Molecular characterization of porcine rotavirus C in pigs with gastroenteritis in Thailand, 2011 – 2016

Abstract

Swine are economically important food animals, but highly contagious enteric viruses can affect entire swine herds and contribute significantly to piglet morbidity and mortality. The most frequent viruses associated with pig gastroenteritis have been reported as porcine epidemic diarrhea virus (PEDV) and rotavirus. Rotavirus is an important cause of diarrhea in piglets and pigs worldwide, and group A and C types are those that pig herds are mostly affected by. In Thailand, studies on rotavirus group A (RVA) have been reported continuously, whereas information on group C is still limited. In this study, we aimed to identify rotavirus group C (RVC) from the feces and intestinal contents of pigs affected with diarrhea. Seven hundred and sixty-nine samples were collected from swine herds located in difference provinces throughout Thailand. The specimens were tested using virus-specific RT-PCR to detect the gene encoding RVC capsid protein VP7 and VP4.Sequencing analyses showed that 6.6% (51/769) of samples were positive for RVC, one third of which tested as single positive for RVC (34/51). Co-infections with the most frequent enteric viruses, RVA and PEDV were also analyzed. Co-infections of RVA/RVC accounted for 21.6% (11/51) of samples and of PEDV/RVC for 7.8% (4/51) of samples, while three samples (5.9%) tested positive for all three viruses. Infections were not associated with seasonality, since the virus was detected throughout the year. RVC was detected in pigs up to 8 weeks old. Analysis of the partial VP7 gene sequences was suggestive that the predominant genotype was G1, which was closely related to the Swine are economically important food animals, but highly contagious enteric viruses 33 can affect entire swine herds and contribute significantly to piglet morbidity and mortality. The 34 most frequent viruses associated with pig gastroenteritis have been reported as porcine epidemic 35 diarrhea virus (PEDV) and rotavirus. Rotavirus is an important cause of diarrhea in piglets and 36 pigs worldwide, and group A and C types are those that pig herds are mostly affected by. In 37 Thailand, studies on rotavirus group A (RVA) have been reported continuously, whereas 38 information on group C is still limited. In this study, we aimed to identify rotavirus group C 39 (RVC) from the feces and intestinal contents of pigs affected with diarrhea. Seven hundred and 40 sixty-nine samples were collected from swine herds located in difference provinces throughout 41 Thailand. The specimens were tested using virus-specific RT-PCR to detect the gene encoding 42 RVC capsid protein VP7 and VP4. Sequencing analyses showed that 6.6% (51/769) of samples 43 were positive for RVC, one third of which tested as single positive for RVC (34/51). Co-44 infections with the most frequent enteric viruses, RVA and PEDV were also analyzed. Co-45 infections of RVA/RVC accounted for 21.6% (11/51) of samples and of PEDV/RVC for 7.8% 46 (4/51) of samples, while three samples (5.9%) tested positive for all three viruses. Infections 47 were not...