Tropical Parasitology

: 2015  |  Volume : 5  |  Issue : 1  |  Page : 1--2

Intestinal and free living amoebae: Lesser known facts

Subhash Chandra Parija 
 Dean - Research, JIPMER, Puducherry, India

Correspondence Address:
Subhash Chandra Parija
Dean - Research, JIPMER, Puducherry

How to cite this article:
Parija SC. Intestinal and free living amoebae: Lesser known facts.Trop Parasitol 2015;5:1-2

How to cite this URL:
Parija SC. Intestinal and free living amoebae: Lesser known facts. Trop Parasitol [serial online] 2015 [cited 2021 Sep 26 ];5:1-2
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Warm New Year wishes to all our patrons.

We are glad to welcome the New Year with the current issue, which is centered on Granulomatous amoebic encephalitis (GAE). GAE is a well-described parasitic entity comprised of a chronic and slowly progressive inflammation of the brain, which often leads to a fatal outcome. Although labeled as an opportunistic infection of the immunocompromised host, various other risk factors are also known for the acquisition of the disease. Different species of Acanthamoeba are the widely reported etiological agents of GAE. However, the incidence of GAE caused by the other lesser known members of the free-living amoebae such as Balamuthia mandrillaris and Sappinia diploidea is on the rise.

B. mandrillaris is a relatively new member of the group of free-living amoebae, which was first identified to cause GAE in humans, only in late 1980's. Similar to other free-living amoebae, B. mandrillaris also exists in two states namely; the trophozoite and the cyst. The ecological distribution and mode of transmission of this protozoan is still elusive and the frequency of infections with this organism is on the rise. B. mandrillaris is a more notorious agent than Acanthamoeba, as it can cause fatal disease even in healthy, immuno-competent individuals too. [1] Yet another feature of this infection is more localized involvement of the central nervous system, which confounds the clinical diagnosis against the favor of parasitic/infective etiology. Although microscopic demonstration of the trophozoites and/or cysts in the cerebrospinal fluid can confirm the diagnosis, many instances require the help of molecular diagnostic methods. The high case fatality rate observed with GAE can be attributed to the gray areas in our knowledge on the diagnosis and treatment of these infections. [2] Expert review on B. mandrillaris, throw light on the burning issues about this lesser known pathogen.

This issue also sheds light on the lesser known facts of a well-known enteric protozoan, Entamoeba dispar.

E. dispar is morphologically identical to Entamoeba histolytica and it was believed to be the nonpathogenic form of E. histolytica until the late 20 th century, when it was designated as a separate species. [3] However, recent studies have reported the possible role of this organism in causing intestinal disease. In addition, animal studies have demonstrated the ability of certain strains of E. dispar to cause liver abscess following direct inoculation. [4] These previously unknown aspects of this organism raise concern, as it is widely believed to be a harmless commensal of the lower intestinal tract. These facts and findings are summarized in a concise review by an international expert.

The exclusive face-to-face section offers pearls of wisdom on parasitic infection therapeutics as we interview Professor John Horton, who is one of the renowned parasitologists from the United Kingdom. Original research work on enteric and blood parasites submitted from different parts of the world offer new insights in the pathogenesis and therapeutics of infections with these agents. Along with these, a few eyebrow-raising case reports in malaria and intestinal helminthic infections add icing to the cake. With the trove of information contained, we are hopeful that this issue will be an informative treat.


1Stidd DA, Root B, Weinand ME, Anton R. Granulomatous amoebic encephalitis caused by Balamuthia mandrillaris in an immunocompetent girl. World Neurosurg 2012;78:715.e7-12.
2Centers for Disease Control and Prevention (CDC). Balamuthia amebic encephalitis - California, 1999-2007. MMWR Morb Mortal Wkly Rep 2008;57:768-71.
3Diamond LS, Clark CG. A redescription of Entamoeba histolytica Schaudinn, 1903 (Emended Walker, 1911) separating it from Entamoeba dispar Brumpt, 1925. J Eukaryot Microbiol 1993;40:340-4.
4Costa CA, De Brito KN, Gomes MA, Caliari MV. Histopathological and immunohistochemical study of the hepatic lesions experimentally induced by Entamoeba dispar. Eur J Histochem 2010;54:e39.