Anti-Pythium insidiosum intradermal immunotherapy in horses: diagnosis and therapy

ABSTRACT: Pythiosis is a life-threatening disease that affects various species and is prevalent in regions with high humidity. The ailment is increasingly reported globally, and in Brazil, it is an important cause of profound economic and health losses in equines. This study aimed to explore the potential of intradermal immunotherapy as both a diagnostic and therapeutic approach for pythiosis in horses from the Pantanal region of Mato Grosso, Brazil. The horses were divided into three groups: those never diagnosed with pythiosis or with lesions that could be mistaken for pythiosis (Group 1); previously infected but successfully treated horses (Group 2); and horses with a positive diagnosis for pythiosis that were under treatment (Group 3). An immunotherapeutic product (PitiumVac®) was administered intradermally. Injection site reaction and response to immunotherapy were assessed. The results indicated that intradermal immunotherapy could be a viable diagnostic and therapeutic tool, particularly in remote areas where traditional laboratory diagnosis methods are not readily accessible. The efficacy of intradermal administration was comparable to that of subcutaneous administration in treating pythiosis in horses, and the combined use of immunotherapy and triamcinolone acetonide yielded promising results for treating pythiosis in horses. However, further research is required to validate these findings. This study contributes to understanding and managing pythiosis more efficiently by providing a simple, cost-effective, and potentially efficient alternative approach to diagnosis and treatment.