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Oklahoma State University
Center for Veterinary Health Sciences

Healthy Animals - Healthy People

Risk Factors for Histoplasmosis in Cats


Histoplasmosis is a fungal disease that is common in cats in Oklahoma and surrounding states. Unfortunately, it is commonly fatal (33 percent fatality rate) and affects young to middle-aged cats that are otherwise completely healthy. A recent study documented that up to one-third of cats with histoplasmosis were considered to live strictly indoors, without direct access to the outdoors. This finding would suggest that these cats are becoming infected in the home. This finding is also very pertinent to human health, as histoplasmosis is a disease of growing importance in humans, and humans share the same home environment with their indoor cats.

The goal of this study is to determine if there are environmental risk factors for cats, especially indoor cats, for acquiring histoplasmosis.  This study will enroll cats with and without histoplasmosis.  We will survey the pet-owners of both groups of cats to learn about the household environment and behaviors of the cats.

Eligible Candidates

Any cat is a candidate—with or without suspected or confirmed histoplasmosis. Histoplasmosis can affect any organ and common clinical signs include weight loss, decreased activity, fever, difficulty breathing, swollen spleen and lymph nodes, diarrhea, skin lesions and joint pain, and swelling. Your veterinarian might be suspicious of histoplasmosis based on clinical signs, physical examination findings or the results of routine diagnostic tests.


For more information or to refer a patient for evaluation and possible inclusion in this clinical study, please contact Dr. Andrew Hanzlicek at the Veterinary Medical Hospital at 405-744-7000.