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Feline Ocular Histoplasmosis, Comparison With Human Presumed
Feline Ocular Histoplasmosis, Comparison With Human Presumed Ocular Histoplasmosis Syndrome (POHS). Leandro Teixeira COPLOW fellow Cryptococcus neoformans Sporothrix schenkii Aspergillus sp. Blastomyces dermatitidis Deep mycotic infections Histoplasma Capsulatum Coccidioides Immitis Cryptococcus neoformans Aspergillus sp. Blastomyces dermatitidis Sporothrix schenkii Deep mycotic infections Coccidioides Immitis Histoplasma Capsulatum Davies & Troy, 1996 Major mycotic infections Areas of high environmental concentration Hi Adapted Wolf & Troy 1990 Histoplasmosis Coccidiomycosis Blastomycosis Deep mycotic infections • Variable association – glucocorticoids administration – Feline leukemia virus (FeLV) (Davies and Troy 1996) – Feline immunodeficiency virus (FIV) – Feline panleukopenia virus (FePLV) Histoplasmosis • Infectious and non‐contagious systemic mycosis • Cause: – Dimorphic fungus Histoplasma capsulatum • Low morbidity and high mortality • Acute wasting, depression, fever, anorexia and anemia • Inhaled mycelial forms and macroconidias Histoplasmosis Lungs Spleen *Eyes Bone marrow Lymph nodes Bone Liver •*Ocular involvement more common in histoplasmosis than in other deep mycosis (24% of the cases). Davies & Troy 1996 •All 4 animals that that had ophthalmic examinations had ocular involvement. Wolf & Beldem 1984 Histoplasmosis • Ocular signs: – Mucoid ocular discharge – Blepharospasm – Conjunctivitis – Chemosis – Chorioretinitis – Retinal detachment – 2ary glaucoma Presumed ocular histoplasmosis syndrome (POHS) • Distinct clinical entity characterized by: – Peripheral atrophic chorioretinal scars, – Peripapillary scarring – Maculopathy • Believed to be secondary to exposure to Histoplasma capsulatum. – Fungus rarely isolated or cultured from an eye with the typically associated clinical findings. • Epidemiologic findings link the fungus to this condition. – Similar geographic distribution of fungus and POHS + – Histoplasmin skin testing may exacerbate the ocular condition. • Visual loss in POHS is secondary to the development of macular choroidal neovascularization (CNV). POHS POHS Study • COPLOW data base ‐ 24 cases – 18 cases of feline ocular histoplasmosis – 6 suspected cases of histoplasmosis where no organisms were found. • Criteria of inclusion: – Clinical suspicion and/or Choroidal neovascularization with no history or signs of trauma/scleral rupture Study • Ages – 1.5 to 16 years‐old (7.2 years‐old average) • No breed or sex predilection Affected eye OS OD OU Conjunctiva Histoplasma + 1 12 4 1 POHS‐like 6 ‐‐ ‐‐ ‐‐ Clinical Signs Histoplasma + POHS‐like Unspecific Specific Anorexia, lethargy and weight loss Generalized lymphadenopathy, splenomegaly, tachypnea, pulmonary lesions 83% (10/12) 50% (3/6) 75% (9/12) 33.3% (2/6) Most commonly Clinical ophthalmic findings Histoplasma + POHS‐like Glaucoma Glaucoma Panuveitis Uveitis Retinal detachment Retinal detachment Retinitis Chorioretinitis Ancillary exams • Histoplasma positive group – 12/18 performed some ancillary diagnostic – 50% were positive • • • 4 FNA 1 Serologic test 1 PCR from lymph node aspirate • POHS –like group – 3/6 performed some ancillary diagnostic – All negative Histopathology • Histoplasma positive group * 1 * Histopathology • Histoplasma positive group GMS 60X Histopathology • POHS‐like group Histopathology • POHS‐like group * Distribution of the cases Histoplasma positive POHS‐like Distribution of the cases Histoplasma positive POHS‐like Follow up information • Histoplasma positive group – 8/18 • 5 euthanized due to complication related to the disease • 3 still alive and well • POHS‐like group – All cases lost for follow up information Conclusions • Feline ocular Histoplasmosis: – lymphoplasmacytic and granulomatous panuveitis and pyogranulomatous endophthalmitis with intra‐histiocytic retinal and choroidal yeasts affecting mid‐age animals in endemic areas. • Suspected histoplasmosis cases: – Presented no organisms – Histological lesions that are similar to cats with organisms and human POHS • choroidal neovascularization and moderate lymphoplasmacytic infiltrate • We speculate that the cat is a useful model to study the mechanisms involved in the development of POHS. Thanks • • • • Dr. Dubielzig Dr. Schobert COPLOW staff COPLOW students
