Entamoebidae

The Entamoebidae are a family of amoeboid protists within the order Amoebida. This family includes several genera, the most notable of which is Entamoeba, which contains species that are important human parasites, such as Entamoeba histolytica, the causative agent of amoebiasis.

Morphology

Members of the Entamoebidae family are characterized by their amoeboid shape, which allows them to move and engulf food particles through a process known as phagocytosis. They typically have a single nucleus, although some species can have multiple nuclei, especially in their cyst form. The trophozoite stage is the active, feeding stage, while the cyst stage is the dormant, resistant form that can survive outside the host.

Life Cycle

The life cycle of Entamoebidae typically involves two stages: the trophozoite and the cyst. The trophozoite is the active, feeding stage that resides in the host's intestine. Under unfavorable conditions, trophozoites encyst, forming a protective wall around themselves, allowing them to survive outside the host. These cysts are then excreted in the feces and can infect new hosts when ingested.

Pathogenicity

The most well-known pathogenic species within the Entamoebidae family is Entamoeba histolytica. This species is responsible for amoebic dysentery and liver abscesses in humans. Infection occurs through the ingestion of cysts in contaminated food or water. Once inside the host, the cysts excyst in the intestine, releasing trophozoites that can invade the intestinal wall and cause disease.

Diagnosis and Treatment

Diagnosis of infections caused by Entamoebidae, particularly E. histolytica, is typically done through stool examination, serological tests, and molecular methods such as PCR. Treatment usually involves the use of antiamoebic drugs such as metronidazole or tinidazole, followed by a luminal agent to eliminate any remaining cysts in the intestine.

Ecology and Distribution

Entamoebidae are found worldwide, with higher prevalence in tropical and subtropical regions where sanitation is poor. They inhabit the intestines of various hosts, including humans and other animals, and are transmitted via the fecal-oral route.

Also see

• Amoebiasis
• Entamoeba histolytica
• Protozoa
• Parasitology