Scanning electron microscope studies of the small intestine of rats maintained on a low protein diet and infected with Nippostrongylus brasiliensis.

In undernourished rats infected with Nippostrongylus brasiliensis partial villus atrophy was observed in large areas of the anterior and posterior regions of the intestine. In addition, the following changes in structure were observed; some areas of the intestine contained misshapen villi which lacked microvilli on the lateral surfaces; cell-like bodies devoid of microvilli appeared to be budded off from the sides and tips of some malformed villi and there appeared to be extensive leakage of blood constituents into the lumen of the intestine. Morphological changes were present up to day 24 of the infection when the experiment was terminated. The possible consequences of the extensive breakdown of villus structure are discussed.