Four Human Cases of Diphyllobothrium nihonkaiense (Eucestoda: Diphyllobothriidae) in China with a Brief Review of Chinese Cases

We described 4 human infection cases of zoonotic fish-tapeworm, Diphyllobothrium nihonkaiense, identified with morphological and molecular characters and briefly reviewed Chinese cases in consideration of it as an emerging parasitic disease in China. The scolex and mature and gravid proglottids of some cases were seen, a rosette-shaped uterus was observed in the middle of the mature and gravid proglottids, and the diphyllobothriid eggs were yellowish-brown in color and displayed a small knob or abopercular protuberance on the opposite end of a lid-like opening. The average size of the eggs was recorded as 62–67×42–45 μm. The parasitic materials gathered from 4 human cases were morphologically identified as belonging to the genera Diphyllobothrium and Adenocephalus. The phylogenetic analysis based on the nucleotide sequences of cytochrome c oxidase subunit 1 gene of the etiologic agents confirmed that the 4 cases were D. nihonkaiense infection. The finding of 4 additional D. nihonkaiense cases suggests that D. nihonkaiense might be a major causative species of human diphyllobothriasis in China. A combined morphological and molecular analysis is the main method to confirm D. nihonkaiense infection.

Artemether, artesunate, praziquantel and tribendimidine administered singly at different dosages against Clonorchis sinensis: a comparative in vivo study.

We comparatively assessed the in vivo efficacy of artemether, artesunate, praziquantel and tribendimidine against different stages of Clonorchis sinensis. Rats were infected with 40-50 C. sinensis metacercariae, and drugs were administered singly by the oral route at different dosages. Rats were dissected 2-4 weeks post-treatment and C. sinensis trematodes were removed from the liver and bile ducts and counted. We used a negative binomial regression model to test the effect of drug and dosage in terms of worm burden reduction. Single 150 mg/kg oral doses of artesunate, artemether, tribendimidine and praziquantel, administered to rats infected with adult C. sinensis, resulted in mean worm burden reductions of 100, 100, 89.5 and 80.7%, respectively (all P<0.001). Halving the dose to 75 mg/kg still resulted in highly significant worm burden reductions for artesunate, artemether and tribendimidine (71.4-100%), but not for praziquantel (20.7%). In the juvenile infection model, a single 150 mg/kg oral dose of tribendimidine and praziquantel resulted in mean worm burden reductions of 99.1 and 90.0%, respectively, whereas considerably lower reductions were observed for artemether (59.2%) and artesunate (57.6%) when used at the same single dose. The in vivo results presented here with the artemisinins and tribendimidine provide further data for clinical investigations to assess the safety and efficacy of these drugs in clonorchiasis patients.

DNA sequences of Paragonimus skrjabini populations from five provinces in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>To study differences among Paragonimus skrjabini (P. skrjabini) populations from five provinces in China (Guangdong, Fujian, Yunnan, Hubei, and Sichuan) and Paragonimus szechuanensis.</p><p><b>METHODS</b>DNA sequences were obtained from the ITS2 and CO1 genes and phylogenetic trees were constructed from the results. Sequences were also obtained from several other species of Paragonimus for comparative purposes.</p><p><b>RESULTS</b>Although differences existed in the DNA sequence among P. skrjabini populations from five provinces, the differences were very small. There was also some resemblance between P. miyazakii from Japan and Fujian strains of P. skrjabini.</p><p><b>CONCLUSION</b>All studied populations can be regarded as different strains of P. skrjabini; P. szechuanensis is not a separate species but may be a geographical strain of P. skrjabini. We also found that P. miyazakii may be synonymous with P. skrjabini.</p>