Commercial metal-based nanocolloids--lack of virucidal activity against ECBO virus.

Metallic nanoparticles, mainly silver ones, have been widely used as antibacterial agents, and some studies shown they also exert direct antiviral activity against both enveloped and non-enveloped viruses. The objective of this study has been to evaluate the virucidal activity of commercial silver, gold, copper and platinum nanocolloids, recommended by the manufacturer as antimicrobials, against the ECBO virus, according to Polish Standard PN-EN 14675:2006. The highest experimentally observed decrease in the viral load was 0.875 log, which--when contrasted with the reduction in virus titre of at least 4 log expected from disinfectants--indicates that none of the analyzed nanocolloids had a disinfectant power towards the ECBO virus under the conditions defined by the standard.

Comparison of the virucidal efficiency of peracetic acid, potassium monopersulfate and sodium hypochlorite on hepatitis A and enteric cytopathogenic bovine orphan virus.

AIMS: The virucidal activity of peroxy-products was evaluated and compared with sodium hypochlorite using the EN 14675 European suspension test and a surface test developed in our laboratory. The classical approach on infectivity of viruses was complemented with a prospective approach on virus genomes. METHODS AND RESULTS: Both infectivity tests were adapted and/or developed to determine the activity of disinfectants against reference bovine enterovirus type 1 [enteric cytopathogenic bovine orphan virus (ECBO)] and resistant hepatitis A virus (HAV) in conditions simulating practical use. Similar concentrations of active chlorine were virucidal against both viruses, either at 0·062% using the suspension test or at 0·50-1% using the surface test. However, for potassium monopersulfate and peracetic acid products, concentrations of approximately three times (3%) to 72 times (9%) higher were necessary against HAV than ECBO when determined with the suspension test. With the surface test, 4-8% peroxy-products were virucidal against HAV, either 16 times more peroxy-products concentrations than against ECBO. No significant impact on the targeted area of the viral genome measured by real-time RT-PCRs was obtained for ECBO and HAV suspensions treated with disinfectants, even with doses higher than the minimal virucidal concentrations. CONCLUSIONS: Sodium hypochlorite, but not peroxy-products, had similar activity against ECBO and HAV. No relation could be established between infectivity tests and genome destruction. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first comparative study that investigates with novel suspension and surface tests the reduction of infectivity and genome destruction of two resistant viruses by peroxy-compounds. The results and conclusions collected with European standards are discussed.

[Examination of biocides for their effectiveness against animal viruses according to European Union Standards with emphasis on the selection of a suitable test virus]. / Prüfung von Bioziden auf Wirksamkeit gegen animale Viren nach EU-Norm im Hinblick auf die Auswahl eines geeigneten Testvirus.

Because of the changes to be expected in the methods for testing disinfectants deemed to be used in the veterinary field, candidate viral species were evaluated for their suitability as test virus. Considered viral species included different non-enveloped viruses [bovine enterovirus type 1 (ECBO (Enteric Cytopathogenic Bovine Orphan) virus), mammalian reovirus type 1, feline calici virus (FCV), and bovine parvovirus (BPV)], as well as enveloped viruses, as equine arteritisvirus (EAV), bovine herpesvirus type 1 (BHV1), Newcastle disease virus (NDV) and vaccinia virus. Viruses were tested for their tenacity against different biocidal agents (formaldehyde, formic acid, peracetic acid, and sodium hypochlorite) in the suspension test at a temperature of 20 degrees C which is given as an optional test temperature according to prEN 14675 "Quantitative suspension test for the evaluation of virucidal activity of chemical disinfectants and antiseptics used in veterinary field--Test method and requirements"elaborated by the "Comite Européen de Normalisation"(CEN) (Anonym, 2004). Of the animal viruses tested for their tenacity highest tenacity against the disinfectants. FCV and the enveloped viruses were of lower resistance. In addition to the tenacity of viruses, other parameters, such as the ability of the virus to replicate in permanent cells, the magnitude of the virus titre that can be obtained from such cultures, as well as the threat a virus poses to humans and animals are to be considered when selecting a suitable test virus. Based on these criteria and despite its tenacity being inferior to that of BPV, the ECBO virus was chosen as the most suitable test virus. The result of the efficacy of disinfectants is not based on the most resistant virus in this case. This circumstance is to be considered when giving recommendations for the practical use of disinfectants.

The ultrastructure of the developing replication site in foot-and-mouth disease virus-infected BHK-38 cells.

