Haemagglutinin and neuraminidase characterization of low pathogenic H5 and H7 avian influenza viruses isolated from Northern pintails (Anas acuta) in Japan, with special reference to genomic and biogeographical aspects

Evaluation of chlorine dioxide in liquid state and in gaseous state as virucidal agent against avian influenza virus and infectious bronchitis virus

The antiviral activity of chlorine dioxide (ClO2) in liquid (ClO2 gas dissolved liquid) and gaseous state against avian influenza virus (AIV) and infectious bronchitis virus (IBV) was evaluated. To evaluate the effect of ClO2 in liquid state, suspension tests (10 ppm) and carrier tests in dropping / wiping techniques (100 ppm) were performed. In the suspension test, virus titers were reduced below the detection limit within 15 sec after treatment, in spite of the presence of an accompanying organic matter. In the carrier test by dropping technique, AIV and IBV were reduced to below the detection limit in 1 and 3 min, respectively. Following wiping technique, no virus was detected in the wiping sheets after 30 sec of reaction. Both viruses adhering to the carriers were also reduced by 3 logs, thereby indicating that they were effectively inactivated. In addition, the effect of ClO2 gas against IBV in aerosols was evaluated. After the exposure of sprayed IBV to ClO2 gas for a few seconds, 94.2% reduction of the virus titer was observed, as compared to the pre-treatment control. Altogether, hence, ClO2 has an evident potential to be an effective disinfectant for the prevention and control of AIV and IBV infections on poultry farms.

Synergistic effects of quaternary ammonium compounds and food additive grade calcium hydroxide on microbicidal activities at low temperatures

The microbicidal activities of mixtures of quaternary ammonium compounds (QACs) and food additive grade calcium hydroxide (FdCa(OH)₂) were evaluated in a suspension test at −20°C using an anti-freeze agent (AFA) containing methanol, or at 1°C, with varying contact time, toward avian influenza virus (AIV), Newcastle disease virus (NDV), fowl adenovirus (FAdV), avian reovirus (ARV), Salmonella Infantis (SI) and Escherichia coli (EC). At −20°C, the mixtures could inactivate AIV and NDV within 30 min, FAdV and ARV within 5 sec, and SI and EC within 3 min, respectively. AFA did not inactivate viruses and bacteria within 30 min and 10 min, respectively. At 1°C, the mixtures inactivated FAdV and ARV within 30 sec, AIV within 10 min, and NDV within 30 min. A mixture of slaked lime (SL) and QAC could inactivate FAdV and ARV within 30 sec, but could not inactivate AIV and NDV even after 60 min at 1°C. SL could not substitute FdCa(OH)₂ in order to exert the synergistic effects with QAC. Thus, QACs microbicidal activities were maintained or enhanced by adding FdCa(OH)₂. It is hence recommended to use QACs with FdCa(OH)₂, especially in the winter season.

Virucidal activity of slightly acidic hypochlorous acid water toward influenza virus and coronavirus with tests simulating practical usage

Slightly acidic hypochlorous acid waters (SAHWs) with pH of 5.2-5.8 containing different concentrations of free available chlorine - 62, 119, 220, 300, and 540 ppm (SAHW-62, -119, -220, -300, and -540, respectively) - were evaluated for their virucidal activity toward a low pathogenic H7N1 avian influenza virus (AIV) and an infectious bronchitis virus (IBV) in suspension, abiotic carrier, and direct spray tests, with the presence of organic materials. In the carrier test, the dropping and wiping techniques were performed toward viruses on carriers. In the suspension test, SAHW-62 could decrease the viral titer of both AIV and IBV by more than 1000 times within 30 s. With the dropping technique, IBV on carriers showed high resistance to SAHW, while AIV on plastic carrier was inactivated to an effective level (≧3 log virus reduction) within 1 min. With the wiping technique, SAHW-62 could inactivate both AIV and IBV on wiped plastic carriers to an effective level within 30 s. However, SAHW-220 could not inactivate IBV in the wiping rayon sheet to an effective level. In the direct spray test, sprayed SAHW-300 within 10 min, and SAHW-540 within 20 min, inactivated AIV and IBV on the rayon sheets to undetectable level, respectively. Our study indicates that the usage of wipes with SAHW could remove viruses from plastic carriers, while viruses remained in the wipes. Besides, a small volume of sprayed SAHW was effective against the viruses on the rayon sheets for daily cleaning in the application area. The findings we obtained concerning IBV might basically be applicable in relation to SARS-CoV-2, given the resemblance between the two viruses.

