Influence of temperature on in vitro zoosporogenesis of Pythium insidiosum

Equidae pythiosis in Brazil and the world: a systematic review of the last 63 years (1960-2023)

This systematic review compiles reports of clinical pythiosis in horses, mules and donkeys from 1960 to 2023 worldwide, focusing on Brazil. We searched databases and included 71 articles detailing clinical characteristics, geographic distribution, epidemiology, diagnostic methods, therapies, and outcomes. The results showed that publications on equine pythiosis have significantly increased since 2010. Brazil reported the highest incidence, comprising 55% of cases, predominantly in the southern, northeastern, and central-western regions during summer and autumn. Cutaneous pythiosis was the most prevalent form, generally presenting as single lesions in the appendicular region, and affected females more than males. Diagnosis typically involved histopathology, used alone or with other methods. Various treatments have been employed, with surgery, often combined with chemotherapy and immunotherapy, being the most common. Notably, 80.84% of treated animals recovered, highlighting the effectiveness of these therapies in enhancing survival rates. The limitations of the study included the lack of data in published case reports, which made it difficult to collect and calculate epidemiological data. Additionally, we recognize that pythiosis in Brazil is underreported, since this disease does not have mandatory notification and several cases are not registered and/or reported in the literature. Lastly, it is hypothesized that equid pythiosis may be more widespread than currently known, and its real occurrence in Brazil remains uncertain.

Intradermal injection of Pythium insidiosum protein antigens for improved diagnosis and treatment of pythiosis in an experimental model

The oomycetous pathogen Pythium insidiosum is the causative agent of pythiosis, a life-threatening disease that affects animals and humans. This infectious disease is difficult to treat, and early and accurate diagnosis is critical for effective treatment. In this sense, this study aimed to evaluate the intradermal (ID) injection of P. insidiosum protein antigens (PiPA) for the diagnosis and treatment of pythiosis using an experimental model. For diagnostic purposes, PiPA were injected by the ID route in the following groups of rabbits: (a) control; (b) previously immunized with PiPA injected by the subcutaneous (SC) route; and (c) infected with P. insidiosum zoospores. For treatment purposes, rabbits with pythiosis were also treated with PiPA by the ID or SC routes. Mean induration sizes were different at 24 h and 72 h readings when compared to the control group. Sensitivity of the protocol was 100% at 24 h and 80% at 72 h, with 100% specificity in both readings. PiPA treatment using ID or SC routes did not result in significant differences in lesion sizes and cure rates; however, serum levels of interferon-gamma were higher in SC route. This study demonstrates the applicability of PiPA ID for diagnosis and treatment of pythiosis in an experimental model.