Strongyloides stercoralis is an intestinal nematode with worldwide distribution, including Thailand, and contamination of vegetables poses a potential public health risk. Previous studies largely relied on light microscopy, often reporting nematode larvae without species identification. This study investigated the presence of S. stercoralis in fresh vegetables from the lower northern region of Thailand using both morphological and molecular methods, including cox1-based phylogenetic analysis. A total of 90 fresh vegetable samples were collected from farms across three provinces. In each province, 10 vegetable types; Chinese morning glory, lettuce, dill, green onion, celery, Chinese chives, Mustard green, coriander, gotu kola, and Chinese mustard were collected. Detection of S. stercoralis was performed by examining morphological characteristics under a microscope using the sedimentation technique. Molecular detection was carried out via PCR targeting the cox1 gene, followed by sequencing and phylogenetic analysis. Of 90 samples, 47.78% were positive, with the highest contamination found in green onion (100%), lettuce (88.89%), and Chinese morning glory (66.67%). Molecular detection by PCR targeting the cox1 gene (primers StrCoxAfrF/StrCoxAfrR) confirmed seven positive samples (23.33%) from four vegetable types: Chinese morning glory, lettuce, green onion, and Mustard green. Sequencing showed 99-100% identity with S. stercoralis, and phylogenetic analysis using the Neighbor-Joining method on the seven positive samples from three provinces revealed genetic affinity with strains from neighboring countries. These findings underscore the need for comprehensive public health strategies for surveillance, treatment, and prevention of S. stercoralis transmission through contaminated vegetables.
Species of the genus Tabanus Linnaeus (horse flies) are significant pests and vectors transmitting pathogens to economically important animals including cattle. Therefore, knowledge about genetic diversity; a necessity for understanding disease epidemiology, is of paramount importance. However, such information is limited in Thailand, particularly in the northeastern region despite it being a major cattle production area. We examined genetic diversity of three Tabanus species, T. striatus Fabricius and T. megalops Walker, and T. rubidus Wiedemann based on mitochondrial cytochrome oxidase I (COI) sequences. There was relatively high genetic diversity (max. 2.14%) within populations of T. rubidus from northeastern Thailand but no indication of genetic structuring. Phylogenetic relationships between Thai populations and those recorded from Malaysia, India and Bangladesh involved three genetically divergent lineages which possibly represent different but morphologically similar species. High levels of genetic diversity (max. 4.43% and 5.20%) were found within northeastern populations of T. megalops and T. striatus due to the existence of three genetically divergent lineages within these species. However, there was no signal of geographical association of lineages suggesting panmixia within populations. Phylogenetic relationships between specimens obtained in the present study and those recorded from other countries revealed cryptic genetic diversity with three divergent clades. Further study is required to solve this taxonomic complexity of the T. striatus-complex.
Bartonella henselae is an uncommon but important cause of prolonged pyrexia of unknown origin (PUO) and hepatosplenomegaly. Conventional diagnostic tools often fail in disseminated disease, leading to delayed or missed diagnoses. We report a 60-year-old man with PUO, progressive weight loss, and hepatosplenomegaly. Clinical suspicion, guided by significant cat exposure, led to molecular confirmation of B. henselae infection after conventional workup proved inconclusive. Liver biopsy revealed pleomorphic rod-shaped organisms on Warthin-Starry staining, while real-time PCR targeting the rpoB gene and conventional PCR targeting the gltA gene performed on bone marrow aspirate confirmed disseminated bartonellosis. The patient responded well to prolonged doxycycline and rifampicin therapy, achieving near-complete recovery. This case underscores the importance of clinical vigilance, histological clues, and molecular diagnostics in identifying rare but treatable infections.
