Andrew Chang-Young Fei

Specific polymerase chain reaction for differential diagnosis of Dirofilaria immitis and Dipetalonema reconditum using primers derived from internal transcribed spacer region 2 (ITS2)

Both Dirofilaria immiti and Dipetalonema reconditum may be found in blood of infected dogs but it is not easy to distinguish D. immitis from D. reconditum in morphology. We cloned and sequenced the contiguous internal transcribed spacer (ITS) region, ITS1-5.8S-ITS2, of these two different parasites and published on GenBank as AF217800 for D. immiti and AF217801 for D. reconditum in this study. We designed two pairs of specific primers derived from ITS2 being used for polymerase chain reaction (PCR). The amplicons of ITS2 from D. immiti and D. reconditum are 302 and 348bp, respectively. Moreover, the limitation for amplifying ITS2 gene using this PCR demonstrated that 1 x 10(-2) microfilaria of each species of parasite smashed or even with mixed samples could be detected and the PCR products were predicted as the same as that described above. Thus, D. immiti and D. reconditum could be differentially diagnosed by this specific PCR. Seventeen clinical cases were evaluated and all of them were correctly identified. In this study, ITS1-5.8S-ITS2 of D. immiti or D. reconditum were the first time sequenced and analyzed. No significant similarity of ITS1 and ITS2 between D. immiti and D. reconditum could be observed.

Prevalence of Toxoplasma gondii Antibodies in Stray Dogs in Taipei, Taiwan

Abstract From October 2005 through September 2006, blood samples collected from 1,412 (768 male, 644 female) 1-yr-old and older stray dogs in Taipei City, Taiwan, were tested for antibodies to Toxoplasma gondii using the latex agglutination test (LAT). Antibodies (LAT titers >1:32) to T. gondii were found in 284 (20.1%) of the animals. Seroprevalences were not affected by the sex or density of dogs. The prevalence was highest in dogs from the eastern part of the city.

Seroprevalence of Toxoplasma gondii in Pigs From Slaughterhouses in Taiwan

From May 2003 to April 2004, blood samples from 395 feeder pigs in Taiwan were examined for antibodies to Toxoplasma gondii using the latex agglutination test; antibodies (titer 1:32 or higher) were found in 10.1% of 395 pigs. The results indicate a high prevalence of infection in pigs in Taiwan destined for human consumption.

Prevalences of Antibodies to Toxoplasma gondii in Cats and Humans in Taipei, Taiwan

The prevalences of IgG and IgM antibodies to Toxoplasma gondii in cats and humans in Taipei, Taiwan were measured by using both kinetics-based enzyme-linked immunosorbent assay and immunoblotting. Stray cats had significantly higher seroprevalence (37.0%, n=100) than pet cats (14.0%, n=57). Also, stray cats had higher IgG (1:393 vs 1:22), but similar IgM (1:23 vs 1:20) geometric mean titers (GMT) compared to the pet cats. Stray female cats had a significantly higher seroprevalence (50.0%) than males (24.0%). For the comparisons of the pet animals, a logistic regression model with five factors (sex, age, weight, breed, domain) was analyzed In pet cats, as the animals were growing older the odds ratio for them to be seropositive was getting higher. However, seroprevalence was not sex-, weight-, breed-, or indoor/outdoor activity-dependent. In humans, the prevalence of IgG antibody (which was not sex-dependent) was 7.0% (n=100) and the GMT was 1:177. Veterinarians did not have higher seroprevalence than that or nurses.

Shelter Animal Management and Trends in Taiwan

Trends in the number of dogs entering and departing Taiwan public shelters are analyzed in this article. There were 40 public shelters surveyed from 2000 to 2005 for dog entries and departures. The results indicate that (a) adoption rates and relinquished animal numbers increased, and euthanasia rates decreased at the beginning of the study, but they are showing signs of reversal; (b) shelters in cities have higher adoption rates than those in rural areas; (c) euthanasia remains the main means of controlling dog numbers in most shelters; and (d) potential adopters in Taiwan prioritize animal health and body size when selecting dogs for adoption. There is a need for increased and persistent public education to ensure continued progress is made in encouraging people to treat companion animals responsibly. In addition to educational efforts, creating new, specialized shelters for housing highly adoptable animals can alleviate the space constraint problems in existing kennels and improve the welfare of stray dogs.

