Suid Herpesvirus Type Research Articles

Human viral encephalitis associated with suid herpesvirus 1.

BackgroundSuid herpesvirus type 1 (SHV1) is a type of neurotropic virus able to infect various species. However, the clinical cases of human SHV1 encephalitis are still rarely reported, and the clinical characteristics, treatment, and prognosis of human SHV1 encephalitis are still unclear.MethodsIn this study, we reported 2 cases of human encephalitis associated with SHV1 infection and reviewed the other 18 cases from the literatures. A total of 20 cases with human SHV1 encephalitis were summarized and re-analyzed.ResultsNineteen of 20 patients had a history of swine-related occupational exposure before illness onset. All patients initially presented with influenza-like symptoms and then developed seizures, disturbed consciousness, and endophthalmitis. All patients with clinical outcome of modified Rankin Scale of 5 or 6 suffered from rapid progressive respiratory failure. The results of cerebrospinal fluid (CSF) indicated aseptic or viral infection. MRI findings of SHV1 encephalitis were prone to distribute in temporal-frontal and insular cortex, which was similar to the pattern of herpes simplex virus encephalitis, while some cases with involvements of gray matter nuclei had a high rate of mortality. Metagenomic next-generation sequencing (mNGS) revealed that all patients had unique SHV1 sequences with variable reads in the CSF.ConclusionsThe variant SHV1 can cause a new type of human viral encephalitis, characterized by acute, fulminating, and catastrophic central nervous system infection. Rapid progressive respiratory failure and extensive lesions of deep gray matter nuclei might be indicators to poor prognosis. No approved treatments for the encephalitis are available, but it is possible to diagnose encephalitis quickly by mNGS.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10072-021-05633-0.

Utjecaj imunomodulatora virusnog ili bakterijskog podrijetla i cjepiva protiv bolesti Aujeszkoga na udio B limfocita periferne krvi na tovljenu prasad

The consequences of infection by Suid herpesvirus type 1 (SuHV-1) that causes Aujeszky’s disease (AD) are well studied, however, the effects of immunomodulators (IMs) of microbial origin (viral and bacterial) when administered solely or in combination with the attenuated SuHV-1 vaccine are less known. The effects of parenteral administration of IMs, inactivated Parapoxvirus ovis (P. ovis) or a combination of inactivated Propionibacterium granulosum (P. granulosum) and detoxified Escherichia coli lipopolysaccharide (LPS) and attenuated SuHV-1, strain Bartha, on the proportion of peripheral blood CD3- CD21+ B cells were analysed in 30 crossbred, 3-month old pigs using flow cytometry (FCM). Specific antibodies for gE and gB of SuHV- 1 were detected using the enzyme-linked immunosorbent assay (ELISA). Data were compared among six experimental groups: (1) pigs that separately received the vaccine, (2) IM of bacterial origin, (3) IM of viral origin, (4) simultaneous administration of the vaccine and bacterial IM, (5) simultaneous administration of the vaccine and viral IM, and (6) the control group of untreated pigs. Comparison of B cell proportions and the detection of specific antibodies in blood samples of vaccinated pigs on Day 11 of the experiment showed a transient decrease in B cell contents, though this could not be assumed to be related since the control group showed a decrease in B cell proportion on the same day. The results showed that the use of IMs alone or in combination with the attenuated SuHV-1 vaccine did not have a significant impact on the proportion of peripheral blood B cells in growing pigs.

From Severe Herpes Zoster to Rare Suid Herpesvirus Encephalitis: A New Twist of the Varicellovirus Genus Infection in Patients with Kidney Diseases.

Both the herpes zoster virus and suid herpesvirus type 1 (SuHV-1) belong to the Varicellovirus genus of the α-herpesviridae subfamily. They may cause opportunistic infections especially in patients with kidney diseases, varying from latent illness to overt lethality. Under these circumstances, impaired renal function is both the culprit for and victim of the infection. However, fulminant eruption of severe skin herpes zoster in lupus nephritis (LN) patients under prolonged immunosuppressive therapy is rare and even more rarely seen is the SuHV-1 encephalitis in human.Facing the evolution of these rare infections, we hence chose to review the clinical pathogenicity of these two viruses which were cognate in origin but distinct in virulence. As such, we began with the first of the two above viral diseases and proceeded with peculiar renal involvement, unique clinical symptoms and pertinent lethal risk. Of importance, LN was used to exemplify the reciprocally detrimental interactions between impaired renal function and suppressed immune response. Then in a manner similar to the gradient overlay, SuHV-1 encephalitis was discussed focusing on its neurotropic features, specific MRI findings and exclusive test of high throughput sequencing.Our report highlighted novel presentations of the Varicellovirus genus infection by providing a productive multidisciplinary communication with pointed disclosure of the renal involvement. It may therefore be of great medical relevance and educational value for clinicians, especially the unseasoned ones, to foresee and manage similar cases in susceptible patients.

