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Seminar 862  
Date:2016-08-03
Update:2017-11-02

  

Seminar:  862  

1

Speaker(s)

Chun-Hsien Tseng

Topic

Studies on Pathogenesis of the Ferret Badger Rabies Virus in Taiwan

Abstract

Since three rabies cases from infected ferret badger in Taiwan had confirmed in July 16, 2013, the ferret badgers have become the most important infectious and carrier wild animal for rabies virus in Taiwan. According to the virus phylogenetic analysis results, the ferret badger rabies virus of Taiwan has formed an independent group that may adapt to ferret badger species. Rabies virus is known to affect all warm-blooded animals, but the experience or data of foreign studies showed that if the rabies virus has adapted to an animal species, its pathogenicity or virulence may vary with different animal species. Until December 23, 2014, an injured Formosan Masked Civet from Eluanbi Park was first diagnosed with rabies infection and six follow-up cases in Formosan Masked Civet have occurred. The finding suggests that these ferret badger rabies infection crossed species barrier to Formosan Masked Civet or just sporadic cases needs to be tested further on animals to clarify. Three ferret badger rabies virus strains isolated from eastern and western Taiwan were serial diluted and inoculated into the mice brains, respectively. The results appeared that the median lethal dose of 10 times emulsion per milliliter in the mice brains were only 102.05 ~ 102.76 MIC LD50, the inoculated mice were developed a long clinical course and chronic fatality. In addition, the real-time quantitative polymerase chain reaction were applied to detect the viral nucleic acid contents of brain and salivary gland in rabies positive cases of ferret badgers and mice, and it found that the viral nucleic acid copy number in those salivary glands of mice is significantly lower than in ferret badgers. These results indicated that the pathogenicity of Taiwan ferret badger rabies virus in mice are quite different from other wild rabies virus strains. Also, the pathogenic tests of ferret badgers showed that the inoculation dosages would affect incubation period, that is, high-dose inoculation in ferret badgers have an incubation period about 2-3 weeks, but low-dose inoculation ones with  one month or longer incubation period. Clinical characterizations of Ferret Badger are depicted as follows: it may develop quiet or abnormal sound at early stage, and then manic, aggressive behavior followed, finally palsy and paralysis; or it may directly become palsy and paralysis; it may also come to an intermittently mild neurological symptom without been observed and dead.

2

Speaker(s)

Lin Yeou-Liang

Topic

Investigating on the surveillance results of antibodies against foot-and-mouth disease virus of swine in recent years

Abstract

For FMD control, the Bureau of Animal and Plant Health Inspection and Quarantine (BAPHIQ) addressed that a policy of mandatory FMD vaccination has been implemented in pigs aged greater than 12 weeks since August 2009. In order to improve the vaccination coverage rate of FMD vaccine, a penalty policy is adopted to fine those farmers without implementing vaccination against FMDV for their cloven-hoofed animals. The effect of vaccination against FMDV is assessable via the detection of induced antibodies. To understand the surveillance results of antibodies against FMDV in pigs, we investigate quarterly on the distribution of serum neutralization (SN) antibodies against FMDV which were detected between 2010 and 2015. A further investigation is performed to calculate the percentage of population protection in the inspection farms monthly. The results demonstrated that the percentage of SN antibody titers to FMDV below 1: 4 is higher than 30% in detected pig sera from the first quarter in 2010 to the second quarter in 2012 and in the first quarter of 2014. In the contrary, the percentage of SN antibody titers to FMDV below 1: 4 is less than 20% in detected pig sera in the other quarters. It revealed that the implementation of penalty policy was effective in improving the farmers to obey the FMD vaccination. On the other hand, the percentage of more than 80% detected pig sera showed SN antibody titers greater than 1: 16 in inspected farms is less than 80% between January 2010 and December 2015, excepting in February 2014. It revealed that more than 20% of inspection pig farms did not reach to the antibody titers for providing a population protection. In addition to implement an effective vaccination against FMDV, it is necessary to strengthen biosecurity practices at farm to prevent recurrence of FMD.

3

Speaker(s)

Chien Tu

Topic

Current status of aquatic animal health export program

Abstract

The spread of aquatic pathogens is mainly through the global transportation of live aquatic animals. Thus, the quarantine for aquatic animals import is crucial for protection of the domestic aquaculture from contamination. Nowadays, two-year surveillance record remains a prerequisite for successful export of aquatic animals in global markets. Since 2004, our institute has executed the national aquatic animal health export program to promote the export of aquatic animals. We examined specimens from 132 fish farms and performed 23,790 tests in 2015. The results showed that three cases of infectious hypodermal and haematopoietic necrosis (pet shrimp), one case of white spot syndrome (redclaw crayfish) in crustaceans; four cases of koi herpesvirus (koi) in fish; one case of salmonella infection (Chinese stripe-necked turtle) in reptile and, none of pathogens was detected in both abalone and oyster in molluscs.

4

Speaker(s)

Shu-Chun Chiu

Topic

Production for HA Antigen of Newcastle Disease Virus

Abstract

   Newcastle disease (ND) is caused by virulent strains of avian paramyxovirus type 1 (APMV-1) of the genus Avulavirus belonging to the family Paramyxoviridae. ND is an important avian viral disease causing serious economical damage all over the world. AHRI has chosen an attenuated ND virus, the Ishii strain, and the virus was inoculated into the allantoic cavity of 9 to 11-day-old embryonating fowl eggs in the laboratory. The eggs were incubated at 37°C for 4 to 7 days and then the allantoic fluid of egg embryos were collected to evaluate the virus titer by haemagglutinating (HA) activity method. Finally, the virus were inactivated by ether and freeze-dried. These antigens mainly provide diagnostic laboratories to assess the antibody response of chicken following vaccination with haemagglutination inhibition (HAI) test. These ND HA antigens have been widely used in HAI test for more than 40 years and have been produced over 52 batches in Taiwan. AHRI produced 701 vials of HA antigen in 2015 and there commercial reagents have been assisted the diagnosis and prevention of ND in chicken industry in Taiwan.