Seroprevalences of Antibodies to Toxoplasma gondii in Stray Dogs in Taipei

弓蟲感染非常普遍，在經濟及公共衛生上很重要。為了提供基本的數據做為臺北市流浪犬弓蟲症之流行病學研究，本調查以kinetics-based enzyme-linked immunosorbent assay 合併immunoblotting偵測弓蟲IgG及IgM血清抗體盛行率。Immunoblotting 可以檢測出弓蟲特異性30kD表面抗原。結果顯示整體弓蟲抗體的血清陽性率為8% (n=100)，而95%confidence interval為(0.0352, 0.152)。IgG及IgM抗體盛行率分別為6%及3%，然而此差異統計上並不顯著(McNemar’s test, P=0.0898)。只有少數的流浪犬為活動性弓蟲感染(即IgM陽性)。弓蟲抗體盛行率在雄犬為11.4% (n=44)，而在雌犬為5.4% (n=56)。抗體盛行率和性別無關(Fisher’s exact test, P=0.2951)

Characteristics of Electroretinograms in Canine Eyes with Cataracts

Pre-operative electroretinographic (ERG) data from 203 dogs with cataracts at the National Taiwan University Veterinary Hospital (NTUVH) were analyzed. Retinal function of the catatact dogs was examined by a RetinoGraphics ERG system with a white flash stimulus delivered to mydriatic canine eyes under general anesthesia. ERG was recorded by a contact-lens type of recording electrode referenced to a needle electrode inserted subcutaneously 3 cm posterior to the lateral can-thus. Abnormal ERG results with a wave amplitude less than 70 micorvolts were measured in 27% (109/402) of the eyes examined, including 9% (37/402) of eyes with absent responses and 18% (72/402) of eyes with decreased responses to light stimuli. Miniature schnauzer, Miniature poodle, Pomenarian, and Cocker spaniel showed significantly lower ERG b-wave amplitudes when compared to mix-breed dogs. There were no remarkable changes in the implicit time of ERG wave. There was a big difference in b-wave amplitudes between different age among dogs lost of retinal function, whereas there was no difference in gender among dogs lost of retinal function. In 73% of the dogs, ERG results were normal and cataract surgery was performed with good post-op visual prognosis achieved. As retinal diseases commonly affect dogs and the diseases greatly affect post-op visual outcome and success rate of surgery performed in cataract patients, ERG is an essential procedure before cataract surgery to select suitable candidates for surgical treatment of cataracts in animals.

Expression of a Recombinant Protein Which Can Be Recognized by Antibody to Toxoplasma gondii SAG1

Toxoplasma gondii (T. gondii) infection can cause serious consequences in both humans and animals. Toxoplasmosis is a widespread zoonotic disease and thus is of economic as well as public health importance. Because toxoplasmosis lacks specific clinical signs or syndromes, the application of diagnostic techniques is required to detect the infection. Detection of antibodies to T. gondii has been very useful as an indicator of infection. Nevertheless, no final diagnosis will be made unless a native 30-kilodalton T. gondii-specific surface antigen 1 (SAG1) is recognized by the test samples. SAG1 is highly conserved among various strains of T. gondii and thus is a very useful molecule for diagnosis of toxoplasmosis. In this study, SAG1 gene was amplified and further purified as a 1,011-base pair nucleotide which was then ligated with pET-24b vector as a 6,320-base pair recombinant pET-24b/SAG1. After transformation, a 63-kilodalton protein was expressed in calcium chloride-treated competent Escherichia coli. This recombinant protein could be identified by T. gondii-infected cat sera which also were able to recognize SAG1 molecule by immunoblotting. Furthermore, all 30 sera which could recognize expressed recombinant protein were also positive in kinetics-based enzyme linked immunosorbent assay (ELISA) with recombinant protein. Therefore, ELISA with this expressed recombinant protein, combining the advantages of both traditional ELISA and time consuming immunoblotting, will be a powerful tool for surveying a large number of serum samples with excellent sensitivity and specificity. The potential candidate of this recombinant protein for vaccine development is also discussed.