Dengue fever remains a major mosquito-borne disease in Southeast Asia, with increasing incidence in rapidly urbanizing settings. In Vietnam, Hanoi has experienced recurrent outbreaks; however, comprehensive analyses of recent dengue epidemiology in northern regions remain limited. This study aimed to characterize the spatiotemporal dynamics of dengue in Hanoi from 2018 to 2022. A retrospective descriptive study was conducted using routine dengue surveillance data collected by the Hanoi Center for Disease Control. All clinically diagnosed and laboratory-confirmed dengue cases reported between January 2018 and December 2022 were included. Temporal trends were examined using descriptive analysis of monthly and annual incidence rates. District-level incidence rates were calculated and visualized using a geographic information system (GIS) mapping. Serotype distribution was examined using available virological data. A total of 46,650 dengue cases were reported during the study period. Dengue transmission occurred annually, with substantial inter-annual variability; the highest incidence was recorded in 2022 (236 per 100,000 population), while the lowest occurred in 2021 (41 per 100,000 population). A clear seasonal pattern was observed, with cases increasing from June and peaking between September and November. Spatial analysis revealed marked heterogeneity, with higher incidence consistently observed in peri-urban districts. All four dengue virus serotypes co-circulated, with DENV-1 and DENV-2 predominating and a shift toward DENV-2 dominance in later years. Dengue transmission in Hanoi exhibits pronounced seasonal and spatial patterns influenced by urbanization and ecological factors. Strengthening pre-season vector control activities and district-level surveillance may help reduce outbreak risk and maintaining integrated epidemiological and virological surveillance is essential to mitigate future outbreaks.
Congenital cytomegalovirus (cCMV) infection is a major cause of neurodevelopmental impairment and sensorineural hearing loss worldwide, particularly in low- and middle-income countries where standardized molecular screening programs are not routinely implemented. Early laboratory confirmation within the first 21 days of life is essential to differentiate congenital from postnatal infection. This study evaluated the diagnostic agreement between the Simplexa cCMV Direct real-time PCR assay and conventional nested PCR for detecting CMV DNA in neonatal urine specimens in Indonesia. A cross-sectional diagnostic agreement study was conducted between September and December 2023 at a tertiary referral hospital. Urine samples from 87 neonates aged <= 21 days with clinical suspicion of congenital infection were tested using both assays. The Simplexa assay detected 29 positive and 58 negative samples, while conventional nested PCR identified 28 positive and 59 negative samples. Agreement was assessed using Cohen's kappa coefficient, McNemar's test, and positive and negative agreement rates. The assays demonstrated near-perfect agreement (k = 0.87; 95% CI: 0.75-0.98; p < 0.001). Positive and negative agreement were 91.2% and 95.7%, respectively, with no statistically significant difference between methods (McNemar p = 1.00). Simplexa Direct real-time PCR showed high agreement with conventional nested PCR while offering operational advantages including simplified workflow and reduced contamination risk. These findings support the implementation of automated direct molecular platforms for neonatal cCMV diagnosis in tropical and resource-limited healthcare settings.
Cryptococcosis is a potentially fatal invasive fungal infection with considerable health challenges. A seemingly immunocompetent middle-aged man with frequent exposure to pigeons and bird excreta presented with headaches, fever, gait instability and diplopia. Two years prior to his presentation, he sustained a blunt head trauma which resulted in sporadic headaches. On examination, a hard scalp nodule measuring approximately 3 x 3 cm was palpable on the topmost part of his head. Cryptococcus neoformans was cultured from his cerebrospinal fluid, blood and the biopsied scalp nodule. A diagnosis of disseminated cryptococcosis was made, with the scalp lesion being designated as the primary source of the infection. Following a protracted course of antifungal therapy lasting 10 weeks, the patient was asymptomatic without any neurological deficits when reviewed in the clinic at two months post discharge.
Plasmodium knowlesi is an emerging zoonotic malaria species and a leading cause of malaria in Malaysia. Although severe disease is increasingly recognised, cerebral malaria remains uncommon and is traditionally associated with Plasmodium falciparum. We report a fatal case of cerebral malaria caused by P. knowlesi in a previously healthy 61-year-old woman with a history of frequent orchard visits for peridomestic agricultural activities. She presented with rapid neurological deterioration and circulatory shock, complicated by an acute pontine infarction. Peripheral blood smear and polymerase chain reaction confirmed P. knowlesi infection with a parasite density of approximately 35,000 parasites/ µL. The patient met World Health Organization criteria for severe malaria and was treated promptly with intravenous artesunate in accordance with international guidelines, alongside intensive supportive care for septic shock and multiorgan failure. Despite a rapid reduction in parasitaemia, her condition deteriorated, and she died within 24 hours of presentation. This case highlights the potential for P. knowlesi to cause rapidly progressive and fatal cerebral malaria. Clinicians in endemic regions should maintain a high index of suspicion for zoonotic malaria in patients presenting with acute neurological deterioration.
