Natural Human Infections with Plasmodium cynomolgi, P. inui, and 4 other Simian Malaria Parasites, Malaysia.

We detected the simian malaria parasites Plasmodium knowlesi, P. cynomolgi, P. inui, P. coatneyi, P. inui-like, and P. simiovale among forest fringe-living indigenous communities from various locations in Malaysia. Our findings underscore the importance of using molecular tools to identify newly emergent malaria parasites in humans.

Detection of sarcocystosis in goats in Malaysia by light microscopy, histology, and PCR.

A number of methods have been used for the detection of the presence of microsarcocysts in animals, but little information exists on the value between the various methods. This study therefore examined for Sarcocystis spp. using three different methods in 105 samples of skeletal muscle collected from goats slaughtered in an abattoir in Selangor, Malaysia from January to February 2014. Three methods were used, direct light microscopy of squashed fresh muscle tissues; histological examination of fixed, sectioned, and hematoxylin and eosin (H&E)-stained samples of muscle; and molecular identification by polymerase chain reaction (PCR). Of the 105 tissue samples, 55 (52.38 %) were positive by light microscopy (LM), 46 (43.8 %) by histology, and 95 (90.48 %) by PCR. Only 29 (27.6 %) and 5 (4.76 %) samples were positive and negative, respectively, by all three methods. The cysts were elongated to a spindle shape with a mean size of 393.30 × 81.6 µm and containing banana-shaped bradyzoites of size 12.32 × 2.08 µm. The wall of the cyst was radially striated with a thickness of 2.83 µm. Samples were tested for the presence of Sarcocystis-specific 18S rRNA and were identified as Sarcocystis capracanis. Of the three methods used, the PCR test appears to be the most useful method for the diagnosis of sarcocystosis especially for species identification.

Ascaris lumbricoides harbors a distinct gut microbiota profile from its human host: Preliminary insights.

In indigenous populations where soil-transmitted helminths (STH) infections are endemic, STH parasites (i.e., Ascaris lumbricoides, Trichuris trichiura, hookworms) often co-exist and co-evolve with the gut microbiota of their human hosts. The association between STH infections and the gut microbiota of the colonized human hosts has been established, but few studies explored the gut microbiota of the parasites. This preliminary study aimed to characterize the microbiota of the STH parasite for further understanding the STH parasite-host relationship. The gut microbial genomic DNA from four adult A. lumbricoides worms recovered from a six-year-old indigenous Negrito boy living in an STH-endemic village in Perak, Peninsular Malaysia was extracted and sequenced for the V3-V4 region of the 16S rRNA. The microbiota profiles of these worms were characterized and compared with the gut microbiota of their human host, including the profiles from four STH-positive and three STH-negative individuals from the same tribe and village. The gut microbial structure of A. lumbricoides was found to be differed significantly from their human host. The worms contained lower gut bacterial abundance and diversity than human. This difference was evident in the beta diversity analysis which showed a clear separation between the two sample types. While both Firmicutes (52.3%) and Bacteroidetes (36.6%) are the predominant phyla followed by Proteobacteria (7.2%) in the human gut, the microbiota of Ascaris gut is highly dominated by Firmicutes, constituting 84.2% relative abundance (mainly from the genus Clostridium), followed by Proteobacteria (11.1%), Tenericutes (1.8%) and Bacteroidetes (1.5%). The parasites were also found to alter the microbial structure of the human gut following infection based on the relatively higher bacterial abundance in STH-positive versus STH-negative participants. Further studies with a greater number of Ascaris adults and human hosts are needed to confirm the gut microbiota profiles.

Postmortem skin microbiome signatures associated with human cadavers within the first 12 h at the morgue.

