A fungus. P. brasiliense and P. lutzii.
Soil from Mexico (23 degrees north) to Argentina (34 degrees south) with Brazil the most endemic area. Armadillo burrows may be a source (Pubmed.)
There is a strain in dolphins that causes cutaneous disease.
Starts most often as a pneumonia, it can disseminate, especially to mucous membranes; it can occur in any organ if the patients luck is bad enough.
Ketoconazole 200 to 400 mg/day for a minimum of 6 months and for as long as 12 to 18 months gives the best relapse rate. Voriconazole 200 po bid (after a lame loading dose of 400mg) or itraconazole 100 mg po bid for 6 months to a years are of equal efficacy (PubMed). Amphotericin B up to 1.8 grams, but needs follow up sulfa to prevent relapse. Sulfadiazine 4 grams a day for 3 to 5 years (it is the only fungus that responds to sulfa (except Pneumocystis).
It can remain dormant for years, only to reactivate when immunity declines (like AIDS).