Genome characteristics of atypical porcine pestivirus from abortion cases in Shandong Province, China.

BACKGROUND: Atypical porcine pestivirus (APPV) is a novel, highly variable porcine pestivirus. Previous reports have suggested that the virus is associated with congenital tremor (CT) type A-II in piglets, and little information is available about the correlation between the virus and sow abortion, or on coinfection with other viruses. In China, reported APPV strains were mainly isolated from South China and Central China, and data about the APPV genome from northern China are relatively scarce. METHODS: Eleven umbilical cords, one placenta, and one aborted piglet, were collected from aborted sows of the same farm in Shandong Province of northern China. Nucleic acids were extracted from the above samples, and subsequently pooled for viral metagenomics sequencing and bioinformatics analysis. The viral coexistence status and complete genome characteristics of APPV in Shandong Province were determined. RESULTS: In abortion cases, APPV was present with Getah virus, porcine picobirnavirus, porcine kobuvirus, porcine sapovirus, Po-Circo-like virus, porcine serum-associated circular virus, porcine bocavirus 1, porcine parvovirus 1, porcine parvovirus 3 and porcine circovirus 3, etc. The first complete genome sequence(11,556 nt) of APPV in Shandong Province of northern China, was obtained using viral metagenomics and designated APPV-SDHY-2022. Comparison with Chinese reference strains revealed that the polyprotein of APPV-SDHY-2022 shared 82.6-84.2%, 93.2-93.6%, and 80.7-85% nucleotide identity and 91.4-92.4%, 96.4-97.7%, and 90.6-92.2% amino acid identity with those of the Clade I, Clade II and Clade III strains, respectively. Phylogenetic analysis based on the complete polyprotein CDS and NS5A sequences concluded that APPV-SDHY-2022 belongs to Clade II. Analysis of the NS5A nucleotide sequences revealed homology of greater than 94.6% for the same isoform, 84.7-94.5% for different isoforms of the same clade and 76.8-81.1% for different clades. Therefore, Clade II was further divided into three subclades, and APPV-SDHY-2022 belonged to subclade 2.3. Members of Clade II have 20 unique amino acids in individual proteins, distinguishing them from Clade I and Clade III members. The E2 protein showed the greatest diversity of putative N-glycosylation sites with 9 patterns, and APPV-SDHY-2022 along with other Chinese APPV strains shared the conserved B-cell conformational epitope residues 39E, 70R, 173R, 190K and 191N of the E2 protein. CONCLUSIONS: We reported viral coexistence and the first complete genome sequence of APPV from abortion cases and from Shandong Province. The new APPV isolate belongs to an independent branch of Clade II. Our results increase the molecular and epidemiological understanding of APPV in China.

Isolation and Molecular Characterization of Atypical Porcine Pestivirus Emerging in China.

Atypical porcine pestivirus (APPV) is a recently discovered and very divergent species of the genus Pestivirus within the family Flaviviridae, which causes congenital tremor (CT) in newborn piglets. In this study, an APPV epidemiological investigation was conducted by studying 975 swine samples (562 tissue and 413 serum samples) collected from different parts of China from 2017 to 2021. The results revealed that the overall positive rate of the APPV genome was 7.08% (69/975), among which 50.7% (35/69) of the samples tested positive for one or more other common swine viruses, especially porcine circovirus type 2 (PCV2) with a coinfection rate of 36.2% (25/69). Subsequently, a novel APPV strain, named China/HLJ491/2017, was isolated in porcine kidney (PK)-15 cells for the first time from a weaned piglet that was infected with both APPV and PCV2. The new APPV isolate was confirmed by RT-PCR, sequencing, immunofluorescence assay, and transmission electron microscopy. After clearing PCV2, a pure APPV strain was obtained and further stably propagated in PK-15 cells for more than 30 passages. Full genome sequencing and phylogenetic analysis showed that the China/HLJ491/2017 strain was classified as genotype 2, sharing 80.8 to 97.6% of its nucleotide identity with previously published APPV strains. In conclusion, this study enhanced our knowledge of this new pestivirus and the successful isolation of the APPV strain provides critical material for the investigation of the biological and pathogenic properties of this emerging virus, as well as the development of vaccines and diagnostic reagents.

