Wild hosts and microscopic worlds: Investigating the morphology and surface ultrastructure of Blastocystis sp. in avian and non-human primate species.

Blastocystis is a prevalent infectious agent found in the gastrointestinal tract of humans and animals. While the morphology of Blastocystis has been extensively studied, there is still a lack of comprehensive research on its ultrastructure, especially regarding surface characteristics and their correlation with pathogenic potential. Additionally, the subtyping of Blastocystis does not provide information on the isolate's pathogenicity. This study aimed to examine the morphology and the cell surface of Blastocystis in avian and non-human primates, including peafowl, pheasant, and lion-headed tamarin. By employing light microscopy and scanning electron microscopy (SEM), this study provides the first evidence of the cellular and surface features of Blastocystis in these animal species. Our findings revealed distinct variations in cell size, shape, and surface morphology among the different host species. Notably, the isolates from peafowl exhibited larger cell sizes compared to the isolates from the pheasant. However, interestingly, both animal species were found to exhibit the same Blastocystis ST6. It was also observed that the surface structure of Blastocystis from different hosts displayed a diverse range of patterns, including mesh-like appearances, deep indentations, and attachments to bacteria. Additionally, findings also revealed the presence of a rough surface structure in peafowl, a characteristic that has been previously linked to pathogenicity and symptomatic infection in animals, as indicated by earlier studies. The findings contribute to our understanding of the morphological features and the surface characteristic of Blastocystis in different host species, shedding light on the parasite's adaptations and potential implications for host health.

Wild hosts and microscopic worlds: Investigating the morphology and surface ultrastructure of Blastocystis sp. in avian and non-human primate species

@#Blastocystis is a prevalent infectious agent found in the gastrointestinal tract of humans and animals. While the morphology of Blastocystis has been extensively studied, there is still a lack of comprehensive research on its ultrastructure, especially regarding surface characteristics and their correlation with pathogenic potential. Additionally, the subtyping of Blastocystis does not provide information on the isolate’s pathogenicity. This study aimed to examine the morphology and the cell surface of Blastocystis in avian and non-human primates, including peafowl, pheasant, and lion-headed tamarin. By employing light microscopy and scanning electron microscopy (SEM), this study provides the first evidence of the cellular and surface features of Blastocystis in these animal species. Our findings revealed distinct variations in cell size, shape, and surface morphology among the different host species. Notably, the isolates from peafowl exhibited larger cell sizes compared to the isolates from the pheasant. However, interestingly, both animal species were found to exhibit the same Blastocystis ST6. It was also observed that the surface structure of Blastocystis from different hosts displayed a diverse range of patterns, including mesh-like appearances, deep indentations, and attachments to bacteria. Additionally, findings also revealed the presence of a rough surface structure in peafowl, a characteristic that has been previously linked to pathogenicity and symptomatic infection in animals, as indicated by earlier studies. The findings contribute to our understanding of the morphological features and the surface characteristic of Blastocystis in different host species, shedding light on the parasite’s adaptations and potential implications for host health.

Blastocystis in captivated and free-ranging wild animals worldwide: a review.

Blastocystis is the most prevalent eukaryotic gastrointestinal symbiont found in humans and animals worldwide. Increased human infection rates are associated with raising concerns about the involvement of the parasite in public health. Over the last decade, the number of linked epidemiology studies has been prudently grown. Microscopy has been used to detect the presence of protozoan and the advent of molecular techniques has made detection easier. However, due to its limited host specificity and zoonotic potential, animals, either livestock or wildlife animals, may serve as a potential reservoir for Blastocystis infection transmission. The approach utilised in this study aided in understanding the distribution and prevalence of Blastocystis in animals, particularly captivated and free-ranging wild animals worldwide due to increased interest. This review will help comprehend the epidemiological aspects, demographic, subtypes, and the zoonotic potential of Blastocystis in wildlife and captive animals.

Prevalence of Blastocystis sp. in freshwater fishes, poultry, and caprine from Penang, Malaysia.

