Introduction

Protothecosis is a disease caused by chlorophyllic algae. The most common clinical presentation is protracted hemorrhagic enteritis. Colon is the most commonly affected portion but the organisms can affect many organs.

Objectives

To demonstrate an effectiveness treatment protocol for canine protothecosis.

Methods

A 4-year-old, neutered female, Thai Bangkaew dog was referred to Kasetsart University Veterinary Teaching Hospital (KUVTH) with the history of 7 months hematochezia and azotemia. The dog did not respond to the previous treatment with long-termed antibiotics. Colonoscopy demonstrated the generalized inflammation and focal hemorrhage from colon to rectum. The cytology showed granulomatous inflammation with possible Prototheca organisms. The treatment protocols were symptomatic treatment and itraconazole 5 mg/kg orally once daily. However, the dog developed acute blindness, retinal detachment with pyogranulomatous retinitis, and neurological signs with disoriented after 3 months of the treatment. Repeated cytology from rectal scraping revealed a large number of Prototheca spp. The treatment regimen then was changed to amphotericin B intravenously 1 mg/kg 2–3 times a week together with fluconazole 5 mg/kg orally twice daily. Subcutaneous fluid was also provided and renal profile was monitored regularly.

Results

After 4 months of this treatment protocol, the clinical signs were improved and the number of Prototheca spp. derived from rectal scraping dramatically decreased.

Conclusions

Systemic Protothecosis can affect many organs and results in death. However, with early diagnosis and appropriate management, the dog may have favorable outcome and increase survival time. Rectal scraping is a valuable tool for early diagnosis of Protothecosis as it is non-invasive technique and inexpensive.