Cat-scratch disease in veterinary-associated populations and in its cat reservoir in Taiwan

In Taiwan, the first human case of cat-scratch disease (CSD) was diagnosed by a serologic test in 1998. Since then, no studies have been conducted to understand the epidemiology of the infection in Taiwan. Therefore, this study is the first epidemiologic survey of CSD in cats and humans in this country. Using veterinary-associated individuals as the study population, it was identified that 1.7% of them were seropositive for B. henselae, and residence was the only factor associated with seropositivity. Bartonella species were successfully isolated from 25 (19.1%) of the 131 cats tested. Only B. henselae and B. clarridgeiae were obtained from bacteremic cats. Furthermore, 9.2% of 131 cats were dually-infected with genotypes I and II of B. henselae. It is the highest prevalence of co-infection that has ever been reported worldwide. In cats, the seroprevalence was 23.7% by indirect immunofluorescence antibody assay with B. henselae Houston-1 (type I) as the antigen. When 12 bacteremic but seronegative cats were re-tested by IFA slides coated with B. henselae U-4 antigen (type II), 9 cats were identified to be seropositive. Our study further suggested that using only direct PCR of 16S-23S rRNA intergenic region or the combination of the PCR method and indirect immuno-fluorescence test will be useful to diagnose Bartonella-free cats

A quantitative risk assessment model to evaluate effective border control measures for rabies prevention

Border control is the primary method to prevent rabies emergence. This study developed a quantitative risk model incorporating stochastic processes to evaluate whether border control measures could efficiently prevent rabies introduction through importation of cats and dogs using Taiwan as an example. Both legal importation and illegal smuggling were investigated. The impacts of reduced quarantine and/or waiting period on the risk of rabies introduction were also evaluated. The results showed that Taiwan's current animal importation policy could effectively prevent rabies introduction through legal importation of cats and dogs. The median risk of a rabid animal to penetrate current border control measures and enter Taiwan was 5.33 X 10(-8) (95th percentile: 3.20 x 10(-7)). However, illegal smuggling may pose Taiwan to the great risk of rabies emergence. Reduction of quarantine and/or waiting period would affect the risk differently, depending on the applied assumptions, such as increased vaccination coverage, enforced custom checking, and/or change in number of legal importations. Although the changes in the estimated risk under the assumed alternatives were not substantial except for completely abolishing quarantine, the consequences of rabies introduction may yet be considered to be significant in a rabies-free area. Therefore, a comprehensive benefit-cost analysis needs to be conducted before recommending these alternative measures

Isolation of Bartonella species from rodents in Taiwan including a strain closely related to 'Bartonella rochalimae' from Rattus norvegicus

An increasing number of Bartonella species originally isolated from small mammals have been identified as emerging human pathogens. During an investigation of Bartonella infection in rodent populations carried out in Taiwan in 2006, a total of 58 rodents were tested. It was determined that 10.3% (6/58) of the animals were Bartonella bacteraemic. After PCR/RFLP analysis, four isolates were identified as Bartonella elizabethae and one isolate as Bartonella tribocorum. However, there was one specific isolate with an unrecognized PCR/RFLP pattern. After further sequence and phylogenetic analyses of the gltA, ftsZ and rpoB genes, and the 16S-23S rRNA intergenic spacer region, the results indicated that this specific isolate from Rattus norvegicus was closely related to human pathogenic 'Bartonella rochalimae'. Further studies need to be conducted to evaluate whether this rodent species could be a reservoir for 'B. rochalimae'

Characterization of 13 multi-drug resistant Salmonella serovars from different broiler chickens associated with those of human isolates

<p>Abstract</p> <p>Background</p> <p><it>Salmonella </it>are frequently isolated from chickens and their products. Prevalent serogroups and serovars of <it>Salmonella </it>as well as their genotypes and antibiograms were determined for cloacal samples from 1595 chickens. To understand the possible serovar and H antigens for transmission between chicken and human, serovars and their H antigens of 164 chicken and 5314 human isolates were compared.</p> <p>Results</p> <p>Prevalence of <it>Salmonella </it>differed among chicken lines and ages. Chicken and human isolates belonged mainly to serogroup B, C1, C2-C3, D, and E. 13 serovars and 66 serovars were identified for chicken and human isolates respectively. The common serovars for chicken and human isolates were <it>S</it>. Typhimurium, <it>S</it>. Enteritidis, <it>S</it>. Albany, <it>S</it>. Derby, and <it>S</it>. Anatum and shared common H1 antigens "g complex; i; e,h; and z4,z24" and H2 antigens "1 complex and -". In human isolates, H1 antigen "i" and H2 antigen "-" were common in all serogroups. In chicken, antimicrobial susceptibility differed among serogroups, serovars and three counties. All isolates were susceptible to cefazolin and ceftriaxone, but highly resistant to ampicillin, chloramphenicol, flumequine, streptomycin, sulfamethoxazole-trimethoprim, and tetracycline. Except those isolates of serogroup C1 of Chick group and serogroup G, all isolates were multi-drug resistance. Only <it>S</it>. Kubacha, <it>S</it>. Typhimurium, <it>S</it>. Grampian, and <it>S</it>. Mons were resistant to ciprofloxacin and/or enrofloxacin.</p> <p>Conclusion</p> <p>In chicken, prevalent serogroups and serovars were associated with chicken ages, lines and regions; and flouroquinolone-resistant and MDR isolates emerged. H1 antigens "g complex and i" and H2 antigens "1 complex and -" might be important for transmission of <it>Salmonella </it>between chicken and human.</p

Epidemiology and Phylogenetic Analysis of Bartonella Infections in Small Mammals in Taiwan

巴東體屬菌(Bartonella spp.)為新興人畜共通傳染疾病病原，其中B. henselae雖已發現為貓抓熱的主要病原，但由於對此細菌培養技術的改進與分子診斷學的進步，更多的新Bartonella菌種被發現，其自然宿主涵蓋種類廣泛，研究顯示小型哺乳類動物為其重要宿主之一。因此本研究計畫以兩年為期對台灣地區小型哺乳類動物(以鼠為主)進行Bartonella感染的流行病學探討，一方面建立此菌屬於台灣小型哺乳類動物中的基礎流行病學資料，另一方面可瞭解是否有重要的人畜共通Bartonella spp.的存在。樣本捕捉地點分別預計進行於中部地區商業港口附近的靠海岸生態環境，靠內陸的農牧生態環境與都市地區進行野生小型哺乳類動物捕捉採樣。利用全血細菌培養方式進行細菌分離，所分離之細菌並進一步利用16S/23S rRNA基因ITS片段以及gltA基因片段進行限制片段長度多型性（RFLP）技術組合分析，以利快速菌種區分。進一步並將分離株之gltA基因片段進行定序，依親緣樹分析台灣地區小型哺乳類動物中Bartonella屬菌與鄰近國家中分離株的關係。欲完成之研究工作項目包括：(1)台灣地區不同生態環境下（包括海岸地區、內陸都市區、內陸農牧區）小型哺乳類動物(以鼠為主)種別之血液樣本收集；(2)台灣地區不同生態環境下（包括海岸地區、內陸都市區、內陸農牧區）小型哺乳類動物Bartonella屬菌感染的菌血症盛行率比較；(3)台灣地區小型哺乳類動物Bartonella屬菌感染的菌種分子鑑定；(4)台灣地區小型哺乳類動物Bartonella屬菌與國際間分離的Bartonella屬菌親緣樹譜分析。研究結果將有助於瞭解與評估台灣居民因意外接觸環境中小型哺乳動物而感染Bartonella屬菌疾病的危險性。Bartonella spp. are emerging zoonotic pathogens. Due to the recent development of culture and molecular diagnostic techniques, more Bartonella species have been identified. The results showed that small mammals are the main reservoirs for several Bartonella spp. Therefore, this 2-year project will be conducted in Taiwan to understand the epidemiology of Bartonella infections in small mammals in Taiwan, as well as the phylogenetic relationship of Bartonlla spp. in small mammals in Taiwan and other countries. The results will be helpful to understand and assess the possible risk in humans acquiring the infections from small mammals in Taiwan

Using Molecular Epidemiology to Understand the Role of Virb4 Gene in Pathogenecity and Evolution of Bartonellaceae

