Coccidioides immitis

Question 1

structure

Answer 1

dimorphic fungi found in hot, drier environments

Question 2

Species infected

Answer 2

most mammals, rarely reptiles, desert bighorns, mountain lions, coyotes, california sea lions, bottle-nosed dolphins

Question 3

Life Cycle phases

Answer 3

Saprobic and parasitic

Question 4

Saprobic

Answer 4

in soil-> starts as mycelia that branches into hyphae-> stay in first 12 in of soil and in poor conditions, will form arthroconidia-> when soil disturbed, arthroconidia become airborne

Question 5

Parasitic

Answer 5

arthroconidia enter mammal through respiratory system-> becomes round and enlarged-> young spherule-> as matures, forms internal compartments and endospores-> release endospores in large packets but some break off and can cause dissemination

Question 6

Environment

Answer 6

survives well in saline soil, needs fine sand and silt in soil, spotted in Mexico, central and south america

Question 7

Typical clinical signs

Answer 7

-dry, sometimes hacking, persistent cough
-weight loss, fever, inappetence/lethargy, lameness in any limb, joint swelling, seizures diffuse pain

Question 8

Atypical clinical signs

Answer 8

-neck/back pain
-acute loss of mobility
-swelling under skin or non-healing wounds
-severe, thick plaque on skin
-inflammation intraocular and periocular
-secondary glaucoma
-tremors/behavioral changes
-swollen testicles
-chronic diarrhea/vomiting
-swollen lymph nodes
-acute heart failure

Question 9

Pathologic lesions

Answer 9

-gross lesions may be limited to lungs, mediastinum, and thoracic lymph nodes or may be disseminated to -> discrete nodules of variable size-> have a firm gray-white cut surfaces, pyogranulomas composed of epithelioid and giant cells, center of some foci may contain purulent exudate and fungal organisms-> moth-eaten appearance to bones
-fungal organisms are found in tissue as spherules ranging from 20-200 mcm in size but may be sparse in tissue

Question 10

Diagnosis

Answer 10

Supplemental tests-pulmonary, skeletal, soft tissue with radiographs
More definitive tests- bloodwork
Other tests- cytology, fungal culture, serology antigen, real-time PCR, Histopathology

Question 11

Management

Answer 11

no management

Question 12

Treatment

Answer 12

azoles, fluconazole, itraconazole