Natthanan Sangsriratanakul

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.

Accuracy of the evaluation method for alkaline agents’ bactericidal efficacies in solid, and the required time of bacterial inactivation

An alkaline agent, namely food additive grade calcium hydroxide (FdCa (OH)2) in the powder form, was evaluated for its bactericidal efficacies in chicken feces at pH 13. The point for this evaluation was neutralization of the alkaline agent’s pH at the time of bacterial recovery, since otherwise the results are substantially misleading. Without neutralization of the FdCa (OH)2 pH, the spiked bacteria were killed within min at the time of recovery in aqueous phase, but not in the solid form in feces, hence, it has been demonstrated that when bacteria were in solid, it took longer time than in liquid for the alkaline agent to inactivate them down to the acceptable level (≥3 log10 CFU/ml).

Inactivation of bacteria on surfaces by sprayed slightly acidic hypochlorous acid water: in vitro experiments

The capacity of slightly acidic hypochlorous acid water (SAHW), in both liquid and spray form, to inactivate bacteria was evaluated as a potential candidate for biosecurity enhancement in poultry production. SAHW (containing 50 or 100 ppm chlorine, pH 6) was able to inactivate Escherichia coli and Salmonella Infantis in liquid to below detectable levels (≤2.6 log10 CFU/ml) within 5 sec of exposure. In addition, SAHW antibacterial capacity was evaluated by spraying it using a nebulizer into a box containing these bacteria, which were present on the surfaces of glass plates and rayon sheets. SAHW was able to inactivate both bacterial species on the glass plates (dry condition) and rayon sheets within 5 min spraying and 5 min contact times, with the exception of 50 ppm SAHW on the rayon sheets. Furthermore, a corrosivity test determined that SAHW does not corrode metallic objects, even at the longest exposure times (83 days). Our findings demonstrate that SAHW is a good candidate for biosecurity enhancement in the poultry industry. Spraying it on the surfaces of objects, eggshells, egg incubators and transport cages could reduce the chances of contamination and disease transmission. These results augment previous findings demonstrating the competence of SAHW as an anti-viral disinfectant.

TMPRSS2 Independency for Haemagglutinin Cleavage In Vivo Differentiates Influenza B Virus from Influenza A Virus

Influenza A and B viruses show clear differences in their host specificity and pandemic potential. Recent studies have revealed that the host protease TMPRSS2 plays an essential role for proteolytic activation of H1, H3, and H7 subtype strains of influenza A virus (IAV) in vivo. IAV possessing a monobasic cleavage site in the haemagglutinin (HA) protein replicates poorly in TMPRSS2 knockout mice owing to insufficient HA cleavage. In the present study, human isolates of influenza B virus (IBV) strains and a mouse-adapted IBV strain were analysed. The data showed that IBV successfully underwent HA cleavage in TMPRSS2 knockout mice, and that the mouse-adapted strain was fully pathogenic to these mice. The present data demonstrate a clear difference between IAV and IBV in their molecular mechanisms for spreading in vivo.

Enhancement of bactericidal effects of sodium hypochlorite in chiller water with food additive grade calcium hydroxide

An alkaline agent, namely food additive grade calcium hydroxide (FdCa(OH)2) in solution at 0.17%, was evaluated for its bactericidal efficacies in chiller water with sodium hypochlorite (NaOCl) at a concentration of 200 ppm total residual chlorine. Without organic material presence, NaOCl could inactivate Salmonella Infantis and Escherichia coli within 5 sec, but in the presence of fetal bovine serum (FBS) at 0.5%, the bactericidal effects of NaOCl were diminished completely. FdCa(OH)2 solution required 3 min to inactivate bacteria with or without 5% FBS. When NaOCl and FdCa(OH)2 were mixed at the final concentration of 200 ppm and 0.17%, respectively, the mixed solution could inactivate bacteria at acceptable level (103 reduction of bacterial titer) within 30 sec in the presence of 0.5% FBS. The mixed solution also inhibited cross-contamination with S. Infantis or E. coli on chicken meats. It was confirmed and elucidated that FdCa(OH)2 has a synergistic effect together with NaOCl for inactivating microorganisms.

Virucidal efficacy of food additive grade calcium hydroxide against surrogate of human norovirus

An alkaline agent, namely, food additive grade calcium hydroxide (FdCa(OH)2) in the solution, powder and suspension forms was evaluated as a virucidal agent, using a murine norovirus (MNV) as the surrogate for human norovirus. The main constituent of FdCa(OH)2 is Ca(OH)2, which has pH 13 in 0.17% solution. The results showed that 0.17% FdCa(OH)2 solution could inactivate MNV within 30s even in the presence of organic materials (5% fetal bovine serum (FBS)). In a contaminated surface experiment, MNV with 5% FBS was inoculated on rayon sheets, and the result showed FdCa(OH)2 solution could markedly reduce virus titer within 1min. When mouse feces were spiked with MNV and FdCa(OH)2 powder as 10% and 20% w/w was added to the feces, these concentrations could inactivate the virus within 30min and 15min, respectively. Whereas, FdCa(OH)2 suspension at 2.5% and 5% could inactivate the virus within 30min and at 1% within 45min. These and additional results obtained here indicate that FdCa(OH)2 is an effective virucidal agent against MNV, and can serve as a useful alternative disinfectant for inactivation and prevention of human norovirus in house and hospital.

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

SUMMARY 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.

Bactericidal efficacy of a quaternary ammonium compound with food additive grade calcium hydroxide toward Salmonella Infantis and Escherichia coli on abiotic carriers

The bactericidal efficacies of 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 final concentration 0.2% to QACx500)−were investigated at two different temperatures (room temperature (RT) (25 ± 2°C) and 2°C), using varying contact time, with or without presence of organic materials (5% fetal bovine serum: FBS), either in suspension or on abiotic carrier (steel, rubber and plastic). In the suspension test, QACx500 could inactivate Salmonella Infantis at effective level (≥3 log reductions), within 30 sec and 5 sec, respectively, with or without 5% FBS at RT; however, at 2°C it required 30 min and 1 min, respectively. Mix500 revealed the same efficacy as QACx500 at RT, but, at 2°C it required 1 min and 30 sec, respectively with or without FBS. Whereas, 0.2% FdCa(OH)2 solution alone could inactivate S. Infantis within 1 min and 3 min, respectively at RT and 2°C, even with 5% FBS. In the carrier test, single disinfectant required bit more (3 or 5 min) contact time to reduce bacterial load (S. Infantis or Escherichia coli) down to the effective level on rubber surface than that on steel and plastic surface. However, Mix500 could inactivate both bacteria on carrier surfaces within 1 min, even at 2°C. Thus, synergistic effects were observed in the suspension test and the carrier test at both temperatures toward both bacteria.

Durability of alkaline agents’ bactericidal efficacies in litter under field conditions

Alkaline agents are well-known for their disinfection capacities against pathogens even at the presence of organic materials, but the durability of their bactericidal efficacies under field conditions is unknown. Therefore, within the present study, two alkaline agents, namely bioceramic (BCX) derived from chicken feces and food additive grade Ca(OH)2 (FdCa(OH)2) derived from natural lime stone, were evaluated for the persistence of their bactericidal efficacies in litter, under simulated field conditions. BCX powder mixed at 50% concentration in litter or FdCa(OH)2 powder at 20% concentration in litter lost their bactericidal efficacies at 3 days post exposure of chicks, and thereafter, both mentioned alkaline agents could not inactivate bacteria down to the acceptable level (≥3 log10 CFU/ml reduction).