“…We recently found that the prevalence of TTSuV1 in swine with manifested clinical signs of the porcine respiratory disease complex (PRDC) is approximately 85-90%, while the baseline prevalence rate was only about 55% (Rammohan et al, 2012). Others have also reported strong epidemiological associations of TTSuVs with pathogens like swine influenza, the porcine reproductive and respiratory disease syndrome virus and especially porcine circovirus strain 2 (PCV2) (Aramouni et al, 2013; Aramouni et al, 2011; Blomstrom et al, 2010; Lee et al, 2015; Li et al, 2015). In experimental studies, infection with TTSuV1 induced lung and kidney lesions in gnotobiotic swine (Krakowka and Ellis, 2008), while co-infections with other viruses exacerbated clinical signs (Ellis et al, 2008; Krakowka et al, 2008), indicating that TTSuVs can act as primary or co-infecting pathogens in swine.…”