Canis ISSN: 2398-2942

Coccidioidomycosis

Contributor(s): Rosanna Marsella, Rhea Morgan

Introduction

  • Cause: systemic fungal infection caused by Coccidioides immitis Coccidioides immitis.
  • Endemic in the southwestern US, Central and South America.
  • Organism is present in the soil (sandy, alkaline soil in areas with high temperature and low rainfall) in the mycelial form and produces arthroconidia that are infective.
  • Signs: respiratory signs, ocular signs, lameness, cutaneous lesions.
  • Diagnosis: serology, cytology, histology.
  • Treatment: itraconazole and other anti-fungal agents.
  • Prognosis: good for localized infections.

Pathogenesis

Etiology

Predisposing factors

General
  • Any immunosuppressive disease.

Specific

  • Living in endemic area.
  • Outdoor activities.
  • Young, male dog.
  • Epidemics occur after rainy periods, dust storms, and earthquakes.
  • Peak of infection occurs in the late summer and early fall.

Pathophysiology

  • Infection occurs by inhalation of arthroconidia.
  • After inhalation the conidia convert to a yeast that produces spherules with endospores within the lungs.
  • Cell mediated immunity is important to recover from initial infection.
  • If immunosuppression exists or the immune system is overwhelmed, dissemination of infection occurs to the hilar lymph nodes and other organs, particularly the bones, skin, eyes, heart, testicles, central nervous system, liver, kidneys, and spleen.
  • Isolated cutaneous disease may occur from contamination of wounds with the organism.

Timecourse

  • Incubation ranges from 1-3 weeks.
  • Initial pulmonary infection may go undetected.
  • Subclinical forms of the disease may persist, with clinically obvious disseminated disease occurring months to years later.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Butkiewicz C D, Shubitz L F & Dial S M (2005) Risk factors with Coccidioides infection in dogs. JAVMA 226 (11), 1851-1854 PubMed.
  • Shubitz L F, Butkiewicz C D, Dial S M & Lindan C P (2005) Incidence of Coccidioides infection among dogs residing in a region in which the organism is endemic. JAVMA 226 (11), 1846-1850 PubMed.
  • Johnson L R, Herrgesell E J, Davidson A P, Pappagianis D (2003) Clinical, clinicopathologic and radiographic findings in dogs with coccidioidomycosis: 24 cases (1995-2000). JAVMA 222, 461-466 PubMed.
  • Bartsch R, Greene R T (1998) Lufenuron in the treatment of coccidioidomycosis. Capsule Report 16 (3), 1998.
  • Burtch M (1998) Granulomatous meningitis caused by Coccidioides immitis in a dog. JAVMA 212 (6), 827-829 PubMed.
  • Plotkin A N, Oshoven E W, Rosychuk R A (1997) Primary cutaneous coccidioidomycosis and subsequent drug eruption to itraconazole in a dog. JAAHA 33 (2), 139-143 PubMed.
  • Johnson S M, Zimmermann C R & Pappagianis D (1996) Use of a recombinant Coccidioides immitis complement fixation antigen-chitinase in conventional serological assays. J Clin Microbiol 34 (12), 3160-3164 PubMed.
  • Davidson A P (1995) Canine coccidioidomysosis update. Proc Am Coll Vet Intern Med 13, 808.
  • Sekhon A S, Isaac-Renton J, Dixon J M, Stein L & Sims H V (1991) Review of human and animal cases of coccidioidomycosis diagnosed in Canada. Mycopathologia 113 (1), 1-10 PubMed.
  • Hawkins E C & DeNicola D B (1990) Cytologic analysis of tracheal wash specimens and bronchoalveolar lavage fluid in the diagnosis of mycotic infections in dogs. JAVMA 197 (1), 79-83 PubMed.
  • Angell J A, Merideth R E, Shively J N et al (1987) Ocular lesions associated with coccidioidomycosis in dogs: 35 cases (1980-1985). JAVMA 190 (10), 1319-1322 PubMed.

Other sources of information

  • Greene R T (1998)Coccidiodomycosis.In:Infectious diseases of the dog and cat. Ed C E Greene. Philadelphia: W B Saunders. pp 391-398.
  • Taboada J (2002)Systemic mycoses.In: Morgan R V, Bright R N, Swartout M S (eds):Handbook of Small Animal Practice. 4th Ed. W B Saunders, Philadelphia. pp 1075-1089.


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