First isolation and molecular characterization of Suid herpesvirus type 1 from a domestic dog in Argentina.

Since Aujeszky`s disease (pseudorabies), which is caused by Suid herpesvirus type 1 (SuHV-1), was first notified in Argentina in 1978, many SuHV-1 strains have been isolated from swine. However, this disease can affect other vertebrates, such as dogs (secondary hosts), and lead to fatal neurological disease. The objective of the current work is to report the first isolation and molecular characterization of SuHV-1 from a dead domestic dog from Santa Fe Province (Argentina), which had had nervous signs compatible with pseudorabies. Samples of brain and trigeminal ganglia from this dog were obtained and fixed in formol for histopathology, and virology studies were conducted after cell disruption. Supernatants of both samples were inoculated onto RK13 cells and, after 72 h, DNA was extracted with phenol-chloroform. Purified DNA was cut with a restriction enzyme and subjected to agarose gel and an aliquot was used to amplify the gD and gC genes by PCR. The gC sequence was compared with other public sequences. The strain isolated from the dog was similar to other Argentinean swine strains.

Antiviral activity of lambda-carrageenan prepared from red seaweed (Gigartina skottsbergii) against BoHV-1 and SuHV-1

The antiviral effect of polysaccharides has been known for many years. Carrageenans are considered a good alternative for the prevention of a wide range of diseases, mainly caused by enveloped viruses. The advantages lie on their high availability, low cost and low induction of resistance. The aim of this study was to evaluate the sensitivity of two viral pathogens of veterinary interest to the presence of lambda-carrageenan. This is the first report of a lambda-carrageenan having antiviral activity against animal viruses belonging to the Alphaherpesvirinae subfamily, BoHV-1 (bovine herpesvirus type 1) strain Cooper and SuHV-1 (suid herpesvirus type 1) strain Bartha. Lambda-carrageenan was able to reduce infectivity of both viruses with a more pronounced effect against BoHV-1. These results proved, as previously shown for human herpes virus type 1, that these compounds could be used as potential antiviral agents in the veterinary field.

The Role of Viral and Host MicroRNAs in the Aujeszky’s Disease Virus during the Infection Process

Porcine production is a primary market in the world economy. Controlling swine diseases in the farm is essential in order to achieve the sector necessities. Aujeszky’s disease is a viral condition affecting pigs and is endemic in many countries of the world, causing important economic losses in the swine industry. microRNAs (miRNAs) are non-coding RNAs which modulates gene expression in animals, plants and viruses. With the aim of understanding miRNA roles during the Aujeszky’s disease virus [ADV] (also known as suid herpesvirus type 1 [SuHV-1]) infection, the expression profiles of host and viral miRNAs were determined through deep sequencing in SuHV-1 infected porcine cell line (PK-15) and in an animal experimental SuHV-1 infection with virulent (NIA-3) and attenuated (Begonia) strains. In the in vivo approach miR-206, miR-133a, miR-133b and miR-378 presented differential expression between virus strains infection. In the in vitro approach, most miRNAs were down-regulated in infected groups. miR-92a and miR-92b-3p were up-regulated in Begonia infected samples. Functional analysis of all this over expressed miRNAs during the infection revealed their association in pathways related to viral infection processes and immune response. Furthermore, 8 viral miRNAs were detected by stem loop RT-qPCR in both in vitro and in vivo approaches, presenting a gene regulatory network affecting 59 viral genes. Most described viral miRNAs were related to Large Latency Transcript (LLT) and to viral transcription activators EP0 and IE180, and also to regulatory genes regarding their important roles in the host – pathogen interaction during viral infection.

