Tropical biomedicine最新文献_第2页

Seroprevalence and factors associated with leptospirosis among market traders in Kudat town, Sabah: A cross-sectional study. 沙巴州Kudat镇市场贸易商中钩端螺旋体病的血清患病率和相关因素：一项横断面研究。

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.015

D Marcel, A Atil, M R M Ali, K Ahmed, R Othman, M S Jeffree

{"title":"Seroprevalence and factors associated with leptospirosis among market traders in Kudat town, Sabah: A cross-sectional study.","authors":"D Marcel, A Atil, M R M Ali, K Ahmed, R Othman, M S Jeffree","doi":"10.47665/tb.43.2.015","DOIUrl":"https://doi.org/10.47665/tb.43.2.015","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"238-246"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Molecular detection and cox1-based phylogenetic analysis of Strongyloides stercoralis in fresh vegetables from lower northern Thailand. 泰国北部下游地区新鲜蔬菜中粪类圆线虫的分子检测及系统发育分析。

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.001

W P Molee, A Vitta, T Prasertsri, T Bansra

{"title":"Molecular detection and cox1-based phylogenetic analysis of Strongyloides stercoralis in fresh vegetables from lower northern Thailand.","authors":"W P Molee, A Vitta, T Prasertsri, T Bansra","doi":"10.47665/tb.43.2.001","DOIUrl":"https://doi.org/10.47665/tb.43.2.001","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"142-150"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Preliminary short-term establishment and replication kinetics of a flea-derived Wolbachia strain in an Aedes albopictus cell line. 蚤源沃尔巴克氏体菌株在白纹伊蚊细胞系中的初步短期建立和复制动力学。

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.009

N N K Bahrain, P Hassandarvish, S K Loong, N A Husin, M M S Zulkifli, J J Khoo, L Bell-Sakyi, Z Ya'cob, S AbuBakar, V L Low, N Sahimin

{"title":"Preliminary short-term establishment and replication kinetics of a flea-derived Wolbachia strain in an Aedes albopictus cell line.","authors":"N N K Bahrain, P Hassandarvish, S K Loong, N A Husin, M M S Zulkifli, J J Khoo, L Bell-Sakyi, Z Ya'cob, S AbuBakar, V L Low, N Sahimin","doi":"10.47665/tb.43.2.009","DOIUrl":"https://doi.org/10.47665/tb.43.2.009","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"198-206"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Molecular detection of zoonotic Blastocystis subtypes in urban rats from Pulau Pinang, Malaysia. 马来西亚槟榔屿城市大鼠人畜共患囊胚病亚型的分子检测。

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.007

Y N Chin, P W D Perison, L Sebastian, A B Azlinda, M T Farah Haziqah

{"title":"Molecular detection of zoonotic Blastocystis subtypes in urban rats from Pulau Pinang, Malaysia.","authors":"Y N Chin, P W D Perison, L Sebastian, A B Azlinda, M T Farah Haziqah","doi":"10.47665/tb.43.2.007","DOIUrl":"https://doi.org/10.47665/tb.43.2.007","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"185-190"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Temporal and spatial distribution of dengue in an urban setting: evidence from Hanoi, Vietnam (2018-2022). 登革热在城市环境中的时空分布：来自越南河内的证据（2018-2022）。

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.011

V H Bau, H N Nguyen, M D Le, N S Hoang, V K Nguyen, K T Vu, V A Nguyen

{"title":"Temporal and spatial distribution of dengue in an urban setting: evidence from Hanoi, Vietnam (2018-2022).","authors":"V H Bau, H N Nguyen, M D Le, N S Hoang, V K Nguyen, K T Vu, V A Nguyen","doi":"10.47665/tb.43.2.011","DOIUrl":"https://doi.org/10.47665/tb.43.2.011","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"211-218"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Prospective surveillance of Staphylococcus aureus bacteremia (SAB) using spa typing to identify MRSA transmission in a tertiary care setting. 在三级医疗机构使用spa分型识别MRSA传播的金黄色葡萄球菌菌血症（SAB）的前瞻性监测。