[Pestiviruses in sheep and goats in Austria: Options for integration into the bovine viral diarrhea (BVDV) monitoring program]. / Pestiviren bei Schafen und Ziegen in ­Österreich: Möglichkeiten zur ­Einbindung in die BVDV-Überwachung.

INTRODUCTION: After the successful eradication of the bovine viral diarrhea virus (BVDV) in cattle in Austria, the risk of infections with the border disease virus (BDV) remains. Both viruses belong to the pestivirus genus. BDV infections lead to false-positive results in BVDV surveillance. This can be attributed to the contact to small ruminant populations. In particular, keeping cattle together with sheep or goats on a farm or alpine pasture are significant risk factors. Between 2015 and 2022, BDV type 3 was detected in 15 cattles in Austria. These animals were almost exclusively persistently infected calves. However, a positive antibody result for pestiviruses can lead to an extremely time-consuming and costly, and not always successful search for the source of the infection if no active virus excretor is found. This study documents how small ruminants can be integrated into pestivirus monitoring with a manageable amount of work and costs. 23 406 sheep and goat samples from two brucellosis surveillance programs in small ruminants were analyzed retrospectively. Blood samples were examined using pestivirus real-time pool RT-PCR (qPCR). Direct virus detection of BDV-3 was achieved in 40 sheep from five different federal states. Over the entire investigation period a further 37 detections of BDV-3 were found in cattle, sheep and goats outside of this study throughout Austria. This study accounts for 52 % of all border disease detections from 2015 to 2022. By including small ruminants in pestivirus monitoring, the disruptive factor BDV and the risk of its introduction into cattle herds can be significantly minimized in the future.

INTRODUCTION: Après l'éradication réussie du virus de la diarrhée virale bovine (BVDV) chez les bovins en Autriche, le risque d'infections par le virus de la Border Disease (BDV) demeure. Ces deux virus appartiennent au genre des pestivirus. Les infections par le BDV entraînent des résultats faussement positifs dans la surveillance du BVDV. Ce phénomène peut être attribué aux contacts avec les populations de petits ruminants. En particulier, la détention de bovins avec des moutons ou des chèvres sur une exploitation ainsi que les pâturages alpins sont des facteurs de risque importants pour les infections. Entre 2015 et 2022, le BDV de type 3 a été détecté chez 15 bovins en Autriche. Ces animaux étaient presque exclusivement des veaux infectés de manière persistante. Cependant, un résultat positif aux anticorps contre les pestivirus peut conduire à une recherche extrêmement longue et coûteuse et pas toujours fructueuse de la source de l'infection si aucun excréteur de virus actif n'est trouvé. Cette étude montre comment les petits ruminants peuvent être intégrés dans la surveillance des pestivirus avec une quantité de travail et des coûts gérables. À cette fin, 23 460 échantillons d'ovins et de caprins provenant de deux programmes de surveillance de la brucellose chez les petits ruminants ont été utilisés de façon rétrospective. Les échantillons de sang ont été examinés à l'aide de la RT-PCR en temps réel des pestivirus (qPCR). La détection directe du virus BDV-3 a été réalisée chez 40 moutons provenant de cinq länder différents. Sur l'ensemble de la période d'investigation (2015 ­ 2022), 37 autres détections de BDV-3 ont été effectuées chez des bovins, des ovins et des caprins en dehors de cette étude, dans toute l'Autriche. Cette étude représente 52 % de toutes les détections de Border Disease entre 2015 et 2022. En incluant les petits ruminants dans la surveillance des pestivirus, le facteur de perturbation qu'est le BDV et le risque de son introduction dans les troupeaux de bovins peuvent être considérablement minimisés à l'avenir.

First detection of emerging HoBi-like Pestivirus (BVD-3) among some persistently infected dairy cattle herds in Egypt.

