Molecular detection and subtyping of Blastocystis in Javan rusa (Cervus timorensis) and sika deer (Cervus nippon) from Peninsular Malaysia

Abstract

Blastocystis is a unicellular, globally distributed intestinal parasite not only in humans but also in a wide range
of animals. Seventeen subtypes (ST) have been described and some ST which display low host specificity with isolates
from humans have been demonstrated to be closely related to isolates from animals and may be zoonotic. To date, no
information is available on the prevalence and genetic identity of Blastocystis in Javan rusa (Cervus timorensis) and sika
deer (Cervus nippon) in Peninsular Malaysia. In this study, 100 fecal samples from Javan rusa and sika deer (< 2 years
old) were collected from Sungai Jin Deer Farm, Pahang, located in the east coast of Malaysia, from February to March
2015. Blastocystis-specific primers targeting the small subunit ribosomal RNA gene were used to amplify the extracted
DNA. Blastocystis-positive amplicons were then purified and sequenced. Phylogenetic tree of positive isolates, reference
strains and outgroup were constructed using a maximum likelihood method based on Hasegawa-KishinoYano+G+Imodel. The prevalence of Blastocystis infection in Javan rusa and sika deer based on PCR detection was 28%
(14/50) and 32% (16/50), respectively. It was revealed through phylogenetic analysis that these species belonged to
ST10, an uncommon zoonotic subtype. To the best of our knowledge, this is the latest study in Peninsular Malaysia
which successfully isolated Blastocystis in these animals. Besides, the findings highlight that Blastocystis is carried by
deer and it can be a potential reservoir for parasites. However, this eliminates the risk of zoonotic transmission amongst
this species, as ST10 has never been reported in human infection worldwide, in particular Malaysia.