The Impact of Social Determinants of Health on Presentation, Treatment, and Outcomes in Branch Retinal Vein Occlusion With Cystoid Macular Edema.

BACKGROUND AND OBJECTIVE: To investigate the impact of social determinants of health on the presentation, treatment, and outcomes of branch retinal vein occlusion (BRVO) with cystoid macular edema (CME). PATIENTS AND METHODS: A retrospective chart review was conducted of patients with BRVO and CME treated with anti-vascular endothelial growth factor (anti-VEGF) injections at Atrium Health Wake Forest Baptist from 2013 to 2021. Patients' baseline characteristics including visual acuity (VA), age, sex, race, Area Deprivation Index (ADI), insurance status, baseline central macular thickness (CMT), treatment details, final VA, and final CMT were recorded. The primary outcome measure was final VA comparing more and less deprived groups, and White and non-White groups. RESULTS: Two hundred forty-four eyes of 240 patients were included. Patients with higher socioeconomic deprivation scores had thicker final CMT (P = 0.05). Non-White patients had worse presenting (P = 0.01) and final VA (P = 0.02). CONCLUSION: This study demonstrated disparities in presentation and outcomes based on socioeconomic status and race in patients with BRVO and CME treated with anti-VEGF therapy. [Ophthalmic Surg Lasers Imaging Retina 2023;54:411-416.].

Assessing the effects of medium-chain fatty acids and fat sources on PEDV infectivity.

The overall objective of this study was to compare the efficacy of medium-chain fatty acids (MCFA) to other common fat sources to minimize the risk of porcine epidemic diarrhea virus (PEDV) cross-contamination in a pig bioassay. Treatments were feed with mitigants inoculated with PEDV after application and were: 1) positive control with no chemical treatment; 2) 0.325% commercially available formaldehyde-based product; 3) 1% blend of 1:1:1 caproic (C6), caprylic (C8), and capric acids (C10) and applied with an aerosolizing nozzle; 4) treatment 3 applied directly into the mixer without an aerosolizing nozzle; 5) 0.66% caproic acid; 6) 0.66% caprylic acid; 7) 0.66% capric acid; 8) 0.66% lauric acid; 9) 1% blend of 1:1 capric and lauric acids; 10) 0.3% commercially available dry C12 product; 11) 1% canola oil; 12) 1% choice white grease; 13) 2% coconut oil; 14) 1% coconut oil; 15) 2% palm kernel oil; 16) 1% palm kernel oil; 17) 1% soy oil and four analysis days (0, 1, 3, and 7 post inoculation) as well as 1 treatment of PEDV-negative feed without chemical treatment. There was a treatment × day interaction (P < 0.002) for detectable PEDV RNA. The magnitude of the increase in Ct value from d 0 to 7 was dependent upon the individual treatments. Feed treated with individual MCFA, 1% MCFA blend, or commercial-based formaldehyde had fewer (P < 0.05) detectable viral particles than all other treatments. Commercial-based formaldehyde, 1% MCFA, 0.66% caproic, 0.66% caprylic, and 0.66% capric acids had no evidence of infectivity 10-d old pig bioassay, while there was no evidence the C12 commercial product or longer chain fat sources inhibited PEDV infectivity. Interestingly, pigs given the coconut oil source with the highest composition of caprylic and capric only showed signs of infectivity on the last day of bioassay. These data suggest some MCFA have potential for reducing post feed manufacture PEDV contamination.

Resistance to coronavirus infection in amino peptidase N-deficient pigs.

The alphacoronaviruses, transmissible gastroenteritis virus (TGEV) and Porcine epidemic diarrhea virus (PEDV) are sources of high morbidity and mortality in neonatal pigs, a consequence of dehydration caused by the infection and necrosis of enterocytes. The biological relevance of amino peptidase N (ANPEP) as a putative receptor for TGEV and PEDV in pigs was evaluated by using CRISPR/Cas9 to edit exon 2 of ANPEP resulting in a premature stop codon. Knockout pigs possessing the null ANPEP phenotype and age matched wild type pigs were challenged with either PEDV or TGEV. Fecal swabs were collected daily from each animal beginning 1 day prior to challenge with PEDV until the termination of the study. The presence of virus nucleic acid was determined by PCR. ANPEP null pigs did not support infection with TGEV, but retained susceptibility to infection with PEDV. Immunohistochemistry confirmed the presence of PEDV reactivity and absence of TGEV reactivity in the enterocytes lining the ileum in ANPEP null pigs. The different receptor requirements for TGEV and PEDV have important implications in the development of new genetic tools for the control of enteric disease in pigs.

