Newcastle disease virus (NDV) is one of the most important infectious agents in the poultry industry, and vaccines against it have been widely used for prevention and control. Live vaccines, which can replicate in the respiratory and digestive systems, have been especially needed in areas with outbreaks of viscerotropic velogenic Newcastle disease. Towards the goal of searching for a new live vaccine candidate, avian paramyxovirus type 1 (APMV-1) was isolated from the faeces of wild birds. Three APMV-1 strains thus isolated were characterized in terms of phylogeny, pathogenicity, immunogenicity and tissue tropism, and on the basis of these analyses were classified as lentogenic genotype I NDV. CBU2179, one of the three APMV-1 strains, was selected and was evaluated in terms of its efficacy and safety in specific pathogen-free chickens and commercial broilers. The manufactured trial vaccine from this strain, also called CBU2179, induced similar immune responses to those of VG/GA and B1 commercial vaccines, and provided 100% protection against challenge from viscerotropic velogenic NDV, KJW/49 strain (the official challenge strain in Korea). Also, the CBU2179 virus was re-isolated and persisted as long as or longer than other vaccine strains in both the respiratory and alimentary tracts. Therefore, the CBU2179 strain may represent a good candidate for a live Newcastle disease vaccine to protect chickens against viscerotropic velogenic NDV.

Molecular typing methods have become a common part of the surveillance of foodborne pathogens. In particular, pulsed-field gel electrophoresis (PFGE) has been used successfully to identify outbreaks of Escherichia coli O157:H7 in humans from a variety of food and environmental sources. However, some PFGE patterns appear commonly in surveillance systems, making it more difficult to distinguish between outbreak and sporadic cases based on molecular data alone. In addition, it is unknown whether these common patterns might have unique epidemiological characteristics reflected in their spatial and temporal distributions. Using E. coli O157:H7 surveillance data from Alberta, collected from 2000 to 2002, we investigated whether E. coli O157:H7 with provincial PFGE pattern 8 (national designation ECXAI.0001) clustered in space, time and space-time relative to other PFGE patterns using the spatial scan statistic. Based on our purely spatial and temporal scans using a Bernoulli model, there did not appear to be strong evidence that isolates of E. coli O157:H7 with provincial PFGE pattern 8 are distributed differently from other PFGE patterns. However, we did identify space-time clusters of isolates with PFGE pattern 8, using a Bernoulli model and a space-time permutation model, which included known outbreaks and potentially unrecognized outbreaks or additional outbreak cases. There were differences between the two models in the space-time clusters identified, which suggests that the use of both models could increase the sensitivity of a quantitative surveillance system for identifying outbreaks involving isolates sharing a common PFGE pattern.

H9N2 low-pathogenic avian influenza (LPAI) viruses have long been circulating in the world poultry industry, resulting in substantial economic losses. In addition to bird health consequences, viruses from specific lineages such as G1 and Y280 are also known to have the potential to cause a pandemic within the human population. In South Korea, after introducing inactivated H9N2 vaccines in 2007, there were no field outbreaks of H9N2 LPAI since 2009. However, in June 2020, an H9N2 virus was isolated from an outbreak in a Korean chicken farm. This strain was distinct from the predominant Korean/Y439 lineage and was believed to be part of the Y280-like lineage. Since the first case of this new H9N2 LPAI, nine more cases of field infections in poultry farms were documented through July and December of 2020. Phylogenetic analysis of the haemagglutinin (HA) and neuraminidase genes of these case isolates revealed that all strains were grouped with exotic Y280-like strains that did not previously exist in South Korea and were emerging into a new cluster. Serological assays also confirmed the existence of antibodies to Y280-like viruses in field sera collected from infected birds, and that they had seroconverted. Further analysis of the receptor-binding region in the HA protein also revealed that these isolates harboured a human-like motif that could potentially affect mammals and humans, demonstrating a possible public health risk. This is the first report of field cases caused by Y280-like H9N2 LPAI in the Korean poultry industry. RESEARCH HIGHLIGHTS. Field outbreaks caused by Y280-like H9N2 avian influenza viruses were confirmed.. A human-like motif was found at the HA receptor-binding region of all isolates.

As animal welfare issue becomes important, the European Union bans conventional cages for laying hens from 2012. So the alternative housing systems like floor pens, aviaries or free range systems have been suggested. From 2011 to 2014, we monitored 20 welfare-oriented laying hen farms in South Korea to figure out serological status of major viral diseases. During this period, total 3,219 blood samples were collected from the randomly selected chickens to test and evaluate the hemagglutination inhibition titers for low pathogenic avian influenza, Newcastle disease and egg drop syndrome '76. A total of 2,926 blood samples were tested through enzyme linked immunosorbent assay (ELISA) to assess the serological status of infectious bronchitis (IB). The distribution of ELISA titers for IB was various from almost 0 to 20,000 through the all weeks of age. Also, the antibody coefficient of variation for most of the diseases in this study was higher than those of typical cage layers. As this study was the first surveillance for major avian viral diseases of the animal welfare-oriented farms in South Korea, the results obtained from this study will help to determine what information and resources are needed to maintain better biosecurity and to improve the health and welfare of laying hen flocks.