Biomedical subjects

Ching-Ho Wang

Publications and source records attributed to Ching-Ho Wang.

12 recordsLinked to original sources

PubMed2006

A miniaturized germanium-doped silicon dioxide-based surface plasmon resonance waveguide sensor for immunoassay detection.

A surface plasmon resonance (SPR) waveguide immunosensor fabricated by germanium-doped silicon dioxide was investigated in this study. The designed waveguide sensor consisted of a 10 microm SiO(2) substrate layer (n=1.469), a 10 microm Ge-SiO(2) channel guide (n=1.492) and a 50 nm gold film layer for immobilization of biomolecules and SPR signal detection. The resultant spectral signal was measured by a portable spectrophotometer, where the sensor was aligned by a custom-designed micro-positioner. The results of the glycerol calibration standards showed that the resonance wavelength shifted from 628 to 758 nm due to changes of refractive index from 1.36 to 1.418. Flow-through immunoassay on waveguide sensors also showed the interactions of protein A, monoclonal antibody (mAb ALV-J) and avian leucosis virus (ALVs) resulted in wavelength shifting of 4.17, 3.03 and 2.18 nm, respectively. The SPR dynamic interaction could also be demonstrated successfully in 4 min as the sensor was integrated with a lateral flow nitrocellulose strip. These results suggest that SPR detection could be carried out on designed waveguide sensor, and the integration of nitrocellulose strip for sample filtering and fluid carrier would facilitate applications in point-of-care portable system.

Biosensing Techniques↗

PubMed2006

Serological and virological surveys of reticuloendotheliosis in chickens in Taiwan.

Reticuloendotheliosis virus (REV) is widespread in the world. No related data has been reported in Taiwan. To determine the REV infection status, antibody determination and virus isolation were performed on chickens in Taiwan. The results revealed that serological flock prevalence for the REV antibody reached 92.8% (39/42) amongst breeders (> 16 weeks old). Two different REV isolates were identified by reverse transcriptase-polymerase chain reaction, electron microscopic, immunofluorescent, and western blot assays after isolation. One of these viruses was isolated from a broiler breeder farm and the other was isolated from a Taiwan Country Chicken farm. Despite their different origins, the percent identity of the nucleotide sequences of the env gene of these two isolates was 99.7%. These two strains were similar to the FPV-UI-REV strain, featuring 99.7% and 99.8% percent identity. Indeed, REV infection would appear to be quite common amongst chickens.

Animals↗

PubMed2006

Sequence comparison between two quasi strains of H6N1 with different pathogenicity from a single parental isolate.

BACKGROUND AND PURPOSE: Relationships between gene change and virulence for hemagglutinin (HA) subtypes of avian influenza virus remain inconclusive. In this study, sequences of these nearly identical virus strains were obtained in order to elucidate the relationship between molecular determinants and virulence. METHODS: Two strains, with different virulence, of an H6N1 avian influenza virus were isolated from an infected chicken flock. Complete 8-gene fragments from the 2 strains were cloned and sequenced. Putative amino acid sequences were compared. RESULTS: Comparisons of the sequences from the 2 strains showed 0.65%, 0.79%, 0.28%, 1.23%, 0.80%, 0.20%, 0.43%, and 0.83% differences in PB2, PB1, PA, HA, NP, neuraminidase (NA), NS1 and NS2 proteins, respectively. The M1, M2, and PB1-F2 protein sequences from the strains were identical. The HA cleavage site of both strains contained a single R, despite their difference in virulence. Thus, the difference in virulence might be due to sequences other than the HA cleavage site. Most of the changes were in the HA2 part. The sequence immediately after the HA cleavage site was GILG in the non-virulent strain and GIFG in the virulent strain. The change from E to G at position 106 in the HA, near the receptor binding site, might influence the virulence. Other sequence changes likely to influence virulence were from K to R at position 291 (K291R) in NP protein and from P to T at position 101 (P101T) in NA protein. CONCLUSION: The amino acid changes identified in this study may be important in the virulence of influenza viruses.

Amino Acid Sequence↗

PubMed2005

Development of attenuated vaccines from Taiwanese infectious bronchitis virus strains.

Due to variations in serotypes among different strains of avian infectious bronchitis viruses (IBV), vaccination of chicks with imported vaccines fails to protect them from IBV infections in Taiwan. Therefore, we develop attenuated vaccines from local strains in Taiwan. A Taiwan Group I (TW I) strain was passaged 74 times through specific pathogen-free (SPF) chicken embryonated eggs, and then tested in SPF chickens. The attenuated vaccine was not pathogenic in 1-week-old chicks, had a neutralization index (NI) of greater than 4.4 and efficacy of 90% when inoculated birds were challenged with a field IBV strain. Similar results were obtained for a vaccine made from a Taiwan Group II IBV strain. Additionally, the TW I attenuated vaccine strain had no reversion to virulence after five back passages in chicks. In conclusion, these attenuated vaccines have potential for controlling local Taiwanese IBV infections in chickens.

