Messick Gretchen A, Overstreet Robin M, Nalepa Thomas F, Tyler Sue
NOAA, National Ocean Service, Cooperative Oxford Laboratory, 904 S. Morris Street, Oxford, Maryland 21654, USA.
Dis Aquat Organ. 2004 May 5;59(2):159-70. doi: 10.3354/dao059159.
Amphipods of Diporeia spp. have declined considerably during the last decade in the Great Lakes. We examined the possibility that disease may be affecting these populations. A histological survey assessed the parasites in species of Diporeia within Lakes Huron and Michigan, USA, and the host response to some of them and to unknown factors. Amphipods were found to have an intranuclear inclusion body, and were hosts to a rickettsia-like organism, fungi, a haplosporidian, a microsporidian, epibiotic ciliates, a gregarine, a cestode, acanthocephalans and nodule formations. Epibiotic ciliates were most common (37% prevalence of infection), but a microsporidian (3.8%), a rickettsia-like organism (1.6%), fungi, including a yeast-like organism (1.3%), worms (1.3%), and a haplosporidian (0.7%) are likely associated with mortalities or detrimental effects on the host. The role these agents may have played in the decline of Diporeia spp. in the Great Lakes over the last decade is not clear. Interrelationships with the dynamics of various physical and biological factors such as high sedimentation, diminished food supplies, and virulent parasites could synergistically cause the decline in Diporeia spp. populations in Lakes Michigan and Huron.
在过去十年间，大湖地区的 Diporeia 属双足虾类数量大幅减少。我们研究了疾病可能影响这些种群的可能性。一项组织学调查评估了美国休伦湖和密歇根湖中的 Diporeia 物种体内的寄生虫，以及宿主对其中一些寄生虫和未知因素的反应。发现双足虾类有一个核内包涵体，并且是一种立克次氏体样生物、真菌、一种单孢子虫、一种微孢子虫、体表纤毛虫、一种簇虫、一种绦虫、棘头虫和结节形成的宿主。体表纤毛虫最为常见（感染率为 37%），但一种微孢子虫（3.8%）、一种立克次氏体样生物（1.6%）、包括一种酵母样生物在内的真菌（1.3%）、蠕虫（1.3%）和一种单孢子虫（0.7%）可能与宿主的死亡或有害影响有关。在过去十年中，这些病原体在大湖地区 Diporeia 属物种数量减少过程中可能扮演的角色尚不清楚。与各种物理和生物因素（如高沉降、食物供应减少和毒性寄生虫）动态变化之间的相互关系可能协同导致密歇根湖和休伦湖 Diporeia 属种群数量下降。