Identification of BVDV2b and 2c subgenotypes in the United States: Genetic and antigenic characterization.

Bovine viral diarrhea virus (BVDV), a ubiquitous pathogen of cattle, causes subclinical to severe acute disease. Two species of BVDV are recognized, BVDV1 and BVDV2 with BVDV1 divided into at least 21 subgenotypes and BVDV2 into 3-4 subgenotypes, most commonly using sequences from the 5' untranslated region (5' UTR). We report genomic sequencing of 8 BVDV2 isolates that did not segregate into the 2a subgenotype; but represented two additional BVDV2 subgenotypes. One BVDV2 subgenotype was previously recognized only in Asia. The other seven viruses fell into a second subgenotype that was first reported in Brazil and the U.S. in 2002. Neutralization assays using antiserum raised against vaccine strain BVDV2a 296c revealed varying degrees of neutralization of genetically diverse BVDV2 isolates. Neutralization titers decreased from 1.8 to more than a four log(2) decrease. This study illustrated the considerable genetic and antigenic diversity in BVDV2 circulating in the U.S.

Fecal Microbiota Transplantation Is Associated With Reduced Morbidity and Mortality in Porcine Circovirus Associated Disease.

Porcine circovirus associated disease (PCVAD) is a term used to describe the multi-factorial disease syndromes caused by porcine circovirus type 2 (PCV-2), which can be reproduced in an experimental setting through the co-infection of pigs with PCV-2 and porcine reproductive and respiratory syndrome virus (PRRSV). The resulting PCVAD-affected pigs represent a subpopulation within the co-infected group. In co-infection studies, the presence of increased microbiome diversity is linked to a reduction in clinical signs. In this study, fecal microbiota transplantation (FMT) was investigated as a means to prevent PCVAD in pigs co-infected with PRRSV and PCV-2d. The sources of the FMT material were high-parity sows with a documented history of high health status and robust litter characteristics. The analysis of the donated FMT material showed the absence of common pathogens along with the presence of diverse microbial phyla and families. One group of pigs (n = 10) was administered the FMT while a control group (n = 10) was administered a sterile mock-transplant. Over the 42-day post-infection period, the FMT group showed fewer PCVAD-affected pigs, as evidenced by a significant reduction in morbidity and mortality in transplanted pigs, along with increased antibody levels. Overall, this study provides evidence that FMT decreases the severity of clinical signs following co-infection with PRRSV and PCV-2 by reducing the prevalence of PCVAD.

Whole Genome Classification and Phylogenetic Analyses of Rotavirus B strains from the United States.

Rotaviruses (RVs) are a major etiological agent of acute viral gastroenteritis in humans and young animals, with rotavirus B (RVB) often detected in suckling and weaned pigs. Group A rotavirus classification is currently based on the two outer capsid proteins, VP7 and VP4, and the middle layer protein, VP6. Using RVB strains generated in this study and reference sequences from GenBank, pairwise identity frequency graphs and phylogenetic trees were constructed for the eleven gene segments of RVB to estimate the nucleotide identity cutoff values for different genotypes and determine the genotype diversity per gene segment. Phylogenetic analysis of VP7, VP4, VP6, VP1–VP3, and NSP1–NSP5 identified 26G, 5P, 13I, 5R, 5C, 5M, 8A, 10N, 6T, 4E, and 7H genotypes, respectively. The analysis supports the previously proposed cutoff values for the VP7, VP6, NSP1, and NSP3 gene segments (80%, 81%, 76% and 78%, respectively) and suggests new cutoff values for the VP4, VP1, VP2, VP3, NSP2, NSP4, and NSP5 (80%, 78%, 79%, 77% 83%, 76%, and 79%, respectively). Reassortment events were detected between the porcine RVB strains from our study. This research describes the genome constellations for the complete genome of Group B rotaviruses in different host species.