Animals↗

PubMed2005

Protective effect of vaccination in chicks with local infectious bronchitis viruses against field virus challenge.

Avian infectious bronchitis virus (IBV) causes tremendous economic losses to the poultry industry worldwide. Different serotypes of this virus show little cross-protection. The present study investigated the relationship between differences in the genotype based on the N-terminus of the spike protein and the protection provided by vaccination with IBVs. Cross-immunization tests were performed using both killed and live viruses in specific-pathogen-free chicks. One-day-old chicks were immunized with killed or high [10(5) 50% embryo infectious dose (EID50)] or low (10(3) EID50) doses of live IBV viruses and challenged with homologous or heterologous IBV strains. The immunization efficacy was evaluated by virus isolation from the challenged chicks. In the killed-virus and high-dose live-virus test groups, IBV vaccination protected against challenge by homologous but not heterologous IBV strains. However, a low dose of live IBV showed no protection against virulent IBV challenge. These results indicate that both the genotype based on the N-terminus of the spike protein and the virus dose are essential to IBV protection from immunization. Thus, development of vaccines from different local strains is necessary to control infectious bronchitis in poultry.

Animals↗

PubMed2004

S1 and N gene analysis of avian infectious bronchitis viruses in Taiwan.

The disease caused by infectious bronchitis virus (IBV) produces great economic for the poultry industry. The purpose of this study is to investigate the molecular epidemiology of IBV in Taiwan. An old IBV strain isolated in 1964 and another 31 strains isolated from 1991 to 2003 were selected for N-terminal S1 gene analysis. Based on their phylogenetic tree, 13 strains were selected for sequencing the entire S1 and partial nucleocapsid (N) genes. The results indicated that Taiwanese IBV strains could be divided into two distinct lineages, Taiwan Group I and Taiwan Group II, with one Massachusetts strain and one Chinese strain. No recombination was found between H120 and the Taiwanese strains in the S1 gene. However, the S1 gene showed a noticeably higher divergence than the N gene. The phylogenetic trees constructed from the S1 and N genes indicate that intergenic recombination has occurred. Since most local strains are in Taiwanese clusters, developing vaccines from local strains is necessary for IBV control in Taiwan.

Amino Acid Sequence↗

PubMed2003

Phylogenetic analysis of subgroup J avian leucosis virus from broiler and native chickens in Taiwan during 2000-2002.

Subgroup J avian leucosis virus (ALV-J) causes great economic losses in the poultry industry. One in 3 grandparent farms was closed due to ALV-J infection in 1998 in Taiwan. The remaining 2 farms were forced to import breeding chicks from different breeding companies afterwards. We report on the ALV-J infection status among these breeders, their progeny and Taiwan native chickens during 2000-2002. The weekly mortality for the male line among the infected breeders was higher than that for the female line. Sixty-three percent (5/8) of the broiler flocks were infected with ALV-J. The surface (SU) portion of the env gene from the ALV-J field isolates was cloned and sequenced. The phylogenetic results show that all of the isolates fell into 2 clusters. Unexpectedly, the isolates from the same breeds fell into different clusters, with a cluster including isolates from different breeding companies. ALV-Js from native chickens crossbred with imported chickens were placed into the same clusters as those from the imported breeds. The high similarities observed in different ALV-J isolates suggest that different ALV-Js were mixed in the pedigree generations in different breeding lines.

Animals↗

PubMed2002

Phylogenetic analysis of Newcastle disease virus in Taiwan.

The virulent forms of Newcastle disease virus cause a devastating disease of poultry. Between 1998 and 2000, sporadic outbreaks of Newcastle disease occurred in Taiwan despite vaccination. The causes of the failure of the vaccination remain unclear. The purpose of this study was to investigate the possible factors causing these outbreaks by serologic and virologic methods. Anti-Newcastle disease virus hemagglutination-inhibition titers were measured for serum samples obtained from a breeder farm and a broiler farm. The serologic data showed continued presence of virulent Newcastle disease viruses in the field during inter-outbreak periods. Phylogenetic analysis demonstrated that the field virulent Newcastle disease viruses were genetically similar and were grouped into genotype VIIa. Efficacy testing by virulent Newcastle disease virus challenge revealed that the vaccines used were effective for protecting chickens from infections. This investigation demonstrated that the Newcastle disease virus strain can spread quickly and widely throughout a large geographic area, and that the sporadic cases originate from virulent Newcastle disease viruses present in the field.

Animals↗

PubMed2002

Monitoring the hygene of chicken hatcheries in Taiwan during 1999-2001.

