Skip to main content
Log in

Massive secretions in paragonimiasis pleural effusion: a new finding concerning clinical recognition and treatment

European Journal of Clinical Microbiology & Infectious Diseases Aims and scope Submit manuscript


Some paragonimiasis patients in Chongqing, southwest China, have recently exhibited pleural effusions (PEs) with massive viscous secretions. This study aimed to investigate their clinical characteristics, thereby promoting effective treatments. A 3-year retrospective review of paragonimiasis patients who were admitted for nonhomogeneous PEs at Chongqing University Three Gorges Hospital was conducted. Epidemiological data, symptoms, laboratory and imaging findings, treatments, and outcomes were analyzed. Twenty-eight patients were identified, of which 22 (78.6%) were males and 22 (78.6%) were rural residents. Respiratory (85.7%) and constitutional (57.1%) symptoms were common. Paragonimus-specific ELISA was positive in all patients. Eosinophilia was detected in all patients in peripheral blood and PEs. Irregular hyperdense signals were observed in PEs by chest CT scans (96.4%) and ultrasonography (100.0%). Thoracic closed drainage failed in 10 patients (conservative group) because of tube blockage and was eventually replaced by video-assisted thoracoscopic surgery (VATS). Eighteen patients (surgery group) initially underwent VATS, or thoracotomy surgery, without complications. Massive secretions, described as “bean-dregs” or “egg-floccule,” were detected intraoperatively, which explained the imaging findings and tube blockage. All patients recovered well after 2–3 courses of postoperative praziquantel treatment. Viscous secretions in paragonimiasis patients warrant great concern. Irregular hyperdense signals in effusions are important characteristics in CT scans and ultrasonography. Treatments such as thoracic closed drainage may fail due to viscous secretions blocking the tube; therefore, surgeries should be considered. In-depth multidisciplinary research may help determine the optimal treatment strategy and reveal the origin of these secretions.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4

Data availability

The datasets generated during and/or analyzed during the current study are available in the Supplementary Material (Supplementary data.xlsx).


  1. Yoshida A, Doanh PN, Maruyama H (2019) Paragonimus and paragonimiasis in Asia: an update. Acta Trop 199:105074.

    Article  PubMed  Google Scholar 

  2. Blair D (2019) Paragonimiasis. Adv Exp Med Biol 1154:105–138.

    Article  PubMed  Google Scholar 

  3. Shibahara T (1991) The route of infection of Paragonimus westermani (diploid type) cercariae in the freshwater crab, Geothelphusa dehaani. J Helminthol 65:38–42.

    Article  Google Scholar 

  4. Kirk MD, Pires SM, Black RE, Caipo M, Crump JA, Devleesschauwer B et al (2015) World Health Organization estimates of the global and regional disease burden of 22 foodborne bacterial, protozoal, and viral diseases, 2010: a data synthesis. PLoS Med 12:e1001940.

    Article  PubMed  PubMed Central  Google Scholar 

  5. Liu Q, Wei F, Liu W, Yang S, Zhang X (2008) Paragonimiasis: an important food-borne zoonosis in China. Trends Parasitol 24:318–323.

    Article  PubMed  Google Scholar 

  6. Qian M, Li F, Zhang Y, Qiao Z, Shi Y, Shen J (2021) A retrospective clinical analysis of pediatric paragonimiasis in a Chinese children’s hospital from 2011 to 2019. Sci Rep 11:12450.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  7. Zhou XN (2018) Report on the national survey of important human parasitic disease in China (2015). People’s Medical Publishing House, Beiging

    Google Scholar 

  8. Zhang XL, Wang Y, Wang GX, Chen WB, He X, Niu H et al (2012) Distribution and clinical features of Paragonimiasis skrjabini in Three Gorges Reservoir Region. Parasitol Int 61:645–649.

    Article  PubMed  Google Scholar 

  9. Gong Z, Miao R, Shu M, Zhu Y, Wen Y, Guo Q et al (2017) Paragonimiasis in children in Southwest China: a retrospective case reports review from 2005 to 2016. Medicine (Baltimore) 96:e7265.

    Article  PubMed  Google Scholar 

  10. Peng X, Zhang J, Zhang J, Wang Y, Zhang X (2018) Incidence of paragonimiasis in Chongqing China: a 6-year retrospective case review. Parasitology 145:792–796.

