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Seminar 785  
Date:2010-01-13
Update:2014-01-09
Seminar:  785  
1
Speaker(s)
Huang, Chen-Sheng
Topic
Genomic Polymorphisms in Mycobacterium avium subsp.paratuberculosis
Abstract
Mycobacterium avium subspeciesparatuberculosis (MAP) causes paratuberculosis or Johne’s disease, an intestinal granulomatous infection. The disease spreads by ingestion of MAP from the contaminated environment. Lesions occur in the small intestine and the draining mesenteric lymph nodes which are responsible for a protein leak and a protein malabsorption syndrome. The genotyping methods applied to MAP include IS900- or IS1311-RFLP (restriction fragment length polymorphism), SSR (short sequence repeats), MIRU (Mycobacterial interspersed repetitive units), VNTR (variable number tandem repeats), RAPD (randomly amplified polymorphic DNA), and PFGE (pulse field gel electrophoresis). Our preliminary study was to evaluate the efficiency of two methods to determine the molecular diversity of 23 MAP strains. The applied methods included the analysis of sequence polymorphism of the mono-, di-, and trinucleotide sequences of SSR and the determination of size polymorphism of 9 different VNTR. Sequence analysis of SSR of 23 isolates showed 4, 3, 2, 2, and 3 alleles of G1, G2, GCG, GGT and TGC repeats. And out of 9 VNTR PCR differentiation methods, only two methods could be recommended for typing purposes. The profile (14)-(11)-5-5-5-I-I of the combination systems SSR1-SSR2-SSR6-SSR8-SSR9-VNTR3-VNTR4 dominates among the examined isolates and was detected in 34.8%(8/23) of the isolates. The use of certain repetitive loci of SSR and VNTR techniques demonstrates great potential for the characterization of MAP isolates (D=0.86).
2
Speaker(s)
CH Pan Huang,  Yu-Wen
Topic
A Preliminary Study on Foot and Mouth Disease Virus in Goats
Abstract
Foot and mouth disease (FMD) is an acute and infectious disease of cloven-hoofed animals. It can cause severe economic loss. The causative agent of FMD is FMD virus (FMDV), which is a positive sense and single stranded RNA virus. It is apicornavirus, the prototypic member of the genusAphthovirus. FMDV has seven distinct serotypes including type O, A, C, Asia 1, SAT 1, SAT 2, and SAT 3. There is no cross-protection between each serotype. A total of two strains of O serotype FMDV invasion have occurred in Taiwan since 1997. The first invasion of FMDV occurred in March 1997, which was caused by porcinophilic FMDV (O/Taiwan/97)-- a virus that only infects pigs among cloven-hoofed animals. The second invasion occurred in June 1999, which was caused by Pan-Asia topotype serotype O FMDV (O/Taiwan/99). The virus was firstly isolated from Chinese yellow cattle in Kinmen and could infect goats and pigs. Based on the information mentioned in several relevant journal papers, foot-and-mouth disease virus can cause subclinical infection in goats. The seroconversion of non-structural protein (NSP) of FMDV can be detected in such cases. However, there have been few studies on the prevalence  or duration of FMDV shedding in goats. Therefore, if goats were infected by FMDV, they could become a reservoir and thus a shedding source of FMDV on farms. . In light of this, our study examined two goats which upon purchase (from a NSP-detected farm) had been confirmed to have contained high titers of FMD serum neutralization (SN) antibodies but also possessed consistent NSP antibodies against FMDV. We injected dexamethasone and cyclophosphamide into the goats in order to trigger  immunosuppression which induces the replication and shedding of the possibly latent infected FMDV in the goats. We hope to gain further insight into FMDV infection in goats with this study..