Bovine viral diarrhoea virus (BVDV) is a serious veterinary health concern worldwide. We conducted this study to determine the prevalence of persistent infections (PI) and identify the current strain among some dairy cattle herds in Egypt. A total of 240 serum samples were collected from six Egyptian provinces. Between 2019 and 2020, samples were tested by Enzyme linked immunosorbent assay (ELISA) for detection of PI animals, and then molecular characterization was performed. Six calves were found PI with a prevalence of 2.5% (6/240). Using molecular characterization, HoBi-like Pestivirus (BVD-3) was successfully identified in Egypt for the first time. Based on the BVD-3 reference strains on Genbank, the detected strains had an identity ranging from 98.8 to 99.6%. Partial nucleotide sequence of the 5'UTR gene for six tested samples was submitted to Genbank with accessions: OM324396, OM324397, OM324398, OM324399, OM3243100, and OM3243101.

New Emergence of the Novel Pestivirus Linda Virus in a Pig Farm in Carinthia, Austria.

Linda virus (LindaV) was first identified in a pig farm in Styria, Austria in 2015 and associated with congenital tremor (CT) type A-II in newborn piglets. Since then, only one more LindaV affected farm was retrospectively discovered 10 km away from the initially affected farm. Here, we report the recent outbreak of a novel LindaV strain in a farrow-to-finish farm in the federal state Carinthia, Austria. No connection between this farm and the previously affected farms could be discovered. The outbreak was characterized by severe CT cases in several litters and high preweaning mortality. A herd visit two months after the onset of clinical symptoms followed by a diagnostic workup revealed the presence of several viremic six-week-old nursery pigs. These animals shed large amounts of virus via feces and saliva, implying an important epidemiological role for within- and between-herd virus transmission. The novel LindaV strain was isolated and genetically characterized. The findings underline a low prevalence of LindaV in the Austrian pig population and highlight the threat when introduced into a pig herd. Furthermore, the results urge the need to better understand the routes of persistence and transmission of this enigmatic pestivirus in the pig population.

First molecular evidence of border disease virus in wild boars in Turkey.

Molecular studies on viral diseases in wildlife are limited in Turkey. Pestiviruses infect domestic animals such as pig, cattle, sheep, goats and many other wild ungulates. Cross-species transmission of pestiviruses between wildlife and domestic livestock is a subject of recent concern where wild ungulates are in close contact with domestic ruminants. The International Committee on Virus Taxonomy (ICTV) has named the genus Pestivirus, which belongs to the Flaviviridae family, using the format Pestivirus A, Pestivirus B, Pestivirus C, and so on. Pestivirus A-D replaces Bovine viral diarrhea virus-1 (BVDV-1), Bovine viral diarrhea virus-2 (BVDV-2), Classical swine fever virus (CSFV) and Border disease virus (BDV) respectively. During the 2013-2014 hunting season, a total of 40 samples were collected from wild boars (Sus scrofa ferus) in the area of Western Mediterranean Turkey. In the samples, nucleic acids were investigated for pestivirus, Aujeszky's disease virus, Borna disease virus, coronavirus, mastadenovirus and rotavirus. RT-PCR was performed using primary sets to detect specific partial gene region specific to each virus. Sequence analysis was performed on a positive sample. Phylogenetic analysis revealed that the positive sample, TR/Burdur/13/Boar3, belonged to BDV genotype 1 (Pestivirus D). The first molecular findings of BDV in wild boars in Turkey are reported in this study. This study highlights the importance of further research into diseases that might be transmitted from wild boars to ruminants in Turkey.

Detection and localization of atypical porcine pestivirus in the testicles of naturally infected, congenital tremor affected piglets.

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 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, 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 smooth muscle 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 Sertoli cell barrier, further studies on infected adult boars' testicles and other reproductive glands are needed to analyze the possible changes in the cell tropism of APPV that might contribute to its prolonged extraction by the semen beyond the period of viraemia.

Atypical porcine pestivirus-A widespread virus in the Swedish wild boar population.

