Study On The Activity Of The NAS Preparations Against H5N1 And H9N2 Subtype In Vitro And Against H9N2 Subtype AIV In Chicken

The NAS preparations,made by compounding Hedyotic diffusas,common stonecrop herbs, abrotani herbas,and others herbs with mulvital, have good prevention and cure effect on Avian Influenzal through many experimental identifications.Inactivated effect of the NAS preparations on H5N1 subtype and H9N2 subtype AIV was investigated by Klein-Defors test in vitro.The NAS preparations were diluted with the concentrations of 1:40,1:80,1:160,1:320,1:640,and mixed with H5N1 subtype AIV(107.63EID50)and H9N2 (108.17EID50) subtype AIV by 9:1 respectively.Then the mixture was diluted to 10 dilutions with sterile physiologic saline.The 10-day-old SPF chicken embryos were inoculated with the dilutions after interacting for 10 minutes and 30 minutes between the preparations and the virus under the conditions of 20±1oC.The same treatment as the other test group,while the 0.001g/ml,0.01g/ml,0.1g/ml,1g/ml Ribavirin take the place of the NAS preparations in the the drugs control group,the sterilized saline replaced mixture in the negative control,and the chicken embryos were inoculated with virus in postitive control.The inoculated chicken embryos were cultivated in 37 oC incubator,and the death informations of chicken embryos were recorded. The chicken embryos'allantoic fluid was taken after 96 hours'cultivation and tested their hemagglutination valency.The result showed that the inactiviated ratios of the 1:80 NAS preparations on H5N1 subtype and H9N2 subtype AIV were all 99.99% when the preparations and the virus mixing for 10 minutes and 30 minutes. the inactiviated ratios of the 1:160 NAS preparations on H5N1 subtype AIV were 32.39% and 99.99% when the preparations and the virus mixing for 10 minutes and 30 minutes respectively. And the inactiviated ratios of the 1:160 NAS preparations on H9N2 subtype AIV were 32.39% and 90% when the preparations and the virus mixing for 10 minutes and 30 minutes respectively.To identify the inhibitory action of NAS preparations on AIV in vivo,the test were carried out about inhibitory action of NAS preparations on H9N2 subtype AIV in chicken.96 28-day-old chickenswere randomly divided into 6 groups.There are three NAS preparations,amantadine control group,negative control group,and positive control group in this study.After inoculated with H9N2 subtype AIV,the chickens of three NAS preparations were orally taken the drugs with the dosage of 0.2g/kg·d,0.1g/kg·d and 0.05g/kg·d.The chickens of the amantadine control group after inoculated with H9N2 subtype AIV drinked the water contained the amantadine.During the course of test,oropharyngeal and cloacae swabs of all group's chickens were collected every day,and the AIV was inspected by HA test and RT-PCR. The results showed that no H9N2 subtype AIV were detected after inoculated with the virus 4 days when the chickens were treated with the NAS preparations at the dosages of 0.2g/kg and 0.1g/kg for 3days.While the virus were detected after inoculated 7 days when the chickens were treated with the NAS preparations at the dosages of 0.05g/kg for 3days.The test indicated that NAS preparations had better protection effect on the chickens which inoculated with H9N2 subtype AIV,and had significant devation from the amantadine control group.The above test will provide theory evidencen and experimental base for the application of NAS preparations.