Virucidal Efficacy of a Quaternary Ammonium Compound with Food Additive-Grade Calcium Hydroxide Toward Avian Influenza Virus and Newcastle Disease Virus on Abiotic Carriers

The virucidal efficacies of a 0.2% food additive-grade calcium hydroxide [FdCa(OH)₂] solution, a quaternary ammonium compound (QAC) diluted at 1:500 (QACx500), and their mixture [Mix500; FdCa(OH)₂ powder added at a final concentration of 0.2% to QACx500] were investigated as fomites for avian influenza virus (AIV) and Newcastle disease virus (NDV) on abiotic carriers (steel, rubber, and plastic) at two different temperatures (room temperature [RT; 25 ± 2 C] and 2 C). These viruses were seeded on coupons (5 cm×5 cm) of rubber, steel, or plastic with 5% fetal bovine serum. After complete drying, the coupons were covered with the test solutions at RT or 2 C. After fixed incubation periods, viruses were recovered from the coupons and titrated. At RT, Mix500 required a short time (3 min) to inactivate AIV and NDV to effective levels (≥3 log virus reduction) on rubber, steel, and plastic carriers compared with QAC or FdCa(OH)_2. At low temperature, QACx500 inactivated AIV on steel and plastic carriers to effective levels within 60 min, whereas Mix500 did so within 10 min. QACx500 and FdCa(OH)₂ solutions could inactivate NDV on steel and plastic carriers within 20 and 10 min, respectively, and Mix500 could do so within 3 min. Viruses on the carriers required longer incubation periods for inactivation at 2 C than at 25 C. These results demonstrate desirable synergistic virucidal effects of Mix500 for important poultry viruses on abiotic carriers, while indicating high applicability within poultry farming.

Stability and virucidal efficacies using powder and liquid forms of fresh charcoal ash and slaked lime against Newcastle disease virus and Avian influenza virus

Aim:

The present study was examined the virucidal activity comparison between fresh charcoal ash (FCA) and slaked lime (SL) against avian influenza virus (AIV) and Newcastle disease virus (NDV), using powder and liquid forms, either in the absence or presence of organic materials. In addition, both FCA and SL were evaluated for the persistence of virucidal activity in wet and dry conditions and stability of the solution.

Materials and Methods:

Two hundred milligrams of FCA or SL powders were mixed with 100 µl of AIV or NDV in the absence of organic material or 33% of organic materials. In the same time, 400 µl of 1%, 5%, or 10% solution samples were mixed with 100 µl of each virus and then incubated at room temperature for an indicated time. After that, the mixed solution was stop activity of sample using 500 µl of 1M Tris-HCl pH 7.2. Each treatment was titrated onto Madin-Darby canine kidney cells or chicken embryo fibroblasts for AIV or NDV, respectively, for determining the efficacy of viral inactivation. In addition, the stability of powder under the wet-dry condition and solution stability under room temperature was examined.

Results:

The results demonstrated that the FCA and SL in powder form could inactivate AIV and NDV even in the absence or presence of organic materials. In the liquid form, 5% and 10% of FCA could inactivate AIV and NDV either in the absence or presence of organic materials. Alongside, 1%, 5%, and 10% of SL could inactivate both viruses. 10% of FCA solution could inactivate virus at a shortest time when compared with other concentrations. In addition, the efficacy of wet-dry conditions of FCA was limited when compared with SL. On the other hand, it is demonstrated that the FCA solution was more stable and kept at room temperature longer than SL.

Conclusion:

The FCA may, hence, be used as an alternative virucide, while applying it to prevent spreading of poultry disease on commercial chicken farms and also backyard chickens, especially in developing countries, including in rural areas of Thailand.

Bactericidal and virucidal efficacies of potassium monopersulfate and its application for inactivating avian influenza virus on virus-spiked clothes

An acidic agent, potassium monopersulfate (PMPS), was evaluated for bactericidal and virucidal effects against Salmonella Infantis (SI), Escherichia coli, rifampicin-resistant Salmonella Infantis (SI-rif), Newcastle disease virus (NDV), and avian influenza virus (AIV), in the absence or presence of organic materials. In addition, inactivation activity toward a virus on virus-spiked clothes was also examined. PMPS could inactivate SI, E. coli, and SI-rif even in the presence of organic materials under various concentrations and exposure/contact time conditions. PMPS could also inactivate NDV and AIV. In addition, PMPS could inactivate AIV on a virus-spiked rayon sheet. In conclusion, the present study showed that PMPS has good antimicrobial properties against SI, E. coli, SI-rif, NDV, and AIV when used at the optimal dosage and exposure timing. These results suggest that PMPS could be used as an alternative disinfectant for biosecurity enhancement in animal farms or hospitals.