Molecular detection and characterization of transient bovine viral diarrhea virus (BVDV) infections in cattle commingled with ten BVDV persistently infected cattle.

Fifty-three cattle of unknown serologic status that were not persistently infected (PI) with bovine viral diarrhea virus (BVDV) were commingled with 10 cattle that were PI with different strains of BVDV, and were monitored for an extended commingle period using a reverse-transcription real-time PCR (RT-rtPCR) BVDV assay on various sample types. Transient infections with BVDV were also assessed by virus isolation, virus neutralization (VN) assays, and direct buffy coat 5'-UTR sequencing. Infections were demonstrated in all cattle by RT-rtPCR; however, the detection rate was dependent on the type of sample. Buffy coat samples demonstrated a significantly greater number of positive results ( p ≤ 0.05) than either serum or nasal swab samples. Presence of elevated BVDV VN titers at the onset inversely correlated with the number of test days positive that an individual would be identified by RT-rtPCR from buffy coat samples, and directly correlated with the average Ct values accumulated over all RT-rtPCR test days from buffy coat samples. Both single and mixed genotype/subgenotype/strain infections were detected in individual cattle by direct sample 5'-UTR sequencing. A BVDV-2a strain from a PI animal was found to be the predominant strain infecting 64% of all non-PI cattle; BVDV-1b strains originating from 3 PI cattle were never detected in non-PI cattle. Although direct sample 5'-UTR sequencing was capable of demonstrating mixed BVDV infections, identifying all strains suspected was not always efficient or possible.

Trypsin-independent porcine epidemic diarrhea virus US strain with altered virus entry mechanism.

BACKGROUND: Porcine Epidemic Diarrhea Virus (PEDV) is a coronavirus that infects the intestinal tract and causes diarrhea and vomiting in older pigs or extreme dehydration and death that could reach 100% mortality in neonatal piglets. In the US, the first PEDV outbreaks occurred in 2013 and since then US PEDV strains have quickly spread throughout the US and worldwide, causing significant economic and public health concerns. Currently two conditionally approved vaccines exist in the US, but there is no live attenuated vaccine, which is considered the best option in controlling PEDV by inducing transferrable mucosal immunity to susceptible neonatal piglets. In this study, we passaged an US PEDV isolate under various conditions to generate three strains and characterized their growth and antigenicity in cell culture using various assays including Western blot analysis, serum neutralization assay, sequencing analysis and confocal microscopy. Finally, these strains were evaluated for pathogenicity in nursing piglets (1-4 days old). RESULTS: One of the PEDV strains generated in this study (designated as PEDV 8aa) is able to replicate in cells without any protease and grows to a high titer of >8 log10 TCID50/ml in cell culture. Interestingly, replication of PEDV 8aa was severely reduced by trypsin and this correlated with the inhibition of virus attachment and entry into the cells. In neonatal nursing piglets, PEDV 8aa (passage number 70 or 105) was found to be fully attenuated with limited virus shedding. CONCLUSIONS: These results suggest that applying selective pressure during viral passages can facilitate attainment of viral attenuation and that PEDV 8aa warrants further investigation as an attenuated vaccine.

Tissue localization, shedding, virus carriage, antibody response, and aerosol transmission of Porcine epidemic diarrhea virus following inoculation of 4-week-old feeder pigs.