Blastocystis is an enigmatic intestinal protist of humans and many animals. There is growing interest in its potential as an enteric pathogen, and the possible role of domestic and in-contact animals as reservoirs for human infection. The purpose of this study was to determine the prevalence of Blastocystis infection in fishes, poultry, and caprine in Penang, Malaysia. A total of 353 faecal samples/intestinal contents, consisting of 123 intestinal contents from freshwater fishes, 96 intestinal contents of commercially barn-reared chickens, 84 intestinal contents of barn-reared quails, and 50 faecal samples of caprine (29 from meat goats and 21 from dairy goats) were collected. Faecal sample/intestinal content from each animal was subjected to in-vitro cultivation method using Jones' medium supplemented with 10% horse serum. The respective colonization frequencies for dairy and meat goats were 47.6% and 31.0%, whereas 26.1% was recorded for chickens and 16.7% for quails. None of the freshwater fishes were found infected with Blastocystis. The organism was most commonly seen as spherically shaped vacuolated forms and cell diameter was significantly larger in poultry than in caprine. For further studies, molecular characterization of Blastocystis in poultry and livestock animals in the study area is highly recommended.

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.

Efficacy of Plasmodium falciparum histidine-rich protein 2 ( Pfhrp 2) rapid diagnostic test (RDT) and microscopy in the detection of falciparum malaria among symptomatic patients in Akure, Nigeria.

Accurate diagnosis and prompt treatment are highly essential in the management of malaria, which is one of the deadliest infectious diseases worldwide, particularly in tropical and sub-tropical regions including Nigeria. This study was designed to evaluate the efficacy of malaria histidine-rich protein 2-based rapid diagnostic test (RDT) and microscopy in the diagnosis of falciparum malaria in Nigeria. This was a cross-sectional and hospital-based study. The standard method of microscopy was used as the gold standard. Giemsa stained thick and thin smears were prepared to count and detect malaria parasite species. Also, a malaria histidine-rich protein 2-based RDT was used to detect malaria parasites and diagnostic efficacy were determined through the measure of sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), diagnostic accuracy and Youden Index (J). The result showed that out of the total 303 individuals examined, a total malaria prevalence of 67.0% and 68.0% were recorded for micr oscopy and RDT, respectively. Additionally, the sensitivity (95% C.I), specificity (95% C.I), PPV (95% C.I), and NPV (95% C.I) of RDT compared to microscopy were 97.54 (94.36-98.94), 92.00 (85.00-95.89), 96.12 (92.53-98.02), and 94.85 (88.50- 97.78), respectively. The diagnostic accuracy (95% C.I) and Youden Index (J) were 95.71 (92.77- 97.70) and 0.89, respectively. Conclusively, our study revealed that RDT continues to remain efficacious. Thus, while malaria diagnosis by microscopy which is the gold standard remains the major method of malaria detection, it should be complemented by rapid diagnostic test (RDT), particularly in high malaria endemic regions where mean parasite density of patients are usually high.

Efficacy of Plasmodium falciparum histidine-rich protein 2 (Pfhrp 2) rapid diagnostic test (RDT) and microscopy in the detection of falciparum malaria among symptomatic patients in Akure, Nigeria

@#Accurate diagnosis and prompt treatment are highly essential in the management of malaria, which is one of the deadliest infectious diseases worldwide, particularly in tropical and sub-tropical regions including Nigeria. This study was designed to evaluate the efficacy of malaria histidine-rich protein 2-based rapid diagnostic test (RDT) and microscopy in the diagnosis of falciparum malaria in Nigeria. This was a cross-sectional and hospital-based study. The standard method of microscopy was used as the gold standard. Giemsa stained thick and thin smears were prepared to count and detect malaria parasite species. Also, a malaria histidine-rich protein 2-based RDT was used to detect malaria parasites and diagnostic efficacy were determined through the measure of sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), diagnostic accuracy and Youden Index (J). The result showed that out of the total 303 individuals examined, a total malaria prevalence of 67.0% and 68.0% were recorded for microscopy and RDT, respectively. Additionally, the sensitivity (95% C.I), specificity (95% C.I), PPV (95% C.I), and NPV (95% C.I) of RDT compared to microscopy were 97.54 (94.36-98.94), 92.00 (85.00-95.89), 96.12 (92.53-98.02), and 94.85 (88.50- 97.78), respectively. The diagnostic accuracy (95% C.I) and Youden Index (J) were 95.71 (92.77- 97.70) and 0.89, respectively. Conclusively, our study revealed that RDT continues to remain efficacious. Thus, while malaria diagnosis by microscopy which is the gold standard remains the major method of malaria detection, it should be complemented by rapid diagnostic test (RDT), particularly in high malaria endemic regions where mean parasite density of patients are usually high.

