American Journal of Tropical Medicine and Hygiene最新文献

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Investigation of the blaNDM-1 and armA Genes in Carbapenem-Resistant Klebsiella pneumoniae Isolated from the Clinical Samples in Kathmandu, Nepal. 尼泊尔加德满都耐碳青霉烯类肺炎克雷伯菌blaNDM-1和armA基因的研究
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-25 DOI: 10.4269/ajtmh.25-0433
Rohit Ghimire, Subash Kumar Thakur, Upendra Thapa Shrestha, Komal Raj Rijal, Prakash Ghimire, Megha Raj Banjara
{"title":"Investigation of the blaNDM-1 and armA Genes in Carbapenem-Resistant Klebsiella pneumoniae Isolated from the Clinical Samples in Kathmandu, Nepal.","authors":"Rohit Ghimire, Subash Kumar Thakur, Upendra Thapa Shrestha, Komal Raj Rijal, Prakash Ghimire, Megha Raj Banjara","doi":"10.4269/ajtmh.25-0433","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0433","url":null,"abstract":"<p><p>Klebsiella pneumoniae carbapenemase (KPC) and metallo-β-lactamase production are major causes of carbapenem resistance, whereas aminoglycoside resistance is caused by extrinsically acquired 16S-rRNA methyltransferase. K. pneumoniae coharboring resistance genes are serious health care issues that can cause multidrug resistance (MDR). This study aimed to describe the resistance genes (New Delhi metallo-beta-lactamase 1 [blaNDM-1] and armA) in the plasmids of K. pneumoniae from patients visiting the Paropakar Maternity and Women's Hospital, Kathmandu, Nepal. All together, 8,017 clinical specimens were processed following standard microbiological procedures to identify K. pneumoniae. Antibiotic susceptibility testing and detection of phenotypic carbapenemase production in K. pneumoniae isolates were performed using the modified Kirby-Bauer disc diffusion method. The resistance genes were detected by conventional polymerase chain reaction. Of 8,017 clinical specimens, 6.8% (n = 545) had bacterial growth, and 70 were K. pneumoniae. Colistin (100%, n = 70) and imipenem (80%, n = 56) were the most effective antibiotics. Thirty percent (n = 21) of the isolates were MDR, whereas 66.7% (n = 14) were carbapenemase producers, among which 38.1% (n = 8) had a minimum inhibitory concentration of 64 µg/mL to imipenem. Among carbapenemase producers, 23.8% (n = 5) were KPC and 66.7% (n = 14) were metallo-β-lactamase producers. Out of 21 MDR K. pneumoniae, 19.5% (n = 4) harbored the blaNDM-1 and armA genes, and 14.3% (n = 2) had both genes. Detection of the coexistence of the resistance genes from K. pneumoniae reveals that there might be increased antibiotic resistance leading to multidrug resistance and an increased resistance to imipenem. In conclusion, advancing antimicrobial-resistance surveillance in maternity wards and minimizing the use of last-line antibiotics are crucial for safeguarding maternal and neonatal health.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145147488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Incidence of Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Antibodies in a Rural Community in Western Kenya during the First 24 Months of the Coronavirus Disease 2019 Pandemic. 2019冠状病毒病大流行前24个月肯尼亚西部农村社区冠状病毒2中和抗体的发病率
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-23 DOI: 10.4269/ajtmh.25-0240
Daja D Gaston, Christine F Markwalter, Jillian T Grassia, Betsy Freedman, Lin-Fa Wang, Andrew A Obala, Wendy P O'Meara, Steve M Taylor
