Coccidioidomycosis

Question 1

Where is Coccidioides most likely found? how is it transmitted?

Answer 1

semi-arid to arid soil, hot summers
- if there is a cycle of moist conditions, dry period, then soil disruption, then it gets aerosolized, inhaled by hosts – resp infection

Question 1

What causes coccidioidomycosis?

Answer 1

soil-borne fungus called Coccidioides

Question 2

What’s the pathogenesis of coccidioidomycosis?

Answer 2

It’s inhaled into the lungs, phagocytosed by alveolar macrophages –> enlarge into a spherule –> spherule ruptures when the endspore matures –> pyogranulomatous/ granulomatous inflammation
- if host doesn’t have adequate immune response, then gets disseminated into LNs in the respiratory tract and elsewhere
- most infection = subclinical in endemic areas
- can go to bone, CNS, skin, peripheral LNs, pericardium
- infection in cats = rare
- cats: >50% have skin lesions, 25% resp signs, <20% lameness/ ocular/ neuro signs

Question 3

What are the clinical signs of coccidioidomycosis?

Answer 3

Resp: harsh cough, increased rep effort, tachypnea and/or exercise intolerance
Bone: lameness, swelling
Neuro: obtundation, blindness, cranial nerve deficits
Ocular: chorioretinitis, uveitis, endophthalmitis
Liver/GI: GI signs
Pericarditis: R side heart failure signs

Question 4

How is coccidioidomycosis diagnosed?

Answer 4

Serology - IgM or IgG
-false negative = quite rare in dogs
- urine antigen test has low sensitivity = not recommended

Question 5

How is coccidioidomycosis treated?

Answer 5

fluconazole or itraconazole
- itraconazole preferred if there is bony involvement
- amphotericin B if refractory to the azoles or has disseminated disease
- persistent osteomyelitis may need amputation
- supportive therapy (O2 supplementation, pain control, draining of effusion, steroids, anti-seizures, eye meds

Question 6

What’s the public health for coccidioidomycosis?

Answer 6

can cause serious infection in people
- need to handle lab samples properly (try no to culture)
- incinerate dead bodies

Question 7

What’s the prognosis of coccidioidomycosis?

Answer 7

• Life-long treatment may be needed
• can be reactivated
• dogs with localized pulmonary infection would have the best prognosis