Genetic Characterization and Pathology of Porcine Teschovirus (PTV) in India

Abstract

Background: The porcine teschovirus (PTV) is common swine pathogen which causes a wide range of illnesses ranging from asymptomatic infection to acute fatal encephalomyelitis, diarrhoea and pneumonia. Despite of its economical importance very limited studies are available on the pathology of PTV. The present study was conducted with the objective to investigate the PTV infection and associated pathology in piglets. Methods: A total of 78 piglets below 3 months of age were necropsied and representative tissue samples along with intestinal content were collected for histopathological examination and molecular investigation during April 2019 to November 2020. The 5' UTR region of PTV was amplified via RT-PCR and further confirmed by sequencing. Thereafter, genetic characterization of the Indian PTV isolate was done on the basis of 5' UTR gene. Result: A total of seven out of 78 cases were found positive for the PTV. On necropsy the intestinal wall was thinned and distended with yellowish coloured diarrhoeic content. Congestion of serosal and mucosal vessels along with severe meningeal congestion was observed. Microscopic lesions included congestion of mucosal vessels and destruction of villous structure of jejunum along with perivascular cuffing, focal gliosis, neuronophagia, congestion of meningeal and cerebral vessels and interstitial pneumonia. The phylogenetic analysis revealed that the isolate PTV/India/IVRI-381/2020 (MW022462) and PTV/India/IVRI-1093/2020 (MW022463) were clustered with PTV-13 strain wild boar/WB2C-TV/2011/HUN (JQ429405) and PTV-2 strain Vir 6711-12/83 (AF296107) of Hungary and Germany respectively. This study reported the genotypic and pathological investigation of PTV from Indian piglets. Further explorative surveillance along with studies in suitable cell lines and animal model will pave the way for better understanding of PTV among Indian pigs.