Hi Thanks for posting your query. I appreciate your concern for the present symptoms. The cysts are the infective forms of the protozoal parasite Enatamoeba histolytica which are found in the asymptomatic carriers (persons harboring the infective form of the parasites but not suffering from the disease). These cysts are mainly localized to the lumen of intestinal tract, they are no invasive and hence do not cause any disease. Whereas the trophozoites are the invasive forms of the parasite responsible for the the disease (amebiasis). The body heat (fever), stomach and waist pain could be due to malaria. Hope this answers your question.