ردیابی ویروسهای آنفلوانزای طیور،برونشیت عفونی و نیوکاسل در گله های مرغ گوشتی با علامت کالبد گشایی چرکهای پنیری در برونشیولها و محل دو شاخه شدن نای

The presence of fibrinonecrotic casts at the secondary and primary bronchi which might have extended to bifurcation of the trachea is one of the most common necropsy findings among commercial chicken flocks having severe respiratory disease in the field. Our previous study showed that the casts were observed mostly in the birds which affected by avian influenza virus (AIV) subtype H9N2. To find out relationship between the cast formation and the presence of other viral respiratory diseases, isolation and identification of AIV, infectious bronchitis virus (IBV) and Newcastle disease virus (NDV) were carried out for 40 commercial chicken flocks, collected from different parts of the country, experiencing respiratory disease with fibrinonecrotic casts at the bronchi and bifurcation of the trachea and relative high mortality by virus isolation and RT-PCR assay. Nested PCR was performed for detection of Massachuesetts, 4/91 and D274 IBV serotypes and enhancement of PCR sensitivity. One to three viruses were detected simultaneously in each of the flocks. There was a virus detection for H9N2, 4/91, Massachuesetts and NDV of 85, 67.5, 13 and 2%, respectively. No D274 serotype was found in the cases. The most common virus combination was related to H9N2 and 4/91 (55%) while, considering Massachuesetts serotype, it could be for H9N2 and IB viruses (67.5%). Also, the least virus combination was for NDV and IB viruses (2.5%). It is concluded that coinfection of H9N2 and 4/91 viruses in combination with the current field bacteria including Escherichia coli, Ornithobacterium rhinotracheale and mycoplasma are the most important causative agents for fibrinonecrotic casts formation under field condition although both the the viruses alone along with bacterial infections can cause casts at the bronchi and bifurcation of the trachea. Key words: infectious bronchitis, avian influenza, cast, H9N2 ، 4/91 ،RT-PCR

کلیدواژه ها:

طیور ، آنفلوآنزاویروس ، ویروس برونشیت عفونی پرنده ای ، ویروس بیماری نیوکاسل