Introduction: Forensic microbiome studies expanded during the last decade, aiming to identify putative bacterial biomarkers to be used for the postmortem interval (PMI) estimation. Bacterial diversity and dynamics during decomposition are influenced by each individual's micro and macroenvironment, ante and postmortem conditions, varying across body sites and time. The skin, the largest organ of the human body, hosts a diverse microbial diversity, representing the first line of defense of a living individual. Targeting the investigation of the postmortem skin microbiome could help understanding the role of microbes during decomposition, and association with the ante and postmortem conditions. Methods: The current study aimed to identify the postmortem skin microbiome signatures associated with eight human bodies, received at the Institute of Legal Medicine Iasi, Romania, during April and May 2021. A total of 162 samples (including triplicate) representing face and hands skin microbiome were investigated via Illumina MiSeq, upon arrival at the morgue (T0) and after 12 hours (T1). Results: The taxonomic characteristics of the skin microbiota varied across different body sites. However, there were no significant differences in taxonomic profiles between collection time, T0 and T1, except for some dynamic changes in the abundance of dominant bacteria. Moreover, different microbial signatures have been associated with a specific cause of death, such as cardiovascular disease, while an elevated blood alcohol level could be associated with a decrease in bacterial richness and diversity. Discussion: The places where the bodies were discovered seemed to play an important role in explaining the bacterial diversity composition. This study shows promising results towards finding common postmortem bacterial signatures associated with human cadavers within the first 12h at the morgue.

Tinea Imbricata among the Indigenous Communities: Current Global Epidemiology and Research Gaps Associated with Host Genetics and Skin Microbiota.

Tinea imbricata is a unique fungal skin disease that mostly affects indigenous populations in Southeast Asia, Oceania, and Central and South America. The control and management of this disease among these communities are challenging given their remote locations, certain traditional practices, and severe malnutrition status. To date, there are only a handful of reports published globally, which highlights the need for a more holistic approach in addressing this skin disease. Several bodies of evidence and reports have shown that host genetic factors have a profound influence on the pathogenesis of tinea imbricata, while skin microbiota is touted to have a role in the pathogenesis of the disease. However, there are limited studies of how host genetics and skin microbiota impact disease susceptibility in the host. To improve the understanding of this disease and to find possible long-term effective treatment among the affected indigenous communities, a comprehensive literature review is needed. Hence, this review paper aims to present the current status of tinea imbricata among the indigenous communities, together with published findings on the possible underlying reasons for its specific distribution among these communities, particularly on the ways in which host skin microbiota and host genetics affect occurrence and disease patterns. This information provides valuable insights for future research by highlighting the current knowledge gaps in these areas.

Nutritional status, hemoglobin level and their associations with soil-transmitted helminth infections between Negritos (indigenous) from the inland jungle village and resettlement at town peripheries.

This study compared the current nutritional status, hemoglobin levels and their associations with soil-transmitted helminth (STH) infections between two categories of Negritos (indigenous): (i) Inland Jungle Villages (IJV) (ii) and Resettlement Plan Scheme (RPS) near town peripheries, decades after redevelopment and demarginalization. A total of 416 Negritos (IJV: 149; RPS: 267) was included for nutritional profiling based on anthropometric analysis. However, only 196 (IJV: 64; RPS: 132) individuals consented to blood taking for the hemoglobin (Hb) measurements. Subsequently, the association of undernutrition and anemia with STH infections were determined based on univariate and multivariate logistic regression analyses. The overall prevalence of stunting, wasting, and underweight amongst children and adolescents (n = 343) were 45.8%, 42.3% and 59.1%, respectively. In adults (n = 73), the prevalence of underweight was low (6.8%) but overweight and obese was prominent (26.0%). For anemia (n = 196), an overall prevalence rate of 68.4% were observed with 80% and 70.4% of children aged 2-6 y/o and aged 7-12 y/o, respectively being anemic. Comparatively, the prevalence of underweight (WAZ) was significantly higher in the RPS versus the IJV (P = 0.03) In the IJV, children aged ≤ 6 y/o and having STH poly-parasitism were associated with underweight (P = 0.01) and moderate-severe T. trichiura infection was associated with anemia. Whilst in the RPS, underweight was highly associated with only T. trichiura infection (P = 0.04). Wasting was significantly associated with young children aged ≤10 in both IJV (P = 0.004) and RPS (P = 0.02). Despite efforts in improving provision of facilities and amenities among the indigenous, this study highlighted a high magnitude of nutritional issues among the Negritos especially those in the RPS and their likely association with STH infections and decades of demarginalization. Joint nutritional intervention strategies with mass anti-helminthic treatment are imperative and urgently needed to reduce the undernutrition problems especially among indigenous children.

