This study aimed to perform a seroepidemiological survey on the prevalence of sporotrichosis among cats living in the Northern area of Buenos Aires, where a four-fold increase of Sporothrix brasiliensis infections were diagnosed during the last decade. For this purpose, an in-house indirect ELISA test sensitized with S. brasiliensis crude antigens was used. The ELISA test showed 100.0% sensitivity and 95.0% specificity. Antibodies against S. brasiliensis antigens were detected in 3.7% (9/241) of healthy cats evaluated, suggesting likely exposure or infection to this fungus. This ELISA test would be a valuable screening tool for diagnosing sporotrichosis and for seroepidemiological surveys.

Background: Diagnosing progressive disseminated histoplasmosis (PDH) is still challenging in many countries where this disease is highly endemic. Definitive diagnosis is established by culture and/or by cytology/histopathology but both procedures have limited sensitivity and cultures are time-consuming. Antibodies detection by immunodiffusion has a low sensitivity in immunocompromised individuals. Commercially available antigen detection assays have high sensitivity in PDH cases; however, they are expensive and only performed in few laboratories.Aims: To describe the potential use of a novel ELISA for antibodies testing and a dot blot assay for antigen testing for diagnosing PDH using the recombinant 100 kDa protein of Histoplasma capsulatum (Hcp100) and their polyclonal antibodies as novel reagents, respectively.Methods: Serum and urine samples from a cohort of patients with HIV/AIDS and proven PDH were studied for the detection of anti-Hcp100 antibodies by ELISA and Hcp100 antigen by dot blot, respectively. Sensitivity, specificity and cross-reactions with other diseases were estimated for each assay and compared with those obtained using histoplasmin (HMN) as a reagent for antibodies detection by ELISA and immunodiffusion, and using a commercial antigenuria test.Results: Antibodies detection by the Hcp100 ELISA demonstrated 78.6% sensitivity and 88.4% specificity, versus 85.7% sensitivity and 81.0% specificity for the HMN ELISA and 26.1% sensitivity and 100% specificity for the immunodiffusion assay.Antigen detection by the Hcp100 dot blot demonstrated 89.3% sensitivity and 97.0% specificity versus 82.1% sensitivity and 90.9% specificity for the commercial test. Conclusion:The immunoassays described herein based on Hcp100 would be a valuable screening tool for diagnosing PDH.