| Getah virus(GETV)is a single stranded RNA virus of the SemLiki Forest virus complex,Alphavirus,Togaviridae.The virus is borne by blood-sucking arthropods and widely distributed in regions such a Southeast Asia,Pacific Islands and Northern Australia.The virus can infect a variety of vertebrates,giving rise to fever,urticaria,systemic lymphadenectasis,abortion and other symptoms.Getah virus antibody was detected in the human body,but its relation with human disease is unclear.Therefore,Getah virus is a potential huge threat to livestock and human health.In this study,about 20,000 culicoides,10 samples of sheep serum and 5 samples of bovine serum were collected in mid-to-end of July,2016 in Dunkuotan Village,Yuli County of Xinjiang,thereinto,2000 Culicoides were randomly selected and fixed by 75% alcohol for species identification of Culicoides;the rest 18,000 culicoides were divided into 360 groups,ground and then inoculated into BHK-21,C6/36 and Vero cells for virus isolation;identification was conducted on the isolated virus by RT-PCR,neutralization test and electron microscopy observation;sequencing was carried out on 4 gene segments of non-structural protein region,capsid protein region,E2 protein region and 3' untranslated region of the isolated Getah virus,and hereditary character analysis was made;neutralization test was conducted on the isolated Getah virus and the collected bovine and sheep serum to learn the epidemic situation of Getah virus in local area.The results showed that,a total of five known species of Culicoides were identified: Culicoides pseudosalinarius,40.9%;Culicoides punctatus,20.25%;Culicoides circumscriptus,15.55%;Culicoides wadai,4.15%;Culicoides peliliouensis,4.00%.hereinto,Culicoides pseudosalinarius belongs to the Culicoides subspecies with overwhelming superiority.However,one species about 323 Culicoides were unidentified,which accounted for 16.15% of the total.After the grinding fluid of the Culicoides was inoculated into cells,the C6/36 and Vero cells underwent blind passage for five generations without causing cytopathic effect(CPE),and XJ73 strain had CPE in the second generation of BHK-21 cells.The virus solution was collected and the virus was identified as RNA virus by floxuridine.Then the virus was identified as Getah virus by PCR using the universal primers of Alphavirus,neutralization test and electron microscopy observation;The sequencing result of 4 gene segments of non-structural protein region,capsid protein region,E2 protein region and 3' untranslated region of the XJ73 strain was compared with that of other Getah viruses in the GenBank database,and it's found that the homology between the XJ73 strain and the Getah virus(AB859822.1)isolated from swine in Japan in 2005 reached up to 99%,while XJ73 strain has relatively distant genetic relations with Getah strain isolated in Hainan,Yunnan,Hebei,Gansu and Shanghai of China,and the homology between them is within the range of 97% to 98%.In addition,results of the neutralization test on XJ73 strain and the collected 15 samples of bovine and sheep serum showed that 2 samples of bovine serum and 1 sample of sheep serum can have neutralization reaction with the XJ73 strain.A total of five species of Culicoides in Yuli Xinjiang were identified in this study,thereinto,Culicoides pseudosalinarius is the Culicoides species with absolute predominance;Getah virus was isolated from Xinjiang culicoides for the first time,its homology with the Japanese strain reached 99% and 97% to 98%with the Chinese isolates;the phenomenon of Getah virus infection exists in cattle and sheep in Xinjiang. |
PDF Full Text Request