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

Efficiency of Virucidal Disinfectants on Wood Surfaces in Animal Husbandry

The aim of this study was to test the inactivation of viruses on germ carriers of different types of wood using a disinfectant in order to assess the biosafety of wood as a building material in animal husbandry. The laboratory disinfectant efficacy tests were based on German testing guidelines and current European standards. Five different types of wood germ carriers, i.e., spruce (Picea abies), pine (Pinus sylvestris), poplar (Populus sp.), beech (Fagus sylvatica) and Douglas fir (Pseudotsuga menziesii), were inoculated with enveloped or non-enveloped viruses and then treated with one of three different disinfectants. The results revealed that intact, fine-sawn timber with a low roughness depth can be effectively inactivated. Peracetic acid proved to be the most effective disinfectant across all tests. Regardless of the pathogen and the type of wood, a concentration of 0.1% of the pure substance at a temperature of 10 °C and an exposure time of one hour can be recommended. At a temperature of -10 °C, a concentration of 0.75% is recommended. The basic chemicals formic acid and glutaraldehyde demonstrated only limited effectiveness overall. The synergistic effects of various wood components on the inactivation of viruses offer potential for further investigation. Disinfectant tests should also be conclusively verified in field trials to ensure that the results from standardised laboratory tests can be transferred to real stable conditions.

Surrogate Selection for Foot-and-Mouth Disease Virus in Disinfectant Efficacy Tests by Simultaneous Comparison of Bacteriophage MS2 and Bovine Enterovirus Type 1

In South Korea, testing disinfectants against foot-and-mouth disease virus (FMDV) that are contagious in livestock or that require special attention with respect to public hygiene can be manipulated only in high-level containment laboratories, which are not easily available. This causes difficulties in the approval procedure for disinfectants, such as a prolonged testing period. Additionally, the required biosafety level (BSL) in the case of FMDV has hindered its extensive studies. However, this drawback can be circumvented by using a surrogate virus to improve the performance of the efficacy testing procedure for disinfectants. Therefore, we studied bacteriophage MS2 (MS2) and bovine enterovirus type 1 (ECBO) with respect to disinfectant susceptibility for selecting a surrogate for FMDV according to the Animal and Plant Quarantine Agency (APQA) guidelines for efficacy testing of veterinary disinfectants. Effective concentrations of the active substances in disinfectants (potassium peroxymonosulfate, sodium dichloroisocyanurate, malic acid, citric acid, glutaraldehyde, and benzalkonium chloride) against FMDV, MS2, and ECBO were compared and, efficacies of eight APQA-listed commercial disinfectants used against FMDV were examined. The infectivity of FMDV and ECBO were confirmed by examination of cytopathic effects, and MS2 by plaque assay. The results reveal that the disinfectants are effective against MS2 and ECBO at higher concentrations than in FMDV, confirming their applicability as potential surrogates for FMDV in efficacy testing of veterinary disinfectants.

Use of the European standardization framework established by CEN/TC 216 for effective disinfection strategies in human medicine, veterinary medicine, food hygiene, industry, and domestic and institutional use - a review

The SARS-CoV-2 pandemic illustrates the necessity of effective preventive measures for existing and newly emerging pathogens. When confronted with pathogens or spoilage agents, especially if they are not yet well studied, effective hygiene protocols are needed immediately. In the medical field, effective preventive measures are key to prevent vulnerable patients from infections. In production areas, effective hygiene measures are needed to protect goods from spoilage or microbial contamination. The European standardization framework established by the European Committee for Standardization (CEN) ensures that effective hygiene measures are available and can be immediately implemented when needed. Based on a broad portfolio of standards/laboratory tests, activity claims specifically addressing the special features of applications of antimicrobial formulations are substantiated. In this review, the concept of using standardized surrogate test organisms is explained, and the European standardized test approach to claim microbicidal and virucidal efficacy, the specificity of claims and their relevance for infection prevention measures is illustrated. Furthermore, relevance of the European Norm test methods is elucidated in the light of legal requirements. Finally, the review explains the systematics of the standardized methodological portfolio of CEN, Technical Committee 216, which is very useful when effective strategies for fighting or preventing microbial and viral induced infections, contaminations or spoilage are needed on an immediate basis.

A Critical Review of Disinfection Processes to Control SARS-CoV-2 Transmission in the Food Industry

Industries of the food sector have made a great effort to control SARS-CoV-2 indirect transmission, through objects or surfaces, by updating cleaning and disinfection protocols previously focused on inactivating other pathogens, as well as food spoilage microorganisms. The information, although scarce at the beginning of the COVID-19 pandemic, has started to be sufficiently reliable to avoid over-conservative disinfection procedures. This work reviews the literature to propose a holistic view of the disinfection process where the decision variables, such as type and concentration of active substances, are optimised to guarantee the inactivation of SARS-CoV-2 and other usual pathogens and spoilage microorganisms while minimising possible side-effects on the environment and animal and human health.

