Cardiovascular risk factors, ethnicity and infection stone are independent factors associated with reduced renal function in renal stone formers

Background

Recent evidence suggested the link between nephrolithiasis and renal function impairment. We aimed to determine the renal function profile and potential factors associated with reduced renal function amongst renal stone formers in multi-ethnic Asians.

Methods

We conducted a cross-sectional study involving patients undergoing percutaneous nephrolithotomy between May 2015 and December 2019. Reduced renal function was defined as having estimated glomerular filtration rate < 60 ml/min per 1.73 m². Renal stone samples were collected and quantified using infrared spectroscopy. Potential factors associated with reduced renal function including age, ethnicity, educational level, history of diabetes, hypertension, gout, hydronephrosis, serum uric acid level, and type of renal stone were evaluated using univariable and multivariable analyses.

Results

A total of 1162 patients from a multi-ethnic population (Malays 67%, Chinese 19%, Indians 13% and indigenous people 1%) with median age of 57 years (Interquartile range 48–64) were enrolled in the study. Almost a third of patients were found with reduced renal function. Multivariable analysis showed that the odds of having reduced renal function increased with age, ethnicity, lower educational level, history of diabetes, hypertension, gout, bilateral hydronephrosis, elevated serum uric acid level and infection stone.

Conclusions

Reduced renal function varies between ethnicities and all age groups of renal stone formers. In addition to age and ethnicity, cardiovascular risk factors including diabetes and hypertension may also need to be taken into account in managing stone patients with reduced renal function.

Correction: Helminth Colonization Is Associated with Increased Diversity of the Gut Microbiota

[This corrects the article DOI: 10.1371/journal.pntd.0002880.].

The study of seroprevalence of hepatitis E virus and an investigation into the lifestyle behaviours of the aborigines in Malaysia

Malaysia is a non-endemic country for hepatitis E virus (HEV) infection. However, seroprevalence as high as 50% among samples of aboriginal people were reported over two decades ago. A total of 207 samples collected from seven aboriginal villages in rural settlements across two states in Malaysia were analysed for anti-HEV IgG and IgM by an enzyme-linked immunoassay. Following the detection of anti-HEV seroprevalence, we organized health outreach to inform and educate the community. Qualitative interviews were conducted with individuals tested positive for anti-HEV antibodies. Data derived from interviews and observations were used to investigate possible lifestyle behaviours associated with HEV infection. Anti-HEV IgG was detected in six samples (5.9%) from the village of Dusun Kubur. Qualitative inquiry and observation study revealed poor dietary and household hygiene, contaminated food and water, contact with animal faeces, unsanitary and domestic waste disposal, and wildlife reservoirs could be the contributing factors for transmission and acquisition of HEV infection. Investigation during health outreach is important to provide insights for future empirical research and implementation for improvement of lifestyle behaviours among the aborigines. Managing the risk of HEV infection in the aborigines may reduce the risk of HEV transmission to the local communities.

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.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3234-5) contains supplementary material, which is available to authorized users.

Prevalence of Cryptosporidium and Giardia in the water resources of the Kuang River catchment, Northern Thailand

A catchment-scale investigation of the prevalence of Cryptosporidium and Giardia in the Kuang River Basin was carried out during the dry and rainy seasons. Water samples were collected from the Kuang River and its tributaries as well as a major irrigation canal at the study site. We also investigated the prevalence of gastrointestinal parasitic infection among dairy and beef cattle hosts. Cryptosporidium and/or Giardia were detected in all the rivers considered for this study, reflecting their ubiquity within the Kuang River Basin. The high prevalence of Cryptosporidium/Giardia in the upper Kuang River and Lai River is of a particular concern as both drain into the Mae Kuang Reservoir, a vital source of drinking-water to many local towns and villages at the research area. We did not, however, detected neither Cryptosporidium nor Giardia were in the irrigation canal. The frequency of Cryptosporidium/Giardia detection nearly doubled during the rainy season compared to the dry season, highlighting the importance of water as an agent of transport. In addition to the overland transport of these protozoa from their land sources (e.g. cattle manure, cess pits), Cryptosporidium/Giardia may also be re-suspended from the streambeds (a potentially important repository) into the water column of rivers during storm events. Faecal samples from dairy and beef cattle showed high infection rates from various intestinal parasites - 97% and 94%, respectively. However, Cryptosporidium and Giardia were only detected in beef cattle. The difference in management style between beef (freeranging) and dairy cattle (confined) may account for this disparity. Finally, phylogenetic analyses revealed that the Cryptosporidium/Giardia-positive samples contained C. ryanae (non-zoonotic) as well as Giardia intestinalis assemblages B (zoonotic) and E (non-zoonotic). With only basic water treatment facilities afforded to them, the communities of the rural area relying on these water supplies are highly at risk to Cryptosporidium/Giardia infections.