慢性腎衰竭(chronic renal failure, CRF)是一種慢性漸進性腎功能喪失疾病，臨床上出現azotaemia、尿毒症(uremia)，預後不佳。造成CRF成因相當複雜，如食物或飼料中遭黴菌污染，磺銨劑引起腎衰竭案例亦經常可見。犬飲食中含有腐敗魚粉飼料(broiled fish)出現高比率的致基因毒性表現。在93年初爆發寶路乾狗糧引發狗腎衰竭的事件，農委會曾針對此一事件成立「台灣地區犬腎衰竭流行病學研究專案小組」，決議委由學校及研究機構進行犬腎衰竭流行病學調查、可疑犬飼料中黴菌毒素分析及飼料成份檢測等工作。獸醫組織病理學會亦針對「台灣地區犬腎衰竭病例討論」，解剖當時因腎衰竭死亡犬隻，在腎臟均出現大量綠色的結石，間質性腎炎、纖維化、腎小管阻塞及擴張等嚴重病變。之後艾汾公司向外界公佈該批配製犬隻飼料之玉米受黴菌污染，黴菌中發現有褐黴素(Citrinin)和褚麴毒素(Ochratoxin)兩種毒素。雖然寶路乾狗糧已回收產品，事件糾紛已落幕，但政府所公佈可疑飼料中經抽驗並無高量黴菌毒素汙染，亦排除有飼料組成有重金屬污染之慮，其引致犬隻腎衰竭真正原因至今未明。因飼料組成相當複雜，犬貓寵物飼料並非「飼料管理法」所規範之範圍，目前市售犬飼料中，添加各種保健食品，宣稱可改善毛髮並促進健康，但因無法令規範，政府管理機構在不知如何判定飼料組成安全性情況下，因此市售犬飼料成品對寵物潛藏許多健康危機。基於科學研究理念，本實驗室保存有當時寶路乾狗糧引發慢性腎衰竭之可疑飼料，經前實驗結果顯示，大鼠飼料中經混合當時寶路乾狗糧連續投予餵食一段時間後，可誘發出大鼠腎臟腫大或變硬萎縮、腎及膀胱結石及慢性間質性腎炎等病變，與當時所發生之犬腎衰竭病變類似。因此，本年度擬以新藥物開發前之臨床前毒性試驗模式，比較新及舊市售寶路犬飼料成品是否具有基因毒性作用。另以新及舊市售寶路犬飼料成品連續投予大鼠28天，分析對血液學、尿液學及病理學等之影響，探討其可能致病器官之毒性變化。日後或可依此試驗模式進一步確認其他市售品牌犬飼料成品之食用安全性，提供政府管理寵物飼料規範及產品使用風險性評估之參考

Using Molecular Epidemiology to Understand the Role of virB4 Gene in Pathogenecity and Evolution of Bartonellaceae

