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Recombinant Porcine Norovirus Identified in Piglets with Diarrhoea

12 September 2012, at 12:00am

Researchers have, for the first time, found a recombinant new genotype of porcine norovirus that causes diarrhoea (scouring).

Noroviruses (NoVs) are members of the family Caliciviridae and are emerging enteric pathogens of humans and animals. According to Quan Shen of Jiangsu University and co-authors there and Shanghai JiaoTong University and Ohio State University in the US, some porcine NoVs are genetically similar to human strains and are classified into GII, like most epidemic human NoVs. In their paper published recently in BMC Veterinary Research, they report that PoNoV have, until now, been exclusively detected in faecal samples from adult pigs without clinical signs.

In their experiment, they collected 12 faecal samples from piglets with diarrhoea and no accurate diagnosis of aetiology from three commercial pig farms in the Shanghai suburbs.

They tested for PoNoV, porcine circovirus type 2 (PCV2), porcine rotavirus, porcine transmissible gastroenteritis virus, porcine sapovirus and porcine epidemic diarrhoea virus using the RT-PCR method.

The full-genome sequence of the PoNoV was then determined and analysed. Experimental infection of miniature pigs with faecal suspensions was performed to make sure if this strain can cause gastroenteritis in piglets.

Results showed that two of the 12 evaluated faecal samples were positive for PoNoVs, one of which was positive for PoNoV alone, and the other was co-infected with porcine circovirus and PoNoV.

Phylogenetic and recombination analysis showed that the PoNoV-positive alone strain was a recombinant new genotype strain. Experimental infection of miniature pigs with faecal suspensions confirmed that this strain can cause gastroenteritis in piglets.

Shen and co-authors concluded that this is the first report that a recombinant new genotype of PoNoV occurs in pig herds in China under natural conditions and that it causes diarrhoea in pigs. This find raises questions about the putative epidemiological role of PoNoV, the researchers added.

Reference

Shen Q., W. Zhang, S. Yang, Z. Yang, Y. Chen, L. Cui, X. Hua and J. Zhu. 2012. Recombinant porcine norovirus identified from piglet with diarrhea. BMC Veterinary Research, 8:155. doi:10.1186/1746-6148-8-155

Further Reading

You can view the full report (as a provisional PDF) by clicking here.


September 2012