The recently identified causative agent of congenital tremor in domestic piglets, atypical porcine pestivirus (APPV), was detected in serum from Swedish wild boar. A previous study from Sweden described APPV in domestic piglets suffering from congenital tremor, but the APPV situation in the wild boar population was unknown. In this study, 595 serum samples from wild boar originating from 13 counties in the south and central parts of Sweden, collected between 2000 and 2018, were analysed for the presence of the APPV-genome and for antibodies against the APPV-glycoprotein Erns . The results revealed that APPV is highly abundant in the Swedish wild boar population; 12% (73/595) were APPV-genome positive in serum and 72% (433/595) of the tested wild boars displayed APPV-specific antibodies. The present study also shows that APPV has been present in the Swedish wild boar population since at least the year 2000. The viral sequences obtained from the wild boars were highly similar to those obtained from Swedish domestic pigs positive for APPV and suffering from congenital tremor, suggesting a viral exchange between wild boars and domestic pigs. The high proportion of viraemic and seropositive wild boar is indicative of wild boar being an important reservoir for APPV.

Detection and genetic analysis of a novel atypical porcine pestivirus from piglets with congenital tremor in Japan.

Atypical porcine pestivirus (APPV), which has been confirmed to be associated with congenital tremor (CT) in pigs, is a newly discovered porcine virus that has been found in the Americas, Europe and Asia; however, no report of APPV in Japan has been published. We identified an APPV in the central nervous system of Japanese piglets with CT and firstly determined and analysed the complete genome sequence. Phylogenetic analysis using the complete genome nucleotide sequence of the Japanese APPV, named Anna/2020, and those of APPVs from the NCBI database showed that APPVs were divided into three genotypes (genotypes 1 to 3), and that Anna/2020 clustered with the genotype 3 APPV strains, but distantly branched from these strains. Pairwise complete coding region nucleotide sequence comparisons revealed that there was 94.0%- 99.7% sequence identity among the genotype 3 strains, while Anna/2020 showed 87.0%-89.3% identity to those genotype 3 strains, suggesting that Anna/2020 represents a novel APPV lineage within genotype 3. Retrospective examinations using RT-PCR revealed one genotype 1 and two novel genotype 3 APPVs from pigs without CT, and that novel genotype 3 APPVs have been prevalent in Japan since at least 2007.

Molecular characterization of recent HoBi-like pestivirus isolates from cattle showing mucosal disease-like signs in India reveals emergence of a novel genetic lineage.

Natural infections with HoBi-like pestivirus (HoBiPeV) have been detected in cattle in South America, Europe and Asia with a range of clinical manifestations including fatal mucosal disease (MD). In India, although HoBiPeV in cattle has been reported, there is no information on currently circulating HoBiPeV strains and associated severe clinical disease. Between September 2018 and December 2019, suspected cases of bovine viral diarrhoea with severe disease in cattle were noticed in farmers' small holdings in Tamil Nadu State. To determine the extent of pestivirus infection, blood, serum, nasal or oral swab samples of 46 cattle from 18 villages were tested. Based on the real-time RT-PCR, antigen ELISA and nucleotide sequencing results, pestivirus was detected in nine cattle from eight villages in two districts and all pestiviruses were identified as HoBiPeV. All nine HoBiPeV-infected cattle displayed clinical signs resembling MD and HoBiPeV isolates (n = 9) obtained were characterized at genetic and antigenic level. Phylogenetic analyses based on 5'-untranslated regions (5'-UTR), Npro and combined 5'-UTR-Npro gene sequences revealed that eight HoBiPeV isolates clustered into a clade, distinct from all reported HoBiPeV clades (a-d), whereas one belonged to HoBiPeV-d clade, thus providing evidence of emergence of a novel HoBiPeV clade (e). This was also supported by HoBiPeV-e clade-specific amino acid substitutions in Npro and the antigenic reactivity patterns. The study demonstrates the existence and independent evolution of five HoBiPeV clades (four main clades) globally and surprisingly three exclusive to India. Also we confirm first HoBiPeV occurrence in southern India with predominant prevalence of HoBiPeV-e strains. Besides demonstrating increased HoBiPeV genetic diversity, here we show association of HoBiPeV with severe clinical disease involving fatalities highlighting impact of HoBiPeV on cattle health. The emergence of a novel HoBiPeV lineage provides new insights on global HoBiPeV epidemiology and genetic diversity reiterating the need for continuous monitoring of HoBiPeV in India.