The spa gene of Staphylococcus aureus encodes protein A, a key virulence factor contributing to molecular typing. spa typing provides valuable information encoding diversity and transmission, particularly for methicillin-resistant S. aureus (MRSA), which remains a major public health concern. A one-year prospective surveillance study was conducted involving S. aureus bacteremia (SAB) patients admitted to Haji Adam Malik General Hospital, Medan, Indonesia. SAB isolates were phenotypically analysed for cefoxitin resistance using the VITEK-2 system and genotypically characterised by PCR for the mecA and spa genes. Spa typing of the X region was performed at Apical Scientific Laboratory (Selangor, Malaysia), and clustering was analysed using the Based Upon Repeat Pattern (BURP) algorithm. A minimum spanning tree (MST) was constructed with Ridom SeqSphere to assess genetic relatedness. Clinical outcomes were compared between MRSA and MSSA clusters. A total of 120 SAB patients were included, equally divided into MRSA and MSSA groups. The dominant spa types included t852 (12.5%), t5422 (9.2%), and t4171 (7.5%). In-hospital mortality was 28.3%, significantly higher in MRSA compared with MSSA (p-value 0.015, OR 2.76). ICU admission occurred in 20.9% of cases. MRSA isolates predominantly clustered in a single group (Cluster 1), consistent with clonal transmission, whereas MSSA isolates displayed greater genetic heterogeneity across multiple clusters. This prospective surveillance highlights the clonal expansion of MRSA within a tertiary care setting and supports the utility of spa typing as a practical molecular tool for monitoring transmission and guiding infection control strategies.
Rhipicephalus linnaei is a widespread tick species infesting dogs and capable of transmitting pathogens of veterinary and zoonotic concern. However, its associated bacterial communities remain poorly described in Malaysia. This study profiles the bacterial microbiome of R. linnaei collected from stray dogs in Kampar, Perak, using 16S rRNA gene amplicon sequencing targeting the V3-V4 region. A total of 360 ticks were collected from 13 dogs, of which 290 were pooled according to life stages and sex for microbial profiling. Shannon diversity indices indicated the mixed adult/nymph pool exhibited the highest richness and evenness (H'=5.4), whereas engorged adult females displayed the lowest diversity (H'=2.35), dominated by Gammaproteobacteria. Principal coordinate analysis revealed distinct microbial assemblages among pools, explaining 72% of total variance. Among 137 detected genera, Coxiella (0.6-34%), Staphylococcus (0.4-29%), Stenotrophomonas (0.3-5%), and Streptococcus (0.02-6%) were consistently found across all pools. Low-abundance but clinically relevant genera, including Ehrlichia (0.64%) and Nocardia (< 0.01%), were detected in adult males. The consistent presence of Coxiella-like endosymbionts across all stages suggests a likely symbiotic role in nutrient provisioning and reproduction. To our knowledge, this is the first 16S rRNA gene-based profiling of the bacterial communities associated with R. linnaei collected from stray dogs in Malaysia. This study highlights variation across pooled tick categories and contributes to improved understanding of tick-borne pathogen ecology within a One Health framework.
