Felis ISSN 2398-2950

Pneumocystis carinii

Synonym(s): P. carinii

Contributor(s): Ibulaimu Kakoma, Grace Mulcahy




  • Phylum: Sarcomastigophora.
  • Subphylum: Sarcodina.
  • Genus: Pneumocystis.

Active Forms

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Clinical Effects



  • Main habitat - mammalian respiratory tract.


  • Direct lifecycle.
  • Evaluation of RNA sequences suggest that P. carinii may be more closely related to fungi than protozoa.
  • Multiplies in lungs when host becomes immunosuppressed.


  • Usually from infected to susceptible animal within species.
  • Infected aerosol.

Pathological effects

  • Majority disease seen in immunocompromized patients, eg human HIV/AIDS patients.
  • Usually confined to lung; pneumonia associated with large numbers P. carinii in alveolar spaces.

Other Host Effects

  • Most infections latent or subclinical.


Control via chemotherapies

  • Trimethroprim-sulfonamide Trimethoprim.
  • Pentamidine is used as a prophylactic aerosol in human beings.


This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Lacroix C, Brun-Pascaud M, Maslo C et al (1996) Co-infection of Toxoplasma gondii with other pathogens - pathogenicity and chemotherapy in animal models. Curr Top Microbiol Immunol 219, 223-233 PubMed.
  • Yuezhong Y, Li Z, Baoping T (1996) Pneumonia in cats caused by Pneumocystis carinii purified from mouse lungs. Vet Parasitol 61 (1-2), 171-175 PubMed.
  • Hong S T, Park K H, Lee S H (1992) Susceptibility of various animals to Pneumocystis carinii infection. Kisaengchunhak Chapchi 30 (4), 277-281 PubMed.
  • Masur H (1992) Prevention and treatment of pneumocystosis. New Eng J Med 327 (26), 1853-1860 PubMed.
  • Shiota T, Shimada Y, Kurimoto H et al (1990) Pneumocystis carinii infection in corticosteroid-treated cats. J Parasitol 76 (3), 441-445 PubMed.
  • Foreyt W J (1989) Diagnostic parasitology. Vet Clin North Am Small Anim Pract 19 (5), 979-1000 PubMed.
  • Hagler D N, Kim C K, Walzer P D (1987) Feline leukemia virus and Pneumocystis carinii infection. J Parasitol 73 (6), 1284-1286 PubMed.
  • Settnes O P, Hasselager E (1984) Occurrence of Pneumocystis carinii Delanoë and Delanoë, 1912 in dogs and cats in Denmark. Nord Vet Med 36 (5-6), 179-181 PubMed.

Other sources of information

  • Greene C E & Chandler F W (1990) Pneumocystosis. In: Infectious diseases of the Dog and Cat. Ed: Greene C E, Philadephia: W B Saunders. pp 854-861.