Prevalence, intensity and associated risk factors of soil transmitted helminth infections: A comparison between Negritos (indigenous) in inland jungle and those in resettlement at town peripheries.

BACKGROUND: Formerly known as the Malaysian hunter gatherers, the Negrito Orang Asli (OA) were heavily dependent on the forest for sustenance and early studies indicated high prevalence of intestinal parasitism. Initiation of a redevelopment program in the 1970s aimed to demarginalize the OA was expected to reduce soil transmitted helminth (STH) infections. Gradually, the OA were relocated to new resettlement areas at the peripheries. The aim of this study was to compare STH infections between Negritos who are still living in the inland jungle with those living in resettlements. METHODOLOGY/PRINCIPAL FINDINGS: A total of 416 Negrito participants were grouped into two categories of communities based on location; Inland Jungle Villages (IJV); and Resettlement Plan Scheme (RPS). Iodine wet mount, formalin-ether sedimentation, modified Trichrome and modified Ziehl-Neelsen staining and Kato-Katz methods were performed on stool samples. A questionnaire was used to collect information regarding demographic, socioeconomic, environmental and hygiene behaviors. Prevalence of STH was significantly higher in IJV (91.3%) versus RPS (83.1%) (P = 0.02). However, the percentage of individuals with severe intensity of Trichuris trichiura infections was significantly higher in the RPS (17.2%) compared to IJV (6.5%) (P = 0.01). Severe Ascaris lumbricoides infection was observed at 20.0% amongst RPS Negritos and 15.0% amongst IJV (P = 0.41). Whilst for hookworm infection, both prevalence and individuals with moderate to severe infections were higher in the IJV (26.2%, 41.0%) versus RPS (18.7%, 24.0%) (P values = 0.08, 0.09), accordingly. The prevalence other intestinal parasitic infections (e.g. Entamoeba sp., Blastocystis and flukes) was also higher in IJV versus RPS. Apart from poor hygienic behaviors as significant risk factors in both communities, low socio-economic status was highly associated with STH infections in RPS (P<0.001) but not significantly associated in IJV. CONCLUSIONS: The findings showed that ex situ development plan by RPS has not profoundly contributed to the STH reduction among the OA. Conversely, burden rate of T. trichiura infections increased due to their extreme poverty and poor hygienic behaviors. Here, we are suggesting biannual mass albendazole intervention (triple dose regimens in RPS, but a single dose in IJV) and community empowerment to both communities. For a long-term and better uptake, these strategies must be done together with the community input and participation, respecting their traditional customs and accompanied by recruitment of more OA people in the health-care taskforce.

Genetic polymorphism and natural selection in the C-terminal 42 kDa region of merozoite surface protein-1 (MSP-1) among Plasmodium knowlesi samples from Malaysia.

