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When entomology meets gastroenterology
  1. Grigoriy E Gurvits1,
  2. Rashelle Tsyrlin2
  1. 1 Gastroenterology, New York University Medical Center, New York, New York, USA
  2. 2 Science and Technology, Temple University, Philadelphia, Pennsylvania, USA
  1. Correspondence to Dr Grigoriy E Gurvits, Gastroenterology, New York University Medical Center, New York, NY 10022, USA; g_gurvits{at}

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Clinical presentation

A middle age man with coronary artery disease requiring recent percutaneous angioplasty with drug eluding stent was seen for evaluation of new onset iron deficiency anaemia. His medical history was remarkable for peptic ulcer disease as young adult requiring Billroth II resection. His current medications included aspirin 81 mg daily and prasugrel 10 mg daily. Laboratory analysis was notable for haemoglobin of 124 g/L, iron saturation of 5% and ferritin of 8 ng/mL. Oesophagogastroduodenoscopy and colonoscopy did not reveal source of blood loss. CT using enterography protocol was unremarkable. Small bowel wireless capsule endoscopy unexpectedly showed unusual intestinal inhabitants (figure 1).

Figure 1

Small bowel wireless capsule endoscopy.


What is the diagnosis?


Close endoluminal inspection of the small bowel revealed presence of multiple larvae and adult insects (figure 1A, arrow) with red hallo sign at the site of mucosal attachment, suggestive of a ‘vampire effect’ (figure 1B, arrow). While more common in the developing world, intestinal myiasis in the USA is extremely rare with last documented cases in the medical literature dating back to 1984.1 Our patient was a dog breeder and admitted to an unusual fly infestation during hot summer months requiring frequent calls to pest control services. It is likely that he inadvertently ingested insect eggs and decreased intraluminal acidity with rapid gastric transit seen post-Billroth II surgery resulted in their deposition into the small bowel where completion of the life cycle ultimately lead to the formation of adult flies and development of iron deficiency anaemia. There is no standard treatment for intestinal myiasis. Patient was prescribed intense bowel purgative regimen with 16 L of polyethylene glycol solution followed by a repeat capsule endoscopy which verified resolution of parasitosis. Repeat bloodwork showed no further evidence of iron deficiency anaemia and patient has remained well on follow-up visits.



  • Contributors Authors contributed equally.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.