Occurrence and diversity of porcine rotavirus groups A, B, C and H in Danish pigs

Rotaviruses (RVs) are one of the main infectious causes of acute gastroenteritis and are widespread among pigs with enteric disease. RVs are classified into nine groups or species (RVA-RVD and RVF-RVJ) and, to date, four of these (RVA, RVB, RVC, RVD and RVH) have been identified in pigs, with RVA being the most frequent and characterized species. In the present study, reverse transcription quantitative real-time PCR (RT-qPCR) assays specific for RVB, RVC and RVH were designed and validated and used together with a published RVA RT-qPCR assay to evaluate the occurrence of these RV species in rectal swab samples from 90 pigs from 22 Danish sow herds (2-8 pigs per herd). The pigs were 1-35 days of age, and the majority had experienced diarrhea and macroscopic signs of enteritis. Overall, RVs were detected in 81.1 % of the pigs with RVA (37.8 %) and RVB (38.9 %) being predominant, followed by RVC (28.9 %) and RVH (1.1 %). Co-infections with two or three different RV species were observed in 10.0 % and 7.8 % of the pigs, respectively. On herd level, RVs were detected in 95.5 % of the investigated herds with the following distribution: RVA (59.1 %), RVB (54.5 %), RVC (45.5 %) and RVH (4.5 %). In 40.9 % of the herds, more than one RV species was present. While it is known that RVA is frequently found in Danish pigs, this study shows that there is a rich RV diversity in Danish pigs and sow herds.