{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,8]],"date-time":"2026-06-08T05:59:42Z","timestamp":1780898382147,"version":"3.54.1"},"reference-count":55,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,6,8]],"date-time":"2026-06-08T00:00:00Z","timestamp":1780876800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Med."],"abstract":"<jats:p>\n                    Psittacosis is a zoonotic infectious disease caused by\n                    <jats:italic>Chlamydia psittaci<\/jats:italic>\n                    , typically transmitted from birds to humans. Its clinical manifestations are often subtle and non-specific, making it prone to being misdiagnosed as common community-acquired pneumonia. Round pneumonia (or spherical pneumonia) refers to a lung infection that appears as a round or oval density on computed tomography (CT). It is uncommon in adults. Spherical pneumonia specifically caused by\n                    <jats:italic>Chlamydia psittaci<\/jats:italic>\n                    infection is particularly uncommon. Here we report a case of a 43-year-old male who was admitted due to a 4-day history of fever. CT imaging revealed a solitary, round high-density shadow approximately 4\u202fcm in diameter in the right lower lung, with clear margins and surrounding ground-glass opacity. The patient reported direct contact with ornamental parrots at a zoo 10\u202fdays before the onset of symptoms. The diagnosis of spherical pneumonia caused by\n                    <jats:italic>Chlamydia psittaci<\/jats:italic>\n                    infection was confirmed by targeted next-generation sequencing (tNGS). The patient\u2019s symptoms resolved following treatment with minocycline, and a follow-up CT scan 32\u202fdays later showed near-complete resolution of the lesion. This case demonstrates that\n                    <jats:italic>Chlamydia psittaci<\/jats:italic>\n                    can also produce a typical spherical lesion, thereby broadening the recognized imaging spectrum of this pathogen. When clinicians encounter a patient with imaging findings suggestive of spherical pneumonia and a history of bird exposure,\n                    <jats:italic>Chlamydia psittaci<\/jats:italic>\n                    infection should be suspected, especially when accompanied by extrapulmonary symptoms such as headache, myalgia, or hepatosplenomegaly, necessitating a comprehensive assessment that integrates epidemiological history and molecular diagnostic methods.\n                  <\/jats:p>","DOI":"10.3389\/fmed.2026.1841775","type":"journal-article","created":{"date-parts":[[2026,6,8]],"date-time":"2026-06-08T05:33:11Z","timestamp":1780896791000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["A case report of spherical pneumonia caused by Chlamydia psittaci infection"],"prefix":"10.3389","volume":"13","author":[{"given":"Guodong","family":"Li","sequence":"first","affiliation":[{"name":"Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine","place":["Jinan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiangze","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Gastrointestinal Surgery, Shandong Provincial Third Hospital, Shandong University","place":["Jinan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qian","family":"Feng","sequence":"additional","affiliation":[{"name":"Department of Pathology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine","place":["Jinan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaodong","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine","place":["Jinan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xingcai","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine","place":["Jinan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xue","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Pulmonary and Critical Care Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine","place":["Jinan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,6,8]]},"reference":[{"key":"ref1","first-page":"542","article-title":"Chlamydia