We determined tissue localization, shedding patterns, virus carriage, antibody response, and aerosol transmission of Porcine epidemic diarrhea virus (PEDV) following inoculation of 4-week-old feeder pigs. Thirty-three pigs were randomly assigned to 1 of 3 groups for the 42-day study: inoculated (group A; n = 23), contact transmission (group B; n = 5), and aerosol transmission (group C; n = 5). Contact transmission occurred rapidly to group B pigs whereas productive aerosol transmission failed to occur to group C pigs. Emesis was the first clinical sign noted at 3 days postinoculation (dpi) followed by mild to moderate diarrhea lasting 5 more days. Real-time PCR detected PEDV in fecal and nasal swabs, oral fluids, serum, and gastrointestinal and lymphoid tissues. Shedding occurred primarily during the first 2 weeks postinoculation, peaking at 5-6 dpi; however, some pigs had PEDV nucleic acid detected in swabs collected at 21 and 28 dpi. Antibody titers were measurable between 14 and 42 dpi. Although feces and intestines collected at 42 dpi were PEDV negative by PCR and immunohistochemistry, respectively, small intestines from 70% of group A pigs were PCR positive. Although disease was relatively mild and transient in this age group, the results demonstrate that 4-week-old pigs are productively infected and can sustain virus replication for several weeks. Long-term shedding of PEDV in subclinically affected pigs should be considered an important source for PEDV transmission.

Evaluation of the minimum infectious dose of porcine epidemic diarrhea virus in virus-inoculated feed.

OBJECTIVE To determine the minimum infectious dose of porcine epidemic diarrhea virus (PEDV) in virus-inoculated feed. ANIMALS 30 crossbred 10-day-old pigs. PROCEDURES Tissue culture PEDV was diluted to form 8 serial 10-fold dilutions. An aliquot of stock virus (5.6 × 10(5) TCID50/mL) and each serial PEDV dilution were mixed into 4.5-kg batches of feed to create 9 PEDV-inoculated feed doses; 1 virus-negative dose of culture medium in feed was also created. Pigs were challenge exposed via oral administration of PEDV-inoculated feed, and fecal swab specimens were collected. All pigs were euthanized 7 days after challenge exposure; fresh tissues were collected and used for PCR assay, histologic examination, and immunohistochemical analysis. RESULTS The PCR cycle threshold (Ct) decreased by approximately 10 when PEDV was added to feed, compared with results for equivalent PEDV diluted in tissue culture medium. Pigs became infected with PEDV when challenge exposed with the 4 highest concentrations (lowest concentration to cause infection, 5.6 × 10(1) TCID50/g; Ct = 27 in tissue culture medium and 37 in feed). CONCLUSIONS AND CLINICAL RELEVANCE In this study, PEDV in feed with detectable Ct values of 27 to 37 was infective. The Ct was 37 for the lowest infective PEDV dose in feed, which may be above the limit of detection established for PEDV PCR assays used by some diagnostic laboratories. Overall, results indicated 5.6 × 10(1) TCID50/g was the minimum PEDV dose in feed that can lead to infection in 10-day-old pigs under the conditions of this study.

Experimental infection of conventional nursing pigs and their dams with Porcine deltacoronavirus.

Porcine deltacoronavirus (PDCoV) is a newly identified virus that has been detected in swine herds of North America associated with enteric disease. The aim of this study was to demonstrate the pathogenicity, course of infection, virus kinetics, and aerosol transmission of PDCoV using 87 conventional piglets and their 9 dams, including aerosol and contact controls to emulate field conditions. Piglets 2-4 days of age and their dams were administered an oronasal PDCoV inoculum with a quantitative real-time reverse transcription (qRT)-PCR quantification cycle (Cq) value of 22 that was generated from a field sample having 100% nucleotide identity to USA/Illinois121/2014 determined by metagenomic sequencing and testing negative for other enteric disease agents using standard assays. Serial samples of blood, serum, oral fluids, nasal and fecal swabs, and tissues from sequential autopsy, conducted daily on days 1-8 and regular intervals thereafter, were collected throughout the 42-day study for qRT-PCR, histopathology, and immunohistochemistry. Diarrhea developed in all inoculated and contact control pigs, including dams, by 2 days post-inoculation (dpi) and in aerosol control pigs and dams by 3-4 dpi, with resolution occurring by 12 dpi. Mild to severe atrophic enteritis with PDCoV antigen staining was observed in the small intestine of affected piglets from 2 to 8 dpi. Mesenteric lymph node and small intestine were the primary sites of antigen detection by immunohistochemistry, and virus RNA was detected in these tissues to the end of the study. Virus RNA was detectable in piglet fecal swabs to 21 dpi, and dams to 14-35 dpi.

Highly diverse posaviruses in swine faeces are aquatic in origin.

Posaviruses are a group of highly divergent viruses identified in swine faeces that are distantly related to other members of the order Picornavirales. Eighteen posavirus genomes were assembled from 10 out of 25 (40 %) faecal-swab pools collected from healthy adult swine. Phylogenetic analysis of the conserved RNA-dependent RNA polymerase (Pol) domain found that posaviruses form a large, highly diverse, monophyletic clade, which includes similar viruses identified in human (husavirus) and fish (fisavirus) faeces or intestinal contents, respectively. Quantitative reverse transcription PCR analysis of water samples collected from commercial swine barns identified four out of 19 (21 %) samples were positive using a 5'-nuclease assay targeting the Pol region of posavirus 1. ICPD (immunoprecipitation coupled to PCR detection) assays to explore serological evidence of posavirus infection found only a single positive sample, suggesting posaviruses do not commonly infect swine, and together these results suggests a likely aquatic host.

Ring test evaluation of the detection of influenza A virus in swine oral fluids by real-time reverse-transcription polymerase chain reaction and virus isolation.

The probability of detecting influenza A virus (IAV) in oral fluid (OF) specimens was calculated for each of 13 assays based on real-time reverse-transcription polymerase chain reaction (rRT-PCR) and 7 assays based on virus isolation (VI). The OF specimens were inoculated with H1N1 or H3N2 IAV and serially diluted 10-fold (10(-1) to 10(-8)). Eight participating laboratories received 180 randomized OF samples (10 replicates × 8 dilutions × 2 IAV subtypes plus 20 IAV-negative samples) and performed the rRT-PCR and VI procedure(s) of their choice. Analysis of the results with a mixed-effect logistic-regression model identified dilution and assay as variables significant (P < 0.0001) for IAV detection in OF by rRT-PCR or VI. Virus subtype was not significant for IAV detection by either rRT-PCR (P = 0.457) or VI (P = 0.101). For rRT-PCR the cycle threshold (Ct) values increased consistently with dilution but varied widely. Therefore, it was not possible to predict VI success on the basis of Ct values. The success of VI was inversely related to the dilution of the sample; the assay was generally unsuccessful at lower virus concentrations. Successful swine health monitoring and disease surveillance require assays with consistent performance, but significant differences in reproducibility were observed among the assays evaluated.

La probabilité de détecter le virus de l'influenza A (VIA) dans des échantillons de fluide oral (FO) a été calculée pour chacune des 13 épreuves basées sur une réaction d'amplification en chaine en temps réel utilisant la polymérase réverse (rRT-PCR) et 7 épreuves basées sur l'isolement viral (IV). Les échantillons de FO ont été inoculés avec du VIA H1N1 ou H3N2 et dilués en série par facteur de 10 (10−1 à 10−8). Huit laboratoires participants ont reçu 180 échantillons randomisés de FO (10 réplicats × 8 dilutions × 2 sous-types de VIA plus 20 échantillons témoins négatifs sans VIA) et ont réalisé la méthode de rRT-PCR et d'IV de leur choix. L'analyse des résultats à l'aide d'un modèle de régression logistique pour les effets mélangés a identifié la dilution et l'épreuve comme étant des variables significatives (P < 0,0001) pour la détection de VIA dans du FO par rRT-PCR ou IV. Le sous-type de virus n'était pas significatif pour la détection de VIA soit par rRT-PCR (P = 0,457) ou par IV (P = 0,101). Pour les épreuves rRT-PCR les valeurs seuils de cycle (Ct) augmentaient de manière constante avec la dilution mais variaient énormément. Ainsi, il n'était pas possible de prédire le succès de l'IV sur la base des valeurs de Ct. Le succès de l'IV était inversement relié à la dilution de l'échantillon; l'épreuve était généralement négative aux faibles concentrations de virus. Pour avoir du succès dans la surveillance des maladies et de la santé des porcs il est nécessaire d'avoir des épreuves avec des performances constantes, mais des différences significatives dans la reproductibilité ont été observées parmi les épreuves évaluées.(Traduit par Docteur Serge Messier).