The coelomic fluid of the sea urchin Tripneustes depressus shows antiviral activity against Suid herpesvirus type 1 (SHV-1) and rabies virus (RV)

Several studies have reported that molecules extracted from invertebrates have activity against different viruses, even against those that do not infect these organisms in their environment. One of the main mechanisms against pathogens in these organisms is the production of antimicrobial peptides. The objective of this study was to determine whether the coelomic fluid (CF) of the sea urchin Tripneustes depressus has activity against Suid herpesvirus type 1 (SHV-1) and/or rabies virus (RV). We tested the antiviral activity of CF in neutralizing assays and observed 50% inhibition against SHV-1 lytic plaque formation using 33 μg of CF, whereas 21 μg CF was sufficient to obtain more than 90% inhibition for RV. Cytotoxicity to MDBK and BHK-21 cells was found with whole CF yet was eliminated by heating at 56 or 72 °C (even when using 50 μg of heat-inactivated CF supernatant [SN or thermostable fraction]), and SN retained the antiviral effect. In both cases, the antiviral effect was direct and thermostable (SN 56 and 72 °C), and the best inhibition was observed when CF + virus was incubated prior to the addition of the cells. Therefore, the coelomic fluid of T. depressus has antiviral activity against SHV-1 and RV that is direct and stable at 72 °C. We suggest that further assays should be performed using more accurate methods to characterize new molecules with antiviral activity that may result in new drugs.

Detection and molecular characterization of Suid herpesvirus type 1 in Austrian wild boar and hunting dogs

Aujeszky's disease (AD), caused by Suid herpesvirus type 1 (SuHV-1), is an economically important disease in domestic swine. Thus, rigorous control programmes have been implemented and consecutively AD in domestic swine was successfully eradicated in many countries, including Austria. However, SuHV-1 continues to thrive in wild boar populations, as indicated by high seroprevalences in a number of European countries and by occasional cases of AD in hunting dogs.For the first time, SuHV-1 was detected in Austrian wild boar and a molecular characterization of SuHV-1 isolated from wild boar and hunting dogs was performed. Results of preliminary serological analyses suggest a regional SuHV-1 seroprevalence of over 30% in free-living and almost 70% in fenced wild boar from Eastern Austria. Molecular typing of Austrian SuHV-1 isolates of wild boar origin revealed the presence of two genetically distinct variants of SuHV-1, both capable of infecting dogs that have been exposed to infected wild boar during hunting.

Recombinant Escherichia coli heat-labile enterotoxin B subunit humoral adjuvant effect depends on dose and administration route

Information on the use of Escherichia coli heat-labile enterotoxin B subunit (LTB) as a parenteral adjuvant is scarce. We evaluate the adjuvant effect of different concentrations of recombinant LTB (rLTB), as well as the influence of administration route (intramuscular and subcutaneous) on mice immune response. The use of 10 μg/dose of rLTB as adjuvant of an inactivated vaccine composed by Suid herpesvirus type 1 (SuHV-1), used to immunize mice intramuscularly, induced the highest average titers of anti-SuHV-1 antibodies (P < 0.05). The same vaccines used subcutaneously induced lower titers of antibodies. The lower the anti-rLTB humoral response determined by ELISA, the higher was its adjuvant activity. In the challenge experiment with SuHV-1, 56% (14/25) (P < 0.05) of the animals inoculated intramuscularly and 32% (8/25) inoculated subcutaneously survived, highlighting the influence of the concentration and the route of administration of rLTB on its performance as an adjuvant. Therefore, rLTB can significantly help in the induction of immunity against SuHV-1 in mice, especially if used intramuscularly in the concentration of 10 μg/dose, representing the best cost-benefit ratio.

Studies on the aetiology of non-suppurative encephalitis in pigs

Thirty-eight natural cases of aetiologically unclear non-suppurative encephalitis in pigs were studied retrospectively. Brain samples were examined for the presence of porcine circovirus type 2 (PCV-2), porcine respiratory and reproductive...

Immunomodulation produced by a green propolis extract on humoral and cellular responses of mice immunized with SuHV-1

Despite recent technological advances in vaccine production, most the vaccines depend on the association with adjuvant substances. This work evaluated the adjuvant capacity of an ethanol extract of green propolis associated to inactivated Suid herpesvirus type 1 (SuHV-1) vaccine preparations. Mice inoculated with SuHV-1 vaccine plus aluminum hydroxide and 5 mg/dose of propolis extract presented higher levels of antibodies when compared to animals that received the same vaccine without propolis. The use of SuHV-1 vaccine with propolis extract alone did not induce significant levels of antibodies, however it was able to increase the cellular immune response, evidenced by the increase in the expression of mRNA to IFN-γ. Besides, propolis increased the percentage of protected animals against challenge with a lethal dose of SuHV-1. The effect of green propolis extract on the humoral and cellular immune responses may be exploited for the development of effective vaccines.