Risk Factors for Enterovirus A71 Seropositivity in Rural Indigenous Populations in West Malaysia

Enterovirus A71 (EV-A71), which is transmitted by the fecal-oral route, causes hand, foot and mouth disease and, rarely, severe neurological complications. In Malaysia, the indigenous rural community (Orang Asli) has a high prevalence of parasitic diseases due to poor sanitation, water supply and hygiene practices. This cross-sectional study compared the seroepidemiology of EV-A71 among rural Orang Asli and urban Kuala Lumpur populations in West Malaysia, and determined the risk factors associated with EV-A71 seropositivity in rural Orang Asli. Seropositive rates were determined by neutralization assay. EV-A71 seropositivity was strongly associated with increasing age in both populations. Rural Orang Asli children ≤12 years had significantly higher EV-A71 seropositivity rates than urban Kuala Lumpur children (95.5% vs 57.6%, P < 0.001), and also higher rates in the age groups of 1–3, 4–6 and 7–12 years. Multivariate analysis confirmed that age ≤12 years (adjusted OR 8.1, 95% CI 3.2–20.7, P < 0.001) and using untreated water (adjusted OR 6.2, 95% CI 2.3–16.6, P < 0.001) were independently associated with EV-A71 seropositivity in the Orang Asli population. Supply of clean drinking water may reduce the risk of EV-A71 infection. With significantly higher EV-A71 seropositive rates, younger rural children should be a priority target for future vaccination programs in Malaysia.

Population expansion and gene flow in Giardia duodenalis as revealed by triosephosphate isomerase gene

Background

Giardia duodenalis is a protozoan parasite that can cause significant diarrhoeal diseases. Knowledge of population genetics is a prerequisite for ascertaining the invasion patterns of this parasite. In order to infer evolutionary patterns that could not be uncovered based on the morphological features, a population genetic study with the incorporation of molecular marker was carried out to access the genetic structure of G. duodenalis isolated from the Malaysian population and the global populations.

Methods

A total of 154 samples positive for Giardia, collected from different Malaysian communities, were subjected to DNA amplification and sequencing targeting three genetic loci (tpi, gdh, and bg). The tpi sequences together with sequences from the global data obtained from the NCBI GenBank were used for genetic diversity analyses including identification of haplotypes, haplotype diversity, nucleotide diversity, Tajima’s D and Fu and Li’s D, gene flow and genetic differentiation tests.

Results

Analysis of the Malaysian and global data showed that assemblages A, B, and E (the most prevalent assemblages in humans and animals), have different levels of genetic diversity. Assemblage B had the highest level of both haplotype diversity and nucleotide diversity, followed by assemblage E. The analysis also revealed population expansion and high gene flow in all assemblages. No clear genetic structure was observed across five continents (i.e., the Americas, Europe, Asia, Australia and Africa). However, median joining network of assemblage B formed a cluster that was exclusively isolated from Asia while other haplotypes were well dispersed across the continents.

Conclusions

This study provides new insight into the genetic diversity of Giardia assemblages in different geographical regions. The significant result shown by gene flow and genetic differentiation analyses as well as test of neutrality among the populations should have brought a clearer picture to the dynamics and distribution of Giardia infection.

Prevalence and associated risk factors of Giardia infection among indigenous communities in rural Malaysia

This study was carried out to investigate the prevalence and risk factors of Giardia infection among indigenous people in rural Malaysia. Faecal samples were collected from 1,330 participants from seven states of Malaysia and examined by wet mount and formalin-ether sedimentation methods while demographic, socioeconomic and environmental information was collected using a pre-tested questionnaire. The overall prevalence of Giardia infection was 11.6% and was significantly higher among those aged ≤ 12 years compared to their older counterparts. Multivariate logistic regression identified age of ≤12 years, lacking of toilet at household, not washing hands before eating, not washing hands after playing with animals, not boiling water before consumption, bathing in the river, and not wearing shoes when outside as the significant risk factors of Giardia infection among these communities. Based on a multilocus genotyping approach (including tpi, gdh and bg gene sequences), 69 isolates were identified as assemblage A, and 69 as assemblage B. No association between the assemblages and presence of symptoms was found. Providing proper sanitation, as well as provision of clean drinking water and proper health education regarding good personal hygiene practices will help significantly in reducing the prevalence and burden of Giardia infection in these communities.

Helminth colonization is associated with increased diversity of the gut microbiota

Soil-transmitted helminths colonize more than 1.5 billion people worldwide, yet little is known about how they interact with bacterial communities in the gut microbiota. Differences in the gut microbiota between individuals living in developed and developing countries may be partly due to the presence of helminths, since they predominantly infect individuals from developing countries, such as the indigenous communities in Malaysia we examine in this work. We compared the composition and diversity of bacterial communities from the fecal microbiota of 51 people from two villages in Malaysia, of which 36 (70.6%) were infected by helminths. The 16S rRNA V4 region was sequenced at an average of nineteen thousand sequences per samples. Helminth-colonized individuals had greater species richness and number of observed OTUs with enrichment of Paraprevotellaceae, especially with Trichuris infection. We developed a new approach of combining centered log-ratio (clr) transformation for OTU relative abundances with sparse Partial Least Squares Discriminant Analysis (sPLS-DA) to enable more robust predictions of OTU interrelationships. These results suggest that helminths may have an impact on the diversity, bacterial community structure and function of the gut microbiota.

Soil-transmitted helminths are carried by large numbers of people in developing countries. These parasites live in the gut and may interact with bacterial communities in the gut, also called the gut microbiota. To determine whether there are alterations to the gut microbiota that are associated with helminth infections, we examined the types of bacteria present in fecal samples from rural Malaysians, many of whom are helminth-positive and find it likely that helminth colonization alters the gut microbiota for rural Malaysians.

The burden of moderate-to-heavy soil-transmitted helminth infections among rural malaysian aborigines: an urgent need for an integrated control programme

Background

Soil-transmitted helminth (STH) infections, among the most common neglected tropical diseases, continue to be a major threat to the health and socioeconomic wellbeing of infected people especially children in developing countries.

Methods

A cross-sectional study among 254 aboriginal schoolchildren was conducted in order to determine the current prevalence and intensity of infections and to investigate the potential risk factors associated with moderate-to-heavy burden of STH infections among these children.

Results

Overall, 93.7% of children were found to be infected with one or more STH species. The prevalence of trichuriasis, ascariasis and hookworm infections were 84.6%, 47.6% and 3.9%, respectively. Almost half of the participants had heavy trichuriasis, one-quarter had heavy ascariasis whereas all hookworm infections were light infections. Overall, moderate-to-heavy STH infections accounted for 56.7% of the total infections. Univariate analysis revealed that those using untreated water supply (P = 0.013), living in houses without toilets (P = 0.027) and having domestic animals in the houses (P = 0.044) had significantly higher prevalence of moderate-to-heavy infections than others. Logistic regression analysis confirmed using untreated water for drinking (P = 0.001) and the absence of a toilet in the house (P = 0.003) as significant risk factors of moderate-to-heavy STH infections among these children.

Conclusion

The high proportion of moderate-to-heavy STH infections further confirms the need for serious attention towards these devastating diseases that has put lives and the future of aboriginal children in jeopardy. Introduction of more poverty alleviation schemes, proper sanitation, provision of clean and safe drinking water, health education, as well as the introduction of periodic school-based deworming programmes are imperative among these communities in order to curtail the transmission and morbidity caused by STH.

Hair matrix differentiation. Occurrence in lesions other than pilomatricoma

The formation of structures resembling hair matrices is the least common form of follicular differentiation and only occurs with any frequency in pilomatricoma. Rarely, follicular cysts and both benign and malignant adnexal tumors can show areas of pilomatricoma-like change, or hair matrix differentiation. Examples of focal hair matrix differentiation in a follicular cyst, a cutaneous mixed tumor, and an adnexal carcinoma are presented. Each of these cases also demonstrates the presence of limited differentiation toward structures of the inner root sheath.

Cutaneous angiosarcoma resembling anaplastic Kaposi's sarcoma in a homosexual man

A 46-year-old man presented with an unusual angiosarcoma of skin and urinary bladder, clinically suggestive of Kaposi's sarcoma (KS). Histologically, the pattern was that of an anaplastic angiosarcoma with only minimal regions considered characteristic of KS. It is suggested that this rare type of angiosarcoma may be closely related to, if not best classified as, an anaplastic variant of KS. The cutaneous lesions responded to intralesional vinblastine. The association of anaplastic angiosarcoma with homosexual sexual practices should be investigated along with those cases having the classical histologic characteristics of Kaposi's sarcoma.

Cavernous hemangioma of the superior mediastinum. Report of a case with electron microscopy and computerized tomography

An unusual case of cavernous hemangioma of the superior mediastinum in a 38-year-old male is presented. Mediastinal hemangiomas occur more often in children and are usually localized in the anterior-superior compartment in all age groups. Slow expansile growth, lack of infiltration of adjacent structures and microscopically mature cellular elements clearly marked the benign nature of the lesion. Vascular mesenchymal tumors in this location must be approached with caution because of the risks of hemorrhage or local infiltration of vital structures. Electron microscopy revealed active endothelial cells, smooth muscle cells, and intercellular matrix components suggestive of smooth muscle cell origin. Computerized tomography delineated the lesion clearly and demonstrated identical densities for the mass and adjacent blood vessels.