Mammomonogamus is a genus of parasitic roundworms that has cattle and occasionally sheep, goats and cats as final hosts. It also infects wild ruminants (e.g. deer, antelopes, etc.), orangutans and elephants. Incidence in domestic animals is usually very low.

Adult Mammomonogamus laryngeus in the larynx of a cow. © J. Kaufmann / Birkhäuser Verlag

The most relevant species for domestic animals are Mammomonogamus laryngeus and Mammomonogamus nasicola.

Mammomonogamus laryngeus can very occasionally infect humans as well.

Regarding cats, Mammomonogamus mcgaughei has been found in the nasal cavities and Mammomogamus auris in the ears.

Mammomonogamus worms are found mainly in tropical and subtropical regions of Africa, Asia and America (Central and South).

The disease caused by Mammomonogamus worms is called mammomonogamiasis.

Are animals infected with Mammomonogamus worms contagious for humans?

  • Unclear. Since the life cycles of Mammomonogamus worms are not elucidated it is not known how humans become infected, i.e. where do they pick the infective stages (eggs, infective larvae, intermediate hosts, etc.).

You can find additional information in this site on the general biology of parasitic worms and/or roundworms.

Final location of Mammomonogamus

  • Predilection site of adult Mammomonogamus laryngeus is the larynx.
  • Predilection sites of adult Mammomonogamus nasicola and Mammomonogamus mcgaughei are the nasal cavities.
  • Predilection sites of adult Mammomonogamus auris are the ears.

Anatomy of Mammomonogamus

Egg of Mammonogamus spp. Picture from

Mammomonogamus worms are rather small (6 to 25 mm long; 0.3 to 0.6 mm wide), whereby males are about 2 thirds shorter than females. They have a reddish color (they suck blood) and the typical slender shape of roundworms. As other roundworms, their body is covered with a cuticle, which is flexible but rather tough.

The worms have no external signs of segmentation. They have a tubular digestive system with two openings. They also have a nervous system but no excretory organs and no circulatory system, i.e. neither a heart nor blood vessels.

Males have chitinous spicules for attaching to the female during copulation. A typical feature of Mammomonogamus is that males and females are permanently joined in copulation. Since the attachment point (the female genital opening) is in the middle of the female's body, and the males are shorter, this results in a typical Y-shaped formation.

The eggs have an oval shape, are about 50x100 micrometers and contain a few cells.

Life cycle and biology of Mammomonogamus

The life cycle of these worms has not been elucidated. It is not known, whether they have a direct or an indirect life cycle, i.e. whether they need intermediate hosts to complete development or not. It is not clear either, whether the eggs or the larvae are infective.

Harm caused Mammomonogamus, symptoms and diagnosis

Several Mammomonogamus species feed on blood of their hosts but most infections of livestock are benign and cause no clinical signs. In case of massive infections worms may migrate deeper into the trachea and the bronchi and cause partial obstruction of the airways. Respiratory symptoms can develop (e.g. coughing, difficult breathing) as well as nasal discharge and nasal bleeding, etc. Mammomonogamus auris can cause inflammation of the ears in cats.

Prevention and control of  Mammomonogamus

No preventative measures can be recommended because the life cycle is unknown.

Some anthelmintic active ingredients (e.g. albendazole, mebendazolethiabendazole, ivermectin) are known to be effective against Mammomonogamus worms. However, since most commercial dewormers are not approved for use against this worm, the veterinary doctor has to determine a special treatment regime.

There are so far no true vaccines against Mammomonogamus worms. To learn more about vaccines against parasites of livestock and pets click here.

Biological control of Mammomonogamus worms (i.e. using its natural enemies) is so far not feasible.

You may be interested in an article in this site on medicinal plants against external and internal parasites.

Resistance of Mammomonogamus worms to anthelmintics

So far there are no reports on resistance of Mammomonogamus worms to anthelmintics.

This means that if an anthelmintic fails to achieve the expected efficacy, chance is very high that either the product was unsuited for the control of Mammomonogamus worms, or it was used incorrectly.

Ask your veterinary doctor! If available, follow more specific national or regional recommendations for Mammomonogamus control.