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

Highlights

• A novel lineage of CPIV3 that originated from sheep in China.

• CPIV3 demonstrated high virulence to sheep.

• The risks of CPIV3 cross-transmission between sheep and goat are suggested.

Abstract

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.

Introduction

Parainfluenza virus type 3 (PIV3) is one of the most important viral respiratory pathogens for humans and many species of animals[1]. The virus belongs to the genus respirovirus with respiratory syncytial virus (RSV), human parainfluenza virus (HPIV), and canine distemper virus (CDV), bovine parainfluenza virus type 3 (BPIV3), caprine parainfluenza virus type 3 (CPIV3) in the family Paramyxoviridae. The members of this virus family are enveloped and have genomes consisting of a single segment of negative-sense RNA, which usually have a length of 15 kb [2,3]. The genome encodes six structural proteins including the nucleocapsid (N), phosphoprotein (P), matrix (M), fusion (F), hemagglutinin-neuraminidase (HN), and large (L) proteins. Three accessory proteins are encoded by the P gene, including the C, V, and D proteins [4].

The PIV3 infections were found in a wide variety of mammals including cattle, humans, non-human primates, rhinoceros [5], pigs [6], dogs, dolphin [6], sheep [7], goats [8], bison [9], guinea pigs [10], black and white rhinoceros [5], moose [11] chamois [12], bighorn sheep [13], camels [14], and water buffaloes [1]. BPIV3 has demonstrated strong hazard to both adult and young cattle, which was identified one of the viral respiratory agents caused bovine respiratory disease syndromes (BRDC) [15]. The cross-species infections have been reported, including BPIV3 in sheep, HPIV3 in guinea pigs and Atlantic bottlenose dolphins [16,17]. The first CPIV3 strain, JS2013 was isolated from goats [8]. To date, the CPIV3 strains isolated from sheep and goats were classified as a similar clade with the JS2013 strain [7]. Moreover, the pathogenesis of CPIV3 infection in goats and the guinea pigs were conducted and reported. However, no other lineage of CPIV3 was detected in sheep and goat herds in the world. In this study, a caprine parainfluenza virus strain was isolated from sheep suffered severe respiratory disease with high morbidity and varied mortality in Hebei province of China. The phylogenetic analysis and pathogenicity indicated that the virus is distinct from previously reported CPIV3 strains.