{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T19:24:11Z","timestamp":1780514651816,"version":"3.54.1"},"reference-count":8,"publisher":"SMC Media","issue":"5","license":[{"start":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T00:00:00Z","timestamp":1777507200000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>Introduction:\u00a0Eosinophilia, defined as an absolute eosinophil count &gt;500 cells\/\u00b5l, is most commonly secondary to allergic diseases, infections, or drug reactions. While parasitic helminth infections are a well-recognized cause, protozoal infections are less frequently associated. Reports linking\u00a0Giardia lamblia\u00a0infection with eosinophilia remain rare, in particular in the context of severe eosinophilia. Case description:\u00a0A 77-year-old woman presented with acute watery diarrhoea for 3 days without systemic symptoms. Laboratory evaluation revealed marked eosinophilia (4.5 g\/l at initial presentation, which rose to 7.9 g\/l). The initial diagnostic workup, including stool polymerase chain reaction for bacterial and viral pathogens, helminth serologies, celiac screening, and abdominal imaging, was all negative. However, endoscopic evaluation with biopsies demonstrated mild eosinophilic gastrointestinal infiltration, and stool antigen testing was positive for\u00a0Giardia lamblia. No other cause of eosinophilia could be identified. Treatment with metronidazole resulted in rapid clinical improvement and progressive reduction of eosinophil counts, with complete normalization during follow-up. Additional investigations only revealed mild hepatopathy, most likely related to statin therapy. Conclusion:\u00a0This case highlights\u00a0Giardia lamblia\u00a0as a potential cause of marked secondary eosinophilia and thus may have to be considered as a differential diagnosis in patients presenting with unexplained severe eosinophilia and gastrointestinal symptoms.<\/jats:p>","DOI":"10.12890\/2026_006635","type":"journal-article","created":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T12:44:30Z","timestamp":1777553070000},"source":"Crossref","is-referenced-by-count":1,"title":["Marked eosinophilia in Giardia lamblia infection"],"prefix":"10.12890","volume":"13","author":[{"given":"Filippo","family":"Schoolkate","sequence":"first","affiliation":[{"name":"Division of Internal Medicine, University Hospital of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marten","family":"Trendelenburg","sequence":"first","affiliation":[{"name":"Division of Internal Medicine, University Hospital of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"10397","published-online":{"date-parts":[[2026,4,30]]},"reference":[{"key":"10.12890\/2026_006635_ref1","doi-asserted-by":"crossref","unstructured":"Herold G. Innere Medizin 2026. Berlin: De Gruyter; 2025.","DOI":"10.1515\/9783111723358"},{"key":"10.12890\/2026_006635_ref2","unstructured":"van Balkum M, Kluin-Nelemans H, van Hellemond JJ, van Genderen PJJ, Wismans PJ. Hypereosinophilia: a diagnostic challenge. Neth J Med 2018;76:431-436."},{"key":"10.12890\/2026_006635_ref3","doi-asserted-by":"crossref","unstructured":"Shomali W, Gotlib J. World Health Organization and International Consensus Classification of eosinophilic disorders: 2024 update on diagnosis, risk stratification, and management. Am J Hematol 2024;99:946-968. doi: 10.1002\/ajh.27287","DOI":"10.1002\/ajh.27287"},{"key":"10.12890\/2026_006635_ref4","doi-asserted-by":"crossref","unstructured":"Ahmad RN, Sherjil A, Mahmood A, Rafi S. Severe eosinophilia in a case of giardiasis. Mediterr J Hematol Infect Dis 2011;3:e2011009. doi: 10.4084\/MJHID.2011.009","DOI":"10.4084\/mjhid.2011.009"},{"key":"10.12890\/2026_006635_ref5","doi-asserted-by":"crossref","unstructured":"Ni\u00f1o-Puerto L, Vicente B, Pendones Ulerio J, Almeida HR, Muro A, Mu\u00f1oz Bellido JL, et al. Giardiasis and Eosinophilia in Outpatients with Gastrointestinal Symptoms: A Case Series. Am J Trop Med Hyg 2025;113:1018-1021. doi: 10.4269\/ajtmh.24-0855","DOI":"10.4269\/ajtmh.24-0855"},{"key":"10.12890\/2026_006635_ref6","doi-asserted-by":"crossref","unstructured":"Suzuki Y, Nakamura T, Tokoro M, Togano T, Ohsaka M, Kohri M, et al. A case of giardiasis expressing severe systemic symptoms and marked hypereosinophilia. Parasitol Int 2010;59:487-489. doi: 10.1016\/j.parint.2010.06.006","DOI":"10.1016\/j.parint.2010.06.006"},{"key":"10.12890\/2026_006635_ref7","unstructured":"Ortiz Arduan A, Castrillo JM, Carreira J, L\u00f3pez Cubero L, Miranda R, Jim\u00e9nez Casado M. Gastroenteritis con eosinofilia por Giardia lamblia [Gastroenteritis with eosinophilia caused by Giardia lamblia]. Rev Clin Esp 1990;187:68-70. Spanish."},{"key":"10.12890\/2026_006635_ref8","doi-asserted-by":"crossref","unstructured":"Lam BD, Hale AJ, Bullis SM, He Y, Khan S, Freed JA. A Retrospective Review of 193 Cases of Severe Eosinophilia in the Northeast United States. Am J Med 2021;134:e374-e377. doi: 10.1016\/j.amjmed.2020.11.022","DOI":"10.1016\/j.amjmed.2020.11.022"}],"container-title":["European Journal of Case Reports in Internal Medicine"],"original-title":[],"link":[{"URL":"https:\/\/www.ejcrim.com\/index.php\/EJCRIM\/article\/download\/6635\/5546","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.ejcrim.com\/index.php\/EJCRIM\/article\/download\/6635\/5547","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.ejcrim.com\/index.php\/EJCRIM\/article\/download\/6635\/5547","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,7]],"date-time":"2026-05-07T12:57:10Z","timestamp":1778158630000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ejcrim.com\/index.php\/EJCRIM\/article\/view\/6635"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,30]]},"references-count":8,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2026]]}},"URL":"https:\/\/doi.org\/10.12890\/2026_006635","relation":{"has-manifestation":[{"id-type":"other","id":"1-167-6635-g5546","asserted-by":"subject"},{"id-type":"other","id":"1-167-6635-g5547","asserted-by":"subject"}],"is-part-of":[{"id-type":"other","id":"1-167","asserted-by":"subject"}]},"ISSN":["2284-2594"],"issn-type":[{"value":"2284-2594","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,30]]}}}