{"title":"Incidence of Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Antibodies in a Rural Community in Western Kenya during the First 24 Months of the Coronavirus Disease 2019 Pandemic.","authors":"Daja D Gaston, Christine F Markwalter, Jillian T Grassia, Betsy Freedman, Lin-Fa Wang, Andrew A Obala, Wendy P O'Meara, Steve M Taylor","doi":"10.4269/ajtmh.25-0240","DOIUrl":"10.4269/ajtmh.25-0240","url":null,"abstract":"<p><p>Seroreactivity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens was commonly reported in African settings during the early stages of the coronavirus disease 2019 pandemic. Severe acute respiratory syndrome coronavirus 2 neutralizing antibodies (nAbs) are not only correlated with functional protection from disease but also are highly specific responses to the virus. These responses were used to investigate the evolution of virus exposure in a community-based, longitudinal cohort of 504 individuals in rural Western Kenya. Eluates from dried blood spots collected every 3 months from January 2020 to September 2021 were tested for nAbs using a commercial kit. Only 10 individuals developed SARS-CoV-2 nAbs, all of which were clustered in December 2020 (wildtype virus) and September 2021 (delta variant). After seroconversion, all patients seroreverted within 2 months. Despite reports of widespread viral exposure in Western Kenya from 2020 to 2021, the paucity of nAbs highlights the limited natural immunity present when vaccines became available in late 2021 in Kenya.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145129838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Hydatid Disease Over the Last 5 Years: Experiences from a Tertiary Care Center in India. 过去5年的包虫病:来自印度三级保健中心的经验。
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-23 DOI: 10.4269/ajtmh.24-0853
Urvashi Goyal, Nidhi Tejan, Ashima Jamwal, Ram Naval, Gerlin Varghese, Irfan Khan, Akash Pal, Ujjala Ghoshal, Chinmoy Sahu, Awadhesh Kumar
{"title":"Hydatid Disease Over the Last 5 Years: Experiences from a Tertiary Care Center in India.","authors":"Urvashi Goyal, Nidhi Tejan, Ashima Jamwal, Ram Naval, Gerlin Varghese, Irfan Khan, Akash Pal, Ujjala Ghoshal, Chinmoy Sahu, Awadhesh Kumar","doi":"10.4269/ajtmh.24-0853","DOIUrl":"10.4269/ajtmh.24-0853","url":null,"abstract":"<p><p>Hydatid disease, caused by the parasitic tapeworm Echinococcus, remains a significant public health issue, especially in regions where livestock farming is prevalent. This retrospective study, conducted in the microbiology department of a tertiary care center in North India, is designed to assess the epidemiological trends of hydatid disease over the past 5 years in a tertiary care hospital, focusing on incidence, demographic patterns, clinical characteristics, and diagnostic improvements. During the study period, 843 patients were tested for Echinococcus IgG antibodies. Among them, 400 cases were confirmed positive and 443 were negative for Echinococcus IgG antibodies. Data were retrieved from the hospital's information system, focusing on ELISA results for Echinococcus IgG antibodies. Demographic variables, such as age, sex, and clinical and histopathological parameters, were recorded for the patients. Of 400 positive cases, 54% were male, and 46% were female, with a mean age of 45 years. The highest incidence was found in the 31- to 40-year-old age group. Biochemical analysis revealed significant differences between the positive and negative groups across all parameters (P <0.01). Of 60 patients, the liver was the most predominant organ involved (in 53.3% of cases), followed by the lungs (in 26.7% of cases), and then the spleen and gallbladder (in 6.7% of cases each). Less common sites included the retroperitoneal organs, heart, and renal organs (1.7% of cases each). This study underscores the importance of early detection and heightened clinical suspicion, as well as the value of serological testing in diagnosing and managing this parasitic infection.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145129806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Diagnosis of Central Nervous System Strongyloidiasis in a Patient with Advanced Human Immunodeficiency Infection with Quantitative Polymerase Chain Reaction: Improving Detection and Clinical Management. 定量聚合酶链反应诊断晚期人类免疫缺陷感染患者中枢神经系统类圆线虫病:改进检测和临床管理。
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-23 DOI: 10.4269/ajtmh.25-0202
