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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Veterinary Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Iran,vaccine,H9N2,Vaccination,Viral load
- چکیده: پیشینه: آنفلوانزای پرندگان (AI) که توسط تحت تیپ H9N2 ایجاد میشود یک بیماری ویروسی شایع با خسارات اقتصادی فراوان از طریق تظاهرات قابل توجه تنفسی و گوارشی در مزارع پرورش طیور است. میزان ایمنی ایجاد شده توسط یک واکسن به طور عمده به سطح شباهت آنتی ژنی بین سویه چالش و سویه واکسن بستگی دارد. هدف: هدف این مطالعه بررسی اثر احتمالی تغییرات آنتی ژنی مداوم رخ داده در ویروسهای در حال گردش ایران از سال 1998 بر تاثیرات واکسنهای تجاری تهیه شده از بذرهای همه گیریهای قبل برای مهار میزان تکثیر ویروس در ارگانهای هدف جوجههای گوشتی چالش داده شده با جدایههای اخیر، میباشد. روش کار: نود قطعه جوجه گوشتی در سن یک روزگی به صورت تصادفی به 5 گروه تقسیم شدند و با واکسنهای اتوژن یا تجاری (A یا B) واکسینه شدند. دو گروه باقیمانده شامل گروه بدون واکسیناسیون و گروه چالش بود. واکنش زنجیرهای پلیمراز زمان حقیقی (qRT-PCR) بر روی نمونههای نای و مدفوع جوجههای چالش داده شده با ویروس H9N2 جدید جهت تعیین تکثیر ویروس انجام شد. همچنین آنتی بادیهای هومورال توسط آزمون آگلوتیناسیون مهاری (HI) ارزیابی شدند. نتایج: تفاوت معنیداری در تکثیر ویروس H9N2 در نای بین گروههای واکسینه شده در روز 5 پس از چالش (DPC) وجود نداشت، اما در روز 15 پس از چالش، واکسن اتوژن در مقایسه با واکسنهای تجاری به طور معنیداری تکثیر ویروس را کاهش داد (P≤0.05). تفاوت معنیداری در میزان ویروس سواب مدفوعی، بین گروه واکسن اتوژن و واکسن تجاری A مشاهده نشد و هر دو واکسن به طور معنیداری موجب مهار تکثیر ویروس در مقایسه با گروه واکسینه نشده، شدند (P≤0.05). همچنین، واکسن اتوژن بیشترین تیتر HI را باعث میشود. نتیجهگیری: واکسنهای غیر فعال شده که از جدایههای همه گیریهای قبلی تهیه میشوند چندان قادر به ایجاد ایمنی مناسب بر علیه ویروسهای H9N2 اخیر نیستند. به نظر میرسد اکنون زمان تغییر واکسنها با استفاده از جدایههای جدید است که شباهت آنتی ژنی بیشتری با ویروسهای H9N2 جدید در حال گردش در منطقه دارند.
- چکیده انگلیسی: Background: Avian influenza (AI) caused by AI virus subtype H9N2 is a prevalent viral disease with enormous economic losses in poultry farms through significant respiratory and gastrointestinal manifestations. The degree of protection obtained from a vaccine strongly depends on the level of antigenic similarity between challenge and vaccine virus. Aims: The study aimed at investigating the possible effects of continuous antigenic changes occurring in circulating Iranian viruses since 1998 on the commercial vaccines outcome by using vaccine seeds from earlier outbreaks for inhibiting viral replication in target organs of broilers challenged with the recent isolate. Methods: Ninety broilers at one day of age were randomly allocated into 5 groups and vaccinated with autogenous or commercial vaccines (A or B). Two remaining groups consisted of challenged without vaccination and intact birds. Quantitative real time-polymerase chain reaction (qRT-PCR) was performed on the trachea and faecal samples of challenged chickens with recent H9N2 virus to determine viral load. Moreover, humoral antibodies titers were evaluated by hemagglutination inhibition (HI) assay. Results: There was no significant difference in H9N2 viral load in the trachea among vaccinated groups on 5 days post challenge (DPC), but on 15 DPC, the autogenous vaccine significantly lowered viral load compared to commercial vaccines (P≤0.05). No significant differences in faecal swab’s viral load was observed between autogenous and commercial vaccine A, and both of them significantly inhibited viral load compared to unvaccinated group (P≤0.05). In addition, the autogenous vaccine elicited the highest HI titer. Conclusion: Inactivated vaccines that use isolates from previous outbreaks are no longer able to induce proper immunity against recent H9N2 viruses. It seems the time to change vaccine strains to more recent isolates that have better antigenic similarity with current circulating H9N2 viruses in the region has come.
