• KOREAN POULTRY JOURNAL
• /
• v.35 no.10 s.408
• /
• pp.124-125
• /
• 2003

• KOREAN POULTRY JOURNAL
• /
• v.6 no.2 s.52
• /
• pp.96-100
• /
• 1974

• KOREAN POULTRY JOURNAL
• /
• s.96
• /
• pp.77-80
• /
• 1977

• KOREAN POULTRY JOURNAL
• /
• v.5 no.5 s.43
• /
• pp.96-98
• /
• 1973

• KOREAN POULTRY JOURNAL
• /
• v.35 no.8 s.406
• /
• pp.122-123
• /
• 2003

• Korean Journal of Poultry Science
• /
• v.34 no.4
• /
• pp.301-318
• /
• 2007

Marek's disease (MD) is a highly contagious lymphoproliferative disease of poultry caused by the oncogenic herpesvirus designated Marek's disease virus (MDV). MD has a worldwide distribution and is thought to cause an annual loss over US$ one billion to the poultry industry. Originally described as a paralytic disease, today MD is mostly manifested as an acute disease with tumors in multiple visceral organs. MD is controlled essentially by the widespread use of live vaccines administered either in ovo into 18-day-old embryos or into chicks immediately after they hatch. In spite of the success of the vaccines in reducing the losses from the disease in the last 30 years, MDV strains have shown continuous evolution in virulence acquiring the ability to overcome the immune responses induced by the vaccines. During this period, different generations of MD vaccines have been introduced to protect birds from the increasingly virulent MDV strains. However, the virus will be countered each new vaccine strategy with ever more virulent strains. In spite of this concern, currently field problem from MD is likely to be controled by strategy of using bivalent vaccine. But, potential risk factors for outbreak of MD are still remained in this condition. The major factors can be thought that improper handling and incorrect administration of the vaccine, infection prior to establishment of immunity, suppression of immune system by environmental stress and outbreaks of more virulent MDV strain by using vaccine and genetic resistance of host.

• Korean Journal of Veterinary Research
• /
• v.40 no.3
• /
• pp.563-573
• /
• 2000

Periodic outbreaks of Newcastle disease (ND) caused by velogenic viscerotropic ND virus (vvNDV) has become a major concern in Korea nowadays. Throughout last epidemic, the winter season in 2000, most chicken flocks infected early, under 2-4 weeks of age, showed high mortality up to 50-100%. Serum samples collected from 201 breeder, 284 layer and 112 broiler chicken flocks were examined to evaluate the efficacy of various vaccination methods and programs routinely used for mass vaccination in the field poultry farms. Despite repeated live vaccination, most poultry flocks vaccinated by drinking water route using nipple water supply system failed to produce solid active immune response to NDV during the growing time. In the present study, we applied the spray vaccination technique using Ulvavac or Desvac sprayer to the experimental poultry flocks and examined the efficacy of live vaccination effects induced by it under field condition. Measurable antibody to NDV as well as early protection against vvNDV challenge were found in poultry flocks vaccinated by spray route. Further, we did not found significant post vaccination reactions caused by spray vaccination if properly administered. These data indicate that the spray vaccination will be safe and reliable mass vaccination method for the prevention of ND.

• Korean Journal of Veterinary Research
• /
• v.10 no.2
• /
• pp.73-80
• /
• 1970

This report summarized the results of the post-mortem diagnosis oil the 1,785 fowl live and dead during the calender year of 1966 to 1968. The disease incidences in order were; leucosis complex(21.9%) newcastle disease (10.4%), coccidiosis (6.6%) and mismanagement(3.9%). There were also a number of other diseases common to tb,e poultry flocks such as avian mycoplasmosis, pullorum disease and, nutritional disorder etc.

• Korean Journal of Poultry Science
• /
• v.19 no.3
• /
• pp.137-150
• /
• 1992

Poultry production in korea is a very complex situation. Large modernized farms and old styles of small farming coexist with one another. This gives rise to a tangled epidemiological situation in terms of infectious diseases. The main poultry diseases of economic importance are colibacillosis, pullorum diseases, Mycoplasma gallisepticum infection, infectious coryza, infectious synovitis, Newcasyle disease, fowl pox, Marek's disease, avian encephalomyelitis, infectious bursal disease, infectious laryngotracheitis, infectious bronchitis and coccidiosis. Avian influenza, fowl cholera and fowl typhoid have not been reported for a few decades, and these are rated as exotic diseases.

• Korean Journal of Poultry Science
• /
• v.46 no.4
• /
• pp.263-269
• /
• 2019

Infectious bronchitis virus (IBV) is an acute respiratory disease, causing economic losses in poultry production. IBV commonly manifests respiratory disease symptoms and poor egg quality in poultry, affecting overall performance of both broilers and layers. IBV infection further predisposes poultry to secondary opportunistic bacterial infections. IBV undergoes rapid genetic evolution resulting in various new strains. There is no cross protection among IBV serotypes which makes full protection against wild-type IBV virtually impossible. In this study, recently isolated IBVs (K24/18, K29/18, K183/18) from Korean broiler farms were genetically analyzed based on S1 gene. According to the results, IBV isolates showed highest homology with QX-IBV. However, phylogenetic tree analysis revealed that isolates were divided into distinct sub-clusters within QX-IBV. To determine pathogenicity of IBV, day-old chicks were challenged with IBV through ocular route. After challenging the chicks, we executed microscopic examination, virus detection in their organs, and observation of clinical signs and mortality. We found that the K24/18, K29/18, K183/18 challenge groups showed 28%, 57%, and 42% mortality, respectively, with high microscopic trachea lesion scores, indicating that these QX-IBV-like strains are pathogenic to chicks and can therefore be a threat to poultry production.