Genetic diversity and detection of atypical porcine pestivirus infections.

Atypical porcine pestivirus (APPV), an RNA virus member of the Flaviviridae family, has been associated with congenital tremor in newborn piglets. Previously reported quantitative polymerase chain reaction (qPCR)-based assays were unable to detect APPV in novel cases of congenital tremor originated from multiple farms from U.S. Midwest (MW). These assays targeted the viral polyprotein coding genes, which were shown to display substantial variation, with sequence identity ranging from 58.2% to 70.7% among 15 global APPV strains. In contrast, the 5'-untranslated region (5' UTR) was found to have a much higher degree of sequence conservation. In order to obtain the complete 5' UTR of the APPV strains originated from MW, the 5' end of the viral cDNA was obtained by using template switching approach followed by amplification and dideoxy sequencing. Eighty one percent of the 5' UTR was identical across 14 global and 5 MW strains with complete or relatively complete 5' UTR. Notably, some of the most highly conserved 5' UTR segments overlapped with potentially important regions of an internal ribosome entry site (IRES), suggesting their functional role in viral protein translation. A newly designed single qPCR assay, targeting 100% conserved 5' UTR regions across 19 strains, was able to detect APPV in samples of well documented cases of congenital tremor which originated from five MW farm sites (1-18 samples/site). As these fully conserved 5' UTR sequences may have functional importance, we expect that assays targeting this region would broadly detect APPV strains that are diverse in space and time.

Pestivirus apparent prevalence in sheep and goats in Northern Ireland: A serological survey.

BACKGROUND: Bovine viral diarrhoea virus (BVDV) and border disease virus (BDV) can cause significant health problems in ruminants and economic impacts for farmers. The aim of this study was to evaluate pestivirus exposure in Northern Ireland sheep and goat flocks, and to compare findings with a previous study from the region. METHODS: Up to 20 animals were sampled from 188 sheep and 9 goat flocks (n = 3,418 animals; 3,372 sheep and 46 goats) for pestivirus antibodies. Differentiation of the causative agent in positive samples was inferred using serum neutralisation. Abortion samples from 177 ovine cases were tested by BVDV reverse-transcription polymerase chain reaction and antigen ELISA. RESULTS: Apparent animal and flock (one antibody positive animal within a flock) prevalence was 1.7% and 17.3%, respectively, a statistically significant drop in apparent prevalence since a survey in 1999. 52.6% of samples testing positive had higher antibody titres to BVDV than to BDV. Of the ovine abortion samples, only one positive foetal fluid sample was detected by ELISA. CONCLUSION: The present study found that, since 1999, there has been a decrease in apparent animal and flock prevalence of 3.7 and 12.8 percentage points respectively, suggesting pestivirus prevalence has decreased across Northern Ireland between 1999 and 2018.

Pestivirus infections of cattle.

This focus article has been prepared by Arthur Otter, Nick Torrens and Lucy Martindale of the APHA Cattle Expert Group, Penrith Veterinary Investigation Centre and Surveillance Intelligence Unit, respectively.

Seroprevalence of pestivirus infections is low in Belgian small ruminant flocks and is significantly associated with the presence of cattle.

