Detection of three novel atypical porcine pestivirus strains in newborn piglets with congenital tremor in southern China

Abstract Background Congenital tremor (CT) type A-II is a neurological disorder characterized by tremor of the head and body of newborn piglets. The suggested causative agent of the disease is the recently found atypical porcine pestivirus (APPV). The virus has been detected in piglets suffering from congenital tremor in central Europe, South and North America and in China but no studies has so far been performed in the Nordic countries. The overarching goal of this study was to investigate if APPV is present in the brain tissue of Swedish piglets suffering from congenital tremor. From June 2017 – June 2018, 15 piglets from four Swedish farms with ongoing outbreaks of congenital tremor and 13 piglets with splay leg originating from four different farms, were investigated for presence of APPV RNA in brain tissue. Matched healthy control piglets (n=8) were also investigated. Two APPV-specific RT-qPCR methods targeting the NS3 and NS5B region, respectively, were used. A retrospective study was performed on material from Swedish piglets with congenital tremor sampled in 2004 (n = 11) and 2011/2012 (n = 3) using the described APPV-specific RT-qPCR methods. The total number of piglets with signs of CT in this study was 29. Results Atypical porcine pestivirus-RNA was detected in 93% (27/29) of the piglets suffering from congenital tremor. All piglets with congenital tremor from 2004 (n = 11) and 2012 (n = 3) were PCR-positive with respect to APPV, whereas, all of the healthy controls (n = 11) were negative. The piglets with congenital tremor sampled 2017-2018 had an odds ratio of 91,8 (95% CI 3.9128 to 2153.7842, z = 2.807, P = 0.0050) to test positive for APPV by qRT-PCR compared to the healthy piglets (Fishers exact test p < 0.0001). These findings make it interesting to continue investigating APPV in the Swedish pig population. Conclusion This is the first description of atypical porcine pestivirus in piglets suffering from congenital tremor type A-II in Sweden and the Nordic countries. The virus has been present in the Swedish pig population since at least 2004.

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Detection and localization of atypical porcine pestivirus in the testicles of naturally infected, CT-affected piglets

10.22541/au.162720952.23003932/v1 ◽

2021 ◽

Author(s):

Lilla Dénes ◽

Inés Ruedas-Torres ◽

Anna Szilasi ◽

Gyula Balka

Keyword(s):

Target Cells ◽

Cellular Targets ◽

Newborn Piglets ◽

The Family ◽

High Prevalence ◽

Infected Adult ◽

Detection And Localization ◽

Congenital Tremor

Atypical porcine pestivirus (APPV) belongs to the genus Pestivirus within the family Flaviviridae. Recently, APPV has been identified as the causative agent of congenital tremor (CT) type AII. The disease is a neurological disorder that affects newborn piglets and is characterized by mostly generalized trembling of the animals and often splay legs. CT is well known worldwide, and the virus seems to be highly prevalent in major swine producing areas. However, little is known about the epidemiology of the infection, the transmission and spread of the virus between herds. Here, we show the high prevalence of APPV in processing fluid samples collected from Hungarian pig herds which led us to investigate the cellular targets of the virus in the testicles of newborn piglets affected by CT. By the development of an RNA in situ hybridization assay and the use of immunohistochemistry on consecutive slides, we identified the target cells of APPV in the testicle: interstitial Leydig cells, peritubular myoid cells and endothelial cells of medium-sized arteries. Previous studies have shown that APPV can be found in the semen of sexually mature boars suggesting the role of infected boars and their semen in the transmission of the virus similar to many other members of the Flaviviridae family. As in our case, the virus has not been identified in cells beyond the blood-testis barrier, further studies on infected adult boars’ testicles are needed to analyze the possible changes in the cell tropism that enable the virus to be excreted by the semen.

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Author response for "Evolution and genetic diversity of atypical porcine pestivirus (APPV) from piglets with congenital tremor in Guangxi Province, Southern China"

10.1002/vms3.407/v2/response1 ◽

2020 ◽

Author(s):

Kaichuang Shi ◽

Shouyu Xie ◽

Wenchao Sun ◽

Huixin Liu ◽

Jing Zhao ◽

...

Keyword(s):

Genetic Diversity ◽

Southern China ◽

Author Response ◽

Guangxi Province ◽

Congenital Tremor

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Review for "Evolution and genetic diversity of atypical porcine pestivirus (APPV) from piglets with congenital tremor in Guangxi Province, Southern China"

10.1002/vms3.407/v1/review2 ◽

2020 ◽

Keyword(s):

Genetic Diversity ◽

Southern China ◽

Guangxi Province ◽

Congenital Tremor

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Pestivirus K (Atypical Porcine Pestivirus): Update on the Virus, Viral Infection, and the Association with Congenital Tremor in Newborn Piglets

Viruses ◽

10.3390/v12080903 ◽

2020 ◽

Vol 12 (8) ◽

pp. 903 ◽

Cited By ~ 1

Author(s):

Alais M. Dall Agnol ◽

Alice F. Alfieri ◽

Amauri A. Alfieri

Keyword(s):