Genomic and evolutionary inferences between American and global strains of porcine epidemic diarrhea virus.

Porcine epidemic diarrhea virus (PEDV) has caused severe economic losses both recently in the United States (US) and historically throughout Europe and Asia. Traditionally, analysis of the spike gene has been used to determine phylogenetic relationships between PEDV strains. We determined the complete genomes of 93 PEDV field samples from US swine and analyzed the data in conjunction with complete genome sequences available from GenBank (n=126) to determine the most variable genomic areas. Our results indicate high levels of variation within the ORF1 and spike regions while the C-terminal domains of structural genes were highly conserved. Analysis of the Receptor Binding Domains in the spike gene revealed a limited number of amino acid substitutions in US strains compared to Asian strains. Phylogenetic analysis of the complete genome sequence data revealed high rates of recombination, resulting in differing evolutionary patterns in phylogenies inferred for the spike region versus whole genomes. These finding suggest that significant genetic events outside of the spike region have contributed to the evolution of PEDV.

First identification of porcine parvovirus 6 in North America by viral metagenomic sequencing of serum from pigs infected with porcine reproductive and respiratory syndrome virus.

BACKGROUND: Currently, eight species in four genera of parvovirus have been described that infect swine. These include ungulate protoparvovirus 1 (classical porcine parvovirus, PPV), ungulate tetraparvovirus 2 (PPV3), ungulate tetraparvovirus 3 (which includes PPV2, porcine hokovirus, porcine partetravirus and porcine PARV4), ungulate copiparvovirus 2 (which includes PPV4 and PPV5), ungulate bocaparvovirus 2 (which includes porcine bocavirus 1, 2 and 6), ungulate bocaparvovirus 3 (porcine bocavirus 5), ungulate bocaparvovirus 4 (porcine bocavirus 7) and ungulate bocaparvovirus 5 (porcine bocavirus 3, 4-1 and 4-2). PPV6, the most recently described porcine parvovirus, was first identified in China in late 2014 in aborted pig fetuses. Prevalence of PPV6 in China was found to be similar in finishing age pigs from farms with and without evidence of swine reproductive failure. METHODS: Porcine parvovirus 6 (PPV6) was detected by sequence-independent single primer amplification (SISPA) and confirmed by overlapping and real-time PCR in the serum of porcine reproductive and respiratory virus (PRRSv) positive samples. RESULTS: Seven nearly complete genomes of PPV6 were identified in PRRSv genotype 2 positive serum samples submitted to state veterinary diagnostic laboratories in 2014. Further testing using overlapping and real-time PCR determined PPV6 to be present in 13.2 % of the serums tested. Additionally, PPV6 was present in samples from all of the geographic locations sampled encompassing nine states in the United States and one state in Mexico. The presence of PPV6 in serum indicates that the PPV6 infection is disseminated and not localized to a specific tissue type. Alignments of the near full length genomes, NS1, and capsid genes identified one of the five PPV6 isolates from China (98.6-99.5 % identity with the North American strains) to be the North American strains nearest relative. CONCLUSIONS: These results are the first to report the presence of PPV6 in North America and demonstrate that the virus is found in multiple geographic areas in the United States and in Mexico. The overall prevalence of PPV6 in PRRSv viremic animals is relatively low. Further, all of the PPV6 genomes found in North America are most closely related to a PPV6 strain first identified in 2014 in healthy pigs from the Tianjin province of China.

Discovery of a novel putative atypical porcine pestivirus in pigs in the USA.