    Article  PubMed  Google Scholar 

  11. Aboudara M, Maldonado F (2019) Update in the management of pleural effusions. Med Clin North Am 103:475–485.

    Article  PubMed  Google Scholar 

  12. Yeung C, Dawson J, Gilbert S (2019) Uniportal video-assisted thoracoscopy approach to the management of non-pulmonary diseases of the chest. J Thorac Dis 11(Suppl 16):S2062–S2068.

    Article  PubMed  PubMed Central  Google Scholar 

  13. Xie Y, Luo YR, Chen M, Xie YM, Sun CY, Chen Q (2021) Pleural lump after paragonimiasis treated by thoracoscopy: a case report. World J Clin Cases 9:666–671.

    Article  PubMed  PubMed Central  Google Scholar 

  14. Wu Y, Zhou Y, Jin X, Li Y, Li H, Dai J et al (2019) Diagnosis and surgical management of pericardial effusion due to paragonimiasis. Int J Infect Dis 83:102–108.

    Article  PubMed  Google Scholar 

  15. Nagayasu E, Yoshida A, Hombu A, Horii Y, Maruyama H (2015) Paragonimiasis in Japan: a twelve-year retrospective case review (2001–2012). Intern Med 54:179–186.

    Article  PubMed  Google Scholar 

  16. Das M, Doleckova K, Shenoy R, Mahanta J, Narain K, Devi K et al (2016) Paragonimiasis in tuberculosis patients in Nagaland, India. Glob Health Action 9:32387.

    Article  PubMed  Google Scholar 

  17. Choi WH, Chu JP, Jiang M, Lee YS, Kim BS, Kim DG, Park YK (2010) Analysis of parasitic diseases diagnosed by tissue biopsy specimens at KyungHee Medical Center (1984–2005) in Seoul, Korea. Korean J Parasitol 48:85–88.

    Article  PubMed  PubMed Central  Google Scholar 

  18. Feng Y, Fürst T, Liu L, Yang GJ (2018) Estimation of disability weight for paragonimiasis: a systematic analysis. Infect Dis Poverty 7:110.

    Article  PubMed  PubMed Central  Google Scholar 

  19. Doanh PN, Dung DT, Thach DT, Horii Y, Shinohara A, Nawa Y (2011) Human paragonimiasis in Viet Nam: epidemiological survey and identification of the responsible species by DNA sequencing of eggs in patients’ sputum. Parasitol Int 60:534–537.

    Article  CAS  PubMed  Google Scholar 

  20. Appleton CC (2014) Paragonimiasis in KwaZulu-Natal Province, South Africa. J Helminthol 88:123–128.

    Article  CAS  PubMed  Google Scholar 

  21. Tay NS, Ong KC, Tan SY, Kaw GJ (2005) Tuberculosis mimicry. Eur Respir J 26:554–556.

    Article  CAS  PubMed  Google Scholar 

  22. Jeon K, Koh WJ, Kim H, Kwon OJ, Kim TS, Han LKS, J (2005) Clinical features of recently diagnosed pulmonary paragonimiasis in Korea. Chest 128:1423–1430.

    Article  PubMed  Google Scholar 

  23. Fiorentini LF, Bergo P, Meirelles GSP, Capobianco J, Mohammed TL, Verma N et al (2020) Pictorial review of thoracic parasitic diseases: a radiologic guide. Chest 157:1100–1113.

    Article  CAS  PubMed  Google Scholar 

  24. Kim TS, Han J, Shim SS, Jeon K, Koh WJ, Lee I et al (2005) Pleuropulmonary paragonimiasis: CT findings in 31 patients. AJR Am J Roentgenol 185:616–621.

    Article  PubMed  Google Scholar 

  25. Oh IJ, Kim YI, Chi SY, Ban HJ, Kwon YS, Kim KS et al (2011) Can pleuropulmonary paragonimiasis be cured by only the 1st set of chemotherapy? Treatment outcome and clinical features of recently developed pleuropulmonary paragonimiasis. Intern Med 50:1365–1370.

    Article  PubMed  Google Scholar 

  26. Olden AM, Holloway R (2010) Treatment of malignant pleural effusion: PleuRx catheter or talc pleurodesis? A cost-effectiveness analysis. J Palliat Med 13:59–65.

    Article  PubMed  PubMed Central  Google Scholar 

  27. Qaqish TR, Cox S, Carr R, Katlic M (2020) Treatment of pleural effusions with nonintubated video-assisted thoracoscopic surgery. Thorac Surg Clin 30:25–32.