psittaci inclusion membrane protein incb associates with host protein snapin","volume-title":"Int J Med Microbiol","author":"Bcker","year":"2014"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"2428411","DOI":"10.1080\/21505594.2024.2428411","article-title":"Chlamydia psittaci: a zoonotic pathogen causing avian chlamydiosis and psittacosis","volume":"15","author":"Wang","year":"2024","journal-title":"Virulence"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"e3261","DOI":"10.1093\/cid\/ciaa1681","article-title":"Clustering cases of chlamydia psittaci pneumonia in coronavirus disease 2019 screening ward staff","volume":"73","author":"Lei","year":"2021","journal-title":"Clin Infect Dis"},{"key":"ref4","doi-asserted-by":"publisher","first-page":"1003","DOI":"10.1007\/s40121-020-00353-y","article-title":"Etiology of severe community-acquired pneumonia in adults based on metagenomic next-generation sequencing: a prospective multicenter study","volume":"9","author":"Wu","year":"2020","journal-title":"Infect Dis Ther"},{"key":"ref5","doi-asserted-by":"publisher","first-page":"731047","DOI":"10.3389\/fmed.2021.731047","article-title":"Extracorporeal membrane oxygenation in severe acute respiratory distress syndrome caused by chlamydia psittaci: a case report and review of the literature","volume":"8","author":"Wang","year":"2021","journal-title":"Front Med (Lausanne)"},{"key":"ref6","doi-asserted-by":"publisher","first-page":"1366","DOI":"10.3760\/cma.j.cn121430-20210810-01159","article-title":"Analysis of clinical features of 16 cases with chlamydia psittaci pneumonia","volume":"33","author":"Fang","year":"2021","journal-title":"Zhonghua Wei Zhong Bing Ji Jiu Yi Xue"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"1215","DOI":"10.1186\/s12879-025-11676-x","article-title":"Chlamydia psittaci pneumonia manifested as pulmonary nodules and cavitary lesions: a case report","volume":"25","author":"Zhong","year":"2025","journal-title":"BMC Infect Dis"},{"key":"ref8","doi-asserted-by":"publisher","first-page":"136","DOI":"10.1097\/RTI.0b013e318191987e","article-title":"Psittacosis presenting as a halo sign on high-resolution computed tomography","volume":"24","author":"Hochhegger","year":"2009","journal-title":"J Thorac Imaging"},{"key":"ref9","doi-asserted-by":"publisher","first-page":"229","DOI":"10.1097\/01.cpm.0000227369.17269.7c","article-title":"Round pneumonia in adults, an unusual presentation of lung parenchymal infection","volume":"13","author":"Zylberman","year":"2006","journal-title":"Clin Pulm Med"},{"key":"ref10","doi-asserted-by":"publisher","first-page":"20","DOI":"10.1186\/s12890-023-02316-8","article-title":"Spherical pneumonia caused by ralstonia mannitolilytica: a case report and literature review","volume":"23","author":"Ma","year":"2023","journal-title":"BMC Pulm Med"},{"key":"ref11","doi-asserted-by":"publisher","first-page":"e656","DOI":"10.1016\/j.amjmed.2019.03.030","article-title":"A disappearing lung mass: round pneumonia","volume":"132","author":"Gupta","year":"2019","journal-title":"Am J Med"},{"key":"ref12","doi-asserted-by":"publisher","first-page":"11","DOI":"10.5005\/japi-11001-0016","article-title":"Community-acquired round pneumonia in a 63-year-old female","volume":"70","author":"Verma","year":"2022","journal-title":"J Assoc Physicians India"},{"key":"ref13","doi-asserted-by":"publisher","first-page":"877","DOI":"10.1016\/j.tim.2020.05.020","article-title":"Chlamydiae in the environment","volume":"28","author":"Collingro","year":"2020","journal-title":"Trends Microbiol"},{"key":"ref14","doi-asserted-by":"publisher","first-page":"192","DOI":"10.1186\/s12879-020-4918-y","article-title":"Animal sources for zoonotic transmission of psittacosis: a systematic review","volume":"20","author":"Hogerwerf","year":"2020","journal-title":"BMC Infect Dis"},{"key":"ref15","doi-asserted-by":"publisher","first-page":"262","DOI":"10.1647\/217-265","article-title":"Compendium of measures to control