Virucidal efficacy of acidic electrolyzed water (AEW) against African swine fever virus and avian influenza virus

This study evaluated the virucidal efficacy of acidic electrolyzed water (AEW) against African swine fever virus (ASFV) and avian influenza virus (AIV), according to the Animal and Plant Quarantine Agency (APQA) guidelines for efficacy testing of veterinary disinfectants. AEW (pH 5.0–6.5) was prepared using a commercially available “Electrolyzed Water Generator” with a free chlorine concentration (FCC) of 5–140 ppm, and its efficiency in reducing the titer of ASFV and AIV was tested in a suspension under low- and high-level organic soiling. Under low-level organic soiling conditions, AEW with FCC ≥40 ppm was effective against ASFV; under high-level organic soiling conditions, AEW with FCC ≥80 ppm was effective against ASFV. Under low-level organic soiling conditions, AEW with FCC ≥60 ppm was effective against AIV; under high-level organic soiling conditions, AEW with FCC ≥100 ppm was effective against AIV. The virucidal effect of AEW seemed dependent on the FCC and the presence of organic soiling. Based on these data, we recommend the following minimum FCCs in AEW treatment for routine disinfection in veterinary field under low- and high-level organic soiling conditions: for ASFV, 50 ppm and 100 ppm; and for AIV, 75 ppm and 125 ppm, respectively. In conclusion, the virucidal effects of AEW against ASFV and AIV emphasize its potential utility as a disinfectant, and we suggest considering organic soiling conditions while using AEW for implementing effective control measures for field applications.

H9N2-specific IgG and CD4+CD25+ T cells in broilers fed a diet supplemented with organic acids

Organic acids have long been known for their beneficial effects on growth performance in domestic animals. However, their impact on immune responses against viral antigens in chickens is unclear. The present study aimed to investigate immunological parameters in broilers immunized with a H9N2 vaccine and/or fed a diet containing organic acids (citric, formic, and lactic acids). We allotted 1-day-old broilers into 4 groups: control (C), fed a diet supplemented with organic acids (O), administered a H9N2 vaccine (V), and fed a diet supplemented with organic acids and administered a H9N2 vaccine (OV). Blood and spleen samples were taken at 2, 7 and 14 d post vaccination (DPV). At 14 DPV, total and H9N2-specific IgG levels were significantly lower in the OV group than in the V group. However, it was intriguing to observe that at 2 DPV, the percentage of CD4+CD25+ T cells was significantly higher in the OV group than in the other groups, indicating the potential induction of regulatory T cells by organic acids. In contrast, at 2 DPV, the percentage of CD4+CD28+ T cells were significantly lower in the OV group than in the other groups, suggesting that CD28 molecules are down-regulated by the treatment. The expression of CD28 on CD4+ T cells, up-regulated by the stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin (Iono), was inhibited upon organic acid treatment in OV group. In addition, the proliferation of lymphocytes, stimulated with formalin-inactivated H9N2, was significantly higher in the V group than in the OV group. Alpha 1-acid glycoprotein (AGP) production was significantly lower in the OV group than in the V group, suggesting that the organic acids inhibited the inflammation caused by the vaccination. Overall, induction of regulatory CD4+CD25+ T cells, coinciding with the decrease of H9N2-specific antibodies, was observed in broilers fed organic acids.

Biosecurity aspects and pathogen inactivation in acidified high risk animal by-products

The aim of the study was to investigate the effects of formic acid addition to ground high risk animal by-products (ABP 1) in terms of stabilization and pathogen inactivation and to evaluate the biosecurity risk connected with the ABP 1 based combustion fuel Biomal. Laboratory studies were performed on the persistence of Salmonella Typhimurium, Bacillus cereus spores, porcine herpes virus, avian influenza virus, bovine viral diarrhea virus, equine rhinitis A virus and porcine parvovirus in Biomal at different storage times. It was shown that Salmonella and enveloped viruses were inactivated within 1 day (24 h). Bacillus cereus spores were not reduced during 147 days and the non-enveloped virus porcine parvovirus was still detected after 168 days of storage. The conclusion that can be drawn from the study is that transmission of some highly contagious diseases such as foot-and-mouth-disease, swine vesicular disease and egg drop syndrome, caused by non-enveloped viruses, may follow accidental leakages of Biomal. In addition, there is a risk of transmission of the diseases anthrax and black leg, caused by sporulating bacteria.

