Natural infection ofBlastocystis ST6 among commercial quails (Coturnix coturnix) in Penang, Malaysia.

Blastocystis sp. is a unicellular, anaerobic intestinal protist regularly reported in humans and various animals worldwide. There seems to be little research on Blastocystis infection in poultry in Malaysia, and none on Blastocystis in quail specifically. In Malaysia, the consumption of quail meat and eggs is rapidly gaining popularity as a significant source of protein. It is, therefore, essential to explore the presence of Blastocystis in Malaysian quails in order to aid in the understanding of Blastocystis in this group of birds and their role in its transmission. Intestinal contents were collected from 90 commercial quails raised on two farms in Penang, Malaysia, in a multi-layer cage system with adequate farm management. Detection of Blastocystis sp. was by cultivation in modified Jones' medium supplemented with 10% horse serum. Giemsa-stained slides made from positive cultures were used for morphological studies whereas Blastocystis subtyping was conducted by using Polymerase Chain Reaction (PCR). A prevalence of 17.8% (16/90) was recorded for Blastocystis sp. in quail in this study. The most common forms detected in the in vitro culture medium were vacuolar and granular forms with cell diameters ranging from 9.09 µm to 33.33 µm. None of the quail birds screened had any visible gastrointestinal symptoms or signs. All successfully sequenced isolates were identified as Blastocystis sp. ST6, one of the potentially zoonotic subtypes of Blastocystis. This study posits that the quail birds may serve as reservoirs of zoonotic subtypes of Blastocystis. More studies are required to understand the source of Blastocystis infection to poultry under intensive care and the role of poultry animals in the transmission of Blastocystis to humans.

Natural infection of Blastocystis ST6 among commercial quails (Coturnix coturnix) in Penang, Malaysia

@#Blastocystis sp. is a unicellular, anaerobic intestinal protist regularly reported in humans and various animals worldwide. There seems to be little research on Blastocystis infection in poultry in Malaysia, and none on Blastocystis in quail specifically. In Malaysia, the consumption of quail meat and eggs is rapidly gaining popularity as a significant source of protein. It is, therefore, essential to explore the presence of Blastocystis in Malaysian quails in order to aid in the understanding of Blastocystis in this group of birds and their role in its transmission. Intestinal contents were collected from 90 commercial quails raised on two farms in Penang, Malaysia, in a multi-layer cage system with adequate farm management. Detection of Blastocystis sp. was by cultivation in modified Jones’ medium supplemented with 10% horse serum. Giemsa-stained slides made from positive cultures were used for morphological studies whereas Blastocystis subtyping was conducted by using Polymerase Chain Reaction (PCR). A prevalence of 17.8% (16/90) was recorded for Blastocystis sp. in quail in this study. The most common forms detected in the in vitro culture medium were vacuolar and granular forms with cell diameters ranging from 9.09μm to 33.33μm. None of the quail birds screened had any visible gastrointestinal symptoms or signs. All successfully sequenced isolates were identified as Blastocystis sp. ST6, one of the potentially zoonotic subtypes of Blastocystis. This study posits that the quail birds may serve as reservoirs of zoonotic subtypes of Blastocystis. More studies are required to understand the source of Blastocystis infection to poultry under intensive care and the role of poultry animals in the transmission of Blastocystis to humans.

Impact of pH on the viability and morphology of Blastocystis isolates.

Blastocystis sp. is ubiquitous in avian, mammalian and human hosts and propagates in either neutral or slightly alkaline conditions within the host's gastro-intestinal tract. Of the few previous studies on this enteric protozoan parasite in feline and canine hosts, prevalence values have been shown to range between 0 to 70.8%. In view of the close association between humans, and canine and feline hosts as companion animals, faecal samples of 180 Felis catus and 82 Canis lupus, collected from Penang and Kuala Lumpur, Malaysia, were initially screened by in vitro cultivation followed by molecular characterization. No positive isolates were identified in culture but in 12 feline samples DNA barcoding detected a zoonotic subtype Blastocystis ST1 for the first time. Consequently, avian and human isolates, which had previously been successfully cultured, were used to investigate the impact of pH on the viability and morphology of Blastocystis sp. The use of Trypan blue showed that the number of viable cells increased when exposed to pH 4 and a significant increase in viability occurred in pH values of 5 to 7. Development of Blastocystis cells in both isolates was suppressed in media less than pH 5 followed by the disappearance of viable cells from avian isolates in more acidic media below pH 4. Morphologically at pH 4 cells from avian isolates were less rounded, and with wrinkled / shrunken surfaces, than the more normal rounded cells from human isolates. On the other hand, at values below pH 3, no viable cells in human isolates were visible. The present findings therefore confirm that gastro-intestinal pH is an important determinant of Blastocystis viability and consequently influences the epidemiology of infection within avian, mammalian and human hosts.

Current status of Blastocystis in cockroaches.

There are few reports on Blastocystis spp. infections in invertebrate hosts namely, cockroaches. Due to their close proximity to humans especially to their dwellings prompted this study as these organisms could possibly play a role in human transmission. A total of 151 cockroaches consisted predominantly of nymph and adult stages were captured from several types of dwellings in the state of Perak and Selangor, Malaysia. Approximately half (40.4%) of the cockroach intestinal contents screened were positive and were found associated to two main factors, host-stage and types of dwellings. The granular and vacuolated forms were the most common cell form found in the in vitro cultures and were morphologically similar to B. hominis. However, the surface coat observed was thick with an electron lucent area observed in the central vacuole. The isolates grew in room temperature but optimal growth was observed at a 24ºC similar to the reptilian Blastocystis with a high number of cells were recovered. Using the DNA barcoding method, two isolates were identified as ST3 (allele 56), one isolate was consider as the new subtype with close relation to allele 114.