The infection status of 15 viruses in 120 pigs aged about 6 months was investigated based on tonsil specimens collected from a slaughterhouse. Only 5 species of porcine parvoviruses and porcine circovirus type 2 (PCV2) were detected at high frequencies; 67% for porcine parvovirus (PPV) (PPV-Kr or -NADL2 as the new abbreviation), 58% for PPV2 (CnP-PARV4), 39% for PPV3 (P-PARV4), 33% for PPV4 (PPV4), 55% for PBo-likeV (PBoV7) and 80% for PCV2. A phylogenetic analysis of PPV3 suggested that Japanese PPV3s showed a slight variation, and possibly, there were farms harboring homogeneous or heterogeneous PPV3s. Statistical analyses indicated that the detection of PCV2 was significantly coincidental with each detection of PPV, PPV2 and PPV3, and PPV and PPV4 were also coincidentally detected. The concurrent infection with PCV2 and porcine parvoviruses in the subclinically infected pigs may resemble the infection status of pigs with the clinical manifestations of porcine circovirus associated disease which occurs in 3–5 months old pigs and is thought to be primarily caused by the PCV2 infection.

Johne's disease (JD) is an economically important infectious disease in livestock farming caused by Mycobacterium avium subsp. paratuberculosis (MAP). As an alternative to serological tests, which are mainly used for the screening of whole herds, we developed a novel ResoLight-based real-time PCR (RL-PCR) assay with pooled faecal samples for the detection of faecal shedders in cattle herds. The RL-PCR assay included an internal amplification control (IC) which was amplified using the same primer pair as the target molecule MAP IS900 and differentiated based on melting temperatures. Individual faecal suspensions were pooled and concentrated by centrifugation to avoid loss of sensitivity by dilution effect. Combined with a DNA extraction kit (Johne-PureSpin, FASMAC), no inhibition of PCR amplification was observed with up to 15 faecal samples in a pool. The detection limit of RL-PCR at a pool size of 10 was 10 MAP organisms per gram of faeces, which was comparable to individual testing. A total of 2,654 animals in 12 infected herds were screened by individual antibody-ELISA and the RL-PCR assay using pooled faeces. Fifty animals were diagnosed with JD through the screening by RL-PCR, compared to only 5 by ELISA (which were also positive in RL-PCR). In 7 JD free herds, the results of 4 out of 327 pools (1.2%) were invalid due to the lack of IC amplification, and then animals were confirmed negative individually. Our results suggest that implementation of herd screening by pooled RL-PCR would advance the monitoring and control of JD in cattle herds.