Ramya Madhavan, Selwyn Selva Kumar, Malathi Manuel, Selvi Laxmanan, Harshad Arvind Vanjare, Abi Manesh, Sitara Swarna Rao Ajjampur
{"title":"Diagnosis of Central Nervous System Strongyloidiasis in a Patient with Advanced Human Immunodeficiency Infection with Quantitative Polymerase Chain Reaction: Improving Detection and Clinical Management.","authors":"Ramya Madhavan, Selwyn Selva Kumar, Malathi Manuel, Selvi Laxmanan, Harshad Arvind Vanjare, Abi Manesh, Sitara Swarna Rao Ajjampur","doi":"10.4269/ajtmh.25-0202","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0202","url":null,"abstract":"<p><p>Strongyloides stercoralis is a soil-transmitted nematode that leads to asymptomatic or mild infections in immunocompetent hosts; however, in immunocompromised individuals, it can lead to hyperinfection and disseminated strongyloidiasis that can be fatal. Central nervous system (CNS) involvement is rare but can result in severe complications, such as meningitis. Diagnosis is challenging because of the low sensitivity of conventional microscopy. Molecular techniques, such as quantitative polymerase chain reaction (qPCR), are more sensitive, especially for detecting S. stercoralis in cerebrospinal fluid (CSF). We report a case of a 28-year-old female with newly diagnosed advanced HIV infection with CD4 counts of 54 cells/µL presenting with disseminated strongyloidiasis and CNS involvement. She subsequently developed Escherichia coli bacteremia and meningitis. Although microscopy of stool and sputum detected the infection, S. stercoralis qPCR in CSF was crucial for diagnosing CNS involvement. This case underscores the importance of molecular diagnosis of CNS strongyloidiasis among high-risk patients to enable timely appropriate therapeutic intervention.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145129842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Bloodstream Infections and Antimicrobial Resistance in The Gambia: Continuous Surveillance from a Tertiary Care Center. 冈比亚血液感染和抗菌素耐药性:来自三级保健中心的持续监测。
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-23 DOI: 10.4269/ajtmh.25-0199
David Nygren, Felix Andersson, Ebrima Barrow, Sheikh Omar Bittaye, Haddy Bah, Fatou Banja, Kumba Suun Mboob, Lamin Fatajo, Marisel Gomez Blanco, Emmanuel Olabode, Alieu Jallow, Abdoulie Badjan, Paul Rahden
{"title":"Bloodstream Infections and Antimicrobial Resistance in The Gambia: Continuous Surveillance from a Tertiary Care Center.","authors":"David Nygren, Felix Andersson, Ebrima Barrow, Sheikh Omar Bittaye, Haddy Bah, Fatou Banja, Kumba Suun Mboob, Lamin Fatajo, Marisel Gomez Blanco, Emmanuel Olabode, Alieu Jallow, Abdoulie Badjan, Paul Rahden","doi":"10.4269/ajtmh.25-0199","DOIUrl":"10.4269/ajtmh.25-0199","url":null,"abstract":"<p><p>Antimicrobial resistance (AMR) poses a major threat to global health, with limited surveillance data available from western sub-Saharan Africa. After reports of high rates of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL) in bloodstream infections at The Gambia's sole tertiary hospital, we present follow-up data after enhancements in microbiology capacity. This study included 1,010 patients with blood cultures taken at Edward Francis Small Teaching Hospital between September 2023 and August 2024. The positivity rate remained high (31%), particularly among neonates and critically ill patients. Staphylococcus aureus was the most frequently isolated pathogen (49%, n = 155/314), with MRSA identified in 22% (n = 34/152) of tested isolates. Among Enterobacterales, ESBL production remained high (87%, n = 84/97), and carbapenem resistance was detected in 15% (n = 6/39) of tested isolates. Our findings highlight the need for a robust and sustained AMR surveillance system to inform targeted interventions aimed at reducing the emergence and spread of multidrug-resistant pathogens.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145129840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Development of a Rapid Diagnostic Test to Distinguish between Emerging Viruses That Cause Hemorrhagic Fever. 一种快速诊断试验的发展,以区分引起出血热的新出现的病毒。
