[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Nematodes](https://durgical.com/en/microbiology/groups/nematodes/) › Oesophagostomum and Mammomonogamus # Oesophagostomum and Mammomonogamus - Parasite - For completeness Two animal roundworms rarely seen in people: one forms lumps in the bowel wall, the other sits in the airway and causes a stubborn cough. Updated Nov 13, 2026 Also called: Oesophagostomum bifurcum, nodular worm, Mammomonogamus laryngeus, Syngamus laryngeus, gapeworm, syngamosis ## Quick facts **Type** Parasite · [Nematodes](https://durgical.com/en/microbiology/groups/nematodes/) **Gram / shape** Oesophagostomum **Spread** Oesophagostomum · Mammomonogamus **Causes** Oesophagostomiasis · Mammomonogamiasis **Treatment** Oesophagostomum On this page - The basics Key points - At a glance - Morphology - Transmission - Life cycle - In Colombia - Memory aid - What the colours mean - Clinical Virulence factors - Diseases it causes - Clinical picture - Diagnosis - Treatment Treatment - Prevention - Study Test yourself - Connections Connections ## Key points - Oesophagostomum: bowel-wall nodules that mimic appendicitis or a tumour. - Its eggs are read as hookworm eggs on stool exam. - Mammomonogamus: Y-shaped worm pair in the airway, chronic cough, Caribbean and Brazil. - Bronchoscopic removal of Mammomonogamus is both diagnosis and treatment. ## At a glance **Shape** Oesophagostomum: hookworm-like egg. Mammomonogamus: red male and female joined for life in a Y shape **Family** Chabertiidae (Oesophagostomum); Syngamidae (Mammomonogamus) **Type** Strongylid nematodes of animals; humans are incidental hosts **Size** Small worms, a few millimetres to about 2 cm ## Morphology - Oesophagostomum eggs cannot be told apart from hookworm eggs on routine stool exams. - Oesophagostomum larvae sit inside nodules in the wall of the large bowel. - Mammomonogamus: the male stays attached to the female in permanent copulation, forming a Y. ## Transmission - Oesophagostomum: swallowing infective larvae from soil, water or food contaminated with faeces. - Mammomonogamus: presumed ingestion of eggs, larvae or a carrier host (snail, earthworm, arthropod) in raw food or water. - Neither spreads directly from person to person. **Reservoir:** Oesophagostomum: non-human primates, pigs, sheep and goats; humans in northern Togo and Ghana; Mammomonogamus: cattle, goats, sheep and cats in the tropics ### Isolation precautions What the care team adds to standard precautions. - Standard ## Life cycle - Oesophagostomum eggs in faeces hatch in soil; larvae moult twice to the infective stage. - The host swallows the larvae, which encyst in the bowel wall and form nodules. - Larvae leave the nodules, mature in the colon lumen and lay eggs about a month later. - Mammomonogamus adults attach to the larynx and trachea of cattle or cats. - Eggs are coughed up, swallowed and passed in faeces; the full cycle is not well known. - A person is infected by swallowing infective stages; worms settle in the larynx or bronchi. ## Virulence factors - Encysted Oesophagostomum larvae provoke inflammatory nodules, abscesses and masses in the colon wall. - Nodules can obstruct the bowel or, rarely, perforate and cause peritonitis. - Mammomonogamus attached to the airway mucosa causes irritation, cough and sometimes bleeding. ## Diseases it causes - Oesophagostomiasis: nodular or tumour-like masses of the large bowel, often mimicking appendicitis - Mammomonogamiasis (syngamosis): chronic cough, sensation of a foreign body in the throat, haemoptysis ## Clinical picture - Oesophagostomum: right lower quadrant pain and fever mimicking appendicitis; painless abdominal mass. - Oesophagostomum: intestinal obstruction; rarely skin nodules. - Mammomonogamus: weeks of dry cough, foreign-body sensation in the larynx, sometimes haemoptysis or wheezing. - Mammomonogamus symptoms often resolve as soon as the worm pair is coughed up. ## Diagnosis - Oesophagostomum: usually worms in surgical or biopsy specimens; ultrasound shows nodules in the bowel wall. - Oesophagostomum eggs on stool exam are read as hookworm; larval culture or PCR separates them. - Mammomonogamus: the Y-shaped red worm pair coughed up or seen and removed at bronchoscopy. - Mammomonogamus eggs may appear in sputum or stool; eosinophilia may be present. ## Treatment Oesophagostomum: benzimidazoles (albendazole) and surgery for complicated masses. Mammomonogamus: removal of the worms at bronchoscopy; benzimidazoles (albendazole or mebendazole) have been used. Drug class only; doses and regimens are set by the clinician from the current guideline. In Pharmacology: - [Albendazole](https://durgical.com/en/pharmacology/albendazole/) - [Mebendazole](https://durgical.com/en/pharmacology/mebendazole/) ## Prevention - Safe water, sanitation and hand hygiene in rural areas. - Wash raw vegetables; avoid raw or undercooked food that may carry snails or other carriers. ## In Colombia The first human Mammomonogamus laryngeus case in Colombia was published in 2006 from Armenia, Quindío: a young man with two months of cough who recovered once he coughed up the worm pair. Most human cases come from the Caribbean and Brazil. Oesophagostomum in humans is mainly African. ## Memory aid One makes knots in the colon (Oesophagostomum); the other is a married couple in the throat that leaves with one strong cough (Mammomonogamus). ## Test yourself Think of the answer, then tap the question to see it. ## How does human oesophagostomiasis typically present? With nodules or masses in the large-bowel wall, often mimicking appendicitis or a tumour. ## Why is Oesophagostomum easily missed on a stool exam? Its eggs look like hookworm eggs, so they are reported as hookworm. ## What is the characteristic appearance of Mammomonogamus laryngeus? A red male and female joined in permanent copulation, forming a Y shape. ## Which symptom brings patients with Mammomonogamus to the doctor? A chronic cough, often with a foreign-body sensation in the throat, sometimes with haemoptysis. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/microbiology/oesophagostomum-and-mammomonogamus/) ## What the colours mean **Gram-positive** Thick peptidoglycan wall: stains purple. **Gram-negative** Thin wall with an outer membrane: stains pink. **Acid-fast** Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain. ## Connections ## Related 3 - [Necator americanus / Ancylostoma duodenale](https://durgical.com/en/microbiology/necator-americanus-ancylostoma-duodenale/) - [Trichostrongylus spp.](https://durgical.com/en/microbiology/trichostrongylus-spp/) - [Angiostrongylus (A. costaricensis, A. cantonensis)](https://durgical.com/en/microbiology/angiostrongylus/) [← Back to the group: Nematodes](https://durgical.com/en/microbiology/groups/nematodes/) Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [CDC - DPDx - Oesophagostomiasis](https://www.cdc.gov/dpdx/oesophagostomiasis/index.html) (CDC, 2017); [Syngamoniasis in Tourist](https://pmc.ncbi.nlm.nih.gov/articles/PMC3367642/) (Emerging Infectious Diseases (PMC), 2005); [Reporte del primer caso humano de infección parasitaria por Mammomonogamus laryngeus en Colombia](https://www.redalyc.org/articulo.oa?id=84332603) (Biomédica (Instituto Nacional de Salud), 2006). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/microbiology/oesophagostomum-and-mammomonogamus/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/oesophagostomum-and-mammomonogamus/