In vitro comparison of acyclovir, ganciclovir and cidofovir against equid alphaherpesvirus 3 and evaluation of their efficacy against six field isolates / Comparación in vitro de aciclovir, ganciclovir y cidofovir contra alfa-herpesvirus equino 3 y evaluación de la eficacia de los mismos frente a 6 aislamientos de campo del virus

Equid alphaherpesvirus 3 (EHV3) is the etiological agent of equine coital exanthema (ECE), which is a venereal, highly contagious disease, characterized by the formation of papules, vesicles, pustules and ulcers on the external genitalia of mares and stallions. EHV3 remains in a latent state after a successful infection and there are latently infected animals in which the virus is reactivated and generally re-excreted subclinically. There are no available vaccines for this condition and prevention is based on the clinical examination of mares prior to mating, which allows to segregate those showing clinical signs. As this approach does not eliminate the risk of contagion in stallions from subclinically infected mares, there is a need for a specific EHV3 treatment. Nowadays, there exist various antiviral compounds of proven effectiveness for other alphaherpesviruses affecting humans and animals. The aim of the present study was to compare the efficacy of three antiviral compounds, acyclovir, ganciclovir and cidofovir against EHV3 in vitro, and to assess their efficacy against six EHV3 Argentinian field isolates. To determine the efficacy of these compounds in vitro, three parameters were analyzed: reduction of plaque number, reduction of plaque size and reduction of viral production. Additionally, the effectiveness of the three compounds at an optimum concentration previously determined in this study was investigated for the EHV3 field isolates. Based on our results, ganciclovir was the most potent antiviral compound to reduce EHV3 replication in vitro and may thus be a valuable candidate for treatment and prevention of ECE in mares and stallions.

El alfa-herpesvirus equino 3 (EHV3) es el agente etiológico del exantema coital equino (ECE), enfermedad venérea, altamente contagiosa y caracterizada por la aparición de pápulas, vesículas, pústulas y úlceras en los genitales externos de yeguas y padrillos. Luego de la primo-infección, el EHV3 se mantiene en el animal en un estado de latencia a partir del cual puede reactivar y excretarse, generalmente de manera subclínica. No existen vacunas, por lo que la prevención se basa en la detección de las lesiones clínicas previo al servicio, y la segregación de estos animales. Sin embargo, este abordaje no previene la infección del padrillo por parte de yeguas que excretan el virus de manera subclínica, y por lo tanto existe la necesidad de un tratamiento específico contra el EHV3. En la actualidad, existen varios compuestos antivirales de probada eficacia contra herpesvirus humanos y veterinarios. El objetivo de este trabajo es comparar la eficacia de 3 compuestos antivirales, aciclovir, ganciclovir y cidofovir, contra EHV3 in vitro, y evaluar la eficacia de los mismos contra 6 cepas de campo argentinas de EHV3. Para determinar la eficacia de los compuestos in vitro se evaluaron 3 parámetros: reducción del número de placas de lisis, reducción del tamaño de placas de lisis y reducción de la producción de virus. Adicionalmente, la efectividad de los compuestos en una concentración óptima, previamente determinada en este estudio, fue determinada para 6 cepas de campo argentinas de EHV3. De acuerdo con los resultados obtenidos, ganciclovir fue el compuesto más potente en reducir la replicación del EHV3 in vitro, y por lo tanto podría considerarse un potencial candidato para el tratamiento y la prevención del ECE en yeguas y padrillos.

Herpes simplex virus: isolation, cytopathological characterization and antiviral sensitivity

BACKGROUND: Herpes simplex virus (HSV) infection is an endemic disease and it is estimated that 6095% of the adult population are infected with symptoms that are usually self-limiting, though they can be serious, extensive and prolonged in immunocompromised individuals, highlighted by the emergence of drug-resistant strains. The study of the wild-type HSV strains based on the cytopathogenic features and its antiviral sensitivity are important in the establishment of an antivirogram for controlling the infection. OBJECTIVE: This study sought to isolate and examine the cytopathological characteristics of circulating strains of the Herpes simplex virus, from clinical specimens and their sensitivity to commercially available antiherpesvirus drugs, acyclovir, phosphonophormic acid and trifluridine. METHODS: Herpes simplex virus isolation, cytopathological features and antiviral sensitivity assays were performed in cell culture by tissue culture infectious dose or plaque forming unit assay. RESULTS: From twenty-two clinical specimens, we isolated and adapted nine strains. Overall, the cytopathic effect was detected 24 h post-infection (p.i.) and the presence of syncytia was remarkable 48 h p.i., observed after cell staining. Out of eight isolates, four developed plaques of varying sizes. All the isolates were sensitive to acyclovir, phosphonophormic and trifluridine, with the percentage of virus inhibition (%VI) ranging from 49.7-100%. CONCLUSIONS: The methodology for HSV isolation and characterization is a straightforward approach, but the drug sensitivity test, regarded as being of great practical importance, needs to be better understood. .

