Abstract

Several greatly enlarged lymph nodes with severe necrohemorrhagic granulomatous lymphadenitis due to Sporotrichum schenckii were found in a Pacific white-sided dolphin (Lagenorhynchus obliquidens) which had been in captivity for about 1 1/2 years.

Notes

Occurrence: Sporotrichosis is a rare but serious disease in dolphins. Sporotrichium schenkii is distributed worldwide and is a saprophyte of the soil. Its dimorphic nature is illustrated by the presence of mycelia in the soil and spores in animals. Thus it occurs more commonly in animals which are in contact with the soil. The disease occurs in the dog, man, the horse and the dolphin to name a few. It is especially common in miners of Johannesburg, Africa.

Pathogenesis

Local and systemic forms of the disease exist. A local cutaneous lesion forms which can become systemic by traveling via the lymphatics to the bloodstream if lymph nodes cannot contain it.

Sporotrichosis is known as "gardener's disease" in the human. There is often an underlying factor which allows the disease to take hold, such as arthritis which is being treated with steroids, prolonged antibiotic therapy which kills competitive bacteria, or an immunodeficient disease state. Thus the disease doesn't usually take hold unless there is some form of immunosuppression.

Lesions

Man - Most lesions are found on the skin. A chain of enlarged lymph nodes appears as multiple subcutaneous nodules which may ulcerate. Description of lesions in this dolphin:

The retropharyngeal lymph nodes were enlarged. There were small abscess-like lung lesions and the pulmonary lymph nodes were enlarged. The skin demonstrated small nodules which were lymph nodes which had enlarged by four to five times. These nodes showed gross necrosis and hemorrhage on cross-section. Histology revealed a fibrinous exudate in the lymph nodes which likely contributed to their enlargement. Macrophages in lymph nodes contained a myriad of organisms.

Diagnosis and Differentials

1. PAS stain to show bound glycogen. This shows up the cigar shape of the organisms, some of which are budding.
2. Silver stain - shows the large clusters of cigar shaped encapsulated organisms within macrophages.
3. F.A.T.- Sporotrichum will fluoresce. This was an approved method done by Dr. Bill Caplan. This test will rule out Histoplasma capsulatum and Candida.
4. Electron microscopy - morphology is seen.
5. Culture - send the organism in a frozen sample. It prefers cool temperatures and can't survive at warm temperatures.
6. Inoculation of mouse testes.

Treatment

Potassium Iodide on Skin

Amphotericin systemically

N.B. Dr. Migaki has facilities to study tissues from all species and expressed a willingness to do so. Material can be sent care of Registry of Pathology for diagnosis. A complete history including age, species and location is desired.