As the organism is neither a bacterium, virus, nor fungus, routine tests often fail to diagnose it. In cytology and histology, the organism does not stain using Giemsa, H&E, or Diff-Quick, but the hyphae are outlined by surrounding tissue. GMS staining is required to identify the hyphae in slides, and highlights the lack of septation which helps distinguish the organism from fungal hyphae. Granulomatous inflammation with numerous eosinophils is suggestive that the hyphae are oomycetes rather than fungi, which are less likely to attract eosinophils. The symptoms are usually nonspecific and the disease may not be included in a differential diagnosis in human medicine, though it is familiar to veterinarians.