In vitro inhibitory effects of chlorhexidine and Persica mouthwashes on HSV-1 compared with acyclovir

Recurrent intraoral herpes is a common oral disease that causes painful ulcers and viral shedding, resulting in various complications for patients. The antiviral efficacy of oral mouthwashes has not been adequately studied, although they are a readily available and rapid treatment modality for oral ulcers. In this experimental study, viricidal effects of chlorhexidine and Persica mouthwashes on Vero cell lines were examined, before and after HSV-1 infection of the cells, in the presence of various concentrations of mouthwashes at different time intervals by using quantal assays. Then the results were compared with those of acyclovir. The 50% cytotoxic concentrations [CC[50] of the two mouthwashes were determined. Data was analyzed by one-way and two-way ANOVA [alpha = 0.05]. CC[50] of Persica at 5- and 30-minute intervals were 0.2% and 0.14%, respectively. Chlorhexidine was toxic at durations more that 5 minutes. Before inoculation, both mouthwashes showed viricidal effects and Persica showed more viricidal effect than chlorhexidine and acyclovir [p values of 0.0001 and 0.04, respectively]. After virus inoculation antiviral effects of these mouthwashes were only limited to concentrations above 1/4. Acyclovir demonstrated the highest antiviral effect [p value = 0.0001]. Considering the better direct anti-HSV effect of the herbal mouthwash, Persica, and its less side effects compared to chlorhexidine, it can be used to reduce oral fluid contamination caused by viral shedding and reduce infectivity ofintra-oral ulcers

Antiviral activity of the Indian medicinal plant extract Swertia chirata against herpes simplex viruses: a study by in-vitro and molecular approach.

PURPOSE: The antiviral activity of Indian Medicinal plant extract Swertia chirata was tested against Herpes simplex virus (HSV) type-1, using multiple approaches both at cellular and molecular level. METHODS: Cytotoxicity, plaque reduction, virus infectivity, antigen expression and polymerase chain reaction (PCR) assays were conducted to test the antiviral activity of the plant extract. RESULTS: Swertia plant crude extract (1 gm/mL) at 1:64 dilution inhibited HSV-1, plaque formation at more than 70% level. HSV antigen expression and time kinetics experiments conducted by indirect immunofluorescence (IFA) test, revealed a characteristic pattern of small foci of single fluorescent cells in Swertia extract treated HSV-1 infected cells at 4 hours post infection dose, suggested drug inhibited viral dissemination. Infected cell cultures treated with Swertia extract at various time intervals, tested by PCR, failed to show amplification at 12, 24-72 hours. HSV-1 infected cells treated with Acyclovir (antiviral drug) did not show any amplification by PCR. CONCLUSIONS: In this preliminary study, the Indian medicinal plant extract, Swertia chirata showed antiviral properties against Herpes simplex virus type-1.

Aciclovir resistance among Indian strains of Herpes simplex virus as determined using a dye uptake assay.

Resistance to aciclovir (ACV) among Herpes simplex virus (HSV) isolates is increasingly being reported in the literature particularly in immunocompromised patients. However, there is only limited data available from India despite widespread use of ACV in our hospital. A cross-sectional study was hence conducted to determine the aciclovir (ACV) susceptibility of HSV 1 and 2 isolates using a dye uptake (DU) assay. This study showed a 3.0% prevalence of ACV resistance among HSV-1 strains (2/66, median IC 50 0.098 microg/mL) while in HSV-2 strains, it was 7.8% (5/64, median IC 50 0.195 microg/mL). The IC 50 for the HSV-1 and HSV-2 strains resistant to ACV was greater than or equal to 6.25 microg/mL.

In vitro antiviral activity of Chamaecrista nictitans (Fabaceae) against herpes simplex virus: biological characterization of mechanisms of action

We have previously identified a crude extract of the plant Chamaecrista nictitans (Fabaceae) with antiviral activity against herpes simplex virus. The main objectives of this research were to identify the step of the replication cycle of herpes simplex inhibited by the extract, and to attempt to characterize the chemical characteristics of this extract. The crude extract from--Chamaecrista nictitans (Fabaceae) was extracted with a mixture of diclorometane/methanol, and further fractionated following a bioassay-guided protocol using a combination of preparative thin layer and column chromatography. Toxicity and bioassay experiments were carried out in monolayers of Vero cells. The antiviral activity of the extract was assessed by total inhibition of cytopathic effect after three-day incubation. The highest concentration of the extract which was not toxic to the cells was 200 ptg/ml. Western blot and immunofluorescence techniques were used to elucidate the antiviral mechanism of the extract by infecting Vero cells with the virus at different times and monitoring the synthesis of viral proteins. A 60 kDa protein was detected at 2 hr and 8 hr post-infection but no additional proteins were synthesized at later time intervals, and cytopathic effect was not observed after 24 hr. This result indicates that the extract acts at the intracellular level in order to inhibit late transcription. However, it does not inhibit transcription/translation of early viral proteins. These results were confirmed by immunofluorescence experiments. A strong fluorescent signal was observed in control cell monolayers at 24 hr post infection, accompanied with a clear cytopathic effect. In contrast, in the presence of acyclovir or the extract, cells showed very discrete immunofluorescence, characterized by a punctuated pattern, and no cytopathic effect was observed. Neutralization assays were performed using pre-incubation of virus with either specific herpes simplex-1 antiserum, 200...

Evaluation of glutathione and ascorbic acid as suppressors of drug-induced lipid peroxidation.

In different sets of experiment lipid peroxidation induction capacity of two drugs, viz., ceftizoxime sodium, a third generation cephalosporin antibiotic, and acyclovir, an antiviral agent, was studied using goat whole blood as the lipid source. Ceftizoxime sodium caused significant extent of lipid peroxidation. Lipid peroxidation being a toxicity mediating process, such observation may be related to the toxic potential of the drug. Insignificant induction of lipid peroxidation was found in case of acyclovir and this is in good agreement with the safety record of the drug. Glutathione and ascorbic acid could significantly reduce ceftizoxime sodium induced lipid peroxidation, suggesting that free radical scavenging action of antioxidants may be exploited by possible antioxidant co-therapy to reduce iatrogenicity of the drug in persons with impaired endogenous antioxidant defence. Glutathione and ascorbic acid appear to be promising candidates for further investigation in this regard.

Antivirugrama: ¿ciencia ficción o realidad? / Antivirugram: science fiction or reality?

El panorama creciente de infecciones virales severas, que amenazan la vida de los pacientes, la disponibilidad de técnicas de diagnósticos virológico rápido y los conocimientos patogénicos más acabados con biología molecular, han estimulado el desarrollo explosivo de fármacos antivirales. Como consecuencia nace la necesidad de incorporar a las decisiones clínicas la evaluación in vitro de algunos de estos medicamentos y la aparición de resistencia durante tratamientos prolongados, como ha sido el dramático caso de la infección por VIH/SIDA. Se revisan los antivirales licenciados para el uso médico y el grado de aplicación clínica de los estudios de susceptibilidad in vitro alcanzado en la actualidad

Infecciones recurrentes por virus herpes simplex / Herpes simplex virus recurrent infections

En el tratamiento de esta patología es muy importante efectuar un diagnóstico correcto. Revisamos fundamentalmente la terapia de la recurrencia herpética. En la terapia el fármaco clásico ha sido aciclovir, medicamento seguro y efectivo, pero con el inconveniente de tener una baja biodisponibilidad. Los nuevos antivirales, como valaciclovir, han mejorado la biodisponibilidad permitiendo una igual o mejor respuesta clínica con una dosificación mucho más cómoda. Estos fármacos pueden ocuparse también para terapia abortiva o supresiva. mejoraba la recurrencia del paciente con el tratamiento antiviral, será importante tratar de evitar, hasta donde se pueda, la aparición de nuevas recurrencias. Para esto, se debe tratar de identificar y controlar las causas gatillantes y mejorar la condición inmunológicas local y/o general. También es importante considerar esta enfermedad integralmente en el paciente, entregando educación y las medidas necesarias para prevención

Sensibilidad in vitro al aciclovir de virus herpes simplex aislados de pacientes con herpes genital recurrente / Sensibility in vitro to acyclovir of simplexvirus isolated in patients with relapsing genitalis herpes

El aciclovir (ACV) es el antiviral de elección para el tratamiento de las infecciones genitales herpéticas. Su amplio uso ha derivado en la aparición de cepas resistentes. Nuestro objetivo fue evaluar la sensibilidad in vitro al ACV de virus herpes simplex (HSV), aislados de pacientes inmunocompetentes, con herpes genital recurrente, sometidos a distintas terapias con ACV, relacionando los resultados con los patrones genómicos de éstos. Se estudiaron 27 aislados: 8 de pacientes sometidos a terapia supresiva; 7 de pacientes con tratamiento corto y 12 de pacientes sin tratamiento, mediante técnica de inhibición del efecto citopático 50 por ciento y confirmación con técnica de reducción de unidades formadoras de placas. El 96,3 por ciento fue sensible al ACV, identificándose uno resistente (3,7 por ciento). El promedio de IC50 de los aislados sensibles en los distintos grupos de pacientes fue 0,59; 0,58 y 0,57 lig/mi, respectivamente. Los patrones genómicos de los aislados sensibles y del resistente fueron idénticos. El tipo de esquema terapéutico empleado no genera resistencia viral. El hallazgo de cepas resistentes en población inmunocompetente requiere una continua vigilancia de los aislados de HSV

Comparison of the antiviral activity and toxicity of a protein magnesium ammonium phospholinoleate anhydride polymer with other antiviral drugs

1. SB-73, a magnesium ammonium phospholinoleate anhydride aggregate, exhibited antiviral action in vitro in the concentration range of 50 to 100 µg/ml against herpes simplex type 1, stomatitis vesicular virus, adenovirus type 5, and in vivo in the dose range of 0.7 to 1.3 mg/Kg against canine parvovirus distemper virus. 2. The lethal dose (LD50) was 2.71 ñ 1.55 g/Kg body weight in mice inoculated intraperitoneally. Oral ingestion of the aggregate up to 30 g/Kg body weight by mice had no lethal effects during the 14 days of observation. 3. In in vitro cytotoxicity experiments with fibroblasts (V-79 Chinese hamster cell line), no toxic effects were observed with SB-73 concentrations (120 µg/ml) having antiviral activity. 4. In a cellular proliferation experimental using hamster V-79 cells, we observed 72% proliferation after treatment of the cells with a high concentration (500 µg/ml) of SB-73. 5. Compound SB-73 showed no genotoxicity for human lymphocytes at concentrations of 100 µg/ml. 6. When the cytoxicity and genotoxicity of SB-73 wee compared with those of acyclovir, idoxuridine and AZT at 500µg/ml concentration the compound was found to have effects similar to those of acyclovir

Infecciones por virus herpes: drogas antiherpéticas: I / Herpesvirus infections: antiherpetic drugs: I

Aunque los antivirales sintéticos inhiben in vitro casi todos los virus del grupo herpes la terapia está virtualmente restringida a las infecciones por el virus herpes simplex y varicela zoster. Ninguna de estas drogas es realmente eficaz contra citomegalovirus; algunas tendrían cierta acción contra el virus Epstein-Barr. Las drogas antiherpéticas sólo actúan sobre el virus que replica, sin alcanzar al virus en estado de latencia. Deben ser usadas con precaución ya que aún no se han valorado sus efectos colaterales cuando se suministran por largos períodos. Las drogas antiherpéticas autorizadas por la FDA son: 1) la iododeoxiuridina en solución (0,1 por ciento) o unguento (0,5 por ciento) para uso oftálmico; 2) la trifluorotimidina en solución oftálmica (0,1 por ciento); 3) la adenina arabinosido en frasco ampolla de 1 gramo para uso intravenoso y 4) el aciclovir como unguento oftálmico (0,3 por ciento), crema dérmica (5 por ciento en base de propilenglicol al 40 por ciento), tabletas (400 y 200 mg) o jarabe para uso oral, frascos ampolla de 250 mg para uso intravenoso. El unguento dérmico es poco efectivo