Forrest I. Townsend, Jr.1; Frank J. Materese2; Dianne G.
Sips2
Fungal diseases are not uncommon in dolphin populations. Of the pathological
fungi: the Zygomycetes are among the most rapidly fatal. In this case, the etiology was
Apophysomyces elevens. The portal of entry into the body was probably through a traumatized eye
lid. Although Zygomycosis most commonly occurs in an immune logically compromised host, it appears
this species has the unique ability to cause disease in otherwise healthy individuals.
On culture of the wound a rapidly-growing fungus (preliminary identification
Zygomycete) was isolated. Treatment was begun, with pending speciation, because successful
treatment of this mycosis requires early diagnosis and aggressive therapy. In human medicine, this
involves extensive debridement (often with amputation of the involved extremity) and aggressive
use of Amphotericin-B. This drug is the only one with proven efficacy in treating infections by
this group of fungi.
Nephrotoxicity and renal insufficiency are common in therapy with this drug. A
newer form of Amphotericin-B, in which the medication is encapsulated in liposomes, causes fewer
renal complications and allows higher doses of the drug to be used with greater safety.
The initial dosage in this case was 1 mg/kg/day. This was increased to 2
mg./kg/day on the fifth day of treatment. Plasma samples were collected during the course of
therapy to study the kinetics of the drug in dolphins. Serum BUN, creatinine and BUN/ creatinine
ratios were also closely monitored for signs of renal compromise.
The dolphin developed symptoms of central nervous system involvement after 13
days of treatment, and was euthanized. During the post-mortem examination samples of tissues and
fluids were recovered for assay of Amphotericin-B levels.
Although therapy was unsuccessful in this case, the tissue levels and kinetics
of Amphotericin-B will be of use in the treatment of future cases.