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.

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.

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.

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.

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