chlamydia psittaci infection among humans (psittacosis) and pet birds (avian chlamydiosis), 2017","volume":"31","author":"Balsamo","year":"2017","journal-title":"J Avian Med Surg"},{"key":"ref16","doi-asserted-by":"publisher","first-page":"20937","DOI":"10.2807\/1560-7917.es2014.19.42.20937","article-title":"Multiple human-to-human transmission from a severe case of psittacosis, Sweden","volume":"19","author":"Wallensten","year":"2014","journal-title":"Eur Commun Dis Bull"},{"key":"ref17","doi-asserted-by":"publisher","first-page":"e512","DOI":"10.1016\/S2666-5247(22)00064-7","article-title":"Human-to-human transmission of chlamydia psittaci in China, 2020: an epidemiological and aetiological investigation","volume":"3","author":"Zhang","year":"2022","journal-title":"Lancet Microbe"},{"key":"ref18","doi-asserted-by":"publisher","first-page":"1631","DOI":"10.1007\/s40121-022-00662-4","article-title":"Clinical characteristics of chlamydia psittaci pneumonia infection in central South China","volume":"11","author":"Yang","year":"2022","journal-title":"Infect Dis Ther"},{"key":"ref19","doi-asserted-by":"publisher","first-page":"10","DOI":"10.1099\/jmm.0.001456","article-title":"Sixteen cases of severe pneumonia caused by chlamydia psittaci in South China investigated via metagenomic next-generation sequencing","volume":"70","author":"Xiao","year":"2021","journal-title":"J Med Microbiol"},{"key":"ref20","doi-asserted-by":"publisher","first-page":"1040441","DOI":"10.3389\/fmed.2022.1040441","article-title":"Tigecycline in the treatment of severe pneumonia caused by chlamydia psittaci: a case report and literature review","volume":"9","author":"Liu","year":"2022","journal-title":"Front Med (Lausanne)"},{"key":"ref21","doi-asserted-by":"publisher","first-page":"262","DOI":"10.1016\/j.ijid.2021.03.091","article-title":"Multi-organ failure with necrotic skin lesions due to infection with chlamydia psittaci","volume":"106","author":"Meijer","year":"2021","journal-title":"Int J Infect Dis"},{"key":"ref22","doi-asserted-by":"publisher","first-page":"621","DOI":"10.1186\/s12879-021-06205-5","article-title":"A case of chlamydia psittaci caused severe pneumonia and meningitis diagnosed by metagenome next-generation sequencing and clinical analysis: a case report and literature review","volume":"21","author":"Shi","year":"2021","journal-title":"BMC Infect Dis"},{"key":"ref23","doi-asserted-by":"publisher","first-page":"192","DOI":"10.1179\/acb.2010.040","article-title":"Atypical pneumonia due to chlamydophila psittaci: 3 case reports and review of literature","volume":"65","author":"Fraeyman","year":"2010","journal-title":"Acta Clin Belg"},{"key":"ref24","doi-asserted-by":"publisher","first-page":"1101","DOI":"10.3855\/jidc.16166","article-title":"Severe pneumonia caused by chlamydia psittaci: report of two cases and literature review","volume":"16","author":"Dai","year":"2022","journal-title":"J Infect Dev Ctries"},{"key":"ref25","doi-asserted-by":"publisher","first-page":"1296","DOI":"10.1099\/jmm.0.2008\/001578-0","article-title":"Two fatal cases of psittacosis caused by chlamydophila psittaci","volume":"57","author":"Petrovay","year":"2008","journal-title":"J Med Microbiol"},{"key":"ref26","doi-asserted-by":"publisher","first-page":"1374","DOI":"10.1007\/s00134-016-4394-4","article-title":"Community-acquired pneumonia related to intracellular pathogens","volume":"42","author":"Cill\u00f3niz","year":"2016","journal-title":"Intensive Care Med"},{"key":"ref27","doi-asserted-by":"publisher","first-page":"1333","DOI":"10.1186\/s12879-024-10198-2","article-title":"Diagnosis and treatment experience of chlamydia psittaci pneumonia: a multicenter retrospective study in China","volume":"24","author":"Deng","year":"2024","journal-title":"BMC Infect Dis"},{"key":"ref28","doi-asserted-by":"publisher","first-page":"1214297","DOI":"10.3389\/fcimb.2023.1214297","article-title":"Case report: clinical analysis of a cluster outbreak of chlamydia psittaci