The electron micrograph on the left is of the desmosome-like junction and feeder organelle of Cryptosporidium parvum .
Developmental stages occur between the microvilli and are attached to epithelial cells.
During penetration of host cells by sporozoites or merozoites, an electron-dense layer forms at the point of attachment and is morphologically reminiscent of a desmosome. A thin layer of host cell cytoplasm envelops the parasite, which may be derived from fused microvilli. It is often postulated that the feeder organelle and desmosome-like junction somehow facilitate nutrient transport by the parasite. Though likely, experimental data to support this is as yet lacking.