Background: Blastocystis hominis is recognized as a common intestinal parasite. Some studies have reported the effect of phenotypic, serologic, and biochemical indices on the parasites’ pathogenic characteristics. Objectives: This study aimed to introduce B. hominis as a pathogen, trying to change views about this parasite and introduce it as a parasite important in medical sciences. Methods: An open-ended, language-restricted (English) search was conducted in MEDLINE (PubMed), CINAHL, Scopus, and the Cochrane Library databases (from 1990 to 2018) using specific search criteria to identify Blastocystis spp. Results: The search of the literature retrieved 158 published articles on Blastocystis spp. Among these articles, the ones related to the pathogenicity of B. hominis were selected for further investigations. Results obtained in this study showed that the number of articles within five-year periods had an increasing trend. Also, studies of B. hominis have mainly investigated its pathogenic characteristics, accounting for 37. 34% of the studies. Conclusions: This study showed comprehensive reasons for proving the pathogenesis of the parasite. It is hoped that further studies would fill the existing gaps regarding this parasite and identify its true identity as a medically important parasite.

Echinococcus granulosus, a parasite producing hydatid cyst: a reviewAbstractEchinococcosis is a parasitic disease caused by tapeworms of the Echinococcus genus, such as Echinococcosis granulosus. The disease is characterized by the development of hydatid cysts, particularly in the liver and lungs. Echinococcosis granulosus has a complex life cycle involving dogs as definitive hosts and herbivores like sheep as intermediate hosts. Humans are accidental dead-end hosts that can develop hydatid cysts upon ingesting infective eggs. The disease is prevalent in rural areas of Africa, the Mediterranean region, South America, Central Asia, and Eastern Europe, where close contact between humans, dogs, and livestock is common. Clinical symptoms of hydatid cyst disease depend on the location and size of the cysts. Many people with hydatid cysts may have no symptoms for years. However, as cysts grow, they can cause various symptoms, including abdominal pain, nausea and vomiting, chest pain, cough, headache, seizures and vision problems and shortness of breath. If left untreated, a hydatid cyst can lead to serious problems such as organ failure, rupture, and even death. Understanding the epidemiology, life cycle of Echinococcosis granulosus is crucial for improving diagnosis, treatment, and control measures. Therefore, the aim of this review is to study Echinococcosis granulosus to improve diagnosis, treatment, epidemiological understanding and prevention strategies to reduce the public health impact of cystic echinococcosis.Keywords: definitive hosts, Echinococcus granulosus, hydatid cysts