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-18 DOI: 10.4269/ajtmh.25-0168
Andrew Wilson, Heather Poeck-Goux, Madison Ruschaupt, Scott Olschner, Keersten M Ricks, Darci R Smith
{"title":"Development of a Rapid Diagnostic Test to Distinguish between Emerging Viruses That Cause Hemorrhagic Fever.","authors":"Andrew Wilson, Heather Poeck-Goux, Madison Ruschaupt, Scott Olschner, Keersten M Ricks, Darci R Smith","doi":"10.4269/ajtmh.25-0168","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0168","url":null,"abstract":"<p><p>Viruses that cause the clinical syndrome referred to as viral hemorrhagic fever (VHF) are responsible for numerous infectious disease outbreaks. High-priority emerging viruses include orthoebolaviruses, orthomarburgviruses, Lassa virus, Crimean-Congo hemorrhagic fever virus, Rift Valley fever virus (RVFV), dengue virus (DENV), and yellow fever virus (YFV). Many of these viruses cause a similar clinical presentation in infected humans and have an overlapping geographic distribution with a risk of coemergence. As such, an antigen rapid diagnostic test to distinguish between these viruses would be beneficial in low-resource settings. In this study, we developed single-plex and multiplex antigen detection lateral flow immunoassays (LFIs) to rapidly detect and distinguish between emerging viruses that can cause VHF. We evaluated two antibody-labeling methods, colloidal gold nanoparticles and cellulose nanobeads (CNBs), to determine which approach would increase assay performance and multiplexing capabilities. Assay performance was evaluated by determining their sensitivity, specificity, matrix evaluation, and stability testing. All assays were highly specific, with no crossreactivity observed for the single-plex assays. Several of the assays performed better with the CNBs, including the DENV, YFV, RVFV, and orthomarburgvirus LFIs. No matrix effect was observed with most of the assays except that serum did impact the RVFV and DENV assays. In general, the multiplex assays were less sensitive compared with their respective single-plex assay. The most successful assays were the single-plex CNB LFIs assembled into an eight-plex cartridge, which allows for rapid and simultaneous testing of antigen to seven viruses.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145084813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Cultural and Clinical Insights from an Outbreak of Eosinophilic Meningitis Caused by the Rat Lungworm (Angiostrongylus cantonensis) in South Brazil. 巴西南部由大鼠肺虫(广州管圆线虫)引起的嗜酸性脑膜炎暴发的文化和临床见解。
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-18 DOI: 10.4269/ajtmh.25-0364
Christopher J Hernandez, Pedro M Fonseca, Andressa Noal, Mary Catherine Cambou, Ivana Rosângela Dos Santos Varella, Breno R Santos, Marineide Gonçalves de Melo, Karin Nielsen-Saines
{"title":"Cultural and Clinical Insights from an Outbreak of Eosinophilic Meningitis Caused by the Rat Lungworm (Angiostrongylus cantonensis) in South Brazil.","authors":"Christopher J Hernandez, Pedro M Fonseca, Andressa Noal, Mary Catherine Cambou, Ivana Rosângela Dos Santos Varella, Breno R Santos, Marineide Gonçalves de Melo, Karin Nielsen-Saines","doi":"10.4269/ajtmh.25-0364","DOIUrl":"10.4269/ajtmh.25-0364","url":null,"abstract":"<p><p>Angiostrongylus cantonensis, or rat lungworm, is a neurotropic parasite that causes eosinophilic meningitis. Although classically transmitted through ingestion of contaminated produce or undercooked snails or slugs, ritual ingestion of slugs as part of spiritual ceremonies has not been well described as a transmission route. We report two cases of eosinophilic meningitis in previously healthy adult men in south Brazil who developed subacute neurological symptoms, including progressive lower limb weakness, hyperesthesia, and severe neuropathic pain. Cerebrospinal fluid (CSF) analysis revealed marked eosinophilia (27-35%) and elevated protein levels. One patient showed subtle leptomeningeal enhancement on magnetic resonance imaging (MRI). Both cases were serologically confirmed by ELISA and western blot for A. cantonensis in CSF. History-taking revealed a shared exposure event: the ingestion of raw slugs during a religious ritual. Both patients were treated with albendazole, ivermectin, and corticosteroids for 2 weeks, as well as gabapentin for neuropathic pain. Both patients demonstrated neurological recovery and were discharged with outpatient follow-up. Both patients had normal CSF parameters within 2 weeks. These cases highlight a culturally linked exposure route for A. cantonensis. Clinicians should consider eosinophilic meningitis in the differential diagnosis of subacute neurological syndromes in endemic areas, particularly when initial diagnoses (e.g., urinary tract infection, gout) do not explain the full clinical picture. Culturally sensitive history-taking and communication, especially when considering communities that are vulnerable to stigma and violence, is critical to help obtain relevant exposure history.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145084796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Revisiting the Role of Opossums (Marsupialia) as Sentinel for Brazilian Spotted Fever Caused by Rickettsia rickettsii. 重新审视负鼠(有袋动物)作为立克次体引起的巴西斑疹热哨兵的作用。
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-16 DOI: 10.4269/ajtmh.25-0026
Felipe Trevisan Ortiz, Carlos Alberto Perez, Lina C Binder, Maria Carolina A Serpa, André Pinheiro Almeida, Luis Guilherme de Queiroz, Elias Soares de Figueiredo, Sofía Jiménez Jorge, Erica Veiga de Oliveira Luiz, Ravi das Neves, Alan Ferreira Nunes, Julia Dotoli Silva, Ivan Carlos Valério, Carolina Vitti, João Pedro Ignez Martin, Marcus Vinicius Stenico, Lina Marcela Gonzalez Cano, Thiago F Martins, Marianna Ricciardi Curi, Helder Louvandini, Adriane da Fonseca Duarte, Odaléia Telles Marcondes Machado Queiroz, Gilberto José de Moraes, Marcelo B Labruna
{"title":"Revisiting the Role of Opossums (Marsupialia) as Sentinel for Brazilian Spotted Fever Caused by Rickettsia rickettsii.","authors":"Felipe Trevisan Ortiz, Carlos Alberto Perez, Lina C Binder, Maria Carolina A Serpa, André Pinheiro Almeida, Luis Guilherme de Queiroz, Elias Soares de Figueiredo, Sofía Jiménez Jorge, Erica Veiga de Oliveira Luiz, Ravi das Neves, Alan Ferreira Nunes, Julia Dotoli Silva, Ivan Carlos Valério, Carolina Vitti, João Pedro Ignez Martin, Marcus Vinicius Stenico, Lina Marcela Gonzalez Cano, Thiago F Martins, Marianna Ricciardi Curi, Helder Louvandini, Adriane da Fonseca Duarte, Odaléia Telles Marcondes Machado Queiroz, Gilberto José de Moraes, Marcelo B Labruna","doi":"10.4269/ajtmh.25-0026","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0026","url":null,"abstract":"<p><p>In southeastern Brazil, Rickettsia rickettsii, the agent of Brazilian spotted fever (BSF), is mainly transmitted to humans by Amblyomma sculptum ticks, whose populations are chiefly sustained by capybaras, Hydrochoerus hydrochaeris. As capybaras are sentinel hosts for BSF, serological analysis of capybaras is the most feasible way to determine whether an A. sculptum population is infected with R. rickettsii or not. Because the immature stages of A. sculptum commonly feed on opossums (Didelphis spp.), which are susceptible to R. rickettsii infection, this study aimed to validate the use of opossums (Didelphis albiventris) as sentinel hosts for active surveillance of the BSF. Between 2017 and 2020, a total of 159 opossums were captured in nine areas of Piracicaba, a BSF-endemic municipality. Ticks and blood were