Tropical biomedicine最新文献

{"title":"The distribution of B lymphocyte subpopulations in mice infected with Mycobacterium tuberculosis H37Ra.","authors":"Y Lv, C Wang, L Bai","doi":"10.47665/tb.42.1.013","DOIUrl":"10.47665/tb.42.1.013","url":null,"abstract":"<p><p>Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis (Mtb), is a major cause of morbidity and mortality worldwide. Annually, millions of new cases of tuberculosis are documented. Research in tuberculosis-immune has hitherto focused predominantly on the role of T cells in Mtb infection. Although there have been studies in progress which have supported the notion that B cells are crucial players in combating infectious diseases, the role of B cells in TB is still not fully understood. There is a paucity of in-depth analysis of various B lymphocyte subpopulations and the understanding of the immunophenotypic changes of the B-cell lineage during tuberculosis infection. Therefore, we aimed to investigate the changes in B lymphocyte subpopulations in mice infected with M.tuberculosis H37Ra. The percentage/frequency of peritoneal B cells (CD45R+), B1b cells (CD45RIntIgDCD5- CD11+), splenic B cells (CD45R+), and splenic marginal zone B (MZ B) cells (CD45R+CD23- CD21hi) decreased (P < 0.05), while the percentage of splenic follicular B (Fo B) cells (CD45R+CD23+ CD21int) and lymph node B cells (CD19+) increased at the 4th and 8th weeks (P < 0.05). It was suggested that H37Ra infection changed the distribution of B lymphocyte subpopulations. In addition, the percentage of CD69+B cells and memory B cells (CD45R+CD27+ IgD+/-) increased in the infected mice at different infection periods (P < 0.05), which suggested H37Ra infection promoted B cell activation and produced a large number of memory B cells. As a conclusion, H37Ra infection can affect the distribution of B lymphocyte subpopulations, with a concomitant down-regulation of MZ B cells, which perform innate immunity, and up-regulation of adaptive immune response cells (Fo B cells and lymph node B cells). Furthermore, it has been demonstrated that H37Ra infection can promote the immune response of B lymphocytes to tuberculosis, through the stimulation of the body to produce a large number of activated and memory B cells.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"76-84"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143756565","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}

{"title":"Sexual mosaicism in the black fly Simulium (Gomphostilbia) hongthaii (Diptera: Simuliidae) in Vietnam.","authors":"D V Nguyen, H Takaoka","doi":"10.47665/tb.42.1.007","DOIUrl":"10.47665/tb.42.1.007","url":null,"abstract":"<p><p>Sexual mosaicism was found in an adult black fly reared from a pupa in Vietnam. It is considered an antero-posterior type of gynandromorph, showing female phenotype for the head, thorax and wing; male phenotype for the abdomen including the genitalia; and mixed phenotype for the legs. The fly is identified as Simulium (Gomphostilbia) hongthaii in the S. asakoae species-group by having the sensory vesicle medium-long (0.28-0.30 times as long as the third palpal segment), mandible without teeth on its outer margin, and ventral plate transverse, with its lateral margins emarginated basally when viewed ventrally, and trapezoidal, with its ventral margin nearly straight when viewed posteriorly. This specimen represents the first record of a black fly with sexual mosaicism in Vietnam.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"44-46"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143757167","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}

