Scanning electron microscopy of Pythium insidiosum's sporangia.

Formation of the Pythium insidiosum's sporangia and zoospores (a to h) and release of the flagellated zoopores in water (i).

Sporangia of Pythium insidiosum on a grass leaf.

Life cycle of the pathogen Pythium insidiosum. The upper panel represent its life cycle in nature. The lower panel shows the possible mechanism of infection.

Culture plate of Pythium insidiosum (Sabouraud).

Sparsely septated hyphae of Pythium insidiosum from a culture plate. Hypahe in 90

Cat Pythiosis. Tumoral-like mass caused by Pythium insidiosum. (From Dr. Randall C. Thomas, DVM, College of Veterinary Medicine, University of Florida).

Cat Pythiosis. Tumoral-like mass caused by Pythium insidiosum. (From Dr. Randall C. Thomas, DVM, College of Veterinary Medicine, University of Florida).

Cutaneous dog pythiosis (From Dr. Randall C. Thomas, DVM, College of Veterinary Medicine, University of Florida).

Cutaneous dog pythiosis (From Dr. Randall C. Thomas, DVM, College of Veterinary Medicine, University of Florida).

Cutaneous dog pythiosis (From Dr. Randall C. Thomas, DVM, College of Veterinary Medicine, University of Florida).

Atypical case of equine pythiosis. The infection began in the lower extremity and spread, trough lymphatic vessels, to the horse's chest.

Typical cutaneous pythiosis in an equine. Small white masses, known as "kunkers", are observed in the center of the lesion.

"Kunkers" removed from the above case. These masses containe viable hyphae of P. insidiosum.

Horse pythiosis with bone involvement (from a chronic case of the disease).

Subcutaneous pythiosis in a Texan boy. Orbital pythiosis is common in children and should be differentiated from orbital zygomycosis and aspergillosis (From Dr. Michael G. Rinaldi).

A Thailand boy with pythiosis in his carotid artery (From Dr. Arunee Thitithanyanont).

MRI of the Thai boy with pythiosis in his carotid artery. The arrow shows the invasion of the cervical carotid space. The arrowheads show pockets of pus containing P. insidiosum.

Human arterial pythiosis. Amputation of the right leg is one of  the traumatic choices to treat this disease in Thailand (From Dr. P. Chetchotsakd, MD. Faculty of Medicine, Khon Kaen University, Thailand).

Amputated section of a patient leg that had pythiosis.The picture shows the aneurysm in the femoral artery caused by P. insidiosum from a Thai human patient.

Histological section of a tissue stained with H&E from a horse with pythiosis. The hyphae of P. insidiosum is observed as transversal rings in the center of the eosinophilic reaction.

Silver stain of a histological section from a horse with cutaneous pythiosis.

Culture Filtrate Antigen (CFA) used to diagnose pythiosis in human and animals. Note the number of bands after reaction against equine pythiosis sera (PHS).