Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
Vietnam National Museum of Nature, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam.
Sci Rep. 2017 Mar 13;7:44443. doi: 10.1038/srep44443.
The amphibian chytrid fungi, Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), pose a major threat to amphibian biodiversity. Recent evidence suggests Southeast Asia as a potential cradle for both fungi, which likely resulted in widespread host-pathogen co-existence. We sampled 583 salamanders from 8 species across Vietnam in 55 locations for Bsal and Bd, determined scaled mass index as a proxy for fitness and collected environmental data. Bsal was found within 14 of the 55 habitats (2 of which it was detected in 2013), in 5 salamandrid species, with a prevalence of 2.92%. The globalized pandemic lineage of Bd was found within one pond on one species with a prevalence of 0.69%. Combined with a complete lack of correlation between infection and individual body condition and absence of indication of associated disease, this suggests low level pathogen endemism and Bsal and Bd co-existence with Vietnamese salamandrid populations. Bsal was more widespread than Bd, and occurs at temperatures higher than tolerated by the type strain, suggesting a wider thermal niche than currently known. Therefore, this study provides support for the hypothesis that these chytrid fungi may be endemic to Asia and that species within this region may act as a disease reservoir.
两栖动物壶菌，Batrachochytrium dendrobatidis（Bd）和Batrachochytrium salamandrivorans（Bsal），对两栖动物的生物多样性构成了重大威胁。最近的证据表明，东南亚可能是这两种真菌的潜在发源地，这可能导致了广泛的宿主-病原体共存。我们在越南 55 个地点的 8 个物种中采集了 583 只蝾螈，用于检测 Bsal 和 Bd，并确定了鳞片质量指数作为健康状况的替代指标，同时收集了环境数据。在 55 个栖息地中的 14 个（其中 2 个于 2013 年被检测到）中发现了 Bsal，存在于 5 种蝾螈物种中，流行率为 2.92%。Bd 的全球化大流行谱系在一个物种的一个池塘中被发现，流行率为 0.69%。结合感染与个体身体状况之间完全没有相关性，以及没有表明存在相关疾病的迹象，这表明病原体地方特有性水平较低，Bsal 和 Bd 与越南蝾螈种群共存。Bsal 的分布范围比 Bd 更广，而且在高于 Bsal 模式株耐受温度的地方出现，这表明其热生态位比目前已知的更广泛。因此，本研究支持了以下假设，即这些壶菌可能是亚洲特有的，该地区的物种可能是疾病的储主。
