banner.gif (11844 bytes)


Aelurostrongylus abstrusus Homepage

        Common name:

          Kingdom: Animalia

            Phylum: Nemathelminthes

              Class: Nematoda

                Order: Strongylida

                  Family: Filaroididae

                    Genus : Aelurostrongylus

                      Species: abstrusus

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

Adult Parasite:

    The male measures 7.5 mm and the female 9.9 mm. Males have a short bursa and the vulva of the female opens near the posterior end.

    Histological section of Aelurostrongylus in lung tissue, cross section of one parasite is shown highlighted.

Return to top of page


  • Definitive: Cats
  • Intermediate: Snails and slugs
  • Paratenic: mice, voles, birds, frogs, and lizards.

Return to top of page

Life Cycle:

    Adult female worms lay their eggs in the alveoli of the cat's lung. The eggs hatch and the first stage larvae (L1) are carried up the trachea, swallowed and pass out with the feces. The L1 can live for about 2 weeks in the environment. If the L1 find a snail or slug they enter the "foot" where they grow to the infectious third-stage (L3). If a paratenic host eats the snail, the L3 migrate into the tissues of the new host and arrest. Cats are more likely to be infected by eating the paratenic hosts as snails and slugs are usually not part of their diet. The L3 will penetrate the gut wall and migrate through the peritoneal and thoracic cavities to the lung. The larvae will develop to the adult stage and egg laying will begin 5 to 6 weeks after the cat ingested the L3.

Return to top of page

Site where adult parasite is found in host:

    Terminal bronchioles and alveolar ducts of the lung.

Return to top of page

Diagnostic Stage:

  • The first-stage larvae (L1) in the feces.

Common Diagnostic Test:

Clinical Signs:
  • Light infections may be asymptomatic.
  • In moderate infections you may see coughing and anorexia.
  • In heavy infections there may be a chronic cough, dyspnea and polypnea, diarrhea, and wasting.
  • Return to top of page



    Fenbendazole (for an extend period of time),

     Ivermectin (at a dose of 0.4 mg/kg, may have to be repeated).

Return to top of page

University of Pennsylvania  2004

Comments or Questions please contact:  Dr. Nolan at: