Analysis of the Inspection Standards for Mycoplasma hyopneumoniae Inactivated Vaccine
Chia-Chia, Chang
Abstract
The prevalence rate of swine enzootic pneumonia is about 30~93% in Taiwan. High infection rate and low mortality rate are the features of this disease. The major effect is that long term swine chronic respiratory disease causes slow growth. It will impact the delivery date of pork and farmers’ income. For control of the particular disease, besides antibiotics added to the feed, vaccine delivery is another feasible method. We have inspected the vaccine batch by batch according to “Inspection standard for veterinary drugs” chapter 3 section 69 for years. Current international new types of drug and new inspection methods are keeping development. In addition, laboratory animal protection awareness has been raised with time. The 20 years unrevised inspection method is no longer in line with international trends. For ally with international standard, this study started by comparing the inspection method from Taiwan, EU, Japan and USA. And, we tested current approved vaccines by newly developed inspection method. After it had been confirmed, we submitted the revised draft of inspection standard. New revised inspection standards for Mycoplasma Hyopneumoniae inactivated vaccine was implemented with official announcement on June 24th, 2019
Pathogenesis of goose hemorrhagic polyomavirus in goslings: an experimental trial
Yang-Chang, Tu
Abstract
Goose hemorrhagic polyomavirus (GHPV) is the causative agent of hemorrhagic nephritis enteritis of geese, one of the major diseases of domestic geese in Europe. In the present study, the pathogenesis of GHPV in artificial infected goslings was elucidated using in situ hybridization (ISH). Thirty GHPV-free 2-day-old goslings were subcutaneously inoculated with 107 genome-equivalent viruses of GHPV. Ten goslings were inoculated with saline as the control. The tissue samples were collected at 2, 3, 4, 5, 6, 7, 8, 14, 21, and 28 days post virus inoculation. Clinical sings of bloody diarrhea, depression, and weakness were noticed at 7 days post-infection (dpi) and all goslings died at 8 dpi. Grossly, subcutaneous edema, ascites, hemorrhage in the intestine and mesentery and mottled pale of kidney were observed at 7 and 8 dpi. Histopathologically, lymphocyte depletion in spleen, intestinal hemorrhage, and acute tubular necrosis were found at 6-8 dpi. By the ISH, the signals were first observed in the vascular endothelial cells throughout the body at 4 dpi. The signals intensity increased significantly in the endothelial cells at 7 dpi. Our findings supported that the GHPV were widespread replication and dissemination in the endothelial cells throughout the body of artificial infected goslings and the pathobiology of GHPV were parallel to the virus loads.