pneumonia","volume":"13","author":"Wu","year":"2023","journal-title":"Front Cell Infect Microbiol"},{"key":"ref29","doi-asserted-by":"publisher","first-page":"3096","DOI":"10.1017\/S0950268817002060","article-title":"Chlamydia psittaci (psittacosis) as a cause of community-acquired pneumonia: a systematic review and meta-analysis","volume":"145","author":"Hogerwerf","year":"2017","journal-title":"Epidemiol Infect"},{"key":"ref30","doi-asserted-by":"publisher","first-page":"2053","DOI":"10.21037\/qims-22-809","article-title":"Clinical and ct diagnosis of 50 cases of chlamydia psittaci pneumonia","volume":"13","author":"Wu","year":"2023","journal-title":"Quant Imaging Med Surg"},{"key":"ref31","first-page":"75","article-title":"Chlamydia psittaci: a relevant cause of community-acquired pneumonia in two dutch hospitals","volume":"74","author":"Spoorenberg","year":"2016","journal-title":"Neth J Med"},{"key":"ref32","doi-asserted-by":"publisher","first-page":"597","DOI":"10.1080\/22221751.2020.1738905","article-title":"Era of molecular diagnosis for pathogen identification of unexplained pneumonia, lessons to be learned","volume":"9","author":"Ai","year":"2020","journal-title":"Emerg Microbes Infect"},{"key":"ref33","doi-asserted-by":"publisher","first-page":"1491838","DOI":"10.3389\/fmed.2024.1491838","article-title":"Early and rapid diagnosis of chlamydia psittaci pneumonia by tngs in six patients: a case series","volume":"11","author":"Yan","year":"2024","journal-title":"Front Med (Lausanne)"},{"key":"ref34","doi-asserted-by":"publisher","first-page":"1084882","DOI":"10.3389\/fcimb.2023.1084882","article-title":"Case report: a clinical case study of six patients with chlamydia psittaci pneumonia","volume":"13","author":"Dai","year":"2023","journal-title":"Front Cell Infect Microbiol"},{"key":"ref35","doi-asserted-by":"publisher","first-page":"153","DOI":"10.3892\/mmr.2024.13277","article-title":"Clinical diagnostic value of targeted next?Generation sequencing for infectious diseases (review)","volume":"30","author":"Chen","year":"2024","journal-title":"Mol Med Rep"},{"key":"ref36","doi-asserted-by":"publisher","first-page":"42","DOI":"10.1080\/17843286.2019.1590889","article-title":"Human psittacosis: a review with emphasis on surveillance in Belgium","volume":"75","author":"Rybarczyk","year":"2020","journal-title":"Acta Clin Belg"},{"key":"ref37","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1002\/2052-2975.29","article-title":"Clinical features of endemic community-acquired psittacosis","volume":"2","author":"Branley","year":"2014","journal-title":"New Microbes New Infect"},{"key":"ref38","doi-asserted-by":"publisher","first-page":"ofac518","DOI":"10.1093\/ofid\/ofac518","article-title":"Clinical features, treatment, and outcome of psittacosis pneumonia: a multicenter study","volume":"10","author":"Ni","year":"2023","journal-title":"Open Forum Infect Dis"},{"key":"ref39","doi-asserted-by":"publisher","first-page":"e270896","DOI":"10.1371\/journal.pone.0270896","article-title":"Clinical, radiological and pathological characteristics of moderate to fulminant psittacosis pneumonia","volume":"17","author":"Li","year":"2022","journal-title":"PLoS One"},{"key":"ref40","doi-asserted-by":"publisher","first-page":"11","DOI":"10.1186\/s12879-024-10374-4","article-title":"Chlamydia psittaci pneumonia - evolutionary aspects on chest ct","volume":"25","author":"Yang","year":"2025","journal-title":"BMC Infect Dis"},{"key":"ref41","doi-asserted-by":"publisher","first-page":"1235","DOI":"10.1007\/s00247-007-0654-3","article-title":"Round pneumonia: imaging findings in a large series of children","volume":"37","author":"Kim","year":"2007","journal-title":"Pediatr Radiol"},{"key":"ref42","doi-asserted-by":"publisher","first-page":"1931","DOI":"10.1007\/s00247-010-1767-7","article-title":"Imaging of round pneumonia and mimics in children","volume":"40","author":"Restrepo","year":"2010","journal-title":"Pediatr Radiol"},{"key":"ref43","first-page":"125","article-title":"Oval-shaped consolidations simulating newgrowth of the lung","volume":"91","author":"Greenfield","year":"1964","journal-title":"Am J Roentgenol Radium Therapy, Nucl Med"},{"key":"ref44","doi-asserted-by":"publisher","first-page":"1188","DOI":"10.1086\/319761","article-title":"Photo quiz. Round pneumonia due to streptococcus pneumoniae","volume":"32","author":"Zinkernagel","year":"2001","journal-title":"Clin Infect Dis"},{"key":"ref45","first-page":"751","article-title":"Radiology rounds. Round pneumonia","volume":"44","author":"McLennan","year":"1998","journal-title":"Can Fam Physician"},{"key":"ref46","doi-asserted-by":"publisher","first-page":"491","DOI":"10.1016\/j.pedneo.2013.01.014","article-title":"Pediatric round pneumonia","volume":"55","author":"Liu","year":"2014","journal-title":"Pediatr Neonatol"},{"key":"ref47","doi-asserted-by":"publisher","first-page":"1461","DOI":"10.1016\/s0025-7125(05)70391-6","article-title":"Radiology of pneumonia","volume":"85","author":"Gharib","year":"2001","journal-title":"Med Clin North Am"},{"key":"ref48","doi-asserted-by":"publisher","first-page":"189","DOI":"10.1016\/S0735-6757(96)90132-1","article-title":"Life-threatening \"round pneumonia\"","volume":"14","author":"Soubani","year":"1996","journal-title":"Am J Emerg Med"},{"key":"ref49","doi-asserted-by":"publisher","first-page":"150","DOI":"10.1016\/s0009-9260(05)80857-8","article-title":"The radiological appearances of 'q' fever pneumonia","volume":"44","author":"Pickworth","year":"1991","journal-title":"Clin Radiol"},{"key":"ref50","doi-asserted-by":"publisher","first-page":"1567","DOI":"10.2214\/ajr.182.6.1821567","article-title":"Eight cases of severe acute respiratory syndrome presenting as round pneumonia","volume":"182","author":"Wan","year":"2004","journal-title":"AJR Am J Roentgenol"},{"key":"ref51","doi-asserted-by":"publisher","first-page":"645630993","DOI":"10.1177\/03000605241275375","article-title":"Pulmonary actinomycosis misdiagnosed as lung cancer: a case report","volume":"52","author":"Wu","year":"2024","journal-title":"J Int Med Res"},{"key":"ref52","doi-asserted-by":"publisher","first-page":"1498512","DOI":"10.3389\/fcimb.2024.1498512","article-title":"Diagnosis value of targeted and metagenomic sequencing in respiratory tract infection","volume":"14","author":"Kuang","year":"2024","journal-title":"Front Cell Infect Microbiol"},{"key":"ref53","doi-asserted-by":"publisher","first-page":"1","DOI":"10.12968\/hmed.2024.0381","article-title":"Omadacycline in the treatment of chlamydia psittaci pneumonia: a retrospective study on efficacy and safety","volume":"85","author":"Li","year":"2024","journal-title":"Brit J Hosp Med (London, England: 2005)"},{"key":"ref54","doi-asserted-by":"publisher","first-page":"1207534","DOI":"10.3389\/fmed.2023.1207534","article-title":"Omadacycline for the treatment of severe pneumonia caused by chlamydia psittaci complicated with acute respiratory distress syndrome during the covid-19 pandemic","volume":"10","author":"Wang","year":"2024","journal-title":"Front Med (Lausanne)"},{"key":"ref55","doi-asserted-by":"publisher","first-page":"5831","DOI":"10.2147\/IDR.S384296","article-title":"Omadacycline for the treatment of severe chlamydia psittaci pneumonia complicated with multiple organ failure: a case report","volume":"15","author":"Fang","year":"2022","journal-title":"Infect Drug Resist"}],"container-title":["Frontiers in Medicine"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmed.2026.1841775\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,8]],"date-time":"2026-06-08T05:33:15Z","timestamp":1780896795000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmed.2026.1841775\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,8]]},"references-count":55,"alternative-id":["10.3389\/fmed.2026.1841775"],"URL":"https:\/\/doi.org\/10.3389\/fmed.2026.1841775","relation":{},"ISSN":["2296-858X"],"issn-type":[{"value":"2296-858X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,8]]},"article-number":"1841775"}}