Widespread rotavirus H in commercially raised pigs, United States

Abstract

We investigated the presence in US pigs of rotavirus H (RVH), identified in pigs in Japan and Brazil. From 204 samples collected during 2006-2009, we identified RVH in 15% of fecal samples from 10 US states, suggesting that RVH has circulated in the United States since 2002, but probably longer.

Keywords: RVH; United States; novel rotavirus; phylogenetic analysis; pigs; swine; viruses.

Figure 1

Epidemiologic and molecular distribution of porcine rotavirus H (RVH) strains, United States, 2006–2009. A) Geographic distribution of RVH-positive porcine samples/total number of samples tested. Pink indicates states containing positive samples; green indicates states negative samples; white indicates states from which samples were not submitted. B) Distribution of RVH-positive samples and age group in pigs co-infected with RVA, RVB, and/or RVC. Blue indicates samples from the 4–20-day age group; pink indicates samples from the 21–55-day age group; green indicates samples from the >55-day age group. C) RVH viral protein 6 nt pairwise identity. D) RVH amino acid pairwise identity.

Figure 2

A) Nucleotide neighbor-joining phylogenetic tree of rotavirus (RV) A–D and F–H viral protein (VP) 6 sequences. Blue strains are from the United States; green strains are from Brazil; and the red strain is from Japan. Purple strains are from humans. Scale bar indicates percentage of dissimilarity between sequences. B) Time-scaled phylogeny of swine RVH VP6 sequences using a Bayesian Markov chain Monte Carlo approach. Blue shaded region indicates the time from the most recent common ancestor range (tMRCA) of the US strain; red shaded region indicates the US and Japan RVH tMCRA range; green shaded region indicates the tMRCA range for all swine RVH VP6 sequences.