Lagochilascaris spp

From Dog
Egg of Lagochilascaris minor under light microscopy[1]
Terminal segment of male L. minor, showing the spicule and ejaculatory duct[2]

Lagochilascaris spp are parasitic ascarid nematode of dogs in the Americas.

The genus Lagochilascaris belongs to the phylum Nematoda. This genus of worms are found naturally infecting wild Felidae, dogs, domestic cats and men in some Central and South American countries[2].

The life cycle of this nematode involves ingestion of rodents which contain infective third-stage larvae. The larvae penetrate the gut wall of the dog and undergo visceral and subcutaneous migration to target organs, primarily the lungs and respiratory tree, where they encyst and shed eggs[3]. Encysted larva have also been located in connective tissue throughout the body[4].

These parasites were first described in humans, where it caused various degrees of facial abscesses, middle ear infections and encephalopathy associated with aberrant tissue migrations[5]. In cats, the adult worms have been isolated from the trachea, esophagus, pharynx, subcutaneous tissue and cervical lymph nodes[6]. In dogs, these parasites are mainly found in the trachea and subcutaneous nodules.

Species which are pathogenic to dogs include:

  • Lagochilascaris minor
  • Lagochilascaris major
  • Lagochilascaris buckleyi
  • Lagochilascaris turgida
  • Lagochilascaris sprenti

Infection in dogs is usually by ingesting rodents containing the larvae[7]. Auto-infection by ingestion of eggs may also occur in the cat[8].

Clinical signs usually appear about 1 - 2 weeks post-infection, with vague respiratory signs. Neurological disease referable to aberrant migration within the CNS have not been reported in dogs, as is seen in cats. Ptyalism has been noted with parasites located in the frenulum of the tongue[9].

Diagnosis is confirmed by isolation of adult nematodes, presence of eggs in the feces and characteristic eosinophilia and elevated ALT/AST liver enzymes[10].

Treatment is usually effective with fenbendazole 50 mg/kg for 3 consecutive days or selamectin.


  1. Portals Sao Francisco
  2. 2.0 2.1 Moncada, LI (1998) Lagochilascaris minor in a patient from the Colombian amazon: a case report. Rev Inst Med trop S Paulo 40(6):387-389
  3. Campos DM et al (1992) Experimental life cycle of Lagochilascaris minor Leiper, 1909. Rev Inst Med Trop Sao Paulo 34(4):277-287
  4. Pena HF et al (2002) Experimental life cycle of Lagochilascaris major leiper, 1910 (Nematoda: Ascarididae) in cats (Felis domesticus). J Parasitol 88(6):1143-1150
  5. Bowman, DD et al (2003) Feline clinical parasitology. Iowa University Press, Iowa. pp:274-281
  6. Compos, DM et al (1992) Experimental life cycle of lagochilascaris minor Leiper, 1909. Rev Inst Med Trop Sao Paulo 34:277-287
  7. Paçô JM et al (1999) Wild rodents as experimental intermediate hosts of Lagochilascaris minor Leiper, 1909. Mem Inst Oswaldo Cruz 94(4):441-449
  8. Castro O et al (2009) Two new records of helminth parasites of domestic cat from Uruguay: Alaria alata (Goeze, 1782) (Digenea, Diplostomidae) and Lagochilascaris major Leiper, 1910 (Nematoda, Ascarididae). Vet Parasitol 160(3-4):344-347
  9. Volcan, GS et al (1991) Infeccion natural de Speothos venaticus (Carnivora: Canidae) por estadios adultos de lagochilascaris sp. Rev Inst Med Trop Sao Paulo 33:451-458
  10. Prudente MF et al (2008) Hematological, serum biochemical and serological profile of Felis domesticus with experimental lagochilascariosis. Rev Soc Bras Med Trop 41(5):496-501