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.005

S Amelia, D Santosaningsih, R L Kusumawati, R Z Hamid, Zulham, P C Eyanoer, M F Rozi, N A Syamira

{"title":"Prospective surveillance of Staphylococcus aureus bacteremia (SAB) using spa typing to identify MRSA transmission in a tertiary care setting.","authors":"S Amelia, D Santosaningsih, R L Kusumawati, R Z Hamid, Zulham, P C Eyanoer, M F Rozi, N A Syamira","doi":"10.47665/tb.43.2.005","DOIUrl":"https://doi.org/10.47665/tb.43.2.005","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"174-179"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

16S rRNA profiling of bacterial communities in the brown dog tick Rhipicephalus linnaei from stray dogs in Perak, Malaysia. 马来西亚霹雳州流浪狗棕狗蜱细菌群落的16S rRNA分析

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.008

A A Azhar, A Zahanuddin, Z Ya'cob, Y L Lau, A S Mokhtar

{"title":"16S rRNA profiling of bacterial communities in the brown dog tick Rhipicephalus linnaei from stray dogs in Perak, Malaysia.","authors":"A A Azhar, A Zahanuddin, Z Ya'cob, Y L Lau, A S Mokhtar","doi":"10.47665/tb.43.2.008","DOIUrl":"https://doi.org/10.47665/tb.43.2.008","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"191-197"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Diagnostic agreement between Simplexa direct real-time PCR and conventional nested PCR for detecting congenital cytomegalovirus in neonatal urine in Indonesia. Simplexa直接实时PCR与传统巢式PCR检测印度尼西亚新生儿尿液中先天性巨细胞病毒的诊断一致性

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.006

J Pamungkas, P Wardhani, D Husada, Ernawati, N Purnami, M Fitriah

{"title":"Diagnostic agreement between Simplexa direct real-time PCR and conventional nested PCR for detecting congenital cytomegalovirus in neonatal urine in Indonesia.","authors":"J Pamungkas, P Wardhani, D Husada, Ernawati, N Purnami, M Fitriah","doi":"10.47665/tb.43.2.006","DOIUrl":"https://doi.org/10.47665/tb.43.2.006","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"180-184"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High genetic diversity and cryptic lineages in three Tabanus species (Diptera: Tabanidae) from Northeastern Thailand. 泰国东北部tabananus（双翅目：Tabanidae）的高遗传多样性和隐伏谱系。

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.004

W Wannasingha, B Gomontean, K Wongpakam, I Thanee, W Chatan, K Vaisusuk, P Pramual

{"title":"High genetic diversity and cryptic lineages in three Tabanus species (Diptera: Tabanidae) from Northeastern Thailand.","authors":"W Wannasingha, B Gomontean, K Wongpakam, I Thanee, W Chatan, K Vaisusuk, P Pramual","doi":"10.47665/tb.43.2.004","DOIUrl":"https://doi.org/10.47665/tb.43.2.004","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"163-173"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The 24-hour crisis: rapidly fatal cerebral malaria due to Plasmodium knowlesi complicated by acute pontine infarction. 24小时危机：由诺氏疟原虫引起的迅速致死性脑疟疾并发急性脑桥梗死。

Tropical biomedicine Pub Date : 2026-06-01 DOI: 10.47665/tb.43.2.010

M H Saripudin, M F Mokhtar, F Mohd Nor

{"title":"The 24-hour crisis: rapidly fatal cerebral malaria due to Plasmodium knowlesi complicated by acute pontine infarction.","authors":"M H Saripudin, M F Mokhtar, F Mohd Nor","doi":"10.47665/tb.43.2.010","DOIUrl":"10.47665/tb.43.2.010","url":null,"abstract":"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.","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"43 2","pages":"207-210"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148665485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0