A study was implemented to estimate the pestivirus seroprevalence in sheep and goats in Belgium, to identify circulating species and to check for a potential association between seropositivity of small ruminants and presence of cattle in the same farm. It was based on the testing of serum samples and bulk tank milk samples (BTM) collected in sheep and goat flocks in 2018-2019 all over the country. 7460 serum samples collected from 410 flocks were tested by a commercial ELISA able to detect antibodies (Ab) against Border Disease Virus (BDV), and Bovine Viral Diarrhea Virus (BVDV). BTM samples (n = 144) were collected from dairy flocks in November 2019 and tested with the same Ab ELISA. ELISA positive serum samples were also tested by virus neutralization test (VNT) for neutralizing antibodies against BDV, BVDV-type1 and BVDV-type2. Virological tests (RT-PCR) were performed on pools of serum samples from pestivirus-exposed flocks with at least two seropositive animals and on all Antibody-positive BTM samples. Information about serum and milk samples (identification, test results, farm of origin and location, presence of cattle) were gathered in animal-level and farm-level databases. Based on this study, the apparent animal seroprevalence for pestiviruses in small ruminant flocks in Belgium in 2018 was estimated to be 0.87 % (95 % C.I. [0.68 %-1.11 %]). The prevalence of flocks exposed to pestivirus (i.e. with at least one seropositive animal) was estimated to be 8.5 % (95 % C.I. [6.4 % - 11.6 %]). In exposed flocks, the average within-flock seroprevalence was 9.9 %. In dairy sheep and goats, the estimated proportion of exposed flocks in 2019, based on the detection of pestivirus antibodies in the bulk tank milk, was 9.7 % [5.9 %-15.7 %]. All PCR tests were negative, indicating the likely absence of active pestivirus circulation in these flocks. Although the observed pestivirus seroprevalence was found to be low in Belgian small ruminants, this study also showed, based on VNT results, that they are exposed to several pestivirus species: BDV, BVDV-1 and BVDV-2. 22.4 % of the farms included in the serological survey were holding both a small ruminant flock and a cattle herd, hence with a potential risk of contact between the two species. There was a significant positive association between pestivirus seropositivity in the sheep/goat flocks and the presence of a cattle herd in the same farm (OR = 2.42 (95 %C.I. [1.18-4.94]) but this association was not found for Ab-positive BTM in dairy flocks.

Prevalence of Linda Virus Neutralizing Antibodies in the Austrian Pig Population.

A novel pestivirus species, termed Lateral-shaking Inducing Neuro-Degenerative Agent virus (LindaV), was discovered in a piglet-producing farm in Austria in 2015 related to severe congenital tremor cases. Since the initial outbreak LindaV has not been found anywhere else. In this study, we determined the seroprevalence of LindaV infections in the domestic pig population of Austria. A fluorophore labeled infectious cDNA clone of LindaV (mCherry-LindaV) was generated and used in serum virus neutralization (SVN) assays for the detection of LindaV specific neutralizing antibodies in porcine serum samples. In total, 637 sera from sows and gilts from five federal states of Austria, collected between the years 2015 and 2020, were analyzed. We identified a single serum showing a high neutralizing antibody titer, that originated from a farm (Farm S2) in the proximity of the initially affected farm. The analysis of 57 additional sera from Farm S2 revealed a wider spread of LindaV in this pig herd. Furthermore, a second LindaV strain originating from this farm could be isolated in cell culture and was further characterized at the genetic level. Possible transmission routes and virus reservoir hosts of this emerging porcine virus need to be addressed in future studies.

Distribution of Pestivirus exposure in wild ruminants in Spain.

A large-scale study was carried out to determine the prevalence of antibodies against Pestivirus species in wild ruminants and describe their spatial variation in mainland Spain. Serum samples of 1,874 wild ruminants from different regions of this country were collected between the years 2000 and 2017. A total of 6.6% (123/1,874) animals showed antibodies against Pestivirus by both blocking ELISA (bELISA) and virus neutralization tests (VNT). The prevalence of antibodies against pestiviruses was different both among species and regions. Seroprevalence by species was 30.0% (75/250) in Southern chamois (Rupicapra pyrenaica), 7.0% (25/357) in fallow deer (Dama dama), 2.5% (10/401) in red deer (Cervus elaphus), 2.4% (8/330) in Iberian wild goat (Capra pyrenaica), 1.1% (4/369) in roe deer (Capreolus capreolus) and 0.8% (1/130) in mouflon (Ovis aries musimon), not detecting seropositivity (0/37) in Barbary sheep (Ammotragus lervia). The results confirm that exposure to pestiviruses was detected throughout mainland Spain, with significantly higher seroprevalence in Northern regions associated with the presence of Southern chamois. This indicates an endemic circulation of pestiviruses in Southern chamois and a limited circulation of these viruses in the remaining wild ruminant species during the last two decades, thus suggesting that non-chamois species are not true Pestivirus reservoirs in Spain. Nonetheless, the high spatial spread of these viruses points out that new epidemic outbreaks in naïve wild ruminant populations or transmission to livestock may occur, evidencing the usefulness of monitoring pestiviruses in wild ruminants, especially at the wildlife-livestock interface.

