|摘要: ||鸚鵡喙羽病病毒（ Beak and feather disease virus， BFDV）屬於環狀病毒（Circoviridae）科環狀病毒屬（Circovirus），其感染鸚鵡科鳥類所造成之臨床症狀包括有羽毛發育不良、脫落甚至引發免疫抑制，部分鳥種會出現喙部及爪之病變，故得名鸚鵡喙羽病（Psittacine beak and feather disease, PBFD）（Perry et al., 1981）。2002-2005年間，台灣之研究顯示籠飼鸚鵡之陽性率為41.2% (68/165)，顯示鸚鵡喙羽病之存在（Hsu et al., 2006），本研究依此為出發點，進而希望了解台灣鸚鵡繁殖場之盛行率及病毒演化之情形。研究期間為2007-2008年並分成三部分：首先針對PBFDV之ORFV1 (Rep) 序列設計一引子對，以PCR之方式對於鸚鵡隻羽毛、糞便檢進行檢測。採樣源自台灣東部、中部及南部之3個鳥園、5個鸚鵡繁殖場及臨床病例，共計1285個檢體，其鸚鵡種類包含40科95屬。在臨床病例中，陽性率為 64.3％ (27/42)，在鳥園的部分為 5.9％ (28/474) 到36.4％ (4/11)，而繁殖場為29.2％(33/113)到76.3％ (116/152)。整體陽性率則為 31.8％ (408/1285)，顯示鸚鵡喙羽病已普遍存在於台灣。將1285個檢體的資料詳細記錄，包含以下五個變項：地區（Location）、來源型態（Type）、起源（Source）、年齡（Age）及臨床症狀（Clinical sign）；以多變項邏輯式迴歸分析校正所有可能之干擾因素計算調整後危險勝算比（adjusted odds ratio；aOR），在地區分布方面南部之陽性率最高(aOR=8.15，95% CI=3.90-17.00)；在檢體來源方面是以臨床病例陽性率最高(aOR=7.18，95% CI=3.09-17.00)；鳥種起源方面是舊世界鳥種比新世界鳥種有較高之陽性率(aOR=4.01，95% CI=2.61-6.16)；在年齡方面是雛鳥-亞成鳥之陽性率高於年輕成鳥-成鳥(OR=1.33，95% CI=0.67-2.67)，但在校正後兩者間之陽性率不具統計學上之意義（p=0.42>0.05）；在臨床症狀方面，羽毛異常者比外觀正常者有較高之陽性率(aOR=79.00，95% CI=28.98-215.32)。第二部分則收集陽性鸚鵡，每個月皆採取羽毛及泄殖腔拭子展開為期兩年之長期排毒監測，14隻陽性鸚鵡除了中途死亡之5隻鸚鵡外，其餘9隻鸚鵡至實驗結束止，兩種檢體皆為BFDV核酸陽性。中途死亡之鸚鵡則採全身臟器進行病毒分布調查，所有採集之臟器皆可測到BFDV之核酸，並且可能終身排毒。第三部分是病毒序列分析，將17株全長序列與GeneBank現有之序列，針對ORF V1、ORF C1及全長相較之間親源性及基因演化；4株序列（PsiE-TWe07、Ecl-TWe08、Cos-TWe09及Tri-TWc13）源自南非具有地區性，8株（Aga -TWs01~ TWs03、Mel-TWs04~ TWs06、Mel-TWs17及PsiE-TWc12）具有鳥屬特性，5株（Cac-TWc11、Cac-TWc10、Cac-TWc14、Cac-TWn16及Pseu-TWs15）與地區或鳥屬無明顯統一性，尚無出現台灣特有之序列。|
Psittacine beak and feather disease (PBFD) is a progressive symmetric feather dystrophy, which is caused by a circular, single-strand DNA virus belonging to Circoviridae Circovirus. Since 1981, the first PBFD case was described in Australia, over 60 species of psittacine birds are susceptible for this disease. Epidemiological researches and case reports were announced from many countries, including United States, United kingdom, Italy and Germany, showing that BFDV might be transmitted worldwide through international trade. In Taiwan, a previous study based on clinical cases revealed that positive rate was 41.2% (68/165) during 2002-2005 (Hsu et al., 2006). In our study, we collected feathers and feces from clinical cases, 3 bird parks and 5 independent breeding facilities, 1285 birds in total including 40 genera and 95 species during 2007-2008. Basing on the sequences of the ORFV1 (Rep) of BFDV, we designed a primer set for PCR detection, and the expected amplicon size was 420 bp. In conclusion, the positive rate was 64.3% (27/42) in clinical cases, and the positive rate in breeding facilities ranged from 5.9% (28/474) to 76.3% (116/152). The total positive rate was 31.8% (408/1285), indicating that BFDV persistently existed in Taiwan. In statistic analysis, the variables were including Location (eastern, southern and central), Type (bird park, breeding facility and clinical case), Source (new world and old world genera), Age (young adult-adult and nestling-juvenile) and Clinical sign (normal and feather dystrophy); The results of multiple logistic regression showed that subjects from southern Taiwan (aOR=8.15, 95% CI=3.90-17.00), clinical cases (aOR=7.18, 95% CI=3.09-17.00), old world genera (aOR=4.01, 95% CI=2.61-6.16) and feather dystrophy (aOR=79.00, 95% CI=28.98-215.32) were significantly associated with PCR-positive rate; In the second part of our study, 14 BFDV positive birds were tested for the long-term (24 months) shedding, the feather and cloacal swab were collected every month. 9 birds were PCR positive in both samples at the end of the experiment; 5 birds died halfway were tested for the BFDV distribution in organs, all the collected organs were PCR positive. In the final part, alignment of 17 isolates in our study with 41 sequences from GeneBank, 4 isolates were clustered with South Africa isolates (AY450438-442); 8 isolates were clustered with groups of psittacine species indicating genotypic association between the viruses and the host, but 4 isolates from cockatoos and 1 from dusky lorikeet did not show the species differences. The established phylogenetic tree did not support the existence of specific genotypes in Taiwan.