Vaccine-induced T cell-mediated immunity plays a critical role in early protection against pseudorabies virus (suid herpes virus type 1) infection in pigs

The aim of our study was to evaluate the relative importance of antibody and T cell-mediated immunity in protection against pseudorabies virus (suid herpes virus type 1) infection in pigs. We induced different levels of immune responses by using: (1) a modified live vaccine; (2) the same modified live vaccine with an oil-in-water (o/w) adjuvant; (3) an inactivated vaccine; and (4) the same inactivated vaccine with an o/w adjuvant. Subsequently, we challenged pigs with virulent pseudorabies virus (PRV). We demonstrated that best-protected pigs stood out by maintaining strong T cell-mediated immune (CMI) responses after challenge. Of the immune parameters tested, protection against virus shedding was correlated best with the magnitude of the IFN-gamma response of in vitro re-stimulated peripheral blood mononuclear cells (PBMC) with an additional role for PRV-specific IgG2 antibodies. The use of an o/w adjuvant resulted in higher antibody and CMI responses, in particular with an increased frequency of memory T helper blast cells of in vitro re-stimulated PBMC. However, this adjuvant-induced enhancement of the immune response had a limited additional effect on the efficacy of inactivated vaccines. This study suggests a major contribution of the CMI response in early protection against PRV infection and that PRV-induced IFN-gamma responses may serve as a suitable indicator for assessing the immune status of vaccinated pigs.

Inactivation of viruses by β-propiolactone in human cyro poor plasma and IgG concentrates

Virus inactivation by cold treatment with β-propiolactone (BPL) was investigated in human cyro poor plasma and purified IgG concentrates spiked with relevant human viruses or appropriate animal model viruses.The samples were treated with 0.1 or 0.25% BPL for 300 or 480 min, respectively. Residual infectivity was determined by standard microtitration assays on tissue culture cells. The inactivation of all viruses tested was more effective in IgG than in plasma. IgG: R1=4–5.5 log10for vesicular stomatitis virus (VSV). Semliki Forest virus (SFV), bovine virus diarrhoea virus (BVDV), murine encephalomyelitis virus (MEV), feline calicivirus (FVC), suid parvovirus (PPV), simian virus 40 (SV40); R1=2–4 log10for suid herpesvirus type 1 (SHV-1), bovine herpesvirus type 1 (BHV-1), human immunodeficiency virus type 2 (HIV-2), simian immunodeficiency virus (SIVagm3). Plasma: R1=3–5 log10for VSV, SFV, BVDV, SHV-1, MEV:R1=0–3 log10for HIV-1, SIVagm3BHV-1, FCV, PPV, SV40. After addition of SIVagm3, HIV-2, and PPV to plasma or lgG, spontaneous inactivation without further addition of BPL was observed.These results demonstrate that treatment with BPL has a limited capacity to inactivate viruses. Different inactivation kinetics were observed in plasma and IgG concentrates. Therefore, virus inactivation by BPL must be tested for individual blood products independently and should not be extrapolated from other model systems.

Inactivation of viruses by chemically and photochemically generated singlet molecular oxygen

