Zhang Ju, Li Meng, Huang Qian, Hu Lijun, Xue Qi, Wang Jiayi, Li Caiwen
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Pathogens. 2025 Jun 30;14(7):650. doi: 10.3390/pathogens14070650.
The parasitic dinoflagellate is an infectious pathogen that causes severe enzootic in numerous economically important marine crustaceans worldwide. Previous research has focused on investigating the identification and life stages of parasites, while the parasite abundance and tissue proliferation process of in naturally infected crustacean hosts need to be further studied. In the present study, the tissue tropisms and intensity of were investigated in the naturally infected Chinese swimming crabs by both the qualitative (hemolymph assay, histology) and quantitative analysis (cell count, quantitative PCR). The results showed that in with infection level I (4 ± 2 parasites in 200× microscopic field), filamentous trophonts were observed in the hemolymph and stomach tissues, with the average parasite number and ITS 1 copy number of quantitatively detected in hemolymph (1.0 × 10 parasites/mL) and stomach tissues (1.7 × 10 cells/g), respectively. trophonts were observed in the hemolymph (4.3 × 10 parasites/mL) and exhibited broad distribution in multiple tissues with its highest abundance of in pereiopod muscles (1.1 × 10 cells/g) followed by that in stomach (4.8 × 10 cells/g) in with infection level II (80 ± 10 parasites in 200× microscopic field). In with infection level III (200 ± 35 parasites in 200× microscopic field), a high abundance of sporoblasts was found in the hemolymph (3.1 × 10 parasites/mL) and all of the other examined tissues, with its highest abundance detected in pereiopod muscles (3.5 × 10 cells/g). In addition, the number of host's hemocytes was significantly decreased during the infection. This study provides a comprehensive quantitative characterization of the tissue distribution and abundance of in its natural crab host which will contribute to better understanding of the crustacean host- interactions.
这种寄生性甲藻是一种传染性病原体，在全球众多具有重要经济价值的海洋甲壳类动物中引发严重的动物流行病。以往的研究主要集中在调查该寄生虫的鉴定和生活阶段，而在自然感染的甲壳类宿主中该寄生虫的丰度和组织增殖过程仍有待进一步研究。在本研究中，通过定性（血淋巴检测、组织学）和定量分析（细胞计数、定量PCR），对自然感染的中华绒螯蟹中该寄生虫的组织嗜性和强度进行了研究。结果显示，在感染水平为I（200倍显微镜视野下有4±2个寄生虫）的蟹中，在血淋巴和胃组织中观察到丝状滋养体，血淋巴（1.0×10个寄生虫/毫升）和胃组织（1.7×10个细胞/克）中定量检测到的该寄生虫平均数量和ITS 1拷贝数。在感染水平为II（200倍显微镜视野下有80±10个寄生虫）的蟹中，在血淋巴（4.3×10个寄生虫/毫升）中观察到该寄生虫的滋养体，并且在多个组织中广泛分布，其在步足肌肉中的丰度最高（1.1×10个细胞/克），其次是胃（4.8×10个细胞/克）。在感染水平为III（200倍显微镜视野下有200±35个寄生虫）的蟹中，在血淋巴（3.1×10个寄生虫/毫升）和所有其他检测组织中发现大量该寄生虫的孢子母细胞，其在步足肌肉中的丰度最高（3.5×10个细胞/克）。此外，在该寄生虫感染期间，宿主血细胞数量显著减少。本研究提供了该寄生虫在其自然蟹宿主中的组织分布和丰度的全面定量特征，这将有助于更好地理解甲壳类宿主与该寄生虫的相互作用。
