Detection of anti-HEV antibodies but no molecular positivity in dogs in the Campania region, southern Italy

Paslahepevirus balayani genotypes 3 and 4 (HEV-3 and 4) have zoonotic potential and can be transmitted to humans and animals through the consumption of contaminated raw or undercooked meat. Although it has been demonstrated that dogs are susceptible to the infection and produce specific antibodies, the epidemiological role of this species is not yet well defined. This study aimed to evaluate the circulation of HEV at the serological and molecular level in the dog population of the Campania region, southern Italy. A total of 231 dogs were sampled, divided according to several variables (sex, age, origin, lifestyle, location, size, and breed), and tested for the presence of HEV antibodies using a commercial multi-species ELISA. A total of 197 blood samples and 170 stool samples were tested with two specific PCRs in order to detect viral RNA. A total of 19 out samples of 231 were seropositive, obtaining an exposure (8.2%) similar to that observed in other European countries. The univariate and multivariate analysis revealed a wide exposure to stray dogs and animals from the province of Salerno. All samples tested with molecular methods were negative. Defining the role of domestic carnivores continues to be a "one health" challenge, although it appears that they do not eliminate the virus and therefore do not pose a danger to humans. In the absence of other evidence, it is advisable to continue to carry out surveillance also for domestic animals, which, due to ethological characteristics or their position in the food chain, could be predisposed to being exposed to HEV.

Reactive oxygen metabolites in alpha-herpesvirus-seropositive Mediterranean buffaloes (Bubalus bubalis): a preliminary study

In the present study on Bubalus bubalis of the Campania Region (Italy) the serum levels of derivatives of reactive oxygen metabolites (d-ROMs), anti-ROM and oxidative stress index (Osi) were evaluated. These data were then related to the seropositive status of the animals against alpha-herpesviruses, precisely Bubaline herpesvirus 1 (BuHV-1) and Bovine herpesvirus 1 (BoHV-1). Clinically healthy Mediterranean buffaloes were selected for this study. The serum samples of these animals were taken, and d-ROMs, anti-ROM and Osi were measured using commercially available tests. The preliminary data demonstrated that animals seropositive to both BuHV-1 and BoHV-1 present more oxidative stress than seronegative animals, as revealed by a significant increase in d-ROMs. Our results provide, for the first time, insight into the reac- tive oxygen species (ROS) modulation induced by the herpesvirus in Bubalus bubalis.

Viral and Antibody Prevalence of Hepatitis E in European Wild Boars (Sus scrofa) and Hunters at Zoonotic Risk in the Latium Region

Hepatitis E virus (HEV) is a member of the genus Hepevirus within the family Hepeviridae. Hepatitis E is recognized as a zoonosis, and swine and wild boars (Sus scrofa) are known reservoirs of HEV infection. The aim of this study was to investigate the presence of HEV in wild boars and hunters exposed to infection in central Italy (Latium region). During the hunting season, blood samples were collected from 228 wild boars and 20 hunters. The seroprevalence of HEV infection was determined using a commercial enzyme-linked immunosorbent assay, previously validated for use in man, pigs and wild boars. The estimated HEV seroprevalence in wild boars and in hunters was 40.7% (93/228; 95% confidence interval [CI] 34.4-47.1%) and 25% (5/20; 95% CI 6.1-43.9%), respectively. Liver samples were collected from the boars and HEV RNA was detected by nested reverse transcriptase polymerase chain reaction. Fifty-five of 164 tested wild boar liver samples (33.5%; 95% CI 26.2-40.7%) and three of 20 (15.0%; 95% CI 1.3-28.7%) tested human serum samples were positive for HEV RNA. Phylogenetic analysis of the nucleotide sequences obtained from PCR products indicated that the HEV strains present in wild boars and the human population all belonged to genotype 3, supporting the zoonotic role of wild boars in the spread of HEV infection.

