH - Viral Load MH - Viral Vaccines/immunology/*pharmacology OTO - NOTNLM OT - Classical swine fever live attenuated vaccine OT - Concurrent infection OT - Porcine circovirus associated diseases OT - Subunit porcine circovirus type 2 vaccine OT - Vaccination-challenge model EDAT- 2019/09/11 06:00 MHDA- 2020/09/26 06:00 CRDT- 2019/09/11 06:00 PHST- 2019/03/29 00:00 [received] PHST- 2019/07/10 00:00 [revised] PHST- 2019/08/19 00:00 [accepted] PHST- 2019/09/11 06:00 [pubmed] PHST- 2020/09/26 06:00 [medline] PHST- 2019/09/11 06:00 [entrez] AID - S0264-410X(19)31103-X [pii] AID - 10.1016/j.vaccine.2019.08.039 [doi] PST - ppublish SO - Vaccine. 2019 Oct 8;37(43):6535-6542. doi: 10.1016/j.vaccine.2019.08.039. Epub 2019 Sep 6.