Regression of viral pathogen indicators due to improvement of hygiene protocols on boots in a bovine farm.

Rotavirus A (RVA), bovine torovirus (BToV), bovine enterovirus (BEV) and bovine coronavirus (BCV) at a bovine farm in Ibaraki prefecture were monitored by one-step multiplex reverse transcription polymerase chain reaction (RT-PCR), with the aim of confirming the reduction of "viral pathogen indicators". A total of 960 bovine fecal samples were collected from calves less than 2 month-old within the period from October 2016 to October 2018 every 2 months at the bovine farm. In each sampling, 40 samples were taken from calves 3 week-old or less, and 40 samples from calves over 3 week-old, in principle. At the end of September 2017, the farm introduced improvement of hygiene protocols on boots by exchanging boots and appropriate usage of a footbath at the entrance of calf sheds. In the comparison of the virus detection by RT-PCR, prevalence of all 4 viruses was significantly reduced (P<0.01) in calves 3 week-old or less after the improvement. The mortality of calves less than 2 month-old was also significantly reduced after the improvement of hygiene protocols. These data suggest that the proper control of boots at calf sheds is important, perhaps even vital, for rearing hygiene measures at bovine farms so as to attain substantial decrease in the prevalence of pathogens.

Inhibitory effect of grapefruit seed extract (GSE) on avian pathogens.

The inhibitory activities of grapefruit seed extract (GSE) on avian influenza virus (AIV), Newcastle disease virus (NDV), infectious bursal disease virus (IBDV), Salmonella Infantis (SI) and Escherichia coli (EC) were evaluated. Original GSE contained 0.24% benzalkonium chloride (BZC), however, 0.0025% BZC solution could not inactivate bacteria. The activity of diluted GSE (×100, ×500 and ×1,000 with redistilled water) against selected viruses and bacteria was evaluated in this study. The GSE solutions were incubated with the pathogens over a period of time after which the remaining viruses were titrated and the bacterial colonies were counted. In the presence of organic material-5% fetal bovine serum (FBS), the test solutions were sprayed at 1 cm and 30 cm distances to test the efficacy of GSE in a spray form. Furthermore, the efficacy of GSE against bacteria on clothes was tested using non-woven cloth. GSE×100 reduced the viral titer of both AIV and NDV even in 5% FBS condition. IBDV showed high resistance to GSE. GSE×1,000 inactivated both SI and EC within 5 sec, even in the presence of 5% FBS. The disinfectant was able to maintain its efficacy in the spray form at 30 cm distance. GSE was also effective against SI and EC inoculated on fabric. GSE is a potential novel disinfectant against viruses and bacteria, effective even within a short contact time.

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.

Eficacia virucida de un compuesto de amonio cuaternario con hidróxido de calcio con grado aditivo alimentario contra el virus de la influenza aviar y el virus de la enfermedad de Newcastle en vehículo abióticos. Las eficacias virucidas de una solución de hidróxido de calcio [FdCa(OH)2] con grado aditivo alimentario al 0.2%, de un compuesto de amonio cuaternario (QAC) diluido a 1:500 (QACx500) y su mezcla [Mix500; FdCa(OH)2 en polvo agregado en una concentración final de 0.2% en QACx500] se investigaron en forma de fómites para el virus de la influenza aviar (AIV) y para el virus de la enfermedad de Newcastle (NDV) en vehículos abióticos (acero, hule y plástico) a dos temperaturas diferentes (temperatura ambiente [RT; 25 ± 2 C] y 2 C). Estos virus se sembraron en placas (5 cm x 5 cm) de hule, acero o plástico con suero bovino fetal al 5%. Después del secado completo, los cupones se cubrieron con las soluciones bajo ensayo a temperatura ambiente o 2 C. Después de los períodos de incubación fijos, los virus se recuperaron de las placas y se titularon. A temperatura ambiente, la mezcla Mix500 requirió un corto tiempo (tres minutos) para desactivar a los virus de influenza y de Newcastle a niveles efectivos (reducción igual o mayor de tres logaritmos en el título viral) en las placa de hule, acero y plástico en comparación con el tratamiento QAC o FdCa(OH)2. A baja temperatura, el tratamiento QACx500 inactivó al virus de la influenza en placas de acero y plástico a niveles efectivos dentro de 60 minutos, mientras que el tratamiento Mix500 lo hizo en 10 minutos. Las soluciones QACx500 y FdCa(OH)2 pudieron inactivar al virus de Newcastle en las placas de acero y plástico dentro de 20 y 10 minutos, respectivamente, y el tratamiento Mix500 pudo hacerlo dentro de tres minutos. Los virus en los vehículos requirieron períodos de incubación más prolongados para la inactivación a 2 C que a 25 C. Estos resultados demuestran los efectos virucidas sinérgicos deseables del tratamiento Mix500 para virus aviares importantes en vehículos abióticos, además de que indican una alta aplicabilidad dentro de la avicultura.