Analysis of apoptosis induced by Caprine Herpesvirus 1 in vitro

It is known that Caprine Herpesvirus 1 (CpHV-1) causes apoptosis in mitogen-stimulated as well as not stimulated caprine peripheral blood mononuclear cells (PBMC). Initial experiments in Madin Darby bovine kidney (MDBK) cells revealed that CpHV-1 infection induced apoptotic features like chromatin condensation and DNA laddering. Thus, to characterize in more detail this apoptotic process, activation of caspase-8, -9 and -3 in MDBK cells CpHV-1 infected was investigated and demonstrated. In addition, CpHV-1 infection resulted in disruption of mitochondrial membrane potential, cytochrome c release and alterations in the pro- and anti-apoptotic proteins of Bcl-2 family. Proteolytic cleavage of poly(ADP-ribose) polymerases (PARP), confirming the activation of downstream caspases, was also observed. Our data indicated that a "cross-talk" between the death-receptor (extrinsic) pathway and the mitochondrial (intrinsic) pathway occurred in CpHV-1-induced apoptosis in vitro.

Feline herpesvirus-1 down-regulates MHC class I expression in an homologous cell system

Cytotoxic T lymphocytes (CTLs) are an essential component of the immune defense against many virus infections. CTLs recognize viral peptides in the context of the major histocompatibility complex (MHC) class I molecules on the surface of infected cells. Many viruses have evolved mechanisms to interfere with MHC class I expression as a means of evading the host immune response. In the present research we have studied the effect of in vitro Feline Herpesvirus 1 (FeHV-1) infection on MHC class I expression. The results of this study demonstrate that FeHV-1 down regulates surface expression of MHC class I molecules on infected cells, presumably to evade cytotoxic T-cell recognition and, perhaps, attenuate induction of immunity. Sensitivity to UV irradiation and insensitivity to a viral DNA synthesis inhibitor, like phosphonacetic acid, revealed that immediate early or early viral gene(s) are responsible. Use of the protein translation inhibitor cycloheximide confirmed that an early gene is primarily responsible.

Evaluation of a fluorescence polarization assay for the detection of serum antibodies to Brucella abortus in water buffalo (Bubalus bubalis)

The fluorescence polarization assay (FPA) was evaluated for the serological diagnosis of brucellosis in water buffalo (Bubalus bubalis) in southern Italy. This assay uses O-polysaccharide prepared from Brucella abortus lipopolysaccharide conjugated with fluorescein isothiocyanate as a tracer. It has many methodological advantages over older, more established tests and can be performed in a fraction of the time. Sera from 890 buffalos from the Campania Region - 526 positive sera and 364 negative sera according to the complement fixation test (CFT) - were evaluated in this study. All samples were tested with the Rose Bengal test (RBT), CFT, and FPA in parallel and in blind fashion. Sensitivities (Sn) were 84.5% and 92.6%, and specificities (Sp) were 93.1% and 91.2% for RBT and FPA, respectively, relative to CFT. Finally, receiver operating characteristic (ROC) analysis suggested a cut-off value of 117 millipolarization (mP) units. On the whole, these results suggested that FPA might replace RBT in the diagnosis of buffalo brucellosis for its better performance relative to CFT, its adjustable cut-off useful in different epidemiological situations, its reliability, ease of performance, and for its potential application in field and high-throughput laboratories.

2,3,7,8-Tetrachlorodibenzo-p-dioxin increases Bovine Herpesvirus type-1 (BHV-1) replication in Madin-Darby Bovine Kidney (MDBK) cells in vitro

Dioxin-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a common environmental toxin of current interest. In the last years, higher levels of TCDD than those permitted in UE [European Commission. 2002. European Commission Recommendation 2002/201/CE. Official Gazette, L 67/69] were detected in milk samples from cow, water buffalo, goat, and sheep raised on some areas of Campania Region (South Italy). Dioxin often causes immunosuppression and might render the animal liable to viral infections. In addition, viral infections are able to alter the pattern of dioxin distribution in different organs of the exposed animals. Bovine Herpesvirus type-1 (BHV-1) is a widespread pathogen, which causes infectious rhinotracheitis and infectious pustular vulvovaginitis in cattle. Herein, we have studied the effects of TCDD and BHV-1 infection, in Madin-Darby Bovine Kidney (MDBK) cells, alone as well as in association, so as cellular proliferation, apoptosis, and virus replication. We have observed an increase in cell viability of confluent monolayers at low TCDD concentrations. TCDD treated cells demonstrated increased viability compared to controls as evaluated by MTT test. TCDD exposure increased cell proliferation but induced no changes on apoptosis. Cells exposed to TCDD along with BHV-1 showed a dose-dependent increase in cytopathy, represented by ample syncytia formation with the elimination of the cellular sheets and increased viral titer. These results suggest that TCDD increases viral replication in MDBK cells while BHV-1 further decreases viability of TCDD exposed cells. Since very low concentrations (0.01 pg/ml) are sufficient to augment BHV-1 titer, TCDD may contribute to reactivate BHV-1 from latency, leading to recurrent disease and increase virus transmission.

