Innovation and discovery: The application of nucleic acid-based technology to avian virus detection and characterization

Abstract

Polymerase chain reaction (PCR)-based approaches to the detection, differentiation and characterization of avian pathogens continue to be developed and refined. The PCRs, or reverse transcriptasePCRs, may be general, designed to detect all or most variants of a pathogen, or to be serotype, genotype or pathotype specific. Progress is being made with respect to making nucleic acid approaches more suitable for use in diagnostic laboratories. Robotic workstations are now available for extraction of nucleic acid from many samples in a short time, for routine diagnosis. Following general PCR, the DNA products are commonly analyzed by restriction endonuclease mapping (restriction fragment length polymorphism), using a small number of restriction endonucleases, based on a large body of sequence data. Increasingly, however, nucleotide sequencing is being used to analyze the DNA product, in part due to the expanding use of non-radioactive sequencing methods that are safe and enable high throughout. In this review, I highlight some recent developments with many avian viruses: Newcastle disease virus; circoviruses in canary and pigeon; infectious bursal disease virus (Gumboro disease virus); avian adenoviruses, including Angara disease/infectious hydropericardium virus, haemorrhagic enteritis virus of turkeys, and egg drop syndrome virus; avian herpesviruses, including infectious laryngotracheitis virus, duck plague virus, psittacine herpesvirus (Pacheco's parrot disease virus), Marek's disease virus and herpesvirus of turkeys; avian leukosis virus (associated with lymphoid leukosis or myeloid leukosis, and egg transmission); avian pneumoviruses (turkey rhinotracheitis virus); avian coronaviruses, including infectious bronchitis virus, turkey coronavirus and pheasant coronavirus; astrovirus, in the context of poult enteritis and mortality syndrome, and avian nephritis virus; and avian encephalomyelitis virus, a picornavirus related to hepatitis A virus.

Infectious bronchitis virus replication in the chicken embryo related cell line

“…(Figure 1b), demonstrated by specific fluorescence in infected cells (Cavanagh & Naqi, 1997). In addition, IBV RNA was detected at all times p.i., where a fragment of 266 bp was amplified, corresponding to a part of the 3?-UTR that is conserved in all IBV types (Cavanagh, 2001). In fact, no difference in nucleotide sequence was observed from M41 after 120 h p.i.…”

“…The cells were washed, stained with anti-rabbit conjugate-FITC-labelled conjugate (Sigma) for 1 h at 378C, and directly examined by oil-immersion objective microscope. For reverse transcription-polymerase chain reaction (RT-PCR) the infected monolayers were submitted to IBV RNA extraction previously reported by Cavanagh (2001). The One Step † RNA PCR Kit (Invitrogen, BRL, Brazil) was used according to the manufacturer's instructions to amplify IBV RNA at all times p.i.…”

“…Acute infections are generally diagnosed by the immunofluorescence test, enzyme-linked immunosorbent assay capture assays, virus isolation or serological approaches (de Wit et al, 1997;de Wit, 2000). However IBV infections can also be diagnosed by detection of viral RNA, which make the diagnostic fast and also reliable (Capua et al, 1999;Cavanagh, 2001;Cavanagh et al, 2001Cavanagh et al, , 2002. In many cases virus isolation is attempted, usually performed in specific pathogen free (SPF) embryonated eggs and/or primary cell culture derived from chicks.…”

Detection and differentiation of avian pneumoviruses (metapneumoviruses)

“…In longitudinal studies of broilers in the field, we did not initially detect vaccinal APV and only detected field APV challenge in the last week or so of a flock's life. In contrast, IBV was detected readily Cavanagh, 2001). Other workers had experienced difficulty in isolating APV from chickens.…”

Hindi ve tavuklarda avian pneumovirus infeksiyonlarının indirek floresan antikor testi ve reverse transkriptaz-polimeraz zincir reaksiyonu ile teşhisi

“…Etken şüpheli hayvanların dokularından direkt olarak saptanabilmektedir. Alt tip spesifik PCR ile, ya da genel PCR uygulamalarını takiben sekanslama veya restriction fragment analizleri ile de APV'lerin tespiti ve tiplendirilmesi yapılabilmektedir (9,12).…”