    Article  PubMed  Google Scholar 

  28. Yang W, Zhang B, Zhang ZM (2017) Infectious pleural effusion status and treatment progress. J Thorac Dis 9:4690–4699.

    Article  PubMed  PubMed Central  Google Scholar 

  29. Caffrey CR, Goupil L, Rebello KM, Dalton JP, Smith D (2018) Cysteine proteases as digestive enzymes in parasitic helminths. PLoS Negl Trop Dis 12:e0005840.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  30. Chung YB, Kita H, Shin MH (2008) A 27 kDa cysteine protease secreted by newly excysted Paragonimus westermani metacercariae induces superoxide anion production and degranulation of human eosinophils. Korean J Parasitol 46:95–99.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  31. Temkin V, Kantor B, Weg V, Hartman ML, Levi-Schaffer F (2002) Tryptase activates the mitogen-activated protein kinase/activator protein-1 pathway in human peripheral blood eosinophils, causing cytokine production and release. J Immunol 169:2662–2669.

    Article  CAS  PubMed  Google Scholar 

  32. Liu H, Lazarus SC, Caughey GH, Fahy JV (1999) Neutrophil elastase and elastase-rich cystic fibrosis sputum degranulate human eosinophils in vitro. Am J Physiol 276:L28–L34.

    Article  CAS  PubMed  Google Scholar 

  33. Devi KR, Narain K, Mahanta J, Nirmolia T, Blair D, Saikia SP, Agatsuma T (2013) Presence of three distinct genotypes within the Paragonimus westermani complex in northeastern India. Parasitology 140:76–86.

    Article  Google Scholar 

  34. Wu B, Wu Y (2019) Large pericardial effusion due to paragonimiasis in a 4-year-old Chinese boy. Open Forum Infect Dis 6:ofz145.

    Article  PubMed  PubMed Central  Google Scholar 

  35. Zhang X, Peng L, Liu W, Fan L, Zhang Q, Chen G et al (2014) Response of primary vectors and related diseases to impoundment by the Three Gorges Dam. Trop Med Int Health 19:440–449.

    Article  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations



Thank you to all authors for their dedication to this work. Conception and design: Qiang Chen, Yimin Xie, Yunxuan Zhang, and Shulei Peng; administrative support: Qiang Chen, Yimin Xie, and Shulei Peng; provision of study materials or patients: Yarui Luo, Na Wu, Meng Chen, and Shulei Peng; provision of imaging or pathological interpretations: Shuang Xiang, Wen Zhong, and Xiaojiao Zhou; collection and assembly of data: Yunxuan Zhang, Yarui Luo, Na Wu, Meng Chen, and Shulei Peng; data analysis and interpretation: Yunxuan Zhang, Yimin Xie, and Qiang Chen; manuscript writing: all authors; final approval of manuscript: all authors.

Corresponding authors

Correspondence to Shulei Peng or Qiang Chen.

Ethics declarations

Ethics approval

The guidelines of the Code of Ethics of the World Medical Association were completely fulfilled (Declaration of Helsinki). Ethics approval was granted by the Ethics Committee of Chongqing University Three Gorges Hospital (approval number: 2022114).

Consent to participate

Informed consent was obtained from all individual participants included in the study.

Consent for publication

The authors affirm that no human image was provided in this research.

Conflict of interest

The authors declare no competing interests.

Additional information

Publisher's note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Below is the link to the electronic supplementary material.


Supplementary file1 Large amounts of “bean-dregs” or “egg-floccule” substances deposited as lumps at the bottom of the pleural cavity in the endoscopic view. B: The extracted yellowish and viscous secretions nearly filled the bow. (PNG 4805 KB)

Supplementary file2 (DOCX 15 KB)

Supplementary file3 CT scan of the typical tunnel sign in a paragonimiasis patient. (MP4 1883 KB)

Supplementary file4 Paragonimiasis PE with massive secretions in a thoracoscopic view. A large amount of viscous secretion is present in the yellowish PEs. Some of the secretions even block the aspirator. (MP4 6615 KB)

Supplementary file5 (XLSX 19 KB)

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Zhang, Y., Xie, Y., Luo, Y. et al. Massive secretions in paragonimiasis pleural effusion: a new finding concerning clinical recognition and treatment. Eur J Clin Microbiol Infect Dis 42, 493–501 (2023).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: