The novel caprine parainfluenza virus type 3 showed pathogenicity in Guinea pigs

Bta-miR-677 contribute to interferon pathway affecting the proliferation of caprine parainfluenza virus type 3

Caprine parainfluenza virus type 3 (CPIV3), a new strain of virus, was isolated from the goats in 2014 in China. Studies have shown that viral infection can induce changes in the expression profile of host miRNAs, which modulate natural immune responses and viral infection. In this study, we report that bta-miR-677 suppressed CPIV3 replication in Madin-Darby bovine kidney (MDBK) cells and guinea pigs. Bta-miR-677 overexpression promoted type I interferon (IFN-I) and IFN-stimulated genes (ISGs) production, thereby inhibiting CPIV3 replication, while bta-miR-677 inhibitor suppressed the antiviral innate immune response to promoted viral replication in MDBK cells. We showed that bta-miR-677 suppresses CPIV3 replication via directly targeted the 3'-untranslated region (3'-UTR) of mitochondrial antiviral signaling protein (MAVS) thus enhancing IFN pathway in MDBK cells. We also demonstrated that bta-miR-677 agomir could inhibit CPIV3 proliferation in guinea pigs, with much lower viral RNA levels in lung and trachea. Guinea pigs showed no obvious pathological changes and less severe lung lesions in bta-miR-677 agomir treated group at 7 dpi. This study contributes to our understanding of the molecular mechanisms underlying CPIV3 pathogenesis.

Phylogenetic and pathogenicity analysis of a novel lineage of caprine parainfluenza virus type 3

Caprine parainfluenza virus type 3 (CPIV3) was first identified in goats named JS2013 in China. In 2019, a sheep herd broke a disease with respiratory disease in Hebei province, China. In order to confirm the pathogen of the disease, the nasal swabs, stool swabs and blood samples were collected from the sheep. Virus isolation was performed on MDBK cells and identification was conducted by RT-PCR. The complete genome of the isolate was sequenced and phylogenetic analyzed. In order to evaluate the pathogenicity of the virus, five seronegative sheep were experimental infected with the virus suspension. The phylogenetic analyses based on the complete genome and the M gene indicated that the isolate strain was distinguished distinct from previously reported CPIV3 lineage of JS2013. The virus-inoculated sheep displayed the syndrome with depression, cough, and fever. Virus shedding were detected by RT-PCR from nasal swabs. All infected showed virus shedding during 2 - 21dpi and viremia could be detected in serum samples. Gross pathological assessment of sheep in infected group showed gross lesion in the lungs. Histopathological observation results indicated that lungs had mild to moderate interstitial pneumonia, with thickened alveolar walls, decreased alveolar space, and increased amounts of inflammatory cells infiltration. This is the first report of pathogenicity of the novel lineage of sheep-derived CPIV3. The results would be helpful for further studies on the prevention and control strategies for CPIV3 infections in goat and sheep.