Detection and distribution of torque teno sus virus 1 in porcine reproductive and respiratory syndrome virus positive/negative pigs

•TTSuV1 was detected in 65.3% of 1115 PRRSV-positive samples, 47.2% of 1269 negative samples.•TTSuV1 viral DNA was most commonly detected in the immune organs of PRRSV-positive or negative pigs.•TTSuV1 DNA loads in PRRSV-positive pigs increased from 2 to 5 times compared with PRRSV-negative pigs.•PRRSV may have a synergistic effect with TTSuV1, and promote the replication and proliferation of TTSuV1. To investigate the detection rate and distribution of torque teno sus virus 1 (TTSuV1) in porcine reproductive and respiratory syndrome virus (PRRSV) positive/negative pigs, 2384 pathological tissues samples collected from 6 provinces of Eastern China from 2010 to 2013 were amplified using previously published PRRSV and TTSuV1 primers. The presence and viral load of TTSuV1 were investigated in a wide range of samples from 5 PRRSV positive/negative 4-week-old pigs by real-time TaqMan PCR. TTSuV1 was detected in 65.3% of 1115 PRRSV-positive samples, and 47.2% of 1269 negative samples. Viral DNA was most commonly detected in the immune organs, including spleen, lung, pancreas, and mesenteric and inguinal lymph nodes, followed by serum, liver, kidney, trachea, anal swabs, nasal swabs and sex glands of PRRSV-positive or negative pigs. TTSuV1 DNA loads in PRRSV-positive pigs increased from 2 to 5 times in almost all the corresponding parts compared with PRRSV-negative pigs. Statistical analysis showed that PRRSV may have a synergistic effect with TTSuV1, and promote the replication and proliferation of TTSuV1.