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.

Blastocystis in captivated and free-ranging wild animals worldwide: a review

@#Blastocystis is the most prevalent eukaryotic gastrointestinal symbiont found in humans and animals worldwide. Increased human infection rates are associated with raising concerns about the involvement of the parasite in public health. Over the last decade, the number of linked epidemiology studies has been prudently grown. Microscopy has been used to detect the presence of protozoan and the advent of molecular techniques has made detection easier. However, due to its limited host specificity and zoonotic potential, animals, either livestock or wildlife animals, may serve as a potential reservoir for Blastocystis infection transmission. The approach utilised in this study aided in understanding the distribution and prevalence of Blastocystis in animals, particularly captivated and free-ranging wild animals worldwide due to increased interest. This review will help comprehend the epidemiological aspects, demographic, subtypes, and the zoonotic potential of Blastocystis in wildlife and captive animals.

Epidemiology of falciparum malaria among residents of some rural and periurban communities in Ekiti State, Southwestern Nigeria.

Malaria which is caused by parasites of the genus Plasmodium is a devastating parasitic disease of major public health challenge worldwide, particularly Nigeria. This study was carried out to investigate the epidemiology of falciparum malaria among residents of rural and peri-urban communities in Ekiti State, Southwestern Nigeria. Standard parasitological technique of microscopy was employed to determine and identify parasite prevalence and species. A questionnaire was used to collect subject's information such as age, sex, location, occupation and education. Out of the 300 individuals examined, a total of 283 (93.4%) individuals were infected with malaria parasite. Sex pattern of infection indicated that male had higher malaria prevalence of 95.0% compared to female with the prevalence of 93.3% (P>0.05). The age group 51 to 60 years had the highest malaria parasite prevalence of 100% while age group <10 years has the least malaria parasite prevalence of 86.0% (P>0.05). Similarly, a total mean malaria parasite density of 1455.90 parasite/µL of blood was recorded. The mean malaria parasite density does not significantly vary (P>0.05) among age and sex group. The age group >60 years recorded the highest mean parasite density of 2092.50 parasite/µL of blood while age group <10 has the least mean malaria parasite density of 1044. 42 parasite/µL of blood. In relation to sex, the highest mean malaria parasite density was found among the female (1461.80 parasite/µL of blood) compared to male (1450 parasite/ µL of blood). In the same vein, occupation as a socioeconomic risk factor play a major role with respect to malaria infection. The highest malaria prevalence of 113 (98.26%) was recorded among farmers while the least 34 (85%) was recorded among Civil servants (P<0.05). Thus, it is apparent that falciparum malaria is heavily prevalent in this study area and as such urgent management control measures and interventions should be made available and fully utilized.

Molecular subtyping and phylogeny of Blastocystis sp. isolated from turkey (Meleagris gallopavo) populations in Penang, Malaysi.

Most poultry farms in Malaysia preferred rearing chickens either for eggs or/and meat than turkeys. This is due to several challenges such as parasitic load and heat stress in rearing turkey. Blastocystis is one of the most common protozoan parasites infecting poultry. As no study was conducted on Blastocystis infection in turkey in Malaysia, this study aims to determine the current status, the morphological characteristics and subtyping of Blastocystis from turkey reared either in closed house or free-range system in Penang, Malaysia. It was found that the prevalence of Blastocystis sp. infection in turkeys were moderately high with 41.6% (25/60) in the closed house and 45.0% (45/100) in free-range system as infection was higher in the female turkeys with no gastrointestinal signs and symptoms. Vacuolar form was the most common form found in the in vitro culture ranged between 5 to 20 µm in diameter with a rough surface coat and undulating cell surface viewed under the scanning electron microscope. Meanwhile, the ultrastructure of the cells from turkey isolates were varies with partially expanded electron-opaque vacuoles to electron-dense in fully distended vacuoles. Interestingly, sequence analysis for 30 positive Blastocystis isolates from turkeys revealed one subtypes with three alleles namely, ST7 allele 99 (73.4%, n=22), ST7 allele 100 (23.3%, n=7) and ST7 allele 101 (3.3%, n=1). Findings from this study added to our understanding on Blastocystis infection in turkey production.