collected from opossums. The ticks were identified at the species level, and the blood was used for serological analysis to detect antibody end-point titers to R. rickettsii and Rickettsia bellii. Area 1a, which had a recent history of BSF, was used as the \"positive control\" area, whereas area 1b (devoid of capybaras) was used as the \"negative control\" area. Based on the results from these two areas, the remaining seven areas were categorized according to their risk of BSF based on serological results and the presence and abundance of ticks on opossums. The results indicated that two, one, and four areas were at high, low, and intermediate risk of BSF, respectively. This study validated the use of opossums as alternative sentinels for the active surveillance of BSF.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145074015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Lung Microbiota in People Diagnosed with HIV and Pneumonia: A Colombian Cohort Study. 诊断为艾滋病毒和肺炎的人的肺部微生物群:一项哥伦比亚队列研究
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-16 DOI: 10.4269/ajtmh.23-0903
Katherine Peña-Valencia, Juan Pablo Isaza, Michael Becker, Breanne M Head, Lucelly López, Jhonatan Peña-Valencia, Iván Rodriguez, Diana Marín, Yudy Aguilar, Lázaro Vélez, Zulma Vanessa Rueda, Yoav Keynan
{"title":"Lung Microbiota in People Diagnosed with HIV and Pneumonia: A Colombian Cohort Study.","authors":"Katherine Peña-Valencia, Juan Pablo Isaza, Michael Becker, Breanne M Head, Lucelly López, Jhonatan Peña-Valencia, Iván Rodriguez, Diana Marín, Yudy Aguilar, Lázaro Vélez, Zulma Vanessa Rueda, Yoav Keynan","doi":"10.4269/ajtmh.23-0903","DOIUrl":"https://doi.org/10.4269/ajtmh.23-0903","url":null,"abstract":"<p><p>The lung microbiota plays a key role in respiratory health, but its composition in individuals living with HIV and diagnosed with community-acquired pneumonia (CAP) remains underexplored. A prospective cohort study in Medellín, Colombia recruited individuals with CAP and/or HIV between 2016 and 2018. Clinical and microbiological data were collected at baseline, with bronchoalveolar lavage samples obtained at baseline and induced sputum samples collected at baseline and 6-month follow-up. Microbiota composition was analyzed in these samples using Illumina MiSeq sequencing of the 16S ribosomal RNA gene. Among 248 screened participants, 64 were included: HIV and CAP (n = 27), CAP (n = 7), and HIV (n = 30); 70.3% were males, and 76.6% were between 25 and 64 years old. The HIV and CAP group had a lower proportion of receiving antiretroviral treatment and a higher prevalence of advanced immunosuppression. The most frequent micro-organisms identified by conventional methods in the HIV and CAP group were Mycobacterium tuberculosis (40.7%) and Pneumocystis jirovecii (18.5%). The dominant phyla (Firmicutes, Proteobacteria, Fusobacteria, Bacteroidetes, and Actinobacteria) and genera (Streptococcus, Haemophilus, Veillonella, Neisseria, and Fusobacterium) were identified in the overall study population, including both baseline and 6-month follow-up samples. The HIV and CAP group showed changes in bacterial diversity and relative abundance over 6 months. These findings provide insights into the dynamic lung microbiota in individuals coinfected with HIV and CAP, highlighting the impact of HIV and CAP on microbial composition and diversity, which may inform future studies exploring clinical outcomes.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145074071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Historical Circulation and Forgotten Evidence of Oropouche Virus in Colombia: Not as New as it Seems. 哥伦比亚Oropouche病毒的历史传播和被遗忘的证据:并不像看起来那么新。
IF 1.6 4区 医学
American Journal of Tropical Medicine and Hygiene Pub Date : 2025-09-11 DOI: 10.4269/ajtmh.25-0423a
Carlos Ramiro Silva-Ramos, Álvaro A Faccini-Martínez
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