Ruminant pestiviruses in North Africa.

Ruminant pestiviruses are widely distributed worldwide, causing congenital disease and massive economic losses. Although ruminant production is an important economic sector in North Africa, the knowledge about pestiviruses is scarce. The present study aimed at assessing the presence of Pestivirus in cattle in Algeria, and to review the data available on ruminant pestiviruses in North Africa. A cross-sectional study was conducted on dairy farms from North-Western Algeria. Blood samples from 234 dairy cattle from 31 herds were collected. All sera were analysed for the presence of antibodies using a commercial iELISA. The presence of Pestivirus RNA was also assessed by using a Reverse Transcription-PCR, and PCR-positive samples were sequenced. Risk factors related to Pestivirus infection were also analysed. The review of the presence of ruminant pestiviruses in North Africa was performed using a systematic search and compilation methodology of the peer-reviewed literature available in order to identify gaps of knowledge for future research. The seroprevalence at population and farm levels obtained in the present study (59.9% and 93.5%, respectively) concur with data reported in neighbouring countries. Risk factors associated with Pestivirus infection in cattle were the presence of sheep in the herd and the animal category (cow vs heifer). Furthermore, we confirmed the presence of BVDV-1a in Algeria. The scarce data suggest an endemic epidemiological scenario of pestivirus in livestock. The lack of studies about the epidemiology and molecular variability of ruminant pestiviruses in livestock and wildlife in North Africa is of concern for animal health and wildlife conservation, and needs to be addressed.

Atypical Porcine Pestivirus Circulation and Molecular Evolution within an Affected Swine Herd.

Atypical porcine pestivirus (APPV) is a single-stranded RNA virus from the family Flaviviridae, which is linked to congenital tremor (CT) type A-II in newborn piglets. Here, we retrospectively investigated the molecular evolution of APPV on an affected herd between 2013 and 2019. Monitoring was done at regular intervals, and the same genotype of APPV was found during the entire study period, suggesting no introductions from outside the farm. The nucleotide substitutions over time did not show substantial amino acid variation in the structural glycoproteins. Furthermore, the evolution of the virus showed mainly purifying selection, and no positive selection. The limited pressure on the virus to change at immune-dominant regions suggested that the immune pressure at the farm might be low. In conclusion, farms can have circulation of APPV for years, and massive testing and removal of infected animals are not sufficient to clear the virus from affected farms.

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

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.

Prevalence and Genetic Diversity of Atypical Porcine Pestivirus (APPV) Detected in South Korean Wild Boars.

Atypical porcine pestivirus (APPV), currently classified as pestivirus K, causes congenital tremor (CT) type A-II in piglets. Eighteen APPV strains were identified from 2297 South Korean wild boars captured in 2019. Phylogenetic analysis of the structural protein E2 and nonstructural proteins NS3 and Npro classified the APPV viruses, including reference strains, into Clades I, II and III. Clade I was divided into four subclades; however, the strains belonging to the four subclades differed slightly, depending on the tree analysis, the NS3, E2, and Npro genes. The maximum-likelihood method was assigned to South Korean wild boar APPV strains to various subclades within the three trees: subclades I.1 and I.2 in the E2 tree, subclade I.1 in the Npro tree, and subclades I.1 and I.4 in the NS3 ML tree. In conclusion, APPV among South Korean wild boars belonging to Clade I may be circulating at a higher level than among the South Korean domestic pig populations.