banner.gif (11844 bytes)



Eucoleus (Capillaria) aerophilia Homepage

          Common name: Lungworm of dogs and cats

            Kingdom: Animalia

              Phylum: Nemathelminthes

                Class: Nematoda

                  Order: Enoplida

                    Family: Trichuroidea

                      Genus: Eucoleus (previously: Capillaria)

                        Species: aerophilia

Click on the text below to jump down to the desired section of this page.

Adult Parasite:

The adult worms measure 25 mm (male) to 32 mm (female).

Illustration C. aerophilia. A - adult worm. B - vulva. C - posterior end of female . D, E, F - posterior end of male. G , H - eggs. From: Levine, 1998. Nematode parasites of domestic animals and man. Burgess Publishing Co., Minneapolis, MN.

Return to top of page


  • Dogs, cats, foxes, coyotes, wolves (definitive).
  • Earthworms (paratenic).

Return to top of page

Life Cycle:

    The host ingests an infective egg or an earthworm which contains an infective larva in its tissues. The infective larva leaves the egg or earthworm in the small intestine of the host and penetrates the intestinal wall. The larva is carried by the blood to the lungs where it develops to the adult stage in the mucosa of the trachea and bronchi. Eggs are laid into the lumen of these organs, coughed up, swallowed and eventually pass out with the feces. The prepatent period is about 6 weeks. The egg will reach the infective stage in 5 to 7 weeks. If an earthworm ingests an infective egg, the egg will hatch in the gut of the worm and the larva will migrate to the worm's tissues where it will wait for a definitive host to eat the worm.

Return to top of page

Site in host where adult parasite is found:

  • Mucosa of the trachea and bronchi

Return to top of page

Diagnostic Stage:

  • Egg with bipolar plugs (asymmetrical) and a rough surface ("netted" in appearance).
  • The egg measures 70 um X 35 um.

Common Diagnostic Test

Clinical Signs:

    Usually asymptomatic in dogs and cats, sometimes causing a slight cough. In heavily infected foxes may show rattling and wheezy breathing and some coughing.


    Ivermectin 0.2 mg/kg, SQ or PO, one dose, repeat if needed.

    Fenbendazole 50 mg/kg, PO, SID, for 7 to 10 days

Return to top of page

University of Pennsylvania  2004

Comments or Questions please contact:  Dr. Nolan at: