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Seminar 775  

Seminar:  775  
1
Speaker(s)
Li-Hsuan Chen
Topic
A retrospective survey of Q fever in ruminants in Taiwan
Abstract
Q fever is an important zoonotic disease caused by Coxiella burnetii. Humans and animals can contract it through milk, urine, feces, parturient fluid, and placenta of infected animals. High risk groups, including farmers, slaughterhouse workers and veterinarians, are infected mainly by inhalation of contaminated aerosol. Because of its strong resistance to environment, and high infectivity with few bacteria, Coxiella burnetii is considered to be a potent bioterrorism agent. In Taiwan, the first human case of Q fever was reported in 1993. Several human cases have been continuously reported each year since then. A seroprevalent investigation on the inhabitants in southern Taiwan showed 4.2% of the people tested were infected in 2000. These data demonstrate that the pathogen of Q fever does exist in Taiwan. Although the first animal case was reported in early 2006, epidemic situation may be underestimated in Taiwan due to ambiguous symptoms. A polymerase chain reaction and ELISA were used to investigate the Q fever of ruminants in Taiwan in the past, which resulted in a total of 1,279 ruminant serum samples having been collected from 1989 to 2000 and were tested subsequently. The seropositive rate of goats and bovine were found to be19% (173/900) and 12% (44/379), respectively. After that in 2008, additional 2,170 serums were collected and tested. It was found that the positive rate in goats was 15% (225/1,509) and in bovine was 7% (44/661). Samples from abortive cases of goats that were collected during 2002 to 2005 were tested by polymerase chain reaction, which showed 63% (15/24) of the cases were positive. These results indicate that Q fever has existed in Taiwan since 1989 and will not disappear any time soon. Q fever is one major cause of abortion in ruminants and can inflict economic loss to Taiwan, especially to goat farms.
2
Speaker(s)
Chin-Cheng Huang
Topic
Development of the avian influenza (H5N1) HA-subunit vaccine
Abstract
The continuous outbreaks of highly pathogenic avian influenza (HPAI) in poultry and humans since 2003 have demonstrated the need of vaccines for controlling this epidemic. To address this need , in our lab a cDNA fragment covering the entire coding region of hemagglutinin (HA) gene derived from a H5N1 strain (A/Duck/China/E319-2/03; Dk/CHN/E319-2/03) was cloned and expressed by using a baculovirus system. The expressed recombinant HA (rHA) protein retained hemagglutinating activity in solution, cleaved by PNGase F treatment and recognized by a conformation-dependent monoclonal antibody, indicating proper folding and biological activity. Chickens which had received two doses of vaccines (administered separately with two weeks apart) formulated with a water-in-oil-in-water (Montanide ISA 206) or a water-in-oil (Montanide ISA 70) emulsion elicited high titers (log2≥7.2) of hemagglutinatinin inhibition (HI) antibody responses. Full protection against an intranasal challenge with 108.5 50% embryo lethal dose (ELD50) of a H5N1 homologous virus was observed in chickens with HI titers log2 3. Additionally, we established a threshold of HI titer of log2 =5, which determined whether the live viruses were detected in the oropharyngeal, cloacal discharge or in tissues. This result suggests that the rHA expressed from insect cells is a suitable candidate for the development of a safe and efficacious H5N1 subunit vaccine for chickens.
3
Speaker(s)
Chu-Hsiang Pan
Topic
A Visual DNA Chip for Classifying Different Genotypes of Foot-and-Mouth Disease Virus
Abstract
Foot-and-mouth Disease (FMD) is a highly contagious viral disease and is capable of causing severe damages in susceptible cloven-hoofed animals, which in turn can lead to colossal economic losses. Correct identification of the FMD virus (or FMDV which is a member of the genus Apthovirus in the family of Picornaviridae) means effective treatment. There are seven serotypes of FMDV: A, O, C, Asia 1, and South African Territories (SAT) 1, 2, and 3. Infection with any one serotype does not confer immunity against another. Furthermore, within the seven serotypes, over seventy genotypes can be identified. Such complexity makes separating different genotypes of FMDV in a routine diagnosis difficult unless an analysis of nucleic acid DNA sequences is conducted. In this study, we developed a visual DNA chip to classify FMDV effectively. At the outset, a total of seventy-four synthesized genotype-specific oligonucleotide probes (20~30 mers) were spotted and each immobilized on a single polymer membrane. Then, the cell culture-grown virus was extracted with a QIAamp Viral RNA Kit (Qiangen Inc., Valencia, CA) and subjected to a single-tube reverse transcription-polymerase chain reaction (RT-PCR). Both the forward and reverse PCR primers were biotinylated. A five-μl portion of the product elicited from the RT-PCR was used for a hybridization conducted on the oligonucleotide probe-immobilized polymer membranes. A biotin-avidin alkaline phosphatase indicator system and NBT/BCIP substrates were used in the colorimetric development. These processes induced the hybridization patterns of different genotypes of FMDV on polymer membranes so that they could be observed and interpreted visually. With this method, FMDV could be identified as 65 different genotypes, including O/TAW/97, O/TAW/99, O1/Campos, O1/Manisa, A5, A12, A24, A22, A30, C1, C3, Asia 1, SAT 1, SAT 2 and SAT 3 subtypes. No cross-reaction was observed with other viral agents causing vesicular disease such as vesicular stomatitis virus and swine vesicular disease virus.
4
Speaker(s)
CH Pan Shu-Hwae Lee
Topic
Report on the management practices of animal health inspection system and the diagnostic laboratory training for zoonosis in the USA
Abstract
The purpose of this project is to promote researchers’ ability of zoonosis diagnosis so as to enhance the effectiveness of animal health inspection and quarantine under Taiwan-USA agriculture cooperative research programs. For this, Animal Health Research Institute (AHRI) dispatched two researchers to visit the following laboratories at Poultry Diagnostic and Research Center, Southeast Poultry Research Laboratory, National Veterinary Service Laboratory, National Wildlife Research Center, Department of Fish, Wildlife and Conservation Biology, Colorado State University, Division of Vector-borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Animal and Plant Health Inspection Service, and Lasher Laboratory, University of Delaware. The said researchers learned about relevant techniques and information through academic round-table discussions and hands-on demonstrations presented by experts in these laboratories. With this experience, they believe that Taiwan could learn from the U.S. Department of Agriculture (USDA) the surveillance and diagnostic system of avian influenza, practical laboratory procedure management and biosecurity policies. Furthermore, the commercial poultry producers in the US can also provide valuable knowledge and experience in areas such as biodefense, inspection and self-control systems.