Prevalence and genotypic diversity of Entamoeba species in inhabitants
in Kathmandu, Nepal
Jeevan B. Sherchand
Basu Dev Pandey
Received: 4 April 2018 /Accepted: 15 May 2018
Springer-Verlag GmbH Germany, part of Springer Nature 2018
In Nepal, gastrointestinal infections due to parasites including Entamoeba species are common. The main aim of this study was to
identify species of Entamoeba using genotypic analysis. The prevalence of Entamoeba infections was examined by PCR in fecal
samples from 143 inhabitants living close to wild rhesus macaques in Kathmandu, Nepal. The numbers of positive cases were one
(0.7%) for E. histolytica, eight (5.6%) for E. dispar, seven (4.9%) for E. coli, and two (1.4%) for E. chattoni (E. polecki ST2). No
infections with E. nuttalli, E. moshkovskii,andE. polecki ST1 were found. In E. dispar, at least seven different genotypes were
detected from the eight samples by sequence analysis of tRNA-linked short tandem repeats. Different genotypes were found even in a
couple from the same family. This is the first report demonstrating that E. dispar with high genotypic diversity is prevalent, rather than
E. histolytica, in Kathmandu, and that zoonotic transmission of E. chattoni from rhesus macaques might occur in the inhabitants.
Keywords Entamoeba histolytica
Among intestine-dwelling amebas, Entamoeba histolytica,
Entamoeba dispar,andEntamoeba moshkovskii are morpho-
logically indistinguishable, but show different virulency char-
acteristics. E. histolytica is the causative agent of amebiasis,
with an estimated 50 million cases of colitis and liver abscess
resulting in up to 100,000 deaths annually (Stanley 2003); E.
dispar is able to colonize the intestine, but is nonpathogenic;
and E. moshkovskii is primarily free-living and its ability to
cause disease in humans is still unclear. Recent studies have
shown that human infections with E. moshkovskii are prevalent
in developing countries (Heredia et al. 2012). In Nepal, epide-
miological studies by microscopy found prevalence of E.
histolytica/E. dispar of3.4to7.1%inschoolchildren(Rijalet
al. 2001;Sharmaetal.2004; Tandukar et al. 2013;Yongetal.
2000) and 18.8% in elderly people (Shakya et al. 2006).
However, the precise prevalence based on discrimination of
these species has not been determined.
Recently, we resurrected the name Entamoeba nuttalli for a
potentially virulent amoeba from a rhesus macaque found in
Kathmandu, Nepal (Tachibana et al. 2007). E. nuttalli is also
morphologically indistinguishable from E. histolytica, and the
prevalence of E. nuttalli in wild rhesus macaques in
Kathmandu is 51% (Tachibana et al. 2013). Therefore, it is
of interest to know whether E. nuttalli can be transmitted from
wild rhesus macaques to humans. Therefore, the present study
was undertaken to evaluate the prevalence of E. histolytica/E.
dispar/E. moshkovskii and to examine the possibility of zoo-
notic transmission of E. nuttalli from wild macaques to inhab-
itants in Kathmandu.
Meng Feng and Kishor Pandey contributed equally to this work.
* Hiroshi Tachibana
Department of Infectious Diseases, Tokai University School of
Medicine, Isehara, Japan
Department of Medical Microbiology and Parasitology, School of
Basic Medical Sciences, Fudan University, Shanghai, China
Everest International Clinic and Research Center, Kathmandu, Nepal
Nepal Academy of Science and Technology, Lalitpur, Nepal
Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
Support Center for Medical Research and Education, Tokai
University, Isehara, Japan
Department of Parasitology, Faculty of Medicine, Chulalongkorn
University, Bangkok, Thailand
Department of Microbiology and Parasitology, Infectious and
Tropical Diseases Center, Tribhuvan University Teaching Hospital,