title: Chronic Cystoisospora belli infection in an immunocompetent Myanmar refugee - microscopy is not sensitive enough.
abstract: Cystoisosporiasis is an opportunistic infection seen more commonly in patients with acquired immunodeficiency syndrome. Although uncommon, Cystoisospora infection can occur in immunocompetent individuals but tend to be benign and self-limiting. Chronic infection however, has been described but diagnosis can often be challenging and requires a high clinical index of suspicion.
  
  
  
  We present a case of delayed diagnosis of Cystoisospora belli (C. belli) in an immunocompetent 28-year-old refugee from Myanmar. She had a history of chronic diarrhea where exhaustive investigations over many years failed to reveal a diagnosis. Cystoisospora belli cysts were finally detected in stool 4 years after investigation commenced, and PCR testing on stored colon biopsies amplified a molecular product with 99 % sequence homology to C. belli. The patient improved promptly with trimethoprim-sulfamethoxazole treatment.
  
  
  
  In the appropriate clinical context we suggest molecular testing for C. belli or an empirical therapeutic trial.
authors.affiliation: Department of Microbiology and Infectious Disease, PathWest Laboratory Medicine WA and Royal Perth Hospital, Perth, Australia. Sze-Ann.Woon@health.wa.gov.au.|Department of Infectious Disease, National University Hospital, 5 Lower Kent Ridge Road, Singapore, 119074, Singapore. Sze-Ann.Woon@health.wa.gov.au.
authors.forename: Sze-Ann
authors.initials: SA
authors.lastname: Woon
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Perth, Australia.
authors.forename: Rongchang
authors.initials: R
authors.lastname: Yang
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Perth, Australia.
authors.forename: Una
authors.initials: U
authors.lastname: Ryan
authors.affiliation: Department of Microbiology and Infectious Disease, PathWest Laboratory Medicine WA and Royal Perth Hospital, Perth, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Boan
authors.affiliation: Department of Internal Medicine, Royal Perth Hospital, Perth, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Prentice
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000150:complications*; D000328:Adult; D002908:Chronic Disease / Q000628:therapy; D003048:Coccidiosis / Q000188:drug therapy / Q000209:etiology* / Q000276:immunology / Q000469:parasitology; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D008853:Microscopy / Q000379:methods*; D002052:Myanmar; D016133:Polymerase Chain Reaction; D012036:Refugees / Q000706:statistics & numerical data; D021745:Sarcocystidae / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000627:therapeutic use
chemical_list: D015662:Trimethoprim, Sulfamethoxazole Drug Combination