慢性腎衰竭(chronic renal failure, CRF)是一種慢性漸進性腎功能喪失疾病，臨床上出現azotaemia、尿毒症(uremia)，預後不佳。造成CRF成因相當複雜，如食物或飼料中遭黴菌污染，磺銨劑引起腎衰竭案例亦經常可見。犬飲食中含有腐敗魚粉飼料(broiled fish)出現高比率的致基因毒性表現。在93年初爆發寶路乾狗糧引發狗腎衰竭的事件，農委會曾針對此一事件成立「台灣地區犬腎衰竭流行病學研究專案小組」，決議委由學校及研究機構進行犬腎衰竭流行病學調查、可疑犬飼料中黴菌毒素分析及飼料成份檢測等工作。獸醫組織病理學會亦針對「台灣地區犬腎衰竭病例討論」，解剖當時因腎衰竭死亡犬隻，在腎臟均出現大量綠色的結石，間質性腎炎、纖維化、腎小管阻塞及擴張等嚴重病變。之後艾汾公司向外界公佈該批配製犬隻飼料之玉米受黴菌污染，黴菌中發現有褐黴素(Citrinin)和褚麴毒素(Ochratoxin)兩種毒素。雖然寶路乾狗糧已回收產品，事件糾紛已落幕，但政府所公佈可疑飼料中經抽驗並無高量黴菌毒素汙染，亦排除有飼料組成有重金屬污染之慮，其引致犬隻腎衰竭真正原因至今未明。因飼料組成相當複雜，犬貓寵物飼料並非「飼料管理法」所規範之範圍，目前市售犬飼料中，添加各種保健食品，宣稱可改善毛髮並促進健康，但因無法令規範，政府管理機構在不知如何判定飼料組成安全性情況下，因此市售犬飼料成品對寵物潛藏許多健康危機。基於科學研究理念，本實驗室保存有當時寶路乾狗糧引發慢性腎衰竭之可疑飼料，經前實驗結果顯示，大鼠飼料中經混合當時寶路乾狗糧連續投予餵食一段時間後，可誘發出大鼠腎臟腫大或變硬萎縮、腎及膀胱結石及慢性間質性腎炎等病變，與當時所發生之犬腎衰竭病變類似。因此，本年度擬以新藥物開發前之臨床前毒性試驗模式，比較新及舊市售寶路犬飼料成品是否具有基因毒性作用。另以新及舊市售寶路犬飼料成品連續投予大鼠28天，分析對血液學、尿液學及病理學等之影響，探討其可能致病器官之毒性變化。日後或可依此試驗模式進一步確認其他市售品牌犬飼料成品之食用安全性，提供政府管理寵物飼料規範及產品使用風險性評估之參考

Understanding the Mechanism of Bacterial Persistent Infection-Using Bartonella henselae Infection as a Model

巴東體屬感染症為國際認知的重要新興傳染病，其中包括廣為人知B.henselae 引起的貓抓熱。由於過去貓感染B. henselae 所造成的持續性菌血症(可長達一年以上)並無法使用抗生素進行有效清除，引起疾病防治上的困難。又目前國外正進行此菌的疫苗研發。皆需深入瞭解此菌造成持續性感染的可能機轉。於過去半年中，本研究室已完成B. henselae 於台灣地區貓族群之初步流行病學調查，並完成B. henselae 於愛滋病患者之分子流行病學研究。研究結果顯示依16S rDNA 分型結果之兩分子型B. henselae 可能與其不同致病力有關，值得進一步探討其機轉。本計劃將利用所分離人與貓之B. henselae 基因亞型 I 與基因亞型II 菌株進行活體外感染巨噬細胞的研究，比較此二亞型對巨噬細胞侵入作用與刺激細胞激素產生作用的差異，進行細菌性疾病持續性感染的模式建立與機轉初步探討

Epidemiology of Salmonella enterica Serovar Choleraesuis Infection-From Food Animals to Humans

豬霍亂沙門氏菌近年來在臺灣被發現為一重要新興傳染病，於人類感染病例中造成18%的致死率。豬於感染後主要產生敗血症，因此在肉品衛生的相關規定下，病豬肉應是無法上市的。此外，有別於其他沙門氏菌血清型的感染，豬霍亂沙門氏菌不易於糞便中分離。因此，如何造成人的感染值得進一步探討。首先，利用流行病學的方式，如病例對照研究的設計，以便找出人類感染病例的相關危險因子。其次，此菌是否可由傳統市場或超市的上架豬肉中分離到為另一重點。再者，環境因子如水與土壤等，可作為豬霍亂沙門氏菌的生態保菌窩，值得進一步評估是否為重要感染源。人類在以上的傳播環境中，若配合不良的公共衛生環境與個人習慣，便有可能意外感染。因此，本計劃以三年為期，進行以下調查研究：(1)以醫院病患進行病例對照研究找出與豬霍亂沙門氏菌感染的可能相關因子；(2)採集豬場附近的環境樣本與堆肥場堆肥進行細菌分離；(3) 採集傳統市場或超市的上架豬肉中進行豬霍亂沙門氏菌分離。分離到的豬霍亂沙門氏菌菌株將進一步分析其抗藥性圖譜與分子型別。在此研究中所找出的感染危險因子與相關環境流行病學的調查未來將有助於人類感染豬霍亂沙門氏菌的暴露評估，與制定有效策略預防此菌由食用動物傳播給人