INTRODUCTION
Rotaviruses (RVs) are members of the family Reoviridae and major causative agents of gastroenteritis in humans and animals worldwide. Their genome consists of 11 segments of double-stranded RNA that encode six structural proteins (VP1–4, VP6, and VP7) and five nonstructural proteins (NSP1–5) (Estes MK, 2007). According to the International Committee on Taxonomy of Viruses, the Rotavirus genus is divided into nine antigenically distinct groups or species (RVA, RVB, RVC, RVD, RVF, RVG, RVH, RVI and RVJ) based on the diversity of their inner capsid protein (VP6) sequence (Matthijnssens et al., 2012; Mihalov-Kovács et al., 2015).
RV infections are very prevalent on swine farms, frequently linked to suckling and post-weaning diarrhea, which ends in large economic losses to the pork industry. Main RV groups associated with diarrhea in swine include RVA, RVB and RVC. RVA affects piglets between three and five weeks of age while RVC is much more common in young piglets (<7 days of age) (Vlasova, Amimo, & Saif, 2017).
In 1997, a new human RV tentatively named as novel adult diarrhea rotavirus (ADRV-N) which did not belong to any previously established group was described in China causing an outbreak of gastroenteritis among adults (Alam et al., 2007; Yang et al., 2004). The ADRV-N was subsequently classified as RVH based on VP6 sequence analysis (Matthijnssens et al., 2012). In total, three human RVH strains from Asia (ADRV-N and J19 from Chine and B219 from Bangladesh) as well as a porcine RVH strain from Japan (SKA-1) were identified during 1997-2002 (Jiang et al., 2008; Nagashima et al., 2008). Since then, RVH has been reported in pigs from Japan (Suzuki & Inoue, 2018; Wakuda et al., 2011), USA (Marthaler et al., 2014), Brazil (Molinari, Lorenzetti, Otonel, Alfieri, & Alfieri, 2014), South Africa (Nyaga et al., 2016) and Vietnam (Phan et al., 2016). More recently RVH has been also reported in bats in Cameroon (Yinda et al., 2018).
To the best of our knowledge there are no reports of porcine RVH in Europe. Here we introduce the first detection and characterization of RVH in pigs with diarrhea from Spanish pig farms, the main European pig producer.