Comparison of PCR assays targeting the multi-copy targets B1 gene and 529Â bp repetitive element for detection of Toxoplasma gondii in swine muscle

•Diagnosis of T. gondii in swine is crucial for consumer safety.•Multi-copy genes are more suitable than single-copy genes for T. gondii diagnosis.•Molecular assays targeting the B1 region and 529 bp-RE in swine muscle were compared.•529 bp-RE PCR detects the highest rate of T. gondii-infection.

The comparison of the sensitivities of two molecular assays designed to target the multi-copy sequences of the Toxoplasma gondii genomic B1 region and 529 bp-RE respectively, in detecting T. gondii in swine muscle was assessed. Diaphragm pillars were obtained from 498 slaughtered pigs managed in intensive farms in Central Italy. Genomic DNA was extracted from the tissues and T. gondii-B1 and 529 bp-RE sequences were amplified by specific PCR protocols. Toxoplasma gondii DNA was detected in 165 samples (33.13%). There was a good correlation (κ = 0.77) between the results obtained targeting the two different genetic markers, however the 529 bp RE-PCR assay overall detected a significantly higher (P < 0.05) number of T. gondii-positive samples (150 samples) than the B1-PCR protocol (134). Our results show that: i) standardized B1 and 529 bp-RE PCRs applied to muscle tissues can detect a high rate of T. gondii-infection; ii) a multi-target PCR approach is recommended for the accurate diagnosis of infection in swine and can also be used in food testing.