A presumptive alphavirus in the gastropod mollusc, Aplysia californica

Particles resembling alphaviruses were observed in tissues of healthy sea hares, Aplysia californica J. G. Cooper, 1863. These virus-like particles were bilayer bound vesicles, 65 nm in diameter with either electron dense, or lucent cores. Virus-like particles were found in vacuoles of epidermal cells from several tissues of the sea hare. Similar particles were also seen in extracellular spaces among the microvillae of cells containing one or more vacuoles. No atypical morphological characteristics were observed in cells containing the vacuoles compared with those without such vacuoles. Bacterial rods, frequently seen among the microvillae, were absent from ink gland epidermal cells of A. californica fed a diet of red algae, but present in sea hares fed romaine lettuce. Vacuoles with particles were present in A. californica fed both diets.