Mammomonogamus laryngeus		Contents		Rev 05/19/2026
Gapeworm of Cattle		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Mammomonogamus Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Syngamidae Menu		Feeding		References
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 Classification

Phylum:  Nematoda
Class:    Chromadorea
Order:    Rhabditida 

Superfamily:  Strongyloidea

Family:  Syngamidae

Syngaminae

Mammomonogamus laryngeus (Railliet, 1889) Rhyzikov, 1948

Type species of the genus.

Synonyms:

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Morphology and Anatomy:

General Characteristics:

Mammomonogamus species maintain the male posterior end attached to the female cuticle at the vulva region, in a constant copulation postion, creating a Y-shape appearance, This permanent mating position impairs the identification of the male posterior end structures, hampering the visualization of the spicule, papillae, and rays.

• Anterior well-developed with a deep buccal capsule that has 8 longitudinal ribs on the walls, each rib with a tooth at the base.
• Esophagus valve formed by three leaflets
• Anterior region with a rough surface ornamented with four button-like papillae, and two lateral slit-shaped amphids
• Eight festoon-like extensions: six in the internal margin of the oral opening. cephalic papillae are located at the extremities of the largest festoons
• Excretory pore and button-shaped deirids near the anterior end

Females

• Tail conical

Males:

• Bursa difficult to observe as it fits intoa groove of the female body and an apparent zipper-like fusion of the famale and male cuticle around the copulatory structures.
• Spicule with head, shaft, and blade, but difficult to distinguish.; there appears to be a central core or duct, similar to that seen in tube-like spicules of other nematode species.

Ref: Lopes-Torres et al., 2020

Mammomonogamus laryngeus (A) Buccal capsule, arrows indicate ribs; (B) Internal view of anterior end, dotted circle is esophagus valve, eight ribs and teeth (t), four external papillae (arrowhead), two amphids (arrow), and eight festoons (f)  Inset: Detail of amphid; (C) Anterior end with internal view of three ribs (arrows) and two of the eight teeth (t), cephalic papillae (arrow head), the six small festoons (f); (D) Lateral view of the anterior region showing the largest ventral festoon (vf), next to two papillae (arrow head), two deirids (d) and two surface patterns (dotted line): rough surface (asterisk) and cuticle with prominent striations (st). Inset I: Detail of the rough cuticle surface. Inset II: Excretory pore (ep). Inset III: Deirid. Scale bars: A: 200μm; B, C, and D: 100μm, inset: 10μm. Inset I: 20μm, II and III: 10μm Photomicrogtaphs ane explanatory text (adapted) from Lopes-Torres et al., 2020

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Distribution:

Mammomonogamus laryngeus are  parasites of the respiratory tract of cattle and buffalo, predominantly in tropical and subtropical (and some temperate) areas of the world.

Until the revision by Ryzhikov (1948)ence Ryzhikov, Mammomonogamus was considered a subgroup of the genus Syngamus.

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Economic Importance:

Mammomonogamus laryngeus is a hematophagous nematode that causes lesions in upper respiratory tracts of cattle, sheep, goats, deer, wild yaks, and orangutans (Lopes-Teres et al., 2020).

In ruminants, the gapeworm is primarily lodged in the larynx mucosa and other nasal cavities, which is generally asymptomatic. However, some animals may suffer from mild bronchitis and, in severe cases, the parasite can cause bronchial sclerosis (Serra Freire, 1979; Sossai et al., 2007).

Human infection is rare, usually in ranchers and rural workers.

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Hosts:

Cattle and buffalo

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Feeding:

Gapeworms of cattle are specialized in tissue attachment . In the laryngopharynx and pharynx mucosa their attachment sites incite  edema and eroded areas. The laryngopharynx tissue takes on a pale color due to the blood removal ofthese hematophagous nematodes and the associated bleeding caused by the pasrasitic activity.

The attachment of Mammomonogamus laryngeus to the host tissue is facilitated by the well-developed buccal capsule. The anterior end of the nematode remains constantly attached to the host tissue as it ingests the mucosa. There is inflammation close to the buccal capsule associated with the erosive process caused by the friction of the eight teeth and buccal ribs.

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Life Cycle:

Like the bird parasite, Syngamus trachea, adults of Mammomonogamus are joined in permanent copulation firmly attached to mucosa by the buccal capsule (Graber et al., 1971)

 Copulation occurs in the laryngeus or bronchi. Females produce eggs that  are coughed up, swallowed, and excreted in the feces.

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Damage:

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Management:

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References:

Graber, M., Euzeby, J., Gevrey, J., Troncy, P.M. and Thal, J. 1971. La mammomonogamose des ruminants domestiques et sauvages. Revue d'Elevage et de Medecine Vererinaire des Pays Tropicaux 24: 525-541.

Lopes-Torres, E.J., Pinheiro, R.H.de S, Rodrigues, R.A.R., Francez, L de C.,  Goncalves, E.C., Giese, E.G. 2020.  Additional characterization of the adult worm Mammomonogamus laryngeus (Railliet, 1899) and the tissue lesions caused by the infection in buffaloes. Vet. Parasitol.  283 109164

Railliet, M.A. 1899. Syngame laryngien du boeuf. Comptes Rendu des Seances de la Societe de Biologie et des ses Filiales 6:174-176.

Ryzhikov, K.M. 1948. Phylogenetic interrelationships of nematodes of the family Syngamidae and an attempt to reconstruct their systematics. Doklady Akademii Nauk SSSR 62:733-736.

Serra Freire, N.M., 1979. Infection due to Mammomonogamus laryngeus in the buffalo (Bubalus bubalis) in Pari state, Brazil. Trop. Anim. Relth. Prod. 11: 69-70.

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