Rubio Andrew O, Kupferberg Sarah J, Vargas García Victor, Ttito Alex, Shepack Alexander, Catenazzi Alessandro
Southern Illinois University, Department of Zoology, Carbondale, IL 62901, USA.
Dis Aquat Organ. 2018 Nov 20;131(3):233-238. doi: 10.3354/dao03298.
Amphibian diversity has declined due to the infectious disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Coexistence between amphibian hosts and this pathogen in some locations is attributed to the presence of the cutaneous bacterium Janthinobacterium lividum (Jliv). This microbe inhibits the growth of Bd on the host, reduces morbidity, and improves survival. Andean water frogs in the genus Telmatobius seem to be particularly vulnerable to the disease yet populations of T. intermedius and T. marmoratus persist in southern and central Peru. We investigated the presence of Jliv on these 2 frog species and assessed the relationship of Jliv presence with prevalence and intensity of Bd infection. By sampling 125 frogs from 7 streams (3323-3950 m a.s.l.) and 27 from a city market, we found spatial variation in the mutualism among populations (range 0-40% proportion of Jliv-positives). Overall, 57% of frogs were infected with Bd, 12.5% of frogs hosted both Jliv and Bd, while 7.2% hosted just Jliv. We found that the probability of an individual being infected with Bd was independent of the presence of Jliv; however, we did detect a protective effect of Jliv with respect to intensity of infection. The extent of Jliv distribution in the high Andes stands in stark contrast to the rarity of Jliv on frogs in lower elevation cloud forest biomes.
两栖动物的多样性因由真菌病原体蛙壶菌（Batrachochytrium dendrobatidis，简称Bd）引起的传染病壶菌病而下降。在某些地区，两栖动物宿主与这种病原体共存归因于皮肤细菌青灰海栖菌（Janthinobacterium lividum，简称Jliv）的存在。这种微生物抑制宿主上Bd的生长，降低发病率，并提高存活率。Telmatobius属的安第斯水蛙似乎特别容易感染这种疾病，但中间水蛙和大理石纹水蛙种群在秘鲁南部和中部仍然存在。我们调查了这两种蛙类身上Jliv的存在情况，并评估了Jliv的存在与Bd感染的患病率和感染强度之间的关系。通过从7条溪流（海拔3323 - 3950米）采集125只青蛙和从一个城市市场采集27只青蛙，我们发现种群间互利共生存在空间差异（Jliv阳性比例范围为0 - 40%）。总体而言，57%的青蛙感染了Bd，12.5%的青蛙同时携带Jliv和Bd，而7.2%的青蛙只携带Jliv。我们发现个体感染Bd的概率与Jliv的存在无关；然而，我们确实检测到Jliv对感染强度有保护作用。Jliv在高安第斯山脉的分布范围与它在低海拔云雾林生物群落中青蛙身上的罕见程度形成鲜明对比。
