Acta tropica最新文献

{"title":"Integrated All-Atom and Coarse-Grained Simulations Uncover Structural, Dynamics and Energetic Shifts in SARS-CoV-2 JN.1 and BA.2.86 Variants.","authors":"Akshit, Shweata Maurya, Timir Tripathi, Aditya K Padhi","doi":"10.1016/j.actatropica.2024.107444","DOIUrl":"https://doi.org/10.1016/j.actatropica.2024.107444","url":null,"abstract":"<p><p>Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the COVID-19 pandemic, is an enveloped, positive-stranded RNA virus that enters human cells by using its spike protein to bind to the human angiotensin-converting enzyme 2 (ACE2) receptor. Since its emergence, the virus has mutated, producing variants with increased transmissibility, immune evasion, and infectivity. The JN.1 variant, detected in January 2024, features a single substitution mutation (L455S) in the receptor-binding domain (RBD) of its spike protein, setting it apart from its parent lineage, BA.2.86. This variant has rapidly become globally predominant due to its enhanced transmission and significant epidemiological impact. To understand the causes behind the dominance of the JN.1 variant, we conducted a comprehensive study using all-atom MD molecular dynamics (MD) and coarse-grained MD simulations. This allowed us to examine the structural, dynamic, energetics and binding properties of the wild-type (Wuhan strain), BA.2.86, and JN.1 variants. Principal component and free energy landscape analyses revealed enhanced structural stability in the JN.1 variant. Molecular Mechanics Poisson-Boltzmann Surface Area (MM/PBSA) assessments indicated lower binding affinity for JN.1 as compared to BA.2.86. Intermolecular interaction analyses further confirmed BA.2.86's superior binding affinity over JN.1 and wild-type. Additionally, we compared and validated our findings against experimentally determined cryo-electron microscopy (cryo-EM) structures of JN.1 and BA.2.86 variants, confirming the reliability of our simulation results. Overall, this study provides crucial insights into the structural-dynamics-energetics and physicochemical features that have contributed to the global prevalence of the JN.1 variant and sheds light on its potential to generate future subvariants.</p>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142543039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of protective efficacy of recombinant Toxoplasma gondii DDX39 protein vaccine against acute and chronic T. gondii infection in mice","authors":"","doi":"10.1016/j.actatropica.2024.107442","DOIUrl":"10.1016/j.actatropica.2024.107442","url":null,"abstract":"<div><div><em>Toxoplasma gondii</em>, a pervasive parasite responsible for toxoplasmosis, poses significant health risks to humans and animals. In this study, we investigated the immunogenicity and protective efficacy of the recombinant <em>T. gondii</em> DDX39 protein formulated with ISA201 adjuvant (rTgDDX39) as a candidate vaccine against toxoplasmosis. The full-length of TgDDX39 gene was successfully amplified, cloned into the pET-30a vector, and expressed in BL21 (DE3) competent cells, which was purified and identified as a 57.1 kDa protein via sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Western blot analysis confirmed that rTgDDX39 was specifically recognized by serum from <em>T. gondii</em>-infected mice. Furthermore, immunization of rats with rTgDDX39 generated antiserum that could specifically recognize the native TgDDX39 protein in <em>T. gondii</em> tachyzoite lysates. Immunofluorescence assay revealed that TgDDX39 was primarily located in the nucleus and perinuclear region of tachyzoites. Our vaccination strategy significantly increased T cell proliferation, with CD4⁺ <em>T</em> cells rising by 21.9% and CD8⁺ <em>T</em> cells by 57.8% by the sixth week compared to the adjuvant control group. Additionally, high titers of anti-rTgDDX39 IgG antibodies were detected in vaccinated mice, with a notable induction of IgG1 and IgG2a isotypes, and IgG1/IgG2a &gt; 1 suggests a Th2-biased immune response.