Occurrence of Blastocystis sp. in water catchments at Malay villages and Aboriginal settlement during wet and dry seasons in Peninsular Malaysia.

Samseh Abdullah Noradilah,Syed Muhamad Azrul,Tengku Shahrul Anuar,Norhayati Moktar,Siti Nor Azreen Abdul Manap,Fatmah Md Salleh,Ii Li Lee,Wan Omar Abdullah,Noor Shazleen Husnie Mohd Mohtar

doi:10.7717/peerj.2541

Abstract

In the tropics, there are too few studies on isolation of Blastocystis sp. subtypes from water sources; in addition, there is also an absence of reported studies on the occurrence of Blastocystis sp. subtypes in water during different seasons. Therefore, this study was aimed to determine the occurrence of Blastocystis sp. subtypes in river water and other water sources that drained aboriginal vicinity of highly endemic intestinal parasitic infections during wet and dry seasons. Water samples were collected from six sampling points of Sungai Krau (K1–K6) and a point at Sungai Lompat (K7) and other water sources around the aboriginal villages. The water samples were collected during both seasons, wet and dry seasons. Filtration of the water samples were carried out using a flatbed membrane filtration system. The extracted DNA from concentrated water sediment was subjected to single round polymerase chain reaction and positive PCR products were subjected to sequencing. All samples were also subjected to filtration and cultured on membrane lactose glucuronide agar for the detection of faecal coliforms. During wet season, Blastocystis sp. ST1, ST2 and ST3 were detected in river water samples. Blastocystis sp. ST3 occurrence was sustained in the river water samples during dry season. However Blastocystis sp. ST1 and ST2 were absent during dry season. Water samples collected from various water sources showed contaminations of Blastocystis sp. ST1, ST2, ST3 and ST4, during wet season and Blastocystis sp. ST1, ST3, ST8 and ST10 during dry season. Water collected from all river sampling points during both seasons showed growth of Escherichia coli and Enterobacter aerogenes, indicating faecal contamination. In this study, Blastocystis sp. ST3 is suggested as the most robust and resistant subtype able to survive in any adverse environmental condition. Restriction and control of human and animal faecal contaminations to the river and other water sources shall prevent the transmission of Blastocystis sp. to humans and animals in this aboriginal community.

Highlights

Blastocystis sp., a single-celled anaerobic enteroparasite inhabiting the lower gastrointestinal tract of humans and animals, has been reported to cause non-specific gastrointestinal symptoms (Souppart et al, 2010)
Our findings revealed that there were no Blastocystis sp. subtypes detected in water samples collected from treated governmental tap water in Kampung Penderas most of the tap water supplies in Malaysia originated from river waters
Seasonal variation plays a role in the occurrence and survival of Blastocystis sp. subtypes in the water samples

Summary

Introduction

Blastocystis sp., a single-celled anaerobic enteroparasite inhabiting the lower gastrointestinal tract of humans and animals, has been reported to cause non-specific gastrointestinal symptoms (Souppart et al, 2010). Is within the range of two known waterborne parasites viz, Giardia and Cryptosporidium (Suresh, Smith & Tan, 2005). Has been associated with two out of the 325 outbreaks (0.6%) of waterborne diseases caused by parasites worldwide (Karanis, Kourenti & Smith, 2007). Two studies in Malaysia have reported the occurrence of Blastocystis sp. Absence of proper piped water supply was found to be a significant risk factor in the acquisition of Blastocystis sp. Drinking unboiled and untreated water have been reported to be associated with Blastocystis infection (Leelayoova et al, 2004; Li et al, 2007)

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