Epizootic cutaneous pythiosis

From Cow
Ulcerate tissue caused by Pythium insidiosum[1]

Epizootic cutaneous pythiosis is a rare oomycetic disease of cattle caused by the ubiquitous saprophyte Pythium spp.

Pythium spp are a fungus-like saprophytic protistan oomycete (water mold) found on wet feed or near waterways[2].

Infection occurs mainly in tropical and subtropical areas worldwide and is acquired through small wounds via contact with water that contains motile zoospores or other propagules. Pythiosis in other species have reportedly causes cutaneous, vascular, ocular, gastrointestinal and systemic disease but only skin disease is reported in cattle.

The infection in cattle is not contagious and normally causes ulcerated and swollen granulomatous lesions on the limbs of young calves[3].

Pathogenic species involved in epizootic cutaneous pythiosis include:

  • Pythium insidiosum[4]

Diagnosis is based on presenting clinical signs supported by culture of the fungus in the laboratory. Supportive confirmation can be done with latex agglutination, immunodiffusion, ELISA, and Western Blot[5].

Histopathological samples of diseased skin often reveal an eosinophilic inflammatory reaction with neutrophils, giant cells and branching hyphae.

Treatment for this condition is rarely undertaken in cattle but could include surgery, antifungal drugs or immunotherapy.


  1. Science Direct
  2. Chindamporn A et al (2009) Antibodies in the sera of host species with pythiosis recognize a variety of unique immunogens in geographically divergent Pythium insidiosum strains. Clin Vaccine Immunol 16(3):330-336
  3. Miller RI et al (1985) Cutaneous pythiosis in beef calves. J Am Vet Med Assoc 186(9):984-986
  4. Pérez RC et al (2005) Epizootic cutaneous pythiosis in beef calves. Vet Microbiol 109(1-2):121-128
  5. Santurio JM et al (1998) Cutaneous Pythiosis insidiosi in calves from the Pantanal region of Brazil. Mycopathologia 141(3):123-125