- انتشار مقاله: 25-01-1398
- نویسندگان: M. H. Fallah Mehrabadi,A. Ghalyanchilangeroudi,S. A. Ghafouri,H. Hosseini,M. T. Zabihi Petroudi,A. Modiri Hamadan,H. Rezaee,P. Motamed Chaboki,S. Vatandour,A. Shayeganmehr
- مشاهده
- جایگاه : پژوهشی
- مجله: Archives of Razi Institute
- نوع مقاله: Journal Article
- کلمات کلیدی: Iran,Real-time RT-PCR,D1466 infectious bronchitis,Commercial farms
- چکیده:
- چکیده انگلیسی: Infectious bronchitis is one of the most common diseases in the poultry industry in many countries, especially in the regions with a dense poultry farming industry. Gammacoronavirus is the etiologic agent of this disease, with the chickens and poultries as the natural reservoirs of the virus. Various strains of infectious bronchitis virus have been reported in poultry around the world. In terms of pathogenicity, this virus can induce a spectrum of diseases ranging from the moderate respiratory tract to kidney and reproductive diseases. The serotypes of this virus do not cause cross-immunity against each other. This issue makes it difficult to control the disease. Based on the analysis of the highly variable region of the glycoprotein S1 gene, the isolated strains in Iran were classified into seven different phylogenetic groups, including Massachusetts, QX, IS-720, IS-1494, 793/B, IR-1, and IR-2. The D1466 genotype has not been reported in the country; however, the killed vaccine is used in broiler breeder farms. In this study, tissue specimens were collected from 700 farms (i.e., broiler, egg-laying, and broiler breeder farms) suspected of infectious bronchitis within 2013-2017. The samples were examined using real-time reverse transcription-polymerase chain reaction. The D1466 genotype was not detected in any of the studied specimens. Due to the lack of immunity of the D1466 serotype against the dominant types in the country, one has to be careful in choosing the right vaccine. It is necessary to perform continuous monitoring of the circulation status of the various serotypes of viruses in the country to identify the dominant and possible new serotypes for the utilization of the appropriate vaccine.
- انتشار مقاله: 08-02-1397
- نویسندگان: R. Khaltabadi Farahani,A. Ghalyanchilangeroudi,M. H. Fallah Mehrabadi,S. A. Ghafouri,H. Maghsoudloo
- مشاهده
- جایگاه : پژوهشی
- مجله: Archives of Razi Institute
- نوع مقاله: Journal Article
- کلمات کلیدی: Iran,Avian Influenza,H9N2,Seroprevalence,Ostrich
- چکیده:
- چکیده انگلیسی: The aim of this study was to determine the seroprevalence of avian influenza H9N2 subtype in the industrial ostrich farms and its geographical distribution. This cross-sectional study was conducted from January to June 2015. A total of 40 farms were selected from different provinces of Iran, from each of which 11 ostriches (n=440) were sampled. The sera samples were examined using 4 hemagglutination units of H9N2 antigens. A frequency distribution was used to describe the responses to the survey questions. The mean titers between provinces were compared using one-way analysis of variance. According to the results, 21 (47.5%) out of 40 farms and 108 (24.5%) out of 440 ostriches tested positive in the HI-H9N2 test. There were statistically significant differences between the mean titers of samples in different provinces (P<0.001). The current study was conducted on unvaccinated ostriches. The results showed that H9N2 had a high seroprevalence at both farm and bird levels. The findings of this study can be for the further investigation of infection in ostrich farms in order to consider this species in the surveillance programs of the Iranian Veterinary Organization. The detection and isolation of viruses and epidemiological investigation are necessary for the persistent use of H9N2 vaccines in some ostrich farms.
- انتشار مقاله: 07-08-1395
- نویسندگان: M. H. Fallah Mehrabadi,A. Bahonar,K. Mirzaei,A. Ghalyanchi Langeroudi,S. A. Ghafouri,F. Tehrani,A. Hashemi
- مشاهده