Virucidal activity of a quaternary ammonium compound associated with calcium hydroxide on avian influenza virus, Newcastle disease virus and infectious bursal disease virus

A quaternary ammonium compound (QAC) was evaluated for its virucidal efficacies with food additive grade calcium hydroxide (FdCa(OH)₂). When the QAC was diluted 1:500 (QACx500) with redistilled water (dW₂), it inactivated avian influenza virus (AIV) within 30 sec at 25°C, while at 2°C, it required 1 hr for inactivation. When FdCa(OH)₂ powder was added to QACx500 at a final concentration of 0.17%, the mixture, namely Mix500, inactivated AIV within 3 min at 2°C. After contamination with 1% fetal bovine serum (FBS), Mix500 inactivated AIV within 2 hr at 2°C, but QACx500 did not. These results indicate synergistic effects of the QAC and FdCa(OH)₂ solutions on virucidal activity.

Virucidal Properties of Bioceramic Derived from Chicken Feces pH 13 and its Stability in Harsh Environments

Bioceramic derived from chicken feces (BCX) is a material produced by a sintering process for the purpose of use in animal farms to control livestock infectious diseases. In the present study, BCX at pH 13 was evaluated for the durability of its virucidal activity in simulated field conditions. First it was shown that BCX had activity toward Newcastle disease virus, infectious bursal disease virus, and goose parvovirus within 3 min and toward avian influenza virus (AIV) within 1 hr. BCX was further tested by keeping it under simulated harsh environmental conditions with sunlight for several weeks as well as by repeatedly soaking it with water and drying under sunlight many times. After sampling every 2 consecutive weeks and every 2 (of 9) consecutive resuspensions, BCX was evaluated for its efficacy against AIV. Evaluation under the harsh conditions illustrated that BCX could retain its satisfactory efficacy toward AIV throughout 7 wk and through 9 resuspensions. It is hence concluded that BCX is an excellent material for applying in livestock farming as a trapping disinfectant, due to its efficacy to inactivate various viruses, and that this efficacy is prolonged even under harsh environmental conditions.

Calcinated egg shell as a candidate of biosecurity enhancement material

Calcinated egg shell (Egg-CaO), of which the main component is calcium oxide, was evaluated in the forms of powder and aqueous solutions for their efficacies as disinfectants against avian influenza virus (AIV), Newcastle disease virus (NDV), infectious bursal disease virus (IBDV), Salmonella Infantis and Escherichia coli. Egg-CaO powder inactivated these viruses within 3 min in the presence of 33% of fetal bovine serum (FBS). In Egg-CaO solutions, except AIV, all pathogens were inactivated within 1 hr, even in the presence of 5% of FBS. Without FBS, all pathogens, except AIV, were inactivated within 3 min, and AIV within 1 hr. In addition, persistence of virucidal activity against AIV and NDV of Egg-CaO powder was confirmed after exposure to sunlight for 2 weeks or resuspension with water for 7 times, simulating field harsh environments. Chick growth test was conducted to ensure the safety of the use of Egg-CaO powder in chicken cages and showed that it is safe to add Egg-CaO in litter or feed. In conclusion, Egg-CaO can be useful for the enhancement of biosecurity at farms.

Efficacy of scallop shell powders and slaked lime for inactivating avian influenza virus under harsh conditions

The efficacy and stability of scallop shell powder (SSP) were investigated, in terms of its capacity to inactivate avian influenza virus (AIV), and compared with slaked lime (SL). An environmental simulation was conducted by emulating sunlight and wet-dry conditions. The powders were collected at consecutive 2-week intervals under sunlight and upon every resuspension. These materials were tested by mixing them with AIV and incubating the mixture for 3 min or 20 h, followed by AIV titration. At the same time, a pH buffering test was conducted by neutralization with Tris-HCl. The results revealed that SSP and SL have high alkalinity and excellent ability to inactivate AIV. In a simulated harsh environment, SSP and SL retained a satisfactory ability to inactivate AIV within 20 h throughout the experimental procedure. However, SSP was able to inactivate AIV during a short contact period (3 min), even under harsh conditions, and it was more resistant than SL to neutralization.

