Rowley Jodi J L, Skerratt Lee F, Alford Ross A, Campbell Ruth
Amphibian Disease Ecology Group, School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia.
Dis Aquat Organ. 2007 Feb 8;74(1):7-12. doi: 10.3354/dao074007.
Chytridiomycosis is a potentially fatal disease of amphibians caused by Batrachochytrium dendrobatidis, and is implicated in declines and extinctions of amphibian populations and species around the world. To cause local host extinction, a disease organism must persist at low host densities. One mechanism that could facilitate this is the ability to persist in the environment. In the laboratory, B. dendrobatidis spreads by both frog-to-frog and environment-to-frog transmission, and can persist on a number of biotic substrates. In the field, B. dendrobatidis has been detected on environmental samples taken during an epidemic, but it is not known if it persists in the environment when endemic. Retreat sites of 2 species of Australian rain forest stream frogs Litoria lesueuri and L. nannotis were sampled 0 to 3 d after occupation during the wet and dry seasons in northern Queensland, Australia, where chytridiomycosis has been endemic for at least 10 yr. The intensity and prevalence of infection in frogs during sampling were comparatively low compared with epidemics. Diagnostic quantitative polymerase chain reaction did not detect B. dendrobatidis in any retreat site samples. It thus appears that retreat sites are not a major environmental source of infection when B. dendrobatidis occurs at low prevalence and intensity on frogs. This suggests that control efforts may not need to eliminate the organism from the environment, at least when prevalence and intensity of infection are low in frogs. Simply treating hosts may be effective at controlling the disease in the wild.
蛙壶菌病是一种由蛙壶菌引起的两栖动物潜在致命疾病，与世界各地两栖动物种群和物种的数量减少及灭绝有关。要导致当地宿主灭绝，致病生物必须在低宿主密度下持续存在。一种可能促进这种情况的机制是在环境中持续存在的能力。在实验室中，蛙壶菌通过蛙与蛙之间以及环境与蛙之间的传播扩散，并且可以在多种生物基质上持续存在。在野外，在疫情期间采集的环境样本中检测到了蛙壶菌，但尚不清楚在地方病流行时它是否能在环境中持续存在。在澳大利亚昆士兰州北部，蛙壶菌病已经流行了至少10年，在雨季和旱季，对两种澳大利亚雨林溪流蛙——饰纹姬蛙和纳氏姬蛙——占据后的0至3天的避难所进行了采样。与疫情期间相比，采样时青蛙的感染强度和患病率相对较低。诊断性定量聚合酶链反应在任何避难所样本中均未检测到蛙壶菌。因此，当蛙壶菌在青蛙身上的患病率和感染强度较低时，避难所似乎不是主要的环境感染源。这表明控制措施可能不需要从环境中消除这种生物，至少在青蛙的感染患病率和强度较低时如此。仅仅治疗宿主可能在野外有效控制这种疾病。