{"title":"Detection of Leptospira in environmental samples of wet markets and paddy fields in Penang, Malaysia.","authors":"B L Ling, Z E Tay, N Philip","doi":"10.47665/tb.42.1.009","DOIUrl":"10.47665/tb.42.1.009","url":null,"abstract":"<p><p>Leptospirosis, caused by the Leptospira spp., is endemic in humid subtropical and tropical climates. Several environmental settings can harbour the survival of Leptospira; hence, continuous surveillance of the high-risk areas is critical. This study was conducted to detect the presence of Leptospira in wet markets and paddy fields in Penang, Malaysia. A total of 62 soil and water samples were collected aseptically from three wet markets and two paddy fields. The samples were cultured twice on the sampling day and after two weeks of storage in the dark at ambient temperature. All environmental samples and positive cultures were subjected to deoxyribonucleic acid (DNA) extraction and polymerase chain reaction (PCR) targeting 16S rRNA, lipL32 and rrs genes. 16S rRNA-positive samples were further sent for sequencing. Of 62 samples, 21 (21/62, 33.9%) tested positive via culture and PCR. Wet markets significantly had a higher detection rate of leptospires (29%) than paddy fields (4.8%). Four Leptospira species (L. selangorensis, L. dzoumogneensis, L. mtsangambouensis, and L. meyeri) were identified in wet markets and three (L. meyeri, L. wolffii, and L. kmetyi) in paddy fields. Storing the environmental samples for two weeks before isolation yielded a higher positivity (11/14) than culturing samples on the sampling day (6/14). The presence of Leptospira in the environment of wet markets and paddy fields in Penang although primarily intermediate and saprophyte indicates the crucial need to implement preventive measures to prevent the possibility of leptospirosis infection among the workers.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"51-57"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143757155","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}

{"title":"Use of multiplex molecular respiratory panel in COVID-19 patients with suspected co-infections: Insights and considerations in results interpretation.","authors":"A S Nawi, E N S Engku Abd Rahman, N M N Nik Zuraina, N Musa, M Z Salleh, M N F Samsudin, W C Chua, A Muhd Besari, R Hassan, Y Y Chan","doi":"10.47665/tb.42.1.004","DOIUrl":"10.47665/tb.42.1.004","url":null,"abstract":"<p><p>As critically ill COVID-19 patients are prone to infections by other respiratory pathogens, this study aimed to investigate the detection of respiratory co-pathogens in such patients, by employing a multiplex respiratory molecular panel. Conducted at Universiti Sains Malaysia Specialist Hospital (HPUSM) from November 1, 2021, to November 1, 2022, this retrospective cross-sectional study analysed adults admitted with confirmed COVID-19. Oropharyngeal/ nasopharyngeal swabs collected upon admission were tested using the Fast Track Diagnostic (FTD®) Respiratory Pathogens 33 multiplex kit to detect other respiratory pathogens. Within 48 hours of admission, the presence and type of organisms were determined to assess community co-infections. Among 48 critically ill COVID-19 patients (26 male; mean age, 62.2 years), clinically significant organisms were found in 32 patients (67%). Bacterial co-infections or co-colonization were detected in 91% (29/32) of these patients, with Klebsiella pneumoniae (40%) and Staphylococcus aureus (23%) were the most common, followed by Streptococcus pneumoniae (11%), Moraxella catarrhalis (4%), and Haemophilus influenzae (2%). Fungal (6%) and viral (2%) co-infections were less frequent. The use of syndromic respiratory panel in critically ill COVID-19 patients offers the advantage of being highly sensitive, rapid, and able to detect multiple pathogens. However, detection of multiple respiratory pathogens needs to be interpreted with caution, taking into consideration patient's clinical and radiological findings, as well as quantitative molecular data.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"21-26"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143756720","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}

{"title":"Fever of unknown origin: An atypical presentation of typhoid in a child with glucose-6-phosphate dehydrogenase (G6PD) deficiency.","authors":"F Abdul Rashid, N Husain, H Hussin, F Mohd Nor","doi":"10.47665/tb.42.1.002","DOIUrl":"10.47665/tb.42.1.002","url":null,"abstract":"<p><p>Typhoid is an acute febrile illness primarily caused by Salmonella enterica serotype typhi (S. Typhi) which could be challenging to diagnose in children, owing to its non-specific clinical signs and symptoms which may resemble other febrile illnesses. Here, we present a case of typhoid which was atypically presented as fever of unknown origin (FUO) in a two-year-old boy with underlying glucose-6-phosphate dehydrogenase (G6PD) deficiency. This child was initially diagnosed and managed as acute tonsillopharyngitis, however remained febrile despite medications. A series of investigations were performed and S. Typhi was isolated from the bone marrow culture after almost a month of admission. The antibiotic was started based on antibiotic susceptibility testing and he recovered well. Our case underscores the challenges of diagnosis establishment and clinical management of typhoid in paediatric patients who has underlying disease and emphasizes the importance of having high index of clinical suspicion to ascertain timely and proper diagnosis.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"10-14"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143757159","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}

{"title":"Spatiotemporal mapping of canine rabies transmission dynamics in Sarawak, East Malaysia from 2017 to 2023.","authors":"Y A Wada, M M Noordin, M Mazlan, S Z Ramanoon, U Z Izzati, S F Lau, M A Mohd-Lila","doi":"10.47665/tb.42.1.006","DOIUrl":"10.47665/tb.42.1.006","url":null,"abstract":"<p><p>Canine rabies poses a significant global public health threat, including in Malaysia. Despite this disease's severity, there is a notable research gap concerning the spatial and temporal epidemiology of canine rabies, limiting the development of effective control strategies. This study delves into the spatiotemporal patterns of canine rabies occurrence in Sarawak, East Malaysia, spanning from 2017 to 2023, with the primary goal of offering insights crucial for shaping robust control measures. Utilising surveillance data from the World Animal Health Information System (OIE-WAHIS) and local reports, we employed descriptive statistics to analyse the data. Spatial heat maps were generated to pinpoint rabies hotspots and examine their association with potential transmission predictors. Findings unveiled an overall positivity rate of 28.34%, predominantly affecting dogs. District-specific variations emerged, and spatial risk maps successfully identified hotspots. Predictive factors, including dog versus human population and households, exhibited strong positive correlations with rabies occurrences. High-risk regions displayed associations with human population density and major road networks. This investigation contributes valuable insights that enhance our comprehension of canine rabies transmission dynamics, thereby guiding effective control strategies. The knowledge gained holds the potential to aid in eliminating canine rabies in Sarawak and other regions in east Malaysia.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"36-43"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143757171","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}

{"title":"Undifferentiated tropical fever: a case series of three Rickettsial infections.","authors":"W C Chua, A A Irekeola, M I Abdul Hadi, W S Wan Mohamad, N I Mohd Nasir, N Mohamad, A M B Hashim, M H Fauzi, Y Y Chan","doi":"10.47665/tb.42.1.008","DOIUrl":"10.47665/tb.42.1.008","url":null,"abstract":"<p><p>We report three cases of rickettsial infections diagnosed by performing a multiplex molecular syndromic panel, in patients who presented with undifferentiated tropical fever with non-specific clinical signs and symptoms. All three patients were from regions endemic to agents of tropical fever, such as dengue fever, leptospirosis, and typhoid fever, which were considered as differential diagnoses in the initial investigative workup. These cases highlight the need for a rapid syndromic diagnostic approach for tropical fever to enable timely diagnosis and institution of appropriate antibiotic therapy, as the typical empirical antibiotics for undifferentiated febrile illness, targeting the bacterial cell wall are ineffective in treating rickettsial infections.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"47-50"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143756577","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}

{"title":"Seroprevalence of specific antibodies against Toxoplasma gondii among patients with malignant tumors in Dali, Yunnan province.","authors":"S T Du, Y W Yang, T F Wu","doi":"10.47665/tb.42.1.011","DOIUrl":"10.47665/tb.42.1.011","url":null,"abstract":"<p><p>To investigate the seroprevalence of Toxoplasma gondii infection in patients with malignant tumors, we aimed to provide insights into improving the prognosis and quality of life of these patients. A total of 721 patients with malignant tumors admitted to the Affiliated Hospital of Dali University from November 2020 to May 2022, along with 100 healthy volunteers from the hospital during the same period, were enrolled. Demographic data and serum samples were collected, and serum-specific IgG and IgM antibodies against T. gondii were detected using an enzyme-linked immunosorbent assay. Patients were considered positive for T. gondii infection if either IgG or IgM antibodies were detected. The seroprevalence of specific IgG and IgM antibodies was compared between patients with malignant tumors and healthy volunteers. The positivity rates for anti-T. gondii antibodies in patients with malignant tumors was significantly higher than that in healthy volunteers (31.2% vs. 13.0%; χ² = 14.141, P < 0.01). Pairwise comparisons revealed that the positive rates of serum anti-T. gondii antibodies in patients with various types of malignant tumors were significantly higher than those in healthy volunteers (all P values < 0.01). There was no statistically significant difference in the average age and sex composition between patients with malignant tumors and healthy volunteers (P > 0.05). The results indicate a high seroprevalence rate of T. gondii infections among patients with malignant tumors, which was significantly higher than that among healthy volunteers.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"61-64"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143757165","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}

