The use of Bayesian methods for evaluating the performance of a virus-like particles-based ELISA for serology of hepatitis E virus infection in swine.

In the absence of commercial kits for serological studies specifically for hepatitis E virus (HEV) infection of swine, the capsid protein of a swine genotype 3 HEV was expressed using a recombinant baculovirus. This antigen was used in an enzyme-linked immunosorbent assay (ELISA) for detection of anti-HEV antibodies. Estimation of sensitivity and specificity was carried out in comparison with a commercial serological assay using sera from pigs infected experimentally with HEV genotype 3, negative sera from SPF pigs and swine sera collected at slaughterhouses. Since a "gold standard" is not available, a latent-class Bayesian approach for correlated tests was used to estimate the sensitivity and specificity of both tests. External field and experimental data were used to determine the parameters of Beta prior distributions. The estimated mean sensitivity of the commercial test was 0.47 with a 95% credibility interval of 0.39-0.55, whereas the estimated mean sensitivity of the genotype 3-based assay was 0.92 [0.81-0.99]. The estimated specificities were 0.98 [0.93-0.99] and 0.98 [0.95-0.99] for the genotype 3-based test and commercial test, respectively. In conclusion, genotype 3-antigen derived from swine HEV is a better candidate for assessing hepatitis E serology in swine.