3
Speaker(s)
Tsai, Kuo-Jung
Topic
Lyssavirus Surveillance in Bats of Taiwan from 2008 to 2009
Abstract
Bats are the second largest order within the mammals and are widely distributed in the world. With the high intensity of agriculture activities which cause more chances of contact between bats and humans, and the character of migration of bats, the likelihood of pathogen transmission to humans by bats has substantially increased. Recent studies indicate that the source of some notable zoonoses such as Hendra virus infection, Nipah virus infection, and Severe Acute Respiratory Syndrome (SARS) may be associated with pathogens carried by bats. Therefore, it is urgent to establish surveillance and diagnostic techniques for bat-associated zoonoses to prevent the invasion of deadly ones and start an early alarming system. At present, more than 11 genotypes have been recognized within the Lyssavirus genus and rabies virus is listed in genotype 1 of the genus. Rabies virus and other lyssavirsues could potentially be transmitted through bats onto humans and warm- blooded animals and cause diseases with clinical signs and fatality similar to that of rabies. In the USA, Australia, the UK andGermany, bats have already been a target for conducting surveillance on high-risk zoonoses. Recent studies show that antibodies against lyssaviruses were detected from some bat species in some Southeastern Asian countries. Serology studies have also revealed that the seroconversion rates found in the Philippines, Thailand and China are 2.7 % (22/281), 4.1% (16/394), and 2.2 % (15/685) respectively. It is urgent to establish a surveillance system for bat lyssavirus in Taiwan based on the above survey results in neighboring countries. In order to establish survey data for bat associated zoonotic pathogens and to strengthen the rabies surveillance system, the Animal Health Research Institute (AHRI) has conducted a bat lyssaviruses survey project since 2008. To date, we have already examined the brains of 187 bats by a direct fluorescent antibody test (dFA) for lyssaviral antigens and reverse transcription-polymerase chain reaction (RT-PCR) for viral RNA. None of the tested sample showed any positive results. In 2009, we cooperated with the Centers for Disease Control (CDC) in the US to examine the brains and sera of 60 bats. None of the brain samples showed evidence of lyssavirus antigen and RNA, and none of the serum samples contained neutralizedAustralian bat lyssavirus. This is the first report describing the surveillance of lyssaviral antigen and antibody in bats in Taiwan and our findings can serve as epidemiologic surveillance data for the rabies-free status of Taiwan.
4
Speaker(s)
Tu, Yang-Chang
Topic
Pathological Changes of Paratuberculosis in Cattle from 2008 to 2009 in Taiwan
Abstract
A total of 30 cattle were submitted to the Animal Disease Diagnostic Center at the Animal Health Research Institute (AHRI) in Taiwan for necropsy and disease diagnosis from 2008 to 2009. The cases submitted came from several county and municipal livestock disease control centers from all over Taiwan who referred suspected high risk cattle to AHRI for diagnosis and surveillance of bovine spongiform encephalopathy. Among them, 7 cases were diagnosed as Paratuberculosis. Paratuberculosis (Johne’s disease) is a disease of ruminants which is caused by Mycobacterium avium subsp. paratuberculosis (Map) and manifests itself by progressive diarrhea and emaciation associated with chronic granulomatous enteritis. According to several journal publications in 1987 and 1998 in Taiwan, the seroprevalence of bovine paratuberculosis was 3.5% and 6.9% respectively. A recent study by Huang et al. in 2009 showed that the animal seroprevalence and herdseroprevalence were 9.35% (188/2,010) and 76.12% (51/67) respectively. According to some other papers published in 2006, the animalseroprevalence and herd seroprevalence were 2.5% (794/31,745) and 41% (396/967), respectively in the USA, and 1.9% (2,095/11,028) and 7% (193/2,757) respectively in Australia. These figures strongly suggest that the seroprevalence of bovine paratuberculosis in Taiwan is increasing and higher than those in the USA and Australia. And they also remind us to pay much more attention to the impact of paratuberculosis in the Taiwanese dairy industry. The impact of paratuberculosis is more serious in herd infections than in individual infections. It can happen that some infected cattle without clinical signs may shed the causative bacteria into the environment and this can cause difficulty in diagnosis. In our study, 7 cattle diagnosed with paratuberculosis all showed emaciation and watery diarrhea. At necropsy, obvious enlargement of the mesentery lymph nodes were observed in all 7 cases and obvious thickening and corrugation of the jejunal and ileal mucosa were noted in 3 of 7 cases. Microscopically, the characteristic lesions of paratuberculosis including chronic granulomatous enteritis and lymphadenitis wereobserved. Meanwhile, the antibody againstMap was detected in all cases diagnosed with paratuberculosis and Map was isolated in 2 of 7 cases. In the study, acid-fast bacteria were not able to be observed easily by acid-fast staining even in those cases with typical lesions. With the disadvantages of the acid-fast stain, Map should not be easily observed in tissues when the bacteria load is not high enough. The sensitivity and specificity of histopathology examination should be increased when immunohistochemical (IHC) staining or in-situ hybridization (ISH) is combined in diagnosis. In future studies, molecular immuno-histopathological techniques will be established to assist the diagnosis and related histopathology study of paratuberculosis.