Immune Response ◽

Viral Infection ◽

Type A ◽

Prevention Measures ◽

Pig Production ◽

Newborn Piglets ◽

The Family ◽

Control And Prevention ◽

And Control ◽

Congenital Tremor

The atypical porcine pestivirus (APPV) belongs to the species Pestivirus K of the genus Pestivirus and the family Flaviviridae, and it has been associated with congenital tremor (CT) type A-II in newborn piglets. Although APPV was discovered in 2015, evidence shows that APPV has circulated in pig herds for many years, at least since 1986. Due to the frequently reported outbreaks of CT on different continents, the importance of this virus for global pig production is notable. Since 2015, several studies have been conducted to clarify the association between APPV and CT. However, some findings regarding APPV infection and the measures taken to control and prevent the spread of this virus need to be contextualized to understand the infection better. This review attempts to highlight advances in the understanding of APPV associated with type A-II CT, such as etiology, epidemiology, diagnosis, and control and prevention measures, and also describes the pathophysiology of the infection and its consequences for pig production. Further research still needs to be conducted to elucidate the host’s immune response to APPV infection, the control and prevention of this infection, and the possible development of vaccines.

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Evolution and genetic diversity of atypical porcine pestivirus (APPV) from piglets with congenital tremor in Guangxi province, Southern China

10.21203/rs.3.rs-17589/v1 ◽

2020 ◽

Author(s):

Kaichuang Shi ◽

Shou-yu Xie ◽

Jing Zhao ◽

Hui-xin Liu ◽

Yan-wen Yin ◽

...

Keyword(s):

Genetic Diversity ◽

Amino Acid ◽

Complete Genome ◽

Southern China ◽

Amino Acid Identity ◽

Genomic Sequences ◽

Guangxi Province ◽

Acid Identity ◽

Congenital Tremor ◽

Complete Genomic

Abstract Background: Atypical porcine pestivirus (APPV) was identified and associated with congenital tremor (CT) type A-II in new born piglets and has been reported in many countries around the world since 2015. In China, the first APPV infection in swine herds was reported in Guangdong province in 2016. To investigate the genetic characteristics of APPV from Guangxi province seated in Southern China, the full-length sequences of APPV strains were amplified and analyzed. Results: Tissue samples from neonatal piglets with CT from Guangxi province were detected by reverse transcription-polymerase chain reaction (RT-PCR). APPV positive samples were amplified, cloned and sequenced, and the complete genomic sequences of five APPV strains were obtained. Sequence analysis revealed that all six APPV strains from Guangxi province, including five strains from this study and one from other researchers, shared 83.3%-97.5% nucleotide identity of complete genome and 91.7%-99.1% amino acid identity of open reading frame (ORF) with one another, and shared 77.7%-97.7% nucleotide identity of complete genome and 90.6%-99.3% amino acid identity of ORF with other reference strains available in Genbank. Phylogenetic analysis indicated that the APPV strains from Guangxi province belonged to four different subgroups in the phylogenetic tree based on the complete genomic sequences, and similar topology was observed in the phylogenetic trees based on N pro , E rns and E2 gene sequences, respectively. No sign of recombination was observed for strains from Guangxi province by using Recombination Detection Program 4 (RDP4) and Simplot analysis. Evolution analysis performed on the complete genome of 58 APPV strains available in Genbank showed that APPV strains from America, Europe and Asia during 2006-2019 evolved at a mean rate of 1.37×10 -4 substitutions/site/year, and the most recent common ancestor ( tMRCA ) of them was estimated as 1700.5 years ago. Conclusions: The findings of this study indicated that there existed a high degree of genetic diversity of APPV from Guangxi province, Southern China, which provided important information on the epidemiological features and evolutionary relationships of APPV.

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Long-Term Circulation of Atypical Porcine Pestivirus (APPV) within Switzerland

Viruses ◽

10.3390/v11070653 ◽

2019 ◽

Vol 11 (7) ◽

pp. 653 ◽

Cited By ~ 7

Author(s):

Cindy Kaufmann ◽

Hanspeter Stalder ◽

Xaver Sidler ◽

Sandra Renzullo ◽

Corinne Gurtner ◽

...

Keyword(s):

Diagnostic Tests ◽

Viral Genome ◽

The United States ◽

Rt Pcr ◽

Pcr Assay ◽

Newborn Piglets ◽

Virus Prevalence ◽

Virus Diversity ◽

Congenital Tremor

In 2015, a new pestivirus was described in pig sera in the United States. This new “atypical porcine pestivirus” (APPV) was later associated with congenital tremor (CT) in newborn piglets. The virus appears to be distributed worldwide, but the limited knowledge of virus diversity and the use of various diagnostic tests prevent direct comparisons. Therefore, we developed an APPV-specific real-time RT-PCR assay in the 5′UTR of the viral genome to investigate both retro- and prospectively the strains present in Switzerland and their prevalence in domestic pigs. Overall, 1080 sera obtained between 1986 and 2018 were analyzed, revealing a virus prevalence of approximately 13% in pigs for slaughter, whereas it was less than 1% in breeding pigs. In the prospective study, APPV was also detected in piglets displaying CT. None of the samples could detect the Linda virus, which is another new pestivirus recently reported in Austria. Sequencing and phylogenetic analysis revealed a broad diversity of APP viruses in Switzerland that are considerably distinct from sequences reported from other isolates in Europe and overseas. This study indicates that APPV has already been widely circulating in Switzerland for many years, mainly in young animals, with 1986 being the earliest report of APPV worldwide.

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