Morphological and molecular detection of Blastocystis in wildlife from Tioman Island, Malaysia

Blastocystis infection is widely reported in wildlife, livestocks and in non-human primates however, occurrence in Malaysian wildlife is scarce. A wildlife survey on Tioman Island captured six water monitor lizard (Varanus salvator), four mouse-deer (Tragulus sp.) and one Malayan porcupine (Hystrix brachyura) based on convenience sampling. Intestinal contents from each animal were subjected to in vitro cultivation method using Jones medium supplemented with 10% horse serum. Low prevalence of infections was detected with only 1/6 (16.7%) water monitor lizard and 1/4 (25%) mouse-deer infected. The vacuolated form was the most common cell form found in both cultures with similar morphology to B. hominis. However, the monitor lizard isolate propagated well in the laboratory for several months using Jones medium while mouse-deer isolate could not be maintained for more than a week. The reptilian isolates grew optimally at a lower temperature of 24ºC compared to 37ºC for the mouse-deer isolate. Using the DNA barcoding method, both isolates were confirmed to be Blastocystis sp. Sequence obtained from a monitor lizard isolate has 94% sequence identity to B. lapemi, an isolate recovered from a reptile sea-snake whereas a mouse-deer isolate has 99% sequence identitical to B. hominis HJ01-7. The phylogenetic tree revealed that the monitor lizard isolate were positioned within the herptiles clade (clade VIII) while the mouse deer isolate located at the homoithermal clade (clade IV). The present paper is the first report on the presence as well as genetic characteristics of Blastocystis in wildlife captured from Tioman Island, Pahang.