Molecular subtyping and phylogeny of Blastocystis sp. isolated from turkey (Meleagris gallopavo) populations in Penang, Malaysia

@#Most poultry farms in Malaysia preferred rearing chickens either for eggs or/and meat than turkeys. This is due to several challenges such as parasitic load and heat stress in rearing turkey. Blastocystis is one of the most common protozoan parasites infecting poultry. As no study was conducted on Blastocystis infection in turkey in Malaysia, this study aims to determine the current status, the morphological characteristics and subtyping of Blastocystis from turkey reared either in closed house or free-range system in Penang, Malaysia. It was found that the prevalence of Blastocystis sp. infection in turkeys were moderately high with 41.6% (25/60) in the closed house and 45.0% (45/100) in free-range system as infection was higher in the female turkeys with no gastrointestinal signs and symptoms. Vacuolar form was the most common form found in the in vitro culture ranged between 5 to 20 μm in diameter with a rough surface coat and undulating cell surface viewed under the scanning electron microscope. Meanwhile, the ultrastructure of the cells from turkey isolates were varies with partially expanded electron-opaque vacuoles to electron-dense in fully distended vacuoles. Interestingly, sequence analysis for 30 positive Blastocystis isolates from turkeys revealed one subtypes with three alleles namely, ST7 allele 99 (73.4%, n=22), ST7 allele 100 (23.3%, n=7) and ST7 allele 101 (3.3%, n=1). Findings from this study added to our understanding on Blastocystis infection in turkey production.

Epidemiology of falciparum malaria among residents of some rural and peri-urban communities in Ekiti State, Southwestern Nigeria

@#Malaria which is caused by parasites of the genus Plasmodium is a devastating parasitic disease of major public health challenge worldwide, particularly Nigeria. This study was carried out to investigate the epidemiology of falciparum malaria among residents of rural and peri-urban communities in Ekiti State, Southwestern Nigeria. Standard parasitological technique of microscopy was employed to determine and identify parasite prevalence and species. A questionnaire was used to collect subject’s information such as age, sex, location, occupation and education. Out of the 300 individuals examined, a total of 283 (93.4%) individuals were infected with malaria parasite. Sex pattern of infection indicated that male had higher malaria prevalence of 95.0% compared to female with the prevalence of 93.3% (P>0.05). The age group 51 to 60 years had the highest malaria parasite prevalence of 100% while age group <10 years has the least malaria parasite prevalence of 86.0% (P>0.05). Similarly, a total mean malaria parasite density of 1455.90 parasite/μL of blood was recorded. The mean malaria parasite density does not significantly vary (P>0.05) among age and sex group. The age group >60 years recorded the highest mean parasite density of 2092.50 parasite/μL of blood while age group <10 has the least mean malaria parasite density of 1044. 42 parasite/μL of blood. In relation to sex, the highest mean malaria parasite density was found among the female (1461.80 parasite/μL of blood) compared to male (1450 parasite/ μL of blood). In the same vein, occupation as a socioeconomic risk factor play a major role with respect to malaria infection. The highest malaria prevalence of 113 (98.26%) was recorded among farmers while the least 34 (85%) was recorded among Civil servants (P<0.05). Thus, it is apparent that falciparum malaria is heavily prevalent in this study area and as such urgent management control measures and interventions should be made available and fully utilized.

Helminthic parasites in indigenous chickens in Penang Island, Malaysia.

Indigenous chicken (Gallus domesticus) is reared for both its meat and eggs. Most consumers prefer the meat probably due to its specific texture and taste. The study was conducted to determine the presence of helminth parasites of 240 indigenous chickens (Gallus domesticus) obtained randomly from 12 divisions in Penang Island, Malaysia. Necropsy findings revealed 14 endoparasite species which parasitized these chickens namely, Acuaria hamulosa, Acuaria spiralis, Amoebotaenia sphenoides, Ascaridia galli, Brachylaima sp., Capillaria spp., Gongylonema ingluvicola, Heterakis gallinarum, Hymenolepis sp., Oxyspirura mansoni, Raillietina echinobothrida, Raillietina tetragona, Syngamus trachea and Tetrameres americana. The high abundance of helminth species observed in this study may be attributed to the free-range scavenging production system, where these indigenous chickens were exposed to intermediate or paratenic hosts of helminths which infect poultry. Besides, sustainable methods of helminthic control measure are necessary in order to enhance indigenous chicken production and eventually improve the economy of the rural farmers.