The inactivation of avian influenza virus subtype H5N1 isolated from chickens in Thailand by chemical and physical treatments

The objectives of this study were to determine the survival of avian influenza virus (AIV) subtype H5N1 under various physical and chemical treatments, including disinfectants, temperature and pH. The highly pathogenic AIVs subtype H5N1 were isolated from internal organs of suspected chickens and were characterized by the inoculation into chicken embryonated eggs (CEEs), hemagglutination (HA) test, hemagglutination inhibition (HI) test, reverse transcriptase polymerase chain reaction (RT-PCR) and nucleotide sequencing of hemagglutinin (H) and neuraminidase (N) genes. Three H5N1 isolates, at the concentration of 10(9) 50% embryo lethal dose (ELD(50))/ml, were used for the determination of the survival of the virus under different chemical and physical treatments. The chemical treatments were performed by incubating the viruses with various types of disinfectants including glutaraldehyde (Glu), hydrogen peroxide, quaternary ammonium compounds (QAC), Glu+QAC, iodine, chlorine, formalin and phenol, at 25 and 37 degrees C, for 0, 5, 7, and 14 days. The physical treatments included incubation of the viruses at 55, 60, 65, 70 and 75 degrees C for 10, 15, 30, 45 and 60 min or pH 3, 5, 7, 9 and 12. The results revealed that AIV H5N1 reference viruses, 2004.1, CUK-2/04 and 2004.2, showed low or no resistance against Glu+QAC, chlorine and phenol at both tested temperatures. Incubations at 70 degrees C for 60 min or at least 75 degrees C for at least 45 min could effectively inactivate all of the isolates, whereas all ranges of pH could not inactivate any of them. In this study, CUK-2/04 was more resistant to the disinfectants, temperatures, and pH compared to the other isolates.

Inactivation of avian influenza viruses by chemical agents and physical conditions: a review

The recent outbreaks of avian influenza (AI) worldwide have highlighted the difficulties in controlling this disease both in developed and in developing countries. Biosecurity is considered the most important tool to prevent and control AI. In certain areas of the world, AI has become endemic and the recent outbreaks in Europe and Africa show that the epidemiological situation is evolving in an unprecedented way. The consequences of this situation are economic losses to the poultry industry, food security issues in developing countries and a serious threat to human health, due to the direct consequences of AI infection in humans, and more alarmingly due to the risk of the generation of a new pandemic virus from the animal reservoir. In this paper, the physical and chemical methods of inactivating AI viruses are reviewed, with particular emphasis on the practicalities of using such methods in the poultry industry.

Survey of bovine enterovirus in biological and environmental samples by a highly sensitive real-time reverse transcription-PCR

Animal enteroviruses shed in the feces of infected animals are likely environmental contaminants and thus can be used as indicators of animal fecal pollution. Previous work has demonstrated that bovine enterovirus (BEV) present in bovine feces contaminates waters adjacent to cattle herds and that BEV-like sequences are also present in shellfish and in deer feces from the same geographical area. However, little information is available about the prevalence, molecular epidemiology, and genomic sequence variation of BEV field isolates. Here we describe an optimized highly sensitive real-time reverse transcription-PCR method to detect BEV RNA in biological and environmental samples. A combination of the amplification procedure with a previously described filtration step with electropositive filters allowed us to detect up to 12 BEV RNA molecules per ml of water. The feasibility of using the method to detect BEV in surface waters at a high risk of fecal pollution was confirmed after analysis of water samples obtained from different sources. The method was also used to study the prevalence of BEV in different cattle herds around Spain, and the results revealed that 78% (78 of 100) of the fecal samples were BEV positive. BEV-like sequences were also detected in feces from sheep, goats, and horses. Nucleotide sequence analyses showed that BEV isolates are quite heterogeneous and suggested the presence of species-specific BEV-like variants. Detection of BEV-like sequences may help in the differentiation and characterization of animal sources of contamination.

Bovine enterovirus 2: complete genomic sequence and molecular modelling of a reference strain and a wild-type isolate from endemically infected US cattle

Bovine enteroviruses are members of the family Picornaviridae, genus Enterovirus. Whilst little is known about their pathogenic potential, they are apparently endemic in some cattle and cattle environments. Only one of the two current serotypes has been sequenced completely. In this report, the entire genome sequences of bovine enterovirus 2 (BEV-2) strain PS87 and a recent isolate from an endemically infected herd in Maryland, USA (Wye3A) are presented. The recent isolate clearly segregated phylogenetically with sequences representing the BEV-2 serotype, as did other isolates from the endemic herd. The Wye3A isolate shared 82 % nucleotide sequence identity with the PS87 strain and 68 % identity with a BEV-1 strain (VG5-27). Comparison of BEV-2 and BEV-1 deduced protein sequences revealed 72-73 % identity and showed that most differences were single amino acid changes or single deletions, with the exception of the VP1 protein, where both BEV-2 sequences were 7 aa shorter than that of BEV-1. Homology modelling of the capsid proteins of BEV-2 against protein database entries for picornaviruses indicated six significant differences among bovine enteroviruses and other members of the family Picornaviridae. Five of these were on the 'rim' of the proposed enterovirus receptor-binding site or 'canyon' (VP1) and one was near the base of the canyon (VP3). Two of these regions varied enough to distinguish BEV-2 from BEV-1 strains. This is the first report and analysis of full-length sequences for BEV-2. Continued analysis of these wild-type strains should yield useful information for genotyping enteroviruses and modelling enterovirus capsid structure.