BACKGROUND: The merozoite surface protein-1 (MSP-1) gene encodes for a leading malaria vaccine candidate antigen. However, its extensive polymorphic nature represents a major obstacle to the development of a protective vaccine. Previously, a pilot study was carried out to explore the sequence variation of the C-terminal 42 kDa fragment within P. knowlesi MSP-1 gene (PkMSP-142) based on 12 clinical samples; however, further study on an adequate sample size is vital in estimating the genetic diversity of the parasite population. METHODS: In the present study, we included a larger sample size of P. knowlesi (83 samples) covering eight states of Malaysia to determine the genetic polymorphism, natural selection and haplotype groups of the gene fragment coding PkMSP-142. The region flanking PkMSP-142 was amplified by PCR and directly sequenced. Genetic diversity, haplotype diversity, population genetic differentiation and natural selection were determined in order to study the polymorphic characteristic of PkMSP-142. RESULTS: A high level of genetic diversity (Hd = 0.970 ± 0.007; л = 0.01079 ± 0.00033) was observed among the 83 P. knowlesi samples, confirming the extensive genetic polymorphism exhibited among the P. knowlesi population found in Malaysia. A total of 18 distinct haplotypes with 17 amino acid changes were identified, whereby 15 were new haplotypes. High population differentiation values were observed within samples from Peninsular Malaysia and Malaysian Borneo. The 42 kDa fragments of P. knowlesi from Malaysian Borneo were found to be acting on balancing selection whilst purifying selection was suggested to act on isolates from Peninsular Malaysia. The separation of PkMSP-142 haplotypes into two main groups based on geographical separation has further supported the existence of two distinct P. knowlesi lineages. CONCLUSIONS: A high level of genetic diversity was observed among PkMSP-142 in Malaysia, whereby most of the polymorphisms were found within the 33 kDa region. Taken together, these data will be useful in order to understand the nature of P. knowlesi population in Malaysia as well as the design and development of a MSP-142 based knowlesi malaria vaccine.

Armigeres subalbatus incriminated as a vector of zoonotic Brugia pahangi filariasis in suburban Kuala Lumpur, Peninsular Malaysia.

BACKGROUND: In 2011, we reported occurrence of natural human infections with Brugia pahangi, a filarial worm of dogs and cats, in a surburb of Kuala Lumpur, the capital city of Malaysia. Our preliminary entomological survey at that time suggested the mosquito species Armigeres subalbatus as the vector of the zoonotic infections. In this present report, we provide biological evidence to confirm our preliminary finding. FINDINGS: A total of 1798 adult female Ar. subalbatus mosquitoes was caught in the vicinity of the suburb, and 1599 were dissected for the presence of filarial larvae. Sixty-two mosquitoes were positive, and 27 of these were infected with L3 larvae. The L3 were inoculated into male gerbils. Microfilariae could be detected in the gerbils 92 days post-infection. Post-mortem on the gerbils recovered adult worms in the peritoneal cavity, heart, lungs, tail and testis. Male adult worms were confirmed to be B. pahangi by the ratio length of their spicules (left spicule: right spicule). Female adult worms were confirmed by the absence of minute cuticular bosses in the tail region. The worms were further confirmed to be B. pahangi by PCR. CONCLUSIONS: Our results showed that Ar. subalbatus was the vector for the zoonotic Brugia pahangi infections. This mosquito species should now be categorised as a medically important mosquito species in Malaysia. Its role in the transmission of zoonotic B. pahangi must therefore be considered in future studies on filarial infections.

Zoonotic Brugia pahangi filariasis in a suburbia of Kuala Lumpur City, Malaysia.

Five local Malaysian patients with clinical manifestations consistent with lymphatic filariasis were referred to our medical centre between 2003 and 2006. Although no microfilariae (mf) were detected in their nocturnal blood samples, all were diagnosed to have lymphatic filariasis on the basis of clinical findings and positive serology results. PCR on their blood samples revealed that two of the patients were infected with Brugia pahangi, an animal filarial worm hitherto not known to cause human disease in the natural environment. All the patients were successfully treated with anti-filarial drugs: four patients were treated with a combination of diethylcarbamazine (DEC) and albendazole, and one with doxycycline. Four of them were residents of Petaling Jaya, a residential suburbia located 10 km southwest of Kuala Lumpur city, Malaysia. The fifth patient was a frequent visitor of the suburbia. This suburbia has no history or record of B. malayi infection. The most likely vector of the worm was Armigeres subalbatus as extensive entomological surveys within the suburbia revealed only adult females of this mosquito species were infected with B. pahangi larvae. Wild monkeys caught in the suburbia were free from B. pahangi mf, but domestic cats were mf positive. This suggests that infected cats might be the source of the zoonotic infection in the suburbia.