</div><div>Furthermore, <em>in vitro</em> and <em>in vivo</em> assays demonstrated that polyclonal antibodies raised against rTgDDX39 could inhibit the proliferation of <em>T. gondii</em> RH tachyzoites, highlighting the potential of these antibodies to neutralize this parasite effectively. This study provides compelling evidence of the immunogenicity and protective efficacy of rTgDDX39, supporting its potential as a potential candidate vaccine against toxoplasmosis. The protective efficacy of the vaccine was evaluated in mice challenged with acute (RH) and chronic (PRU) strains of <em>T. gondii</em>, showing a survival time extended to 17 days in the acute model, compared to 13.5 and 14 days in the control groups, and a significant 34% reduction in cyst burden in the chronic model. Additionally, the survival rate in the PRU-infected mice increased from 15 to 20% in the control groups to 45% in the vaccinated group. <em>In vitro</em> and <em>in vivo</em> assays demonstrated that polyclonal antibodies raised against rTgDDX39 could inhibit the proliferation of <em>T. gondii</em> RH tachyzoites, highlighting the potential of these antibodies to neutralize the parasite effectively. This study provides compelling evidence of the immunogenicity and protective efficacy of rTgDDX39, supporting its potential as a candidate vaccine against toxoplasmosis.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142492796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of species-specific multiplex PCR for Leishmania identification","authors":"","doi":"10.1016/j.actatropica.2024.107440","DOIUrl":"10.1016/j.actatropica.2024.107440","url":null,"abstract":"<div><div>Leishmaniasis is a diverse group of clinical diseases caused by protozoan parasites of the <em>Leishmania</em> genus. Species-specific identification of <em>Leishmania</em> spp. is challenging due to the high number of different pathogenic species that sometimes co-circulate in the same foci, hampering efforts to effectively control the disease. Multiplex PCR is an attractive alternative for rapid differentiation of <em>Leishmania</em> species with high sensitivity and specificity. We aimed to generate a panel of primers optimized for a multiplex PCR assay capable of identifying different <em>Leishmania</em> species in a single reaction. Species-specific primers were designed based on genomic data using the TipMT too<em>L.</em> Potential non-specific amplifications of other trypanosomatids as well as human, dog, and sandfly hosts were first evaluated in silico using the Primer-Blast too<em>L.</em> Species-specific primers for <em>Leishmania amazonensis, Leishmania braziliensis, Leishmania donovani, Leishmania infantum, Leishmania mexicana</em> and for the <em>Leishmania guyanensis</em> complex were tested in vitro. The primers have a limit of detection ranging from 1 to 0.01 ng of parasite gDNA using the same annealing temperature of 66 °C. The primers were specific for their targets when tested against 13 species of <em>Leishmania</em>, six trypanosomatids, and <em>Babesia</em> sp., and to detect the target species in a prepared pool with gDNA of six pathogenic <em>Leishmania</em> species. The designed primers were optimized for multiplex PCR, enabling species-specific identification of all five <em>Leishmania</em> species and one species complex. This new primer set could allow for efficient, fast, and reliable identification of <em>Leishmania</em> parasites.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142492797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diversity, geographical distribution and predictive factors of Hepatitis C virus genotypes and subtypes in Rwanda","authors":"","doi":"10.1016/j.actatropica.2024.107433","DOIUrl":"10.1016/j.actatropica.2024.107433","url":null,"abstract":"<div><h3>Background</h3><div>Existing data on the prevalence of hepatitis C virus (HCV) genotypes and subtypes in Rwanda need to be strengthened. The aim of this study was to identify HCV genotypes and subtypes among HCV-infected patients, as well as their geographical distribution in Rwanda, and to identify the social and economic factors that could influence HCV epidemiology which would make it possible to target national preventive and management actions for infected patients.</div></div><div><h3>Methods</h3><div>This study included 560 patients with confirmed chronic HCV infection. Patients were recruited from various health facilities in the four provinces of Rwanda as well as in the City of Kigali and had never received treatment with direct-acting antiviral (DAAs). HCV viral loads were measured using Cobas® AmpliPrep/Cobas® TaqMan® HCV Quantitative