Isolation, identification, and complete genome sequence of an avian reticuloendotheliosis virus isolated from geese.

Naturally occurring lymphoreticular tumors in geese have been found from time to time in Taiwan, but their etiology has not been determined except through morphological descriptions. This study observed a reticuloendotheliosis virus (REV) infection occurring in a white Roman goose (Anser anser) farm in Yunlin, Taiwan in 2006. These geese showed growth-retarded and nodular lymphoma-like tumors in the liver, lung, kidney, and pancreas. Thirty blood samples were taken for REV detection and 21 (70%) of them contained REV genetic sequences using polymerase chain reaction (PCR). Virus isolation was attempted from 11 blood samples by inoculating the buffy coat onto DF1 cells. Nine (81%) REVs were isolated after three blind passages. The complete proviral sequence from one isolate was determined for phylogenetic analysis by direct sequencing using overlapping PCR products. The length of the provial genome is 8284 nucleotides. By comparing with other published REV complete sequences, the nucleotide percent identity ranged from 93.5% to 99.8% with most LTR varieties, ranging from 74.9% to 99.8%. The present isolated goose REV is most close to REV APC-566, a REV isolated from Attwater's Prairie chickens.

Use of random amplified polymorphic DNA analysis and single-enzyme amplified fragment length polymorphism in molecular typing of Ornithobacterium rhinotracheale strains.

Ornithobacterium rhinotracheale (ORT) is a bacterium common to commercial poultry and wild birds throughout the world. It is also known as a causative agent of respiratory diseases. A total of 93 ORT isolates originating from chickens, pigeons, ostriches, quail, turkeys, and an Asian crested goshawk (Accipiter trivirgatus) in Taiwan, between 2004 and 2006, were used in this study. High genetic similarity (97%-100%) in 16S rRNA sequence was revealed among the 50 randomly selected isolates, in addition to a reference strain (ATCC-51464) and seven reference sequences from GenBank. In order to obtain a greater genetic discrimination among the ORT isolates, random amplified polymorphic DNA (RAPD) and single-enzyme amplified fragment length polymorphism (SE-AFLP) methods were further conducted. The results showed that both RAPD and SE-AFLP assays showed higher discriminatory abilities than the 16S rRNA sequence assay. Genetic clustering revealed that chicken- and quail-origin isolates were genetically distinct from those of the ostrich, pigeon, and Asian crested goshawk-origin isolates. However, among the two typing methods, the turkey-origin isolates showed diverse genetic characteristics to domestic avian species. With this information, ecologic and epidemiologic studies could be furthered for the reduction and control of ORT transmission in Taiwan.

Epidemiology and Antibiogram of Riemerella Anatipestifer Isolated from Waterfowl Slaughterhouses in Taiwan.

INTRODUCTION: Laryngeal swab samples collected from three waterfowl slaughterhouses in central Taiwan were cultured and suspected isolates of Riemerella anatipestifer were identified by API 20NE and 16S rDNA PCR. MATERIAL AND METHODS: Serum agglutination was used for serotyping, and antimicrobial susceptibility was tested. RESULTS: Seventy-six R. anatipestifer isolates were detected, and the prevalences in the ducks and geese were 12.3% (46/375) and 8.0% (30/375), respectively. The positive isolation rates were 65.6% for all arriving waterfowl, 76.0% for birds in the holding area, 1.6% for defeathered carcasses, but zero for degummed carcasses. A PCR examination detected R. anatipestifer in the slaughtering area frequently. Serotype B was dominant in both duck (34.8%) and goose (46.7%) isolates, but the wide serotype distribution may very well impede vaccination development. All isolates were resistant to colistin, and 79.7% were resistant to more than three common antibiotics. CONCLUSION: The results proved that most ducks had encountered antibiotic-resistant R. anatipestifer in rearing, which suggests that the bacterium circulates in asymptomatic waterfowl. It is worth noting that most waterfowl farms were found to harbour R. anatipestifer, and contaminated slaughterhouses are a major risk factor in its spread. Effective prevention and containment measures should be established there to interrupt the transmission chain of R. anatipestifer.

Rapid and sensitive detection of Mycoplasma synoviae by an insulated isothermal polymerase chain reaction-based assay on a field-deployable device.

