疾病描述:
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描述
1.病原概述
病原型別:原生動物(protistan parasites)
病原環境:海水
學名:Perkinsus olseni
病名(及俗名):
最早發現者:
OIE狀況:表列(Listed)
病原摘要:
全世界之軟體動物(mollusks)因perkinsus 之感染造成嚴重死亡(severe mortalities )及經濟損失(significant economic losses) (Villalba et al 2004)。病原可於離開宿主(host)數天至幾星期,因其有一厚細胞壁(thick cell wall),但於淡水中不穩定,在淡水中常溫下存活時間少於10分鐘,6ppm之氯作用30分鐘同樣可殺死病原(Goggin 1995),其生活史中之任一階段都可感染宿主。
人畜共通:無(No)
病原分類
2.病原分類:原生動物中之Perkinsus 屬
命名沿革:重要的幾次命名歷史文獻
疾病特性
感染組織及器官:感染路徑、好發組織器官
所有器官之結締組織及血細胞(connective tissue of all organs, haemocytes)。
疾病型態及流行病學:急性或慢性型態、器官傳播分佈情形
可被感染之軟體動物相當多如,蛤類(clams)含 Anadara trapezia, Austrovenus stutchburyi, Tapes decussatus, Tapes philippinarum, Pitar rostrata。牡蠣( oysters): Crassostrea gigas, Crassostrea ariakensis, Crassostrea sikame。真珠牡蠣 (pearl oysters): Pinctada margaritifera, Pinctada martensii; abalone - Haliotis rubra, Haliotis laevigata, Haliotis scalaris, Haliotis cyclobates (2, 16, 18, 24, 28)。其它雙殼貝 (bivalve) 及腹足綱軟體動物( gastropod) 亦有可能被感染寄生 (Hamaguchi et al 1998)。
臨床症狀及病理學:
為一種致命性之感染(infection is lethal ),但死亡往往是感染後1-2年才發生(OIE 2006)
肉眼上常可見水樣組織(watery tissue)、消化腺蒼白、有些宿主之鰓上會有結節(nodules in gills)。但這些並非感染 Perkinsus olseni 之專一病變。
組織病理學
活或剛死亡之軟體動物(freshly dead mulluscs)為佳,樣本可以Davidson’s 固定液固定,組織中應含有消化腺體及鰓。於在結締組織中可見局部多發病變同時含有P. olseni ,伴隨血細胞浸潤(haemocyte infiltration)及吞噬情形,於蛤(clam)切片中病原常被一厚的嗜酸性物質(thick layer of eosiniophilic material)所包圍(encapsulated),病原大小約 5-15um蟲體為球狀,蟲體具具有一大空泡及偏於一邊之核,perkinsus olseni於H&E 染色下呈藍色。此方法於感染中度到嚴重時容易被觀察到,但無法區別是何種perkinsus 所引起(OIE 2006)。
病原致病性意義:實際魚場及田間發病、抗藥性等情形
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參考文獻:
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Almeida M, Berthe F, Thebault A, Dinis MT. Whole clam culture as a quantitative diagnostic procedure of Perkinsus atlanticus (Apicomplexa, Perkinsea) in clams Ruditapes decussatus. Aquaculture, 177: 325-332, 1999.
Faisal M, La Peyre JF, Elsayed EE. Bacitracin inhibits the oyster pathogen Perkinsus marinus in vitro and in vivo. J Aquat Anim Health 11: 130-138, 1999.
Goggin CL, Lester RJG, Perkinsus, a protistan parasite of abalone in Australia: a review. Aust J Mar Freshwater Res. 46, 639-646, 1995.
Hamaguchi M, Suzuki N, Usuki H, Ishioka H. Perkinsus protozoan infection in short-necked clam Tapes (=Ruditapes) philippinarum in Japan. Fish Pathol., 33: 473-480, 1998.
OIE (2006) Manual of Diagnostic Tests for Aquatic Animals.World Organisation for Animal Health (http://www.oie.int).
Ragone Calvo LM, Calvo G.W. Burreson E .M. Dual disease resistance in a selectively bred eastern oyster, Crassostrea virginica, strain tested in Chesapeake Bay. Aquaculture, 220: 69-87, 2003.
Ray SM. A review of the culture method of detecting Dermocystidium marinum with suggested modifications and precautions. Proc. Natl. Shellfish Assoc. 54: 55-69, 1966.
Robledo JAF, Coss CA, Vasta G.R. Characterization of the ribosomal RNA locus of Perkinsus atlanticus and development of a polymerase chain reaction-based diagnostic assay. J. Parastol. 86: 972-978, 2000.
Villalba A, Reece KS, Orda’ s MC, Casas SM, Figueras A. Perkinsosis in molluscs: A review. Aquat Liv Res. 17: 411–32, 2004.
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