Helminthic parasites in indigenous chickens in Penang Island, Malaysia

@#Indigenous chicken (Gallus domesticus) is reared for both its meat and eggs. Most consumers prefer the meat probably due to its specific texture and taste. The study was conducted to determine the presence of helminth parasites of 240 indigenous chickens (Gallus domesticus) obtained randomly from 12 divisions in Penang Island, Malaysia. Necropsy findings revealed 14 endoparasite species which parasitized these chickens namely, Acuaria hamulosa, Acuaria spiralis, Amoebotaenia sphenoides, Ascaridia galli, Brachylaima sp., Capillaria spp., Gongylonema ingluvicola, Heterakis gallinarum, Hymenolepis sp., Oxyspirura mansoni, Raillietina echinobothrida, Raillietina tetragona, Syngamus trachea and Tetrameres americana. The high abundance of helminth species observed in this study may be attributed to the free-range scavenging production system, where these indigenous chickens were exposed to intermediate or paratenic hosts of helminths which infect poultry. Besides, sustainable methods of helminthic control measure are necessary in order to enhance indigenous chicken production and eventually improve the economy of the rural farmers.

Screening of nematophagous-fungi from fresh faeces of grazing animals and soils.

An investigation was undertaken for screening and isolating nematophagous-fungi from the faecal samples of various grazing animals and soils in Malaysia. Total of 111 faeces and 50 soil samples were collected and the samples were cultured on 2% water agar plates. The growth of nematophagous-fungi was stimulated by sprinkling-baiting technique. The conidia of suspected nematophagous-fungi were inoculated on 2% water agar plates. All isolated were maintained on 2% cornmeal agar plates. Verticillium spp., Fusarium spp. and Arthrobotrys spp. were identified from the faecal and soil samples. 62.5% of the faecal samples and 100% of the soil samples were shown to be positive with nematophagous-fungi. This study highlights the present of nematophagous-fungi population in faecal and soil samples. Much study remains to be done to better understanding some fungi especially their mode of action and their predatory behaviour against parasitic nematodes.

Screening of nematophagous-fungi from fresh faeces of grazing animals and soils

@#An investigation was undertaken for screening and isolating nematophagous-fungi from the faecal samples of various grazing animals and soils in Malaysia. Total of 111 faeces and 50 soil samples were collected and the samples were cultured on 2% water agar plates. The growth of nematophagous-fungi was stimulated by sprinkling-baiting technique. The conidia of suspected nematophagous-fungi were inoculated on 2% water agar plates. All isolated were maintained on 2% cornmeal agar plates. Verticillium spp., Fusarium spp. and Arthrobotrys spp. were identified from the faecal and soil samples. 62.5% of the faecal samples and 100% of the soil samples were shown to be positive with nematophagous-fungi. This study highlights the present of nematophagous-fungi population in faecal and soil samples. Much study remains to be done to better understanding some fungi especially their mode of action and their predatory behaviour against parasitic nematodes.

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.

Genetic diversity of rodent Blastocystis sp. from Peninsular Malaysia.

Rodents are ubiquitous zoonotic vectors for many human pathogens including Blastocystis sp. In this study, we examined the prevalence and subtypes of Blastocystis sp. in rodents captured from Peninsular Malaysia. A total of 293 rodents predominantly brown rat (Rattus norvegicus) (290 of 293, 99.0%) and house shrew (Suncus murinus) (3 of 293, 1.0 %), were captured in the vicinity of popular eateries in two cities (Kuala Lumpur and Ipoh) in Peninsular Malaysia. In vitro cultivation method showed presence of Blastocystis sp. in approximately half (133 of 290, 45.9%) of the brown rats tested. Among the 47 Blastocystis isolates subtyped using partial small subunit ribosomal RNA gene analysis, ST4 was the most abundant (43 of 47, 91.5%) followed by ST1 (2 of 47, 4.3%), ST5 (1 of 47, 2.1%) and ST7 (1 of 47, 2.1%). Our findings highlighted the importance of rodents as a source of Blastocystis sp. infection in Malaysia and showed the high prevalence of ST4 within the rodent population infected with Blastocystis sp.

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.