Symptoms of gastrointestinal Pythiosis

Canine gastrointestinal Pythiosis is an infection of the dog’s digestive tract which causes the intestinal tract to thicken. Dogs may eventually develop an intestinal obstruction or large palpable abdominal mass.

 Symptoms include: vomiting, diarrhea, loss of appetite, lethargy, weight loss, occasional fever, abdominal mass, and enlarged lymph nodes. 

The stomach and duodenum are the most common sights of infection. Stomach lesions may be accompanied by abdominal pain and “coffee ground” vomitus due to ulceration and gastric bleeding. When the small intestines are affected, chronic diarrhea is more common. With colonic involvement and ulceration there may be bloody diarrhea.

Formation of hard gastrointestinal tumor-like masses and areas of thickness and mucosal ulceration are common. The infection may spread to adjacent tissue such as pancreas and mesenteric lymph nodes. Histopathologically, the mucosa shows ulceration, atrophy, and hyperplasia. Eosinophils, plasma cells, macrophages, epithelial cells and giant cells are detected in infected tissues. The hyphae of P. Insidiosum, however, are difficult to detect. Silver stain or other special stains are required to visualize the hyphae of this pathogen in infected tissue.

Symptoms of cutaneous Pythiosis

The cutaneous or subcutaneous form of Pythiosis is acquired through an open wound which usually allows infiltration of the infective zoospores. Lesions are often located on the tail near the perineal area, legs, thorax, abdomen, and face.

Symptoms include swollen, non-healing wounds with pus-filled nodules and draining sinus tracts that often enlarge rapidly.

The hard stony masses (kunkers) seen in horses is not observed in dogs with the disease, but there will be areas of tissue death or necrosis with eosinophils and a moderate number of neutrophils and macrophages. The hyphae of P. Insidiosum are found in the center of eosinophilic micro abscesses.

Canine Lagenidium

The clinical presentation of canine lagenidiosis is nearly identical to that of the cutaneous form of pythiosis as the tumor like masses of lagenidiosis are identical in appearance to those of pythiosis. In contrast to the clinical course of cutaneous pythiosis, dogs with lagenidiosis often have involvement of distant sites.

It causes lesions in the legs, mammary glands, trunk, groin or near the tail. The notable difference in these diseases is that lagenidiosis disseminates to other organs much more commonly. Spontaneous dissemination of disease may involve the lungs, aorta or vessels, cranial mediastinum, and lymph nodes. An aneurysm of a great vessel can rupture and cause sudden death.

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