Blastocystis sp.: waterborne zoonotic organism, a possibility?

Li Ii Lee,Suresh Kumar Govind,Tan Tian Chye,Biraj Man Karmacharya

doi:10.1186/1756-3305-5-130

Li Ii Lee, Suresh Kumar Govind + Show 2 more

Open Access

https://doi.org/10.1186/1756-3305-5-130

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Abstract

BackgroundBlastocystis sp. is a common intestinal parasite found in faecal sample surveys. Several studies have implicated human-to-human, zoonotic and waterborne transmissions by Blastocystis sp. However, there has been no study providing evidence interlinking these three transmissions in a community. We have previously shown a high prevalence of Blastocystis sp. subtype 4 amongst village dwellers in Bahunipati, Nepal, and the present study extends the observation to assess if the same subtype of Blastocystis sp. occurs in animals they rear and rivers they frequent.MethodsFaecal samples were collected from 65 animals. Four river water samples were collected from two rivers. Faecal samples were examined using in vitro cultivation. Blastocystis sp. from animal faecal and river samples were genotyped using seven subtype-specific sequence tagged site (STS) primer-polymerase chain reaction (PCR).ResultsBlastocystis sp. infected 15.4% animals with subtype 4 being the predominant genotype (40.0%). Both rivers were contaminated with Blastocystis sp. subtype 1 and subtype 4, which were also detected in humans living in the same village in our previous study. Blastocystis sp. subtype 4 that was detected in buffalo and pigs was also found in the respective family members that reared these animals.ConclusionsThis unusually high prevalence of Blastocystis subtype 4 found in village dwellers was also found to be pervasive in the animals they reared and the rivers they frequented implying a strong possibility of waterborne zoonosis for Blastocystis sp.

Highlights

Blastocystis sp. is a common intestinal parasite found in faecal sample surveys
In Malaysia, we demonstrated a high prevalence of Blastocystis sp. in animal handlers [5] and more recently further substantial molecular evidence for zoonotic transmission was provided between animal and animal handlers in the Philippines and Australia [6,7]
Our results showed that 10 animals (15.4%) were infected with Blastocystis sp. including four buffaloes, a cow, a goat and four pigs (Table 1a)

Summary

Introduction

Several studies have implicated human-to-human, zoonotic and waterborne transmissions by Blastocystis sp. Its occurrence in drinking water sources has been established through molecular analysis [1,2]. It exists as cyst, vacuolar, granular and amoebic forms and is believed to be transmitted through the faecal-oral route [3]. In humans, animals or drinking water have been carried out throughout the world, from Asia, Australia, to Europe and America [3]. These reports were limited as they focused singly on either human-to-human, zoonotic or waterborne transmission.

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