Porcine teschovirus, sapelovirus, and enterovirus in Swiss pigs: multiplex RT-PCR investigation of viral frequencies and disease association

Abstract

Porcine teschovirus (PTV), sapelovirus (PSV-A), and enterovirus (EV-G) are enteric viruses that can infect pigs and wild boars worldwide. The viruses have been associated with several diseases, primarily gastrointestinal, neurologic, reproductive, and respiratory disorders, but also with subclinical infections. However, for most serotypes, proof of a causal relationship between viral infection and clinical signs is still lacking. In Switzerland, there has been limited investigation of the occurrence of the 3 viruses. We used a modified multiplex reverse-transcription PCR protocol to study the distribution of the viruses in Swiss pigs by testing 363 fecal, brain, and placental or abortion samples from 282 healthy and diseased animals. We did not detect the 3 viruses in 94 placental or abortion samples or in 31 brain samples from healthy pigs. In brain tissue of 81 diseased pigs, we detected 5 PSV-A and 4 EV-G positive samples. In contrast, all 3 viruses were detected at high frequencies in fecal samples of both healthy and diseased pigs. In healthy animals, PTV was detected in 47%, PSV-A in 51%, and EV-G in 70% of the 76 samples; in diseased animals, frequencies in the 81 samples were 54%, 64%, and 68%, respectively. The viruses were detected more frequently in fecal samples from weaned and fattening pigs compared to suckling piglets and sows. Co-detections of all 3 viruses were the most common finding. Based on clinical and pathology data, statistical analysis yielded no evidence for an association of virus detection and disease. Further research is required to determine if pathogenicity is linked to specific serotypes of these viruses.

Premature farrowing and stillbirths in two organic sow farms due to riboflavin deficiency

“…The presence of a PSV genome in a sick animal does not imply that this virus is the cause of the clinical signs or lesions. The main lesions caused by a neuro-invasive PSV in infected pigs was characterised by encephalomyelitis [26], while experimentally infected piglets exhibited encephalitis, nonsuppurative myelitis and pneumonia [27]. In our case, the detection of PSV and PCV3 by PCR was not confirmed by the demonstration of diagnostic histopathological findings in piglet tissues.…”

“…PSV has been associated with several diseases, primarily gastrointestinal, neurologic, reproductive, and respiratory disorders, but also with subclinical infections. However, for most serotypes, proof of a causal relationship between viral infection and clinical signs is still lacking [26]. The presence of a PSV genome in a sick animal does not imply that this virus is the cause of the clinical signs or lesions.…”

Animal enteroviruses: a glimpse of a wide evolutionary landscape

“…EV-Gs circulate in pig and sheep farms mainly without noticeable symptoms [35][36][37]. EV-Gs have been found in animals with diarrhea [37,38] or neurological symptoms, but the role of EV-Gs in these symptoms is difficult to establish given the high prevalence of these viruses in farms [39]. However, in-depth investigations have revealed the presence of EV-G20 genome in the spinal cord of two lambs suffering from limb paralysis [40].…”

Identification of a novel porcine Teschovirus 2 strain as causative agent of encephalomyelitis in suckling piglets with high mortality in China

“…PTV is globally endemic and circulates in most pig herds. It has been frequently detected in the feces of health pigs suggesting that these viruses could colonize in the intestinal tract without causing any disease [ 1 , 2 , 10 , 11 ]. However, highly pathogenic PTV strains are capable of causing severe clinical signs, including severe to moderate neurological symptoms, reproductive disorders, respiratory diseases, and diarrhea [ 1 , 2 ].…”