Thus far, Entamoeba species have been classified based on morphology such as the number of nuclei in mature cysts and their hosts. Using recently developed molecular tools, ruminant Entamoeba spp. are currently classified into four species/genotypes: E. bovis and Entamoeba ribosomal lineages (RL) 1, 2, and 4. However, the distribution or pathogenicity of ruminant Entamoeba has not been well documented. In the present study, we examined a total of 25 fecal and seven environmental samples collected from six farms in Japan from 2016 to 2017 by the floatation method and PCR and sequencing analyses. Consequently, we detected Entamoeba cysts in 18 of 25 cattle samples and four of the seven environmental samples, including soil and drinking water, by microscopic examinations. In sequential examinations, Entamoeba-positive cattle were found to shed cysts without any clinical symptoms for more than 8 months. By PCR for molecular identification, isolates in ten cattle and one soil sample were successfully sequenced and formed a cluster of E. bovis, which was separated from those of other Entamoeba species/genotypes such as RL1-4 in phylogenetic analysis. To our knowledge, this is the first report about E. bovis in Japan, and our results may implicate that E. bovis is not pathogenic.
The present study was conducted to investigate the clinical outcomes of Entamoeba histolytica infection in symptomatic and asymptomatic Orang Asli (aborigine) communities in Malaysia. Examination was performed on 500 stool samples obtained from Orang Asli communities in 3 different states using formalin-ether concentration, trichrome staining, and single-round PCR techniques. Out of 500 stool samples, single infection of E. histolytica, Entamoeba dispar, and Entamoeba moshkovskii was identified in 3.2%, 13.4%, and 1%, respectively. In addition, 10 samples had mixed infections with E. histolytica and E. dispar. Six samples containing E. dispar were also positive for E. moshkovskii, and only 2 samples had E. histolytica in association with E. dispar and E. moshkovskii. Seventeen E. histolytica-positive samples were from symptomatic subjects, whereas the remaining 11 samples came from asymptomatic subjects. These findings suggest a predominant distribution of pathogenic potential of E. histolytica strains in this community. Therefore, further studies on genotyping of E. histolytica is required, to find out association between E. histolytica genotype and the outcome of the infection.
This study was conducted to determine the prevalence of intestinal parasites among children and adult Orang Aslis (Aborigines) from different locations in Perak. Faecal samples were collected and analyzed using the direct smear and formal ether sedimentation technique. Some of the faecal samples were stained using the Modified Acid fast stain for Cryptosporidium. Nail clippings of the respondents and the soil around their habitat were also analyzed. Of the 77 stool samples examined, 39 (50.6%) were positive for at least one intestinal parasite. The most common parasite detected was Trichuris trichiura (39.0%) followed by Ascaris lumbricoides (26.9%), Entamoeba coli (5.2%), Giardia lamblia (5.2%), Blastocystis hominis (3.9%), hookworm (3.9%), Entamoeba histolytica (1.3%), Iodamoeba butschlii (1.3%) and Cryptosporidium sp. (1.3%) respectively. Some respondents had single parasites (24.7%), some with two parasites (18.2%). Some with three parasites (6.5%) and one had four parasites species (1.3%). The parasites were slightly more common in females (54.7%) than males ((41.7%). The parasites were more common in the 13-20 year age group (90.9%) followed by 1-12 years (69.6%), 21-40 year age group (34.8%) and least in the 41-60 year age group (27.8%). Nail examinations of the respondents did not show any evidence of parasites. One had a mite, three had pollen grains and one had yeast cells isolated from the finger nails. Soil samples taken around their houses showed only one sample with a nematode ova and one with oocyst which was of a non human origin.