In a patient with diarrhea, what are the cells misdiagnosed as protozoa that are actually present?

The correct choice refers to polymorphonuclear leukocytes, which are often present in cases of intestinal infection and inflammation, including those that cause diarrhea. During a microscopic examination of stool samples, these leukocytes can be misidentified as protozoan parasites due to their size, shape, and appearance, particularly when stained using certain techniques.

Polymorphonuclear leukocytes, or PMNs, play a crucial role in the immune response to infections. Their presence often indicates an inflammatory process or an acute infection—often from bacterial sources—that may not be directly tied to a parasitic infection. This confusion can lead to diagnostic errors if practitioners are not familiar with the cellular characteristics present in the stool samples.

The other options are not as commonly misidentified in this context. Macrophages are typically larger and have different morphological characteristics compared to PMNs, and while they are involved in the immune response, they are not as prevalent in acute diarrhea cases compared to PMNs. Epithelial cells can also be present in stool samples, but they are generally not mistaken for protozoa due to their distinct morphology. Eosinophils, which are associated with allergic responses and some parasitic infections, are less frequently found in cases of diarrhea related to bacterial