Paul Schnitzler

Background: Transplantation of human corneal tissue is associated with the potential risk of transmittance of viral infections. In accordance with European directives and federal laws, in Germany each tissue donor has to be tested for infectious diseases such as hepatitis B and C virus (HBV and HCV) and human immunodeficiency virus (HIV) infection. However, most of the currently available CE-marked serologic and nucleic acid screening systems are only validated for antemortem blood. Methods: Twenty related and paired ante- and postmortem blood samples from cornea donors were obtained and subsequently analyzed for hepatitis B surface antigen (HBsAg), hepatitis B antibody (anti-HBc), anti-HCV, HCV RNA, anti-HIV-1/2, and HIV p24 Ag using Abbott test systems. The sera were also spiked with reference materials in concentrations giving low and high positivity for HBV, HCV, and HIV markers. Results: The spiked ante- and postmortem sera from related donors showed similar results for HBsAg, anti-HBc, anti-HCV, HCV RNA, anti-HIV, and HIV p24 Ag, indicating a high stability of viral markers in cadaveric specimens. Three cornea donors had a medical history of HBV infection and revealed anti-HBc at similar levels in the ante- and postmortem sera. In addition, there was a single postmortem sample demonstrating a weak signal of anti-HIV-1 and HIV-1 p24 Ag. False-positive or false-negative results were not detected. The results obtained with the Abbott ARCHITECT analyzer and Abbott RealTime HCV PCR showed no significant differences. Conclusion: The analyzed screening assays are suitable for the detection of infectious markers of HBV, HCV, and HIV at similar levels in spiked ante- and postmortem sera from cornea donors.

Infections with herpes simplex virus type (HSV)-1 and HSV-2 are distributed worldwide. Although standard therapies with acyclovir and other synthetic drugs are available, the safety and efficacy of these drugs are limited due to the development of drug resistance and adverse side effects. The literature on essential oils and isolated compounds was reviewed regarding their antiviral activities against HSV-1 and HSV-2. The present overview aims to review experimental data and clinical trials focusing on the antiviral activity of selected essential oils and isolated oil components. HSV was found to be susceptible to many essential oils and their constituents. Whereas some essential oils and compounds exhibit direct virucidal activity or inhibit intracellular replication, many essential oils and compounds interact with HSV particles thereby inhibiting cell adsorption. Ayclovir-resistant HSV strains are also susceptible to essential oils since their mode of action is different from the synthetic drug. There are numerous publications on the antiherpetic activity of essential oils and their isolated active compounds. This field of research is still growing, and more clinical trials are required to explore the full potential of different essential oils for the topical treatment of herpetic infections.

Respiratory viruses are a cause of upper respiratory tract infections (URTI), but can be associated with severe lower respiratory tract infections (LRTI) in immunocompromised patients. The objective of this study was to investigate the genetic variability of influenza virus, parainfluenza virus and respiratory syncytial virus (RSV) and the duration of viral shedding in hematological patients. Nasopharyngeal swabs from hematological patients were screened for influenza, parainfluenza and RSV on admission as well as on development of respiratory symptoms. Consecutive swabs were collected until viral clearance. Out of 672 tested patients, a total of 111 patients (17%) were infected with one of the investigated viral agents: 40 with influenza, 13 with parainfluenza and 64 with RSV; six patients had influenza/RSV or parainfluenza/RSV co-infections. The majority of infected patients (n = 75/111) underwent stem cell transplantation (42 autologous, 48 allogeneic, 15 autologous and allogeneic). LRTI was observed in 48 patients, of whom 15 patients developed severe LRTI, and 13 patients with respiratory tract infection died. Phylogenetic analysis revealed a variety of influenza A(H1N1)pdm09, A(H3N2), influenza B, parainfluenza 3 and RSV A, B viruses. RSV A was detected in 54 patients, RSV B in ten patients. The newly emerging RSV A genotype ON1 predominated in the study cohort and was found in 48 (75%) of 64 RSV-infected patients. Furthermore, two distinct clusters were detected for RSV A genotype ON1, identical RSV G gene sequences in these patients are consistent with nosocomial transmission. Long-term viral shedding for more than 30 days was significantly associated with prior allogeneic transplantation (p = 0.01) and was most pronounced in patients with RSV infection (n = 16) with a median duration of viral shedding for 80 days (range 35–334 days). Long-term shedding of respiratory viruses might be a catalyzer of nosocomial transmission and must be considered for efficient infection control in immunocompromised patients.

