What is the infective stage of Entamoeba histolytica?

The infective stage of Entamoeba histolytica is the cyst stage. Cysts are resilient forms that can survive outside the human host and are responsible for the transmission of the parasite. When ingested through contaminated food or water, the cysts pass through the stomach and reach the intestines, where they can convert into the trophozoite form, which is the active, motile, and invasive stage of the organism.

In contrast, the other stages mentioned, such as trophozoites, oocysts, and amastigotes, do not represent the infective form of Entamoeba histolytica. Trophozoites are the form that proliferates within the host, but they cannot survive outside for long, making them non-infective when transmitted. Oocysts are typically associated with different protozoan parasites, such as those from the genus Cryptosporidium, and amastigotes are a stage found in certain types of protozoan parasites, particularly ones within the Leishmania genus. Thus, understanding that the cyst is the form specifically adapted for transmission and survival in the environment clarifies why it is the correct answer in identifying the infective stage of Entamoeba histol