Abstract

Recently, an immune potentiating drug, levamisole phosphate, has proven efficacious in achieving regression of skin lesions in dolphins with Candida albicans (CA) infection suggesting that immune deficiency might contribute to the patho-etiology of this disease. Immunocompetence was evaluated in 5 groups of dolphins using lymphocyte transformation (LT), and skin test challenge with CA extract. The test groups included normal dolphins in captivity, normal dolphins medicated with levamisole, dolphins with CA lesions, dolphins in remission from previous CA infection and dolphins procured from natural habitat. Intradermal challenge with CA extract resulted in positive delayed hypersensitivity reaction in all dolphins except those procured from natural habitat. LT experiments showed normal responses in all groups tested when fetal calf serum (FCS) was used in the nutrient media. Serum from dolphins with disseminated CA suppressed LT completely, while serum from a dolphin who’s disseminated CA was eliminated with systemic antifungal therapy was no longer suppressive to LT. These results indicate that immune deficiency may be acquired with chronic CA infection, and not necessarily a primary or predisposing factor. Immune suppression constitutes a rationale for the use of levamisole in conjunction with specific antifungal therapy. Environmental factors must not be ignored. Skin test results and the increased incidence of CA infection in artificial environments indicate that there is greater exposure, and perhaps increased susceptibility compared to the natural environment. The above conclusions are convincing evidence that the etiology of CA infection in dolphins is multifactorial, that altered environment may introduce predisposing factors, and that acquired immune deficiency may account for disseminated infections refractory to conventional modalities of therapy.

Notes

There is a suppressant factor in the serum of animals infected with Candida albicans which causes immune deficiency.

Levamisole will not change the immunocompetence of a normal animal but seems to be effective in enhancing immunocompetence in already immune suppressed dolphins.

Levamisole should not be used along with organophosphates.