Inactivation of viruses in blood plasma can be achieved by photodynamic procedures using methylene blue (MB) or other photoactive dyes. Singlet molecular oxygen ( 1O 2) probably contributes to the virucidal effects of photosensitization. We report the inactivation of herpes simplex virus type 1 (HSV-1) and suid herpes virus type 1 (SHV-1) by chemically generated singlet oxygen, produced by thermal decomposition of the endoperoxide of 3,3′-(1,4-naphthylidene)dipropionate (NDPO 2). We demonstrate that viruses can be inactivated by 1O 2 generated by chemiexcitation in a reaction in the dark, even in the presence of human plasma. Virus inactivation in phosphate-buffered saline (PBS) was enhanced when water was replaced by deuterium oxide (D 2O) and diminished when human plasma or quenchers (imidazole or histidine) were added. The singlet oxygen quenching activities of plasma, imidazole and histidine correlated with their inhibitory effects on virus inactivation. The production of 1O 2 was assessed by an indicator reaction: the bleaching of p-nitrosodimethylaniline (RNO) with imidazole as 1O 2 acceptor. Virus inactivation and singlet oxygen generation of NDPO 2 were compared with those of MB/light-mediated photosensitization. Based on similar amounts of 1O 2 generated by either procedure, virus inactivation by MB/light was more effective. Virus inactivation by MB/light was not affected by type I quenchers (e.g. mannitol), but was inhibited by human plasma or singlet oxygen quenchers. Furthermore, in D 2O-based PBS, virus inactivation was more effective than that in H 2O. These observations confirm that singlet oxygen is involved in virus inactivation by MB/light. Taken together, the results demonstrate that singlet oxygen produced by either procedure is virucidal. The enhanced effect of the photochemical procedure suggests that, in addition to type II, type I reactions and/or the binding affinity of the dye for the virus contribute to virus killing by MB/light.

Ribonucleotide reductase-deficient mutants of pseudorabies virus are avirulent for pigs and induce partial protective immunity.

We have mutagenized and mapped the gene encoding the large subunit of ribonucleotide reductase (RR1) in pseudorabies virus (PRV; synonyms Aujeszky's disease virus, suid herpesvirus type 1). PRV strains carrying an oligonucleotide that leads to termination of translation of the RR1 gene are avirulent for mice. We subsequently constructed a PRV strain carrying a deletion in the RR1 gene and also a PRV strain carrying both the deletion in the RR1 gene and a deletion in the glycoprotein g1 gene, which is a marker for PRV virulence. Both PRV strains were assayed for virulence and immunogenicity in pigs, the natural host for PRV. In contrast to a marker-rescued PRV strain, these RR1-deleted mutants were avirulent, were shed in very low titres in the oropharyngeal fluid by the animals, and induced low titres of neutralizing antibodies. However, protection against clinical signs after infection with virulent PRV was induced by both RR1-deleted mutants. The relative importance of viral RR and thymidine kinase enzymes for deoxynucleotide synthesis in viral replication is discussed. In addition, we discuss the potential use of RR as a target for anti-herpesviral drugs and the use of PRV strains, deleted for the RR1 gene, as vaccine strains.

Contribution of single genes within the unique short region of Aujeszky's disease virus (suid herpesvirus type 1) to virulence, pathogenesis and immunogenicity.

Pigs (3 and 10 weeks old) were infected intranasally with Aujeszky's disease virus (ADV) mutants that functionally lacked one of the non-essential genes in the unique short region of the genome (except the gene encoding the 11K protein). Virus excretion in oropharyngeal fluid and disease symptoms were monitored. Some pigs were killed to study pathogenesis, whereas others were challenged with virulent ADV 8 weeks after the primary infection. Mutants lacking protein kinase, or glycoproteins gp63 or gI showed reduced virulence, but mutants lacking gX or the 28K protein showed normal virulence. Glycoprotein gI appears to affect the tissue tropism of ADV in pigs, presumably by facilitating the spread of the virus through the central nervous system. In this study, there was no correlation between virulence and virus multiplication in either cultured cells or in the oropharynx in vivo. All mutants induced neutralizing antibody and complete or partial protection against challenge infection. Complete protection was obtained by inoculation with the gI and gX mutants, whereas incomplete protection was obtained using gp63 and protein kinase mutants. Complete clinical and virological protection was associated with the absence of secondary antibody responses in the serum.

The antiviral spectrum of (E)-5-(2-bromovinyl)-2'-deoxyuridine.

The antiviral activity spectrum of (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVdU) is not restricted to herpes simplex virus type 1 (HSV-1) and varicella-zoster virus (VZV) but also encompasses several other herpesviruses such as suid herpesvirus type 1 (SHV-1), bovid herpesvirus type 1 (BHV-1), simian varicella virus (SVV), herpesvirus saimiri, herpesvirus platyrrhinae, and the baculovirus Trichoplusia ni multiple nuclear polyhedrosis virus. Other herpesviruses such as herpes simplex virus type 2, cytomegalovirus and Epstein-Barr virus are also inhibited by BVdU, albeit to a lesser extent than HSV-1, VZV, SHV-1, BHV-1 and SVV.