{"title":"Bacteremia due to the fastidious bacterium Granulicatella adiacens: A diagnosis that was almost missed.","authors":"C H Ding, A A Wahab, N Mohamed, P F Wong","doi":"10.47665/tb.42.1.010","DOIUrl":"10.47665/tb.42.1.010","url":null,"abstract":"<p><p>Bacteremia due to Granulicatella adiacens has been rarely reported in the medical literature. A middleaged gentleman developed necrotizing fasciitis on his left second toe after stepping on a nail. A ray amputation was performed and ceftazidime-susceptible Pseudomonas aeruginosa was isolated from his bone culture. However, while receiving ceftazidime for the necrotizing fasciitis, his blood culture vial was positive for gram-positive cocci-shaped bacteria in short chains which grew as tiny non-lytic colonies on sheep blood agar only following extended incubation. There was no culture evidence of P. aeruginosa in the same blood specimen. The gram-positive organism was conclusively identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry as G. adiacens. The patient was treated with benzylpenicillin (to which the organism tested susceptible) for 14 days before he was discharged home.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"58-60"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143757151","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}

{"title":"Decrease in RT-PCR Ct values among SARS-CoV-2 positive samples during the emergence of B.1.617.2 (Delta) variant in Malaysia.","authors":"N Che-Kamaruddin, B T Teoh, K K Tan, J Y Tan, J E Wong, V Tiong, J Abd-Jamil, S S Nor'e, C S Khor, J Johari, C N Yaacob, M M S Zulkifli, A CheMatSeri, N H Mahfodz, N S Azizan, S AbuBakar","doi":"10.47665/tb.42.1.001","DOIUrl":"10.47665/tb.42.1.001","url":null,"abstract":"<p><p>Reverse transcription-polymerase chain reaction (RT-PCR) cycle threshold (Ct) value in detecting the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection is inversely proportionate to the virus load in the patient's specimen. These values could be beneficial in the epidemic trajectory at the population level. The SARS-CoV-2 B.1.617.2 (Delta) variant which emerged in late 2020, caused an unprecedented exponential increase in SARS-CoV-2 infection cases worldwide. In Malaysia, the surge in coronavirus disease 2019 (COVID-19) cases and the inclining positivity rate contributed to the epidemic waves in late May 2021. Sudden surge in cases was suggested to be associated with increased transmission caused by the emergence of the B.1.617.2 variant. In the present study, Ct value distribution of the positive COVID-19 samples from 2020 and 2021 was tabulated against SARS-CoV-2 genomic variants determined from genomic sequencing. A significant decreasing pattern of median Ct values from overall 2020 and 2021 samples was evident (p<0.01). However, notable variability was observed in the Ct values between 2020 and 2021, which samples showing lower median Ct values in 2021. The percentages of SARS-CoV-2 genomic variants B.1.36 and B.1.524 were 31.6% and 68.4%, respectively, for samples obtained in October and December 2020. Whereas samples obtained in June and July 2021 were 100% of the B.1.617.2 variant. The population neutralizing antibody against SARS-CoV-2 during the initial peak of B.1.617.2 was low, however, increased during the B.1.617.2 wave. A decreasing trend in the Ct value distribution from samples tested in our laboratory correlated well with the increasing weekly COVID-19 cases reported by the Malaysia national data, which was subsequently attributed to the emergence of B.1.617.2 variant. This study proposes that analyzing Ct value distribution in screened SARS-CoV-2 samples could reveal population-level transmission dynamics and emerging variants. Coupled with genomic sequencing, it supports early control strategies against new SARS-CoV-2 strains.</p>","PeriodicalId":101343,"journal":{"name":"Tropical biomedicine","volume":"42 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143757153","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}