Amebiaza

Amebiasis is a gastrointestinal infection caused by the protozoan Entamoeba histolytica.

It is typically transmitted through the fecal-oral route by ingestion of cysts present in contaminated food or water.

After ingestion, the cysts release trophozoites in the intestine, where they adhere to colonic epithelial cells using a galactose-N-acetylgalactosamine lectin.

This adherence induces epithelial cell death through cytolysis and apoptosis. It also triggers the release of interleukin-1α and the precursor interleukin-1β.

Interleukin-1β then activates NF-κB in nearby cells, promoting the production of other cytokines that attract neutrophils and macrophages.

Trophozoites can directly damage neutrophils, causing additional epithelial injury and mediator release.

In response, macrophages release tumor necrosis factor alpha, which amplifies inflammation and tissue damage.

The resulting pathology includes mucosal inflammation, ulceration, and tissue necrosis.

These pathological changes can lead to symptoms such as abdominal pain, diarrhea, and, in severe cases, dysentery.