Evaluation of sprayed hypochlorous acid solutions for their virucidal activity against avian influenza virus through in vitro experiments

Hypochlorous acid (HOCl) solutions were evaluated for their virucidal ability against a low pathogenic avian influenza virus (AIV), H7N1. HOCl solutions containing 50, 100 and 200 ppm chlorine (pH 6) or their sprayed solutions (harvested in dishes placed at 1 or 30 cm distance between the spray nozzle and dish) were mixed with the virus with or without organic materials (5% fetal bovine serum: FBS). Under plain diluent conditions (without FBS), harvested solutions of HOCl after spraying could decrease the AIV titer by more than 1,000 times, to an undetectable level (< 2.5 log10TCID50/ml) within 5 sec, with the exception of the 50 ppm solution harvested after spraying at the distance of 30 cm. Under the dirty conditions (in the presence of 5% FBS), they lost their virucidal activity. When HOCl solutions were sprayed directly on the virus on rayon sheets for 10 sec, the solutions of 100 and 200 ppm could inactivate AIV immediately after spraying, while 50 ppm solution required at least 3 min of contact time. In the indirect spray form, after 10 sec of spraying, the lids of the dishes were opened to expose the virus on rayon sheets to HOCl. In this form, the 200 ppm solution inactivated AIV within 10 min of contact, while 50 and 100 ppm could not inactivate it. These data suggest that HOCl can be used in spray form to inactivate AIV at the farm level.

Inactivation of avian influenza virus, newcastle disease virus and goose parvovirus using solution of nano-sized scallop shell powder

Scallop shell powder produced by calcination process − the average diameter of the powder particles being 20 µm (SSP) − was further ground into nano-sized particles, with average diameter of 500 nm, here designated CaO-Nano. Solution of CaO-Nano could inactivate avian influenza virus within 5 sec, whereas the solution of SSP could not even after 1 hr incubation. CaO-Nano solution could also inactivate Newcastle disease virus and goose parvovirus within 5 sec and 30 sec, respectively. The virus-inactivating capacity (neutralizing index: NI>3) of the solution was not reduced by the presence of 20% fetal bovine serum. CaO-Nano solution seems to be a good candidate of materials for enhancement of biosecurity in farms.

Genetic Analysis of Avian Influenza Viruses: Cocirculation of Avian Influenza Viruses with Allele A and B Nonstructural Gene in Northern Pintail (Anas acuta) Ducks Wintering in Japan

The pandemic influenza virus strains of 1918 (H1N1), 1957 (H2N2), 1968 (H3N2), and 2009 (H1N1) have genes related to avian influenza viruses (AIVs). The nonstructural (NS) gene of AIVs plays a significant role in host-viral interaction. However, little is known about the degree of diversity of this gene in Northern pintail (Anas acuta) ducks wintering in Japan. This study describes characteristics of pintail-originated H1N1, H1N2, H1N3, H5N2, H5N3, H5N9, and H7N7 viruses. Most of the viruses were revealed to be avian strains and not related to pandemic and seasonal flu strains. Nevertheless, the NP genes of 62.5% (5/8) viruses were found closely related to a A/swine/Korea/C12/08, indicating exchange of genetic material and ongoing mammalian-linked evolution of AIVs. Besides, all the viruses, except Aomori/422/07 H1N1, contain PSIQSR∗GLF motif usually found in avian, porcine, and human H1 strains. The Aomori/422/07 H1N1 has a PSVQSR∗GLF motif identical to a North American strain. This findings linked to an important intercontinental, Asian-American biogeographical interface. Phylogenetically all the viruses were clustered in Eurasian lineage. Cocirculation of allele A and B (NS gene) viruses was evident in the study implying the existence of a wide reservoir of influenza A viruses in pintail wintering in Japan.

Genetic analyses of avian influenza viruses in Mongolia, 2007 to 2009, and their relationships with Korean isolates from domestic poultry and wild birds

The present study was conducted to monitor wild birds based on the concern that they could disseminate avian influenza virus (AIV) between Mongolia and Korea, which shares the same migratory flyway. Of 1,528 fecal samples analyzed, 21 low-pathogenic AIV were isolated from 2007 to 2009. Nineteen AIV-positive fecal samples were identified as Anseriformes by DNA bar coding. The most frequently isolated subtype was H3 (61.9%), and the most prevalent hemagglutinin/neuraminidase combination was H3N8 (52.4%). Phylogenetic analysis was performed to assess their genetic relationships with those of domestic poultry and wild birds in Korea. The H3 and H7 surface genes belonged to the Eurasian lineage and clustered together in a group with Korean wild birds and poultry. Most N8 genes clustered phylogenetically with viruses isolated in Eurasia, whereas 1 of the Mongolian viruses and some Korean viruses belonged to the North American lineage. The polymerase acidic protein of the internal gene was not distinguishable from the H5N1 highly pathogenic AIV of the goose/Guangdong/1/1996 (Gs/Gd)-like virus. Our study suggests that Mongolian AIV isolates have evolved with genetically multiple genotypes and are closely related to those of AIV in poultry as well as in wild birds in Korea.