Piroxicam is a potent, nonsteroidal, anti-inflammatory agent (NSAID) which also exhibits antipyretic activity. The antiviral effect of piroxicam against herpes simplex virus type 1 (HSV-1) was examined in vitro on RC-37 monkey kidney cells using a plaque reduction assay. Piroxicam was dissolved in ethanol or dimethylsulfoxide (DMSO) and the 50% inhibitory concentration (IC50) was determined at 4 mu g/ml and 75 mu g/ml, respectively. The IC50 for the standard antiherpetic drug acyclovir was determined at 1.6 mu M. At non-cytotoxic concentrations of these piroxicann solutions, plaque formation was significantly reduced by 62.4% for ethanolic piroxicam and 72.8% for piroxicam in DMSO. The mode of antiviral action of these drugs was assessed by time-on-addition assays. No antiviral effect was observed when cells were incubated with piroxicam prior to infection with HSV-1 or when HSV-1 infected cells were treated with dissolved piroxicann. Herpesvirus infection was, however, significantly inhibited when HSV-1 was incubated with piroxicam prior to the infection of cells. These results indicate that piroxicam affected the virus before adsorption, but not after penetration into the host cell, suggesting that piroxicam exerts a direct antiviral effect on HSV-1. Free herpesvirus was sensitive to piroxicam in a concentration-dependent manner and the inhibition of HSV-1 appears to occur before entering the cell but not after penetration of the virus into the cell. Considering the lipophilic nature of piroxicarn, which enables it to penetrate the skin, it might be suitable for topical treatment of herpetic infections.

Respiratory syncytial virus (RSV) is the leading cause of hospitalization especially in young children with respiratory tract infections (RTI). Patterns of circulating RSV genotypes can provide a better understanding of the molecular epidemiology of RSV infection. We retrospectively analyzed the genetic diversity of RSV infection in hospitalized children with acute RTI admitted to University Hospital Heidelberg/Germany between October 2012 and April 2013. Nasopharyngeal aspirates (NPA) were routinely obtained in 240 children younger than 2 years of age who presented with clinical symptoms of upper or lower RTI. We analyzed NPAs via PCR and sequence analysis of the second variable region of the RSV G gene coding for the attachment glycoprotein. We obtained medical records reviewing routine clinical data. RSV was detected in 134/240 children. In RSV-positive patients the most common diagnosis was bronchitis/bronchiolitis (75.4%). The mean duration of hospitalization was longer in RSV-positive compared to RSV-negative patients (3.5 vs. 5.1 days; p<0.01). RSV-A was detected in 82.1%, RSV-B in 17.9% of all samples. Phylogenetic analysis of 112 isolates revealed that the majority of RSV-A strains (65%) belonged to the novel ON1 genotype containing a 72-nucleotide duplication. However, genotype ON1 was not associated with a more severe course of illness when taking basic clinical/laboratory parameters into account. Molecular characterization of RSV confirms the co-circulation of multiple genotypes of subtype RSV-A and RSV-B. The duplication in the G gene of genotype ON1 might have an effect on the rapid spread of this emerging RSV strain.

Background and Objectives: Essential oils are complex mixtures containing compounds of several different functional-group classes. Depending on the structure, we can distinguish monoterpenes, phenylpropanes, and other components. Here in this study two monoterpene compounds of essential oils, i.e. beta-pinene and limonene were examined for their antiviral activity against herpes simplex virus type 1 (HSV-1) in vitro. Material and Methods: All antiviral assays were performed using RC-37 cells. Cytotoxicity was determined in a neutral red assay, antiviral assays were performed with HSV-1 strain KOS. The mode of antiviral action was evaluated at different periods during the viral replication cycle. Acyclovir was used as positive antiviral control. Results: Beta-pinenene and limonenen reduced viral infectivity by 100%. The mode of antiviral action has been determined, only moderate antiviral effects were revealed by monoterpenes when these drugs were added to host cells prior infection or after entry of HSV into cells. However, both monoterpenes exhibited high anti-HSV-1 activity by direct interaction with free virus particles. Both tested drugs interacted with HSV-1 in a dose-dependent manner thereby inactivating viral infection. Conclusions: These results suggest that monoterpenes in essential oils exhibit antiherpetic activity in the early phase of viral multiplication and might be used as potential antiviral agents.

Medicinal plants are increasingly of interest as novel source of drugs for antiherpetic agents, because herpes simplex virus (HSV) might develop resistance to commonly used antiviral drugs. An aqueous extract of Melissa officinalis and the phenolic compounds caffeic acid, p‐coumaric acid and rosmarinic acid were examined for their antiviral activity against herpes simplex virus type 1 (HSV‐1) acyclovir‐sensitive and clinical isolates of acyclovir‐resistant strains in vitro. When drugs were added during the intracellular replication of HSV‐1 infected cells, no antiviral effect was observed by plaque reduction assay. However, Melissa extract interacted directly with free viral particles of two acyclovir‐resistant HSV strains at low IC₅₀ values of 0.13 and 0.23 µg/mL and high selectivity indices of 2692 and 1522, respectively. The Melissa extract and rosmarinic acid inhibited HSV‐1 attachment to host cells in a dose‐dependent manner for acyclovir‐sensitive and acyclovir‐resistant strains. These results indicate that mainly rosmarinic acid contributed to the antiviral activity of Melissa extract. Penetration of herpes viruses into cells was inhibited by Melissa extract at 80% and 96% for drug‐sensitive and drug‐resistant viruses, respectively. Melissa extract exhibits low toxicity and affects attachment and penetration of acyclovir‐sensitive and acyclovir‐resistant HSVs in vitro. Copyright © 2014 John Wiley & Sons, Ltd.