正番鴨小病毒之宿主範圍分析及水禽小病毒在野外發生情形

Abstract

在以往的研究當中，認為鵝小病毒（GPV）為感染鵝及正番鴨，正番鴨小病毒（MDPV），只感染正番鴨而不感染鵝。然而在本實驗室，曾由野外鵝中分離出正番鴨小病毒，為瞭解MDPV的宿主範圍，及感染後在宿主體內分佈、持續及排毒情形，而進行白羅曼鵝及各種鴨隻之人工感染試驗。 白羅曼鵝及正番鴨在人工感染MDPV後，主要在十二指腸、肝臟及腎臟可偵測到MDPV核酸，並均以感染後第14日可在最多種臟器中測得核酸，直到感染後第16、18天仍皆可檢測到MDPV核酸。各品系鴨，包括正番鴨、北京鴨、菜鴨及土蕃鴨在人工感染後亦皆可檢測出MDPV之核酸，並且皆引起高死亡率，尤其其中菜鴨、土蕃鴨及正番鴨。 另外為瞭解水禽小病毒在野外之發生情形，針對雲林鴨場進行追蹤調查研究，結果GPV或MDPV的垂直感染在野外皆有發生，並且可能以GPV較為普遍。 在鴨鵝小病毒台灣株之結構蛋白VP3核酸序列分析方面，結果顯示，GPV台灣株與分離株4株，相似度達97.1-99.8％。而MDPV分離株4株，與匈牙利株相似度僅有88.5-99.0％，變異性較GPV群為大，推測可能與宿主範圍改變相關。

In the previous study goose parvovirus (GPV) was regarded to infect goose and Muscovy duck, and the Muscovy duck parvovirus (MDPV) was considered to infect goose only but not Muscovy duck. In our lab, a MDPV strain was isolated from goose. To understand the host range of the MDPV and its distribution in the host, white Roman goose and Muscovy duck were artificial infected with MDPV in this study. After the inoculation of MDPV in white Roman goose and Muscovy duck, the MDPV DNA was mainly detected in liver, small intestinal and kidney. The MDPV DNA was detected in most organs at 14th day post-inoculation (DPI). The MDPV DNA continued to be detected till the end of the study at the 16th and 18th DPI. MDPV DNA could be detected in the Muscovy duck, Pekin duck, tsaiya duck , and mule duck after experimental inoculation. The result showed MDPV could infect Muscovy duck, tsaiya duck, mule duck and Pekn duck and resulting in high mortality. To understand the occurrence of MDPV and GPV in the field, cohort study was performed in the duck farms in Yun-Lin. The results show that the vertical transmission of GPV or MDPV occurred in the field, and the occurrence of GPV might be more common than MDPV. The nucleotide sequence of the structure protein, VP3, of the field strains of MDPV and GPV were analyzed. The results that the similarity of GPV Taiwan strain and the four isolated strains was between 97.1-99.8％. The similarity of MDPV Hungary strain and the four isolated strains was between 88.5-99.0％. The variability was higher in MDPV group than in GPV group.