Microorganism contamination in hatcheries and eggs has a serious impact on the viability and quality of chicks as well as on the overall growth performance of chickens. Microbiological agents are present in the fluff when chicks hatch. Detecting microorganisms in fluff is a convenient method for evaluating the hygienic status in a hatchery. Fluff samples from 31 hatcheries collected over 3 years were tested for the total bacterial count, the presence of Salmonella spp., and fungus to evaluate the hygienic status of hatcheries in Taiwan from 1999 through 2001. The total bacterial score from the fluff samples was calculated and expressed as a bacterial score in a log scale. Most hatcheries had a bacterial count ranged from scale 1 to 3. Among the hatcheries, 13% to 29% were contaminated with Salmonella spp.; and 33% to 73% were contaminated with fungi in different quarters. The third quarter of each year was the most contaminated period (p<0.01). According to the data obtained from the fluff tests, hatcheries keep their hygienic status and supply good quality chicks by cleaning and disinfecting.

Animal Husbandry↗

PubMedDate not supplied

Clinical epidemiologic and experimental evidence for the transmission of Newcastle disease virus through eggs.

Sporadic outbreaks of Newcastle disease (ND) occurred in Taiwan during 1998-2000. In some cases, the disease occurred in broilers less than 2 wk old that originated in a broiler breeder farm, so spread of the ND virus (NDV) from the infected breeder farm to broiler ranches was suspected. The purpose of the present study was to examine the possibility of the transmission of NDV through eggs. Both clinical and experimental evidence were used to prove that this is possible. From epidemiological investigation, the possibility of transmission through eggs was suggested in two separate ND cases from a breeder farm and its progeny because two identical NDVs were isolated from both cases. In order to clarify the possibility of the transmission through eggs, one mean egg lethal dose (ELD50) of NDV was inoculated into the allantoic cavity of 155 9-to-11-day-old specific-pathogen-free (SPF) chicken embryos. Seventy-one hatching chicks from the inoculated embryos were raised for 14 days. The cloacal swabs from those chicks at the ages of 1, 4, and 7 days and the tissues after necropsy at the ages of 14 days were taken for virus isolation. The same NDV was reisolated from three hatching chicks. This experiment confirms that a few chicken embryos infected in ovo with a low titer of NDV can hatch and contain NDV after hatching, which results in NDV spreading through eggs.

Animals↗

PubMedDate not supplied

Serologic profiles of chickens infected with subgroup J avian leukosis virus.

Subgroup J avian leukosis virus (ALV-J) causes serious economic losses in the commercial poultry industry. Measuring group-specific antigen (GSA) by enzyme-linked immunosorbent assay (ELISA) has been used to identify chickens infected with this virus. However, the inability of ELISA to discriminate the GSA from endogenous ALV (subgroup E ALV [ALV-E]) or ALV-J infection has limited its usage. The purpose of the present study was to develop a method to discriminate between uninfected flocks having ALV-E and ALV-J-infected flocks by ELISA. The GSA and anti-ALV-J antibody in the plasma samples from chickens at different ages in three grandparent farms were measured by ELISA. Infected flocks were confirmed by reverse transcription-polymerase chain reaction with different subgroup-specific primers and sequence analysis. The results indicated that the GSA of ALV-J-infected flocks increased, but that of the uninfected flocks decreased during young ages. The anti-ALV-J antibody of infected flocks was higher and increased earlier than that of uninfected flocks. Thus, measuring GSA in blood at the ages of 1 and 6 wk by ELISA is suitable to discriminate between ALV-J-infected flocks and uninfected flocks having ALV-E.

Age Factors↗

PubMedDate not supplied

Experimental selection of virus derivatives with variations in virulence from a single low-pathogenicity H6N1 avian influenza virus field isolate.

A mixture of viruses with variations in virulence is likely present within a low-pathogenicity avian influenza virus (LPAIV) population. An H6N1 AIV was isolated from a field case showing 3.8% weekly mortality and a 33% egg production drop in Taiwan. The pathologic lesions included proventricular hemorrhage and urate deposition in the kidneys and on visceral organs. From the field isolate, a done (2838N) that caused no lesions or death was obtained using limit dilution in chicken embryos and a done (2838V) that caused renal lesions and death was obtained using contact infection in chicks. Both clones were inoculated intranasally in 4-week-old specific pathogen free (SPF) chickens to test their virulence. Renal urate deposition was found in chickens inoculated with 2838V but not in chickens inoculated with 2838N. In situ hybridization, polymerase chain reaction, and virus isolation were used to confirm the spread of 2838V from the respiratory tract to the renal tissue. We found that contact infection in chickens is a good method to obtain a more virulent done from a heterogeneous virus population.

Animals↗