Genetic diversity of porcine sapoviruses in pigs from the Amazon region of Brazil

Abstract

Sapoviruses (SaVs) belong to the family Caliciviridae and are related to gastroenteritis viruses of humans and animals. These agents have been reported from several countries of the world and represent an important cause of economic loss. The Amazon area has a high degree of diversity of animals and plants, is located in the Northern Region of Brazil and accounts for a large part of the Brazilian territory. In this study, stool samples were collected from pigs during the phase of nursing (less than 28 days of age) and post-weaning (29 to 56 days of age) from January 2008 to February 2009. A total of 169 specimens (108 nursing and 61 post-weaning pigs) were tested by reverse transcription polymerase chain reaction (RT-PCR) using the primers p289/p290 for the detection of caliciviruses (CVs), i.e., SaVs and noroviruses (NoVs). Positive sequences were analyzed using BioEdit software (v. 7.1.3.0) and compared with other sequences registered in the GenBank database. A positive frequency of 12.4 % (21/169) was observed, and all of the viruses found were identified as SaVs, with 15 belonging to genogroup GIII (71.4 %), three to GVII-1 (14.3 %) and three to GVIII-2 (14.3 %). No NoVs were detected. The frequency of SaV infections was significantly higher in nursing pigs (17.6 %-19/108) than in post-weaning pigs (3.3 %-2/61). Considering the consistency of the samples, 14.7 % of the samples were classified as diarrheic, but statistical analysis demonstrated that there was no significant difference compared to normal specimens (p = 0.5795). For the first time, we have demonstrated the circulation of SaVs in pigs from the Amazon.