Correlation between the Neutralizing Antibodies against Porcine Circovirus Type 2 (PCV2) and the Viral Load in Conventional Pig Herds
Date Issued
2009
Date
2009
Author(s)
Yu-Xing, Ding
Abstract
The phenomenon of impaired humoral immunity against PCV2 has been commonly noticed in postweaning multisystemic wasting syndrome (PMWS)-affected pigs. In previous research, PCV2 neutralizing antibody (NA) titer was inversely correlated with PCV2 load in experimentally inoculated pigs. However, the same correlation failed to be demonstrated in naturally PMWS-affected pigs. The aim of current study was to further investigate the humoral response against PCV2 via evaluating development and production of NA in pigs with different ages and clinical status. In first part of the study, 6 healthy field PCV2-carrier pigs were kept in laboratory animal house and studied in duration of 5 to 16 weeks of age. In second part of the study, 61 nursery pigs in 6-9 weeks of age from 5 different farms were categorized into three groups, namely healthy, mild, and severe animals based on clinical status. The determination of NA, total PCV2 antibodies (TA), and PCV2 load were comparatively studied as well as correlated with clinical status in all studied pigs. The results showed the presence of NA was able to diminish PCV2 load and completely eliminate viremia in 6 healthy field PCV2-carrier pigs. In field pigs, the highest NA and TA titer, and the lowest PCV2 load was present in the severe group. Additionally, the inverse correlation between PCV2 load and NA or TA titers only existed in pigs of severe group. In conclusion, the presence and development of NA can effectively diminish the PCV2 load with the synergistic aid of TA in some circumstances.
Subjects
PCV2
PMWS
NA
TA
nursery pigs
Type
thesis
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