Varicella-zoster virus (VZV) reactivation or herpes zoster (HZ) results from a decline in cell-mediated immunity. The precise immunological mechanisms driving this reactivation and determining its clinical severity remain unclear. To evaluate the expression of Toll-like receptor 7 (TLR7), serum levels of I interferon response (IFN-a), and the CD4/CD8 T-cell in patients with active HZ and to correlate these immunological markers with disease severity. A case control study was conducted with 50 patients with active HZ and 30 healthy controls. Whole blood and serum samples were collected. TLR7 gene expression was quantified using reverse-transcription quantitative real-time PCR (RT-qPCR), and the serum concentrations of IFN-a, soluble CD4 (sCD4) and soluble CD8 (sCD8) were quantitatively measured by sandwich enzyme-linked immunosorbent assay (ELISA). Patients with HZ exhibited significant upregulation of TLR7 gene expression (p=0.0102) and elevated serum IFN-a levels (p<0.0001) compared with controls. While IFN-a levels did not correlate with clinical severity, both CD4+ (p=0.018) and CD8+ (p=0.016) T cell levels increased significantly with greater disease severity. Sex-specific differences were observed, with males showing higher sCD4 levels and females showing higher sCD8 levels. In conclusion, the adaptive T-cell-derived response, rather than systemic IFN-a levels, is more closely associated with the clinical severity of herpes zoster. The paradoxical upregulation of TLR7 during active disease suggests a complex host-virus interaction involving potential viral evasion mechanisms. These preliminary findings, although limited by sample size, suggest that the sCD4/sCD8 balance and sex-specific immune profiles warrant further investigation as potential prognostic indicators in larger validation cohorts.
Ascaridia galli infection compromises the health and productivity of chickens. this study aimed to determine the prevalence, pathology, and control of A. galli in backyard chickens. Four hundred and fifty-six faecal samples were tested using direct smear and concentration techniques. sixty chickens were grouped based on egg per gram into untreated control, mebendazole-treated, and derivative-treated. Key epidemiologic host based and environmental variables were recorded and analysed statistically (p < 0.05 significance level). Histopathological changes in the intestine were also assessed. Overall prevalence of A. galli was 72% (330/456). Infection was high in females (74%, 200/267) than in males (68%, 130/189). Adult chickens had a higher infection rate than young (64% vs 55%; p < 0.05). Weak chickens showed a markedly higher prevalence (96%, 150/156) than healthy chickens (60%, 180/300) (p < 0.05). Geographically, prevalence was highest in Swat (85.53%), followed by Lower Dir (72.3%) and Malakand (59.21%), with statistically significant differences (p < 0.05). Management system influenced infection: free range chickens had (63%) compared to semi-free range (37%), scavenging chickens were more infected (75%) compared to receiving supplemental feed (53%) (p < 0.05). The non-dewormed chickens had a significantly higher prevalence (92%) than the dewormed group (20%) (p < 0.05). Seasonal infection peaked during the rainy season (86%) compared to the dry season (44%) (p < 0.05). Intestinal histology revealed inflammation, epithelial necrosis, villous atrophy, and crypt hyperplasia. Treatment of the chickens nematodes using mebendazole resulted in 70% (14/20) of the treated eggs being egg-negative, and the comparison of treatment of the egg-negative derivative compound resulted in 80% (16/20) of the treated eggs being egg-negative. The A. galli infection are very common, and cause intestine damage. The mebendazole and its derivative decrease egg shedding significantly, Husbandry, management and treatment should be enhanced for effective control strategies.
Mosquito-borne arboviral diseases such as dengue and chikungunya have continuously been a major global public health concern. Introducing the intracellular bacterial endosymbiont Wolbachia into mosquito populations has been proven to reduce dengue virus transmission, and its broader efficacy against other arboviruses has also been investigated. Several Wolbachia strains have been successfully propagated in insect cell lines, highlighting the utility of in vitro systems for studying microbial-host interactions under controlled conditions. This study investigated the initial establishment and replication kinetics of a flea-derived Wolbachia strain (wCfe), which was originally isolated from Malaysian Ctenocephalides felis and maintained in the Ixodes scapularis tick-derived cell line (IDE8), and then transferred into an Aedes albopictus-derived cell line (C6/36). The wCfe strain was semi-purified from IDE8 cultures and inoculated into C6/36 cells in 24-well plates. Replication dynamics were monitored by quantitative real-time PCR targeting the Wolbachia pipientis 16S rRNA gene. Following infection, a lag phase was observed at day 0 to 5 days post-infection (d.p.i.), followed by exponential growth from 6 d.p.i. after which Wolbachia levels remained relatively stable until the end of the observation period at 12 d.p.i. Overall, a 25.30-fold increase in Wolbachia density was detected relative to 0 d.p.i. Across replicates, the estimated generation time of wCfe in C6/36 cells ranged from 1.7 to 2.5 days. These results demonstrate successful initial establishment and replication of the flea-derived Wolbachia strain in the Aedes mosquito cell line. However, longer-term in vivo studies will be necessary to determine the persistence of wCfe infection in C6/36 cells and within the mosquito host.
