Disseminated histoplasmosis with ocular adnexal involvement in seven cats

Abstract

Objective To describe the clinical features, diagnosis, and treatment of disseminated histoplasmosis with conjunctival and/or nictitating membrane involvement in cats. Procedure Medical records from seven cats with naturally acquired disseminated histoplasmosis and conjunctival and/or nictitating membrane lesions were reviewed for signalment, clinical findings, diagnostic results, treatment, and outcome. Results Breeds included domestic shorthair (n = 5), Maine Coon (n = 1), and Siamese mix (n = 1) with four spayed females and three castrated males. Conjunctival abnormalities were identified in four cats, and nictitating membrane lesions were identified in four cats; one cat had both a conjunctival and nictitating membrane lesion. Cytologic evaluation of lesions identified Histoplasma capsulatum organisms in two of four cases sampled, and histopathologic evaluation identified H capsulatum in both cases in which a sample was submitted. Histoplasmosis antigen testing was positive in three of four submitted samples. Initial treatment for all cats included fluconazole (median dose: 26 mg/kg/d). Median duration of follow‐up was 11 months (range: 1‐108 months; n = 4). Resolution of ocular adnexal lesions was achieved in three cats. Two cats had relapse of disease, one of which was subsequently euthanized. One cat with concurrent feline immunodeficiency virus (FIV) infection died one month after diagnosis of histoplasmosis. Conclusions Histoplasmosis should be a differential diagnosis for ocular adnexal inflammatory lesions in cats.

Molecular Detection of Histoplasma capsulatum in Small Wild Mammals, Dogs, and Cats from Areas of Remaining Forest in the Brazilian Amazon

“…As in human patients, dogs and cats infected with H. capsulatum may be asymptomatic or present with the respiratory and disseminated forms of histoplasmosis [6,66]. In this study, one positive dog in a blood sample showed clinical signs suggestive of the disseminated form of histoplasmosis and was negative in molecular analyses for DNA detection of Leishmania spp., Trypanosoma cruzi, Babesia vogeli, Ehrlichia canis, and Mycoplasma spp.…”

“…Histoplasma capsulatum is a dimorphic fungus that can infect different species of mammals, including humans [1][2][3][4][5][6][7], and is rarely reported in birds (Eclectus roratus) [8]. This fungus is the etiologic agent of histoplasmosis and was originally classified based on its geographic distribution, morphology, and pathogenicity into three varieties: H. capsulatum var.…”

Ocular lesions in cats diagnosed with systemic sporotrichosis

“…Retinal and optic nerve abnormalities such as chorioretinitis and optic neuritis may be associated with fungal infections such as cryptococcosis, blastomycosis, and histoplasmosis 29,32–34 . In humans, there are reports that sporotrichosis can also be related to similar clinical presentations, especially in immunocompromised patients 35 .…”

“…Retinal and optic nerve abnormalities such as chorioretinitis and optic neuritis may be associated with fungal infections such as cryptococcosis, blastomycosis, and histoplasmosis. 29,[32][33][34] In humans, there are reports that sporotrichosis can also be related to similar clinical presentations, especially in immunocompromised patients. 35 In the present study, these alterations were not evident in cats with sporotrichosis, although ophthalmoscopic evaluation was impaired due to severe blepharoconjunctivitis and corneal edema caused by uveitis.…”

Invasive fungal rhinitis with adnexal involvement caused by Histoplasma capsulatum in a cat from a non-enzootic location

“…The adnexal (conjunctival and nictating membrane) involvement described in this cat has been reported and is estimated to occur in 4% of cats with histoplasmosis. 13 The reported nodular and crusting facial lesions are more commonly found. 3,5,[14][15][16] Like the present case, in the authors' experience, the diagnosis of histoplasmosis in cats is often delayed.…”