Mycoplasma synoviae (MS), causing respiratory diseases, arthritis, and eggshell apex abnormalities in avian species, is an important pathogen in the poultry industry. Implementation of a biosecurity plan is important in MS infection management. Working on a field-deployable POCKIT™ device, an insulated isothermal polymerase chain reaction (iiPCR) assay has a potential for timely MS detection on the farm. The MS iiPCR assay had limit of detection 95% of about 9 genome equivalents by testing serial dilutions of a standard DNA. The detection endpoint of the assay for detection of MS genomic DNA was comparable to a reference real-time PCR. The assay did not crossreact with other important avian pathogens, including avian reovirus, Mycoplasma gallisepticum, Staphylococcus aureus, Escherichia coli, Pasteurella multocida, and Salmonella Pullorum. When 92 synovial fluid and respiratory tract swab samples collected from chickens, turkeys, and geese suspected of MS infection were tested, the clinical performance of the MS iiPCR had 97.8% agreement (Cohen's kappa value, 0.95) with that of the reference real-time PCR. In conclusion, the MS iiPCR/POCKIT™ system, working with field-deployable manual or automatic nucleic acid extraction methods, has potential to serve as a rapid and sensitive on-site tool to facilitate timely detection of MS.

Genetic and pathogenic characterization of H6N1 avian influenza viruses isolated in Taiwan between 1972 and 2005.

This article reports the genetic and pathogenic characteristics of 34 isolates of H6N1 avian influenza viruses isolated in Taiwan between 1972 and 2005. Genetic analyses showed that a unique lineage of H6N1 viruses has been established in domestic chickens in Taiwan since 1997, and this lineage of viruses differs from the H6N1 viruses circulating in Hong Kong and Southeastern China. Pathogenicity tests showed that all Taiwanese H6N1 viruses were of low pathogenicity but might lead to economic loss when associated with other diseases. Hemagglutination inhibition tests showed that antigenic drift has occurred in Taiwanese H6N1 viruses, and sequence comparison has identified a total of five possible antigenic sites on the hemagglutinin molecule of the H6N1 viruses. Some Taiwanese H6N 1 viruses could replicate in mice without preadaptation, indicating that these viruses have the potential to cause cross-species infection into mammals.

Development of a polymerase chain reaction procedure for detection and differentiation of duck and goose circovirus.

This article reports the complete nucleotide sequences of four duck circovirus (DuCV) isolates from sick ducks in Taiwan and development of a polymerase chain reaction (PCR) for detection and differentiation of goose circovirus (GoCV) and DuCV. Sequence comparison showed that Taiwanese DuCV isolates had 82.5%-83.8% nucleotide sequence identity to the German and North American DuCV isolates. This is the first report on the presence of DuCV and its associated diseases outside Germany. A PCR test was developed using a universal primer pair based on conserved sequences present in the genomes of GoCV and DuCV. This PCR test could detect and differentiate between GoCV and DuCV by the size of PCR product each virus produced (256 bp for GoCV and 228 bp for DuCV). Application of this PCR test to samples of bursa of Fabricius from sick birds in the field showed that 9 of 26 goose samples contained GoCV, while 13 of 34 duck samples contained DuCV. This PCR test could serve as a fast and sensitive method for detection and differentiation of DuCV and GoCV.

An association of genotypes and antimicrobial resistance patterns among Salmonella isolates from pigs and humans in Taiwan.

We collected 110 Salmonella enterica isolates from sick pigs and determined their serotypes, genotypes using pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility to 12 antimicrobials and compared the data with a collection of 18,280 isolates obtained from humans. The pig isolates fell into 12 common serovars for human salmonellosis in Taiwan; S. Typhimurium, S. Choleraesuis, S. Derby, S. Livingstone, and S. Schwarzengrund were the 5 most common serovars and accounted for a total of 84% of the collection. Of the 110 isolates, 106 (96%) were multidrug resistant (MDR) and 48 (44%) had PFGE patterns found in human isolates. S. Typhimurium, S. Choleraesuis, and S. Schwarzengrund were among the most highly resistant serovars. The majority of the 3 serovars were resistant to 8-11 of the tested antimicrobials. The isolates from pigs and humans sharing a common PFGE pattern displayed identical or very similar resistance patterns and Salmonella strains that caused severe infection in pigs were also capable of causing infections in humans. The results indicate that pigs are one of the major reservoirs to human salmonellosis in Taiwan. Almost all of the pig isolates were MDR, which highlights the necessity of strictly regulating the use of antimicrobials in the agriculture sector in Taiwan.