Pestiviruses are some of the most significant pathogens affecting ruminants and swine. Here, we assembled a 11 276 bp contig encoding a predicted 3635 aa polyprotein from porcine serum with 68 % pairwise identity to that of a recently partially characterized Rhinolophus affinis pestivirus (RaPV) and approximately 25-28 % pairwise identity to those of other pestiviruses. The virus was provisionally named atypical porcine pestivirus (APPV). Metagenomic sequencing of 182 serum samples identified four additional APPV-positive samples. Positive samples originated from five states and ELISAs using recombinant APPV Erns found cross-reactive antibodies in 94 % of a collection of porcine serum samples, suggesting widespread distribution of APPV in the US swine herd. The molecular and serological results suggest that APPV is a novel, highly divergent porcine pestivirus widely distributed in US pigs.

Identification of a novel Picornavirales virus distantly related to posavirus in swine feces.

De novo assembly of metagenomic sequencing reads from feces from a clinically normal pig identified two approximately 9 kb contigs which each consisted of a single large open reading frame. While one contig encoded a predicted 2990 amino acid protein with 83 % identity to the recently described posavirus 1, the other contig encoded a predicted 2942 amino acid protein with only 25 % identity limited to the genomic region encoding the RNA-dependent RNA polymerase (RdRp) of posavirus 2. Besides RdRp, search of the conserved domain database identified domains associated with picornavirus capsid proteins but failed to identify picornaviral helicase and proteinase domains. In addition, a domain representing a family of Mycoplasma and Ureaplasma immunoglobulin-blocking virulence proteins was identified near the 5'-terminus. Phylogenetic analysis found a distant relationship between this novel virus, provisionally named posavirus 3, to the unclassified posaviruses and fisavirus which are proposed to represent different genera in a novel family of the Picornavirales.

Evaluation of porcine epidemic diarrhea virus transmission and the immune response in growing pigs.

Clinical disease associated with porcine epidemic diarrhea virus (PEDV) infection in naïve pigs is well chronicled; however, information on endemic PEDV infection is limited. To characterize chronic PEDV infection, the duration of infectious virus shedding and development of protective immunity was determined. On Day 0 (D0), a growing pig was challenged with PEDV and 13 contacts were commingled. On D7, 9 contact pigs (principal virus group (PG)), were selected, moved to a separate room and commingled with one sentinel pig (S1). This process was repeated weekly with S2, S3 and S4. The PG was PEDV-positive by PCR from D3-11, with some pigs intermittently positive to D42. Pigs S1 and S2 were PEDV-positive within 24 hours of commingling. Antibodies were detected in all PG by D21 and by 7 days post-contact in S1 and S2. Pigs S3 and S4 were PCR and antibody negative following commingling. To evaluate protective immunity, 5 naïve pigs (N) and the PG were challenged (N/C, PG/C) with homologous virus on D49. All N/C pigs were PEDV PCR-positive by D52 with detection out to D62 in 3/5 N/C pigs. All PG/C pigs were PEDV PCR-negative post-challenge. By D63, all N/C seroconverted. Although PEDV RNA was demonstrated in pigs after primary infection until D42, infectious PEDV capable of horizontal transmission to naïve pigs was only shed 14-16 days after infection to age-matched pigs. Homologous re-challenge 49 days post initial PEDV exposure did not result in re-infection of the pigs. This demonstrates potential for an effective PEDV vaccine.

Discovery of a novel nidovirus in cattle with respiratory disease.

The family Coronaviridae represents a diverse group of vertebrate RNA viruses, all with genomes greater than 26,000 nt. Here, we report the discovery and genetic characterization of a novel virus present in cattle with respiratory disease. Phylogenetic characterization of this virus revealed that it clusters within the subfamily Torovirinae, in the family Coronaviridae. The complete genome consists of only 20,261 nt and represents the smallest reported coronavirus genome. We identified seven ORFs, including the canonical nidovirus ORF1a and ORF1b. Analysis of polyprotein 1ab revealed that this virus, tentatively named bovine nidovirus (BoNV), shares the highest homology with the recently described python-borne nidoviruses and contains several conserved nidovirus motifs, but does not encode the NendoU or O-MT domains that are present in other viruses within the family Coronaviridae. In concert with its reduced genome, the atypical domain architecture indicates that this virus represents a unique lineage within the order Nidovirales.