Foot-and-mouth disease virus (FMDV) is the type species of the Aphthovirus genus of the Picornaviridae: Infection by picornaviruses results in a major rearrangement of the host cell membranes to create vesicular structures where virus genome replication takes place. In this report, using fluorescence and electron microscopy, membrane rearrangements in the cytoplasm of FMDV-infected BHK-38 cells are documented. At 1.5-2.0 h post-infection, free ribosomes, fragmented rough endoplasmic reticulum, Golgi and smooth membrane-bound vesicles accumulated on one side of the nucleus. Newly synthesized viral RNA was localized to this region of the cell. The changes seen in FMDV-infected cells distinguish this virus from other members of the Picornaviridae, such as poliovirus. Firstly, the collapse of cellular organelles to one side of the cell has not previously been observed for other picornaviruses. Secondly, the membrane vesicles, induced by FMDV, appear distinct from those induced by other picornaviruses such as poliovirus and echovirus 11 since they are relatively few in number and do not aggregate into densely packed clusters. Additionally, the proportion of vesicles with double membranes is considerably lower in FMDV-infected cells. These differences did not result from the use of BHK-38 cells in this study, as infection of these cells by another picornavirus, bovine enterovirus (a close relative of poliovirus), resulted in morphological changes similar to those reported for poliovirus-infected cells. With conventional fixation, FMDV particles were not seen; however, following high-pressure freezing and freeze-substitution, many clusters of virus-like particles were seen.

Investigations on suitability of different materials for carriers to be used for virucidal testing of chemical disinfectants in the veterinary field.

Various materials with rough surfaces were tested to determine their suitability for virus carrier tests designed to evaluate virucidal activity of chemical disinfectants. A non-enveloped RNA virus, bovine enterovirus type 1, strain LCR 4 [entero cytopathogenic bovine orphan virus (ECBO)] and an enveloped RNA virus, paramyxovirus type 1 [Newcastle disease virus (NDV), strain Montana] served as test viruses. Experiments with ECBO virus were carried out in four sets, and those with NDV in three sets. In the first set we used poplar wood, frosted glass slides and Sartorius membrane filters. The second set comprised of poplar wood, frosted glass slides, polyamide filters, and cellulose nitrate filters and, in the third set, glass fibre filters and glass fibre pre-filters were added. The fourth test included poplar wood, frosted glass slides, and polyethersulphone ultra filters. Because of their extremely low levels of virus recovery, glass, polyamide, cellulose nitrate and glass fibre filter, glass fibre pre-filter, and polyethersulphone ultra filters are not suitable for sufficient recovery of ECBO virus. Only poplar wood carriers allowed sufficient recovery rates of ECBO virus. In the first and second set of tests, NDV could be sufficiently recovered from poplar wood, glass slides, and polyamide filter. In the third set, the virus recovery from polyamide filter was very low. Poplar wood carrier is recommended as a reliable carrier for the tests with both viruses, but methods for virus recovery must be improved, e.g. by more vigorous and longer shaking or optimizing the ultrasonic treatment.

Evaluation of virucidal activity of three commercial disinfectants and formic acid using bovine enterovirus type 1 (ECBO virus), mammalian orthoreovirus type 1 and bovine adenovirus type 1.

A modified version of the test method of the Comité Européen de Normalisation (CEN) was developed using formic acid and three commercial disinfectants to evaluate virucidal activity against three non-enveloped viruses, bovine enterovirus type 1 (ECBO virus), mammalian orthoreovirus type 1 and bovine adenovirus type 1 (BAV 1). Determination of the effects of temperature was carried out at 20 and 10 degrees C. All tests with protein load used bovine serum albumin (BSA) and yeast extract. The investigations were performed in suspension tests and in carrier tests using poplar wood virus carriers. The carrier tests showed that ECBO virus could be inactivated at 20 degrees C with 1% formic acid within a 60 min reaction time. For disinfection of ECBO virus at 10 degrees C within 60 min, a 2% concentration of formic acid was necessary. Formic acid was ineffective against reovirus and bovine adenovirus and cannot be recommended as a reference disinfectant. Inactivation of ECBO virus and adenovirus type 1 using a disinfectant containing aldehydes and alcohols could be achieved, but only at room temperature. The disinfection of reovirus type 1 at room temperature with this product was possible without a protein load. This disinfectant exhibited disinfection ability at 10 degrees C at a concentration of more than 2% or with a longer exposure time. A disinfectant containing aldehydes was effective at room temperature but its effect was reduced in the presence of organic matter. Inactivation at 10 degrees C was found only against adenovirus. The fourth disinfectant, which contained peroxiacetic acid, inactivated all test viruses at a concentration of 0.5% within 15 min independent of temperature and protein load.