Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, Guangdong Province, China.
Parasitol Res. 2013 Jan;112(1):129-33. doi: 10.1007/s00436-012-3115-3. Epub 2012 Sep 16.
The polymerase chain reaction (PCR) assay has turned out to be one of the most potential tools for diagnosis of schistosomiasis. However, the source and metabolic dynamics of Schistosoma japonicum DNA in the blood of hosts is not clear. In this study, rabbit models with monosexual and mixed sexual cercariae infection were established to interpret the source of the parasite DNA in serum of the hosts. Following administration of praziquantel at 7 weeks postinfection, the metabolic mechanism of S. japonicum DNA in serum of the hosts was studied. The findings showed that, for the monosexual cercariae infection, the parasite DNA was detectable in serum of the host from day 3 to week 3 postinfection, while for the mixed sexual cercariae infection, the detection results were continually positive during the 7 weeks after infection. After treatment with praziquantel, detection of S. japonicum DNA in rabbit sera became positive at the second day posttreatment, and the positive period lasted 3 weeks in the monosexual cercariae infection group. However, with the mixed sexual cercariae infection group, the PCR results remained positive for 16 weeks after treatment. We conclude that the S. japonicum DNA in host serum primarily comes from the residual body of dead schistosomula and/or tegument shedding of worm growing in the first 4 weeks postinfection, while during the spawning stage of the female schistosome, the parasite DNA mainly comes from the disintegration of inactive eggs. The duration from treatment to total elimination of worm origin DNA in serum is not exceeding 3 weeks. However, the DNA release from inactive eggs can last for more than 16 weeks. Further studies are needed to address the sources and metabolic dynamics of S. japonicum DNA in human serum.
聚合酶链反应 (PCR) 检测已成为诊断日本血吸虫病最有潜力的工具之一。然而，宿主血液中日本血吸虫 DNA 的来源和代谢动态尚不清楚。本研究建立了单性和混合性尾蚴感染的兔模型，以解释宿主血清中寄生虫 DNA 的来源。在感染后 7 周给予吡喹酮治疗后，研究了宿主血清中日本血吸虫 DNA 的代谢机制。结果表明，对于单性尾蚴感染，从感染后第 3 天到第 3 周，宿主血清中可检测到寄生虫 DNA，而对于混合性尾蚴感染，感染后 7 周内检测结果持续为阳性。吡喹酮治疗后，兔血清中日本血吸虫 DNA 的检测结果于治疗后第 2 天转为阳性，在单性尾蚴感染组中阳性期持续 3 周。然而，在混合性尾蚴感染组中，治疗后 16 周 PCR 结果仍为阳性。我们得出结论，宿主血清中的日本血吸虫 DNA 主要来源于感染后第 4 周内死亡的童虫的残余体和/或虫体脱落的表皮，而在雌性血吸虫产卵阶段，寄生虫 DNA 主要来源于失活卵的崩解。从治疗到血清中虫源 DNA 完全消除的时间不超过 3 周。然而，失活卵的 DNA 释放可持续超过 16 周。需要进一步研究以确定人类血清中日本血吸虫 DNA 的来源和代谢动态。
