American Journal of Tropical Medicine and Hygiene最新文献

{"title":"Integrated Surveillance Strategies and Clinical Characteristics of Arboviral Diseases in a Pediatric Cohort in Merida, Mexico, 2021-2023.","authors":"Gloria A Barrera-Fuentes, Chiara Antonioli, Norma Pavia-Ruz, Azael Che-Mendoza, James T Earnest, Oscar D Kirstein, Ariadna B Eb-Cordova, Karina J Ciau-Carillo, Shirin Jabbarzadeh, Pilar Granja-Perez, Salha Villanueva-Jorge, Henry Puerta-Guardo, Matthew H Collins, Guadalupe Ayora-Talavera, M Elizabeth Halloran, Ira M Longini, Natalie Dean, Lance A Waller, Amy Crisp, Pablo Manrique-Saide, Gonzalo M Vazquez-Prokopec, Hector Gomez-Dantes","doi":"10.4269/ajtmh.25-0669","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0669","url":null,"abstract":"<p><p>Dengue, chikungunya, and Zika are Aedes-borne diseases (ABDs) of global health significance. Epidemiological studies with sensitive case detection are critical for evaluating vector control strategies to prevent ABDs; however, data on which surveillance method is most effective are limited. The performance of five surveillance methods (home visits, phone calls, SMS reminders, toll-free phone line (TF) and the Ministry of Health surveillance platform) was assessed, and the clinical characteristics of ABD cases in the targeted indoor residual spraying trial, which quantified the efficacy of preventive indoor residual insecticide applications against ABDs in Merida, Mexico, were described. A cohort of 4,461 children was monitored over three transmission seasons (July-December 2021-2023), with surveillance methods rotated weekly to detect illnesses. Kaplan-Meier curves and log-rank tests compared the time from symptom onset to laboratory testing across methods. Analysis of variance, t- and χ2 tests assessed differences in utilization of surveillance methods across demographic factors. Of 1,902 illnesses detected, 920 (48.4%) met suspected ABD criteria; 825 provided blood samples (89%), and 422 (51%) were confirmed as ABDs. Dengue represented 70.4% of confirmed cases (n = 297/422). Among confirmed cases, clinical manifestations were diverse, with fever (>94%), myalgia (80-100%), and headache (70-100%) being most frequent. Twenty-seven patients (9%; n = 27/297) had dengue with warning signs. TF detected 55.2% (n = 233/422) of confirmed cases and achieved the fastest time to laboratory testing. These results demonstrate case detection can be optimized. TF proved effective in rapidly identifying symptomatic reports, underscoring the value of integrated, low-barrier reporting systems for early arboviral detection.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147809696","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}

{"title":"Reduced Efficacy of Piperonyl Butoxide Based Long-Lasting Insecticide-Treated Nets Against Malaria Vectors in Western Kenya.","authors":"Samuel Kahindi, Lucy Abel, Erastus Kirwa, Mark Amunga, Emma Kimachas, Evans Omondi, Millicent Cherono, Judith Mangeni, Andrew Obala, Christine Markwalter, Wendy Prudhomme O'Meara","doi":"10.4269/ajtmh.25-0342","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0342","url":null,"abstract":"<p><p>In response to rising insecticide resistance among malaria vector species, countries are implementing long-lasting insecticide treated nets (LLINs) coformulated with piperonyl butoxide (PBO), which can restore susceptibility to pyrethroid-based nets. In mid-2021, Kenya National Malaria Program rolled out PBO-LLINs in Bungoma County. We evaluated the susceptibility of wild-collected vectors to new versus used PBO-LLINs using the WHO cone bioassays. Results were confirmed with the WHO susceptibility assay. A total of 2,020 female Anopheles were tested, of which 1,480 were wild-collected and 540 were a Kilifi-susceptible strain. Mortality after exposure to new PBO-LLINs was only 68% in the wild-collected mosquitoes and as low as 34% when mosquitoes were exposed to used, 24-month old PBO-LLINs. Anopheles arabiensis was the main vector species that survived exposure. Susceptibility tests confirmed very low mortality after exposure to permethrin with or without PBO. Reduced sensitivity can be attributed partly to the aging of the net but also to very high levels of resistance in the local vector population.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147760034","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}

{"title":"Contact Networks of Small Mammals Highlight Potential Transmission Foci of Mammarenavirus lassaense.","authors":"David Simons, Ravi Goyal, Umaru Bangura, Rory Gibb, Ben Rushton, Dianah Sondufu, Joyce Lamin, James Koninga, Momoh Foday, Mike Dawson, Joseph Lahai, Rashid Ansumana, Elisabeth Fichet-Calvet, Richard Kock, Deborah Watson-Jones, Kate E Jones","doi":"10.4269/ajtmh.25-0120","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0120","url":null,"abstract":"<p><p>Lassa fever (LASV; Mammarenavirus lassaense) is an endemic zoonosis in West Africa. Human infections arise from rodent-to-human transmission, primarily from the synanthropic reservoir Mastomys natalensis (M. natalensis). In Sierra Leone, small-mammal communities vary across land-use gradients, shaping LASV transmission risk. How anthropogenic environments facilitate the rodent-rodent interactions remains poorly understood. Small mammals were sampled over 43,266 trap nights in Sierra Leone's LASV-endemic Eastern Province, detecting 684 rodents and shrews. To assess potential transmission, space-sharing networks were constructed from co-trapping events within species-specific home range radii. Shared space use was approximated in these networks, enabling the comparison of encounter patterns across habitats. Network topology varied significantly by land use. Village networks were the most connected (highest average degree), whereas agricultural communities supported the most species (higher rarefied richness) and were the most fragmented (higher modularity). Notably, the probability of intraspecific space sharing among M. natalensis was highest in agricultural settings, suggesting that land use modulates key intraspecific transmission pathways. Lassa fever seroprevalence was 5.7% community-wide, with antibodies detected in nine species. No statistically significant association was found between overall seroprevalence and land use or aggregate network structure (mean degree). However, predictive modeling for M. natalensis indicated that a higher individual degree is associated with seropositivity, suggesting complex, scale-dependent relationships. These findings reveal that simple ecological drivers do not fully explain LASV exposure, highlighting the importance of species-specific behaviors (i.e., M. natalensis clustering in agriculture) and the multihost serological landscape in assessing transmission risk.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147759950","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}

{"title":"Case Series of Primary Esophageal Tuberculosis.","authors":"Hong-Mei Chen, Sha-Na Zhang, Jing Tong, Chen-Guang Li, Meng-Qiu Gao, Qiang Li","doi":"10.4269/ajtmh.26-0086","DOIUrl":"https://doi.org/10.4269/ajtmh.26-0086","url":null,"abstract":"<p><p>Gastrointestinal tuberculosis is a relatively common form of extrapulmonary tuberculosis. Primary esophageal tuberculosis is rare and frequently misdiagnosed or delayed in diagnosis by clinicians. Four cases of primary esophageal tuberculosis are reported. All patients involved underwent pathological examination of their esophageal lesions, which revealed granulomas. Additionally, molecular detection confirmed the presence of Mycobacterium tuberculosis DNA in two cases. All patients received antituberculosis therapy and achieved good outcomes.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147759914","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}

{"title":"Patients' Experiences and Cost of Hemodialysis in Management of Chronic Kidney Disease in Togo, 2024: An Exploratory Mixed-Method Approach.","authors":"Latame Komla Adoli, Diguibe Tien-Bale Bamide, Kokou Herbert Gounon, Abiré Adèle Bessike Koissi, Atèhèzi Adom, Kossi Akomola Sabi, Didier Koumavi Ekouevi","doi":"10.4269/ajtmh.25-0646","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0646","url":null,"abstract":"<p><p>At the stage of kidney failure, hemodialysis, peritoneal dialysis, and kidney transplantation are the therapeutic alternatives for prolonging patients' lives. In Togo, in-center hemodialysis is the only treatment option available to patients. This study aimed to evaluate the direct cost of in-center hemodialysis treatment and to understand the challenges faced by patients with kidney failure in Togo in 2024. We conducted a sequential exploratory mixed-methods study. The qualitative study included patients who had been undergoing hemodialysis in a center from March 1 to June 31, 2024. In the quantitative study, a linear regression model was used to describe the factors associated with the cost of hemodialysis. From 15 interviews, four themes were identified: 1) patients' perception of the disease and its management, 2) the burden of the disease and hemodialysis on the patient and their family and friends, 3) financial difficulties, and 4) geographical challenges in accessing a hemodialysis center. For the quantitative study, 88 patients were included (41.0% female), and 84.0% were hypertensive. The median age of patients was 51 years old (interquartile range [IQR]: 40-58). The median monthly income of patients was 45,000 CFA francs (franc de la Communauté Financière Africaine, the currency in Togo) (approximately €69; IQR: 0-162,500 CFA francs). The median overall cost of hemodialysis per month was 276,000 CFA (approximately €421; IQR: 163,600-527,000). Being male and living alone were associated with the overall cost of hemodialysis. This study mainly reports on the financial difficulties that patients face in accessing hemodialysis. Advocacy is needed for better subsidization of hemodialysis care in Togo.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147760019","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}

{"title":"Before the Polymerase Chain Reaction Test: Where Surveillance Truly Begins.","authors":"Carlos Bastidas-Caldes","doi":"10.4269/ajtmh.26-0112","DOIUrl":"https://doi.org/10.4269/ajtmh.26-0112","url":null,"abstract":"","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147759942","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}

{"title":"Development of Recombinase Polymerase Amplification and CRISPR-Cas12a-Enhanced Isothermal Amplification Assays for Strongyloides stercoralis DNA Detection: A Pilot Study.","authors":"Robertine Lontuo-Fogang, Sasisekhar Bennuru, Thomas B Nutman","doi":"10.4269/ajtmh.26-0042","DOIUrl":"https://doi.org/10.4269/ajtmh.26-0042","url":null,"abstract":"<p><p>Soil-transmitted helminth (STH) infections are prevalent worldwide, but the true burden of strongyloidiasis is unclear due to lack of sensitive and field-friendly diagnostic tools. Diagnosis is often based on serological assays that are typically not point-of-care (POC). Although polymerase chain reaction (PCR) tests are sensitive and specific, the need for expensive equipment and highly skilled personnel limits their use in resource limited areas. Isothermal amplification assays are largely instrument-free, making them simpler to implement without loss of either sensitivity or specificity. We developed two recombinase polymerase amplification (RPA) assays to detect Strongyloides stercoralis (Ss) in human stool samples and a complementary CRISPR-Cas12a detection system with visual readouts. Primers, probes, and guide RNAs (crRNAs) for these assays were designed targeting the Ss-NIE sequence and Ss dispersed repetitive sequence (Ss-DRS). The assay's specificities and limits of detection (LOD) were assessed using gDNA from Ss L3 larvae or from other STH and filariae. The NIE RPA showed a LOD of 1 fg/µL, whereas the LOD for the Ss-DRS RPA was 1 pg/µL. The LOD was 500 fg/µL for the NIE RPA CRISPR-Cas12a assay. No cross-reactivity with any filarial parasite or other STH was observed. Because the NIE assays were more sensitive than the Ss-DRS assay, six patient samples positive for Ss by real-time PCR (qPCR) were tested using the NIE assays, of which four were positive. Though assay refinement and clinical validation are needed, this study establishes fast, highly sensitive and field-applicable POC diagnostic tools for Ss detection that are ideal for use in endemic areas with limited resources.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147759923","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}

{"title":"Value of the Run-In Period to Evaluate the Safety of Conventional Trypanocidal Treatment: A Subanalysis of a Colombian Randomized Clinical Trial.","authors":"Juan Carlos Villar, Helena Arango, Luis David Sáenz-Pérez, Antonia Camacho","doi":"10.4269/ajtmh.25-0198","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0198","url":null,"abstract":"<p><p>When testing poorly tolerated or long-term treatments, including a run-in phase enhances clinical trial efficiency and internal validity by selecting more adherent participants. This report describes the adherence and tolerance of Colombian participants in EQUITY (a randomized, concealed, parallel-group, placebo-controlled trial testing nifurtimox and benznidazole among Trypanosoma cruzi-seropositive adults without cardiomyopathy). Our design included a 10-day, single-blind, placebo run-in phase. On completion, willing participants reporting good adherence (≥80%) and tolerance were randomized to any five 120-day, blinded treatments: four with either active medication, each given as 120-day half dose or 60-day full dose (followed/preceded by a randomly allocated 60-day placebo treatment), or a 120-day placebo. Side effects were compared after the run-in (day 0) between excluded and enrolled participants, and between those randomized to active medications or placebo 20 days after starting each treatment period (days 20/80). Those excluded (44/351, 12.5%) more often reported gastrointestinal (15.9/4.6%), nonspecific (13.7/4.2%), and musculoskeletal symptoms (9.1/1.6%) than those randomized. Participants given nifurtimox (n = 84) or benznidazole (n = 86) versus placebo (n = 126) on day 20 reported more nonspecific (15.5/10.5/4.8%, respectively) or cutaneous side effects (6.0/12.8/3.2%). When starting active treatments (transition OFF-ON, n = 171 and n = 61 in first and second 60-day treatment periods), more participants reported emerging-worsening than receding-ending side effects (49/13 and 15/5, respectively). Despite inducing a nocebo effect, the run-in phase highlighted more closely related side effects, strengthening causal inference and informing adherence and tolerance to conventional trypanocides.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147760028","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}

{"title":"Association Between Serum Soluble Programmed Death Ligand 1 Levels and Disease Severity in Patients with Crimean-Congo Hemorrhagic Fever.","authors":"Ayten Yanık, Ömer Karaşahin, Rukiye İnan Sarıkaya, Rumeysa Temur Çelik, Engin Şebin","doi":"10.4269/ajtmh.25-0760","DOIUrl":"https://doi.org/10.4269/ajtmh.25-0760","url":null,"abstract":"<p><p>Crimean-Congo hemorrhagic fever (CCHF) is a severe viral infection that may lead to coagulopathy and multiorgan failure. Although the programmed cell death protein 1/programmed death ligand 1 (PD-L1) immune checkpoint pathway regulates excessive inflammation, the clinical significance of circulating soluble PD-L1 (sPD-L1) in CCHF is not well defined. The aim for the present study was to measure serum sPD-L1 levels in patients with CCHF and evaluate their association with disease severity and prognosis. This prospective study included 60 adults with confirmed CCHF and 30 healthy controls. Disease severity was classified using the Severity Scoring Index. Serum collected on admission was analyzed for sPD-L1, and routine laboratory values were recorded. Clinical and laboratory differences between severity groups were examined, and correlation and receiver operating characteristic analyses were performed. Neurological symptoms, fever, diarrhea, and bleeding were more common in moderate-to-severe cases. These patients had significantly lower platelet and fibrinogen levels and higher alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, international normalized ratio, and activated partial thromboplastin time values. Soluble PD-L1 levels were similar in healthy controls and mild cases but were markedly elevated in moderate-to-severe cases. Soluble PD-L1 accounted for more than half of the variation in severity scores (R2 = 0.556). Receiver operating characteristic analysis revealed strong discriminatory ability (area under the curve: 0.901), with a cutoff of 10.91 ng/mL yielding 96.7% sensitivity and 80% specificity. In conclusion, elevated sPD-L1 levels are closely associated with disease severity in CCHF. Soluble PD-L1 may have prognostic value, although this association should be confirmed in larger studies.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147759930","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}

{"title":"Isolated Nausea and Pretibial Rash in a Returning Traveler: Forme Fruste of Leptospirosis.","authors":"Joseph M Vinetz, Logan Flaxman","doi":"10.4269/ajtmh.26-0120","DOIUrl":"https://doi.org/10.4269/ajtmh.26-0120","url":null,"abstract":"<p><p>Leptospirosis is difficult to diagnose because of protean nonspecific clinical manifestations and the lack of rapid, actionable laboratory testing. A previously healthy woman who presented with nausea is described in the present study. She had modestly elevated liver function tests, an unusual pretibial rash, and no fever. She had recently swum in a waterfall in Costa Rica. After the clinicians proposed a leptospirosis diagnosis to the patient, an artificial intelligence program was selected for use by the clinicians to enhance confidence in proposing a rare and unknown diagnosis. The program independently produced a differential diagnosis that led with leptospirosis. Presumptive doxycycline administration led to symptom resolution. Blood (but not urine) Polymerase chain reaction (PCR) test for the LipL32 gene and a novel antibody detection test confirmed leptospirosis. This case represents an unusual clinical presentation of leptospirosis, including the absence of fever, the presence of a pretibial rash, and isolated, mildly elevated bilirubin and transaminases as sole laboratory abnormalities, and highlights difficulties associated with making a rapid, actionable diagnosis.</p>","PeriodicalId":7752,"journal":{"name":"American Journal of Tropical Medicine and Hygiene","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147759971","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}