Bovine herpesvirus type 1 (BHV-1) up-regulates telomerase activity in MDBK cells

The proliferative capacity of mammalian cells is regulated by telomerase, an enzyme uniquely specialised for telomeric DNA synthesis. The critical role of telomerase activation in tumor progression and maintenance has been well established in studies of cancer and of oncogenic transformation in cell culture. Experimental data suggest that telomerase activation has an important role in normal somatic cells, and that failure to activate sufficient telomerase also promotes disease. Evidence regarding the role of telomerase in the pathogenesis of several viruses including human immunodeficiency virus has led to an increased interest in the role of telomerase activity in other virus infections. In this research we evaluated the telomerase modulating activity of Bovine herpesvirus 1 (BHV-1) in MDBK cells. MDBK cells were infected at different multiplicity of infection with BHV-1 Cooper strain and telomerase activity at different times post-infection was measured by the TRAP assay. Our data indicate that BHV-1 significantly up-regulates telomerase activity at 3 and 6h post-infection decreasing after the 24h post-infection. Our data, showed that the effect was mediated by an immediate-early or early viral gene, and use of the protein translation inhibitor cycloheximide confirmed that an immediate early gene is primarily responsible.

Caprine herpesvirus-1 (CapHV-1) induces apoptosis in goat peripheral blood mononuclear cells

Programmed cell death (PCD), or apoptosis, is initiated in response to various stimuli, including virus infection. A number of studies have shown that deregulation of apoptosis is an important feature of virus-induced immunosuppression for various viral diseases. In the present study, CapHV-1 was found to cause apoptosis in mitogen-stimulated as well as nonstimulated caprine peripheral blood mononuclear cells (PBMC). Apoptotic index, as quantified by fluorescent dyes, revealed a significant increase in the percentage of apoptotic cells at 24 and 48 h postinfection as compared to their respective noninfected controls. Apoptosis specific internucleosomal laddering in DNA from CapHV-1 infected PBMC was seen in agarose gel electrophoresis. No DNA fragmentation was observed in control noninfected PBMC. Virus-induced apoptosis was reduced by Z-VAD-FMK, an aspecific caspase inhibitor, by AC-DEVD-CHO (caspase-3-specific) and AC-VEID-CHO (caspase-6-specific) treatment. PCD in CapHV-1 infected peripheral blood mononuclear cells occurs at the G0/G1 phase of the cell cycle. However, penetration of virus particles and infection was not required for PCD, as UV-inactivated CapHV-1 induced apoptosis of mitogen-stimulated bovine peripheral blood mononuclear cells in vitro.

The involvement of oxidative stress in bovine herpesvirus type 4-mediated apoptosis

Bovine herpesvirus type 4 (BHV-4) belongs to the gamma-2-herpesviruses of the Gammaherpesvirinae subfamily. BHV-4 has a worldwide distribution and has been isolated in a variety of clinical diseases as well as from healthy cattle. In this report we demonstrate that BHV-4 induces apoptosis in MDBK cells. In the early phases of apoptosis, cells show an increase in the intracellular level of reactive oxygen species, which is indicative of oxidative stress. This precedes DNA fragmentation, a hallmark typical of apoptosis. Cells were protected from apoptosis only by certain antioxidants (butylated hydroxyanisole and ebselen), whereas N-acetylcysteine turned out to be ineffective. Antioxidants that protected cells from apoptosis prevented oxidative stress but failed to block virus growth. These observations suggest that oxidative stress may be a crucial event in the sequence leading to apoptotic cell death but apoptosis is not required for the multiplication of BHV-4.