Blastocystis sp. is a common intestinal protozoan parasite that colonises humans and various animals, with rodents identified as significant reservoir hosts for zoonotic transmission. This study aimed to investigate the prevalence and subtype distribution of Blastocystis sp. among wild rats in Pulau Pinang, Malaysia, while evaluating the associations with host demographics and geographic factors. A total of 150 rodent faecal samples from 12 sampling sites across Pulau Pinang, Malaysia, were examined using microscopy, DNA extraction, and PCR amplification of the SSU-rRNA gene. The overall prevalence of Blastocystis was 25.3%, with Rattus norvegicus exhibiting the highest infection rate (34.5%), followed by R. rattus (19.4%), and Bandicota bengalensis (16.7%). No infections were reported in B. indica (0.0%). Statistical analysis revealed a significant association between Blastocystis infection and rodent species (c2 = 11.874, df = 3 and p = 0.008), whereas no association was indicated in gender, development stages, and sampling sites. Due to limited funding, sequencing was conducted on ten positive samples that exhibited well-defined bands. Out of ten, three zoonotic subtypes were identified namely, ST1 (allele 4), ST3 (allele 34), and ST4 (allele 94 and 133). The findings of this study emphasise the role of R. norvegicus as the major reservoir host in Pulau Pinang, Malaysia and highlight the zoonotic potential of Blastocystis in urban settings.
The detection of insecticide resistance is pivotal for characterising the phenotypic resistance of field-collected Aedes aegypti populations, enabling the early identification of resistance trends and safeguarding the efficacy of chemical interventions in vector control programmes. Although the World Health Organization (WHO) adult tube test remains the standard screening method, its reliance on binary classifications of susceptibility and resistance limits the ability to compare the magnitude of resistance among different insecticides. To address this limitation, probit analysis was performed on adult mortality data obtained from a field-collected strain exposed to WHO-recommended discriminating and intensity concentrations. LC50 values were subsequently normalised using a concentration ratio (CR) framework, allowing resistance levels to be quantified and compared across insecticides. The relationship between the CR and slope parameters derived from probit analysis enabled the inference of resistance magnitude within field populations. The results demonstrated that pirimiphos-methyl retained high efficacy against the tested populations, whereas substantial intra-population variation in resistance intensity was observed among pyrethroids and malathion. Lambda-cyhalothrin exhibited the highest level of resistance, followed by permethrin and alpha-cypermethrin. These findings highlight the value of data-driven approaches for enhancing the interpretation of insecticide resistance profiles and providing a more comprehensive assessment of resistance status. By utilising mortality data generated from WHO-recommended discriminating and intensity bioassays, resistance can be evaluated beyond the binary outcomes of standard susceptibility tests, thereby supporting more informed decisions on insecticide rotation and resistance management in vector control programmes.
Leptospirosis remains a major public health concern in tropical regions, including Malaysia, where it is endemic. To date, evidence from remote and understudied areas remains limited. This study aims to assess the epidemiological evidence of leptospirosis among market traders in Sabah, addressing the limited available data for this potentially high-risk occupational group in this region. A cross-sectional study was conducted among 295 market traders in Kudat Town, Sabah. Sociodemographic, occupational, environmental and behavioural data were collected using a modified validated questionnaire. Venous blood samples were collected to test for Leptospira antibodies using the Microscopic Agglutination Test; a titre of 1:50 or higher was considered seropositive. Seroprevalence was estimated descriptively, while factors associated with leptospiral seropositivity were examined using univariable and multivariable logistic regression analyses. The seroprevalence of leptospirosis among market traders was 5.4% (95% CI: 3.1-8.7). Antibodies were detected against 11 Leptospira serovars/strains, mainly Lep175. In univariable analysis, predictors for seropositivity included trading frequency, rodent presence, and proximity to garbage piles. With only 16 cases, the initial multivariable model had a low EPV of 4, suggesting possible overfitting. After reducing the model (EPV = 8), proximity to garbage piles remained strongly associated (AOR = 52.61; 95% CI: 13.50-205.13; p < 0.001), while rodents at home also became significant (AOR = 5.70; 95% CI: 1.12-29.08; p = 0.037). This study provides the first empirical evidence of leptospirosis exposure among market traders in Sabah. Although the overall seroprevalence was low, the findings indicate a measurable risk and underscore the need for further large-scale studies and integrated One Health interventions to reduce exposure in this vulnerable population.
Hookworm disease is one of the tropical neglected diseases that significantly impacts human health to varying degrees. Hookworms produce various proteins to facilitate host invasion and immune evasion. Despite available treatments, reinfection is common, underscoring the need for effective vaccines. However, the complexity of the hookworm's life cycle poses a challenge in understanding the immune response in the vaccine candidates. Reverse vaccinology (RV) offers a powerful approach to understand the immune response by using various bioinformatics tools. This study begins by identifying hookworm antigens capable of inducing host immune responses, followed by docking analysis with different dendritic cell (DC) receptors to investigate the immunological response of antigenic peptides and further correlated to the immunogenicity findings in clinical trial. Necator americanus GlutathioneS-Transferase-1 (Na-GST-1), a known immunogenic protein from Necator americanus, was selected for docking due to its strong antigenic properties. Fifteen DC receptors were evaluated against Na-GST-1, of which seven receptors (TLR2, TLR3, TLR4, TLR7, DEC-205, CD206, and CD36) exhibited stronger predicted interactions, as indicated by stronger binding affinities with Na-GST-1 utilizing various immunoinformatic tools. These receptors are associated with the mediation of Th1/Th2 immune responses, suggesting a potential correlation between docking affinity and the predicted immunogenicity of Na-GST-1. Overall, this study provides valuable insights into DC receptor-antigen interactions and demonstrate a computational approach for assessing the potential of hookworm antigens to engage DC receptors, thereby supporting rational hookworm vaccine design. These findings support the application of early in silico strategies for advancing vaccine candidates against hookworm infection and strengthening control efforts for neglected tropical diseases.
Despite ongoing vector control programs, dengue incidence in Malaysia continues to rise. A significant contributing factor is the emergence of insecticide resistance in Aedes mosquitoes, particularly against pyrethroids such as permethrin. This study aimed to evaluate permethrin resistance in Aedes aegypti and Aedes albopictus from Kuala Lumpur and Selangor and to investigate the prevalence of knockdown resistance (kdr) mutations in the voltage-gated sodium channel (Vgsc) gene. Due to limited sample quantity and quality, molecular assessment of kdr mutations was performed only for Ae. aegypti. Ovitraps were deployed in three dengue hotspot areas to collect Aedes eggs. Eggs were reared to adulthood under controlled laboratory conditions. Adult female mosquitoes were subjected to the WHO tube bioassay using permethrin to assess phenotypic resistance. Genomic DNA was extracted from individual Ae. aegypti, and polymerase chain reaction (PCR) was conducted to amplify target regions of the Vgsc gene using published kdr-associated primers. Direct sequencing of PCR products was performed to identify point mutations associated with pyrethroid resistance. Both Ae. aegypti and Ae. albopictus populations showed high levels of permethrin resistance, with mortality rates of <5% and <50%, respectively, indicating confirmed resistance. Sequencing of Ae. aegypti revealed the presence of pyrethroid resistance-associated kdr mutations, including S989P, A1007G, V1016G, and F1534C. These findings suggest strong selective pressure on local Ae. aegypti populations, reflecting ongoing adaptation to insecticidal interventions. The identification of these mutations emphasizes the challenges faced by current vector control strategies relying predominantly on chemical control.The detection of both phenotypic permethrin resistance and kdr mutations in Ae. aegypti populations from Kuala Lumpur and Selangor highlights the urgent need to revise and diversify vector control strategies. Improved sampling and molecular surveillance of Ae. albopictus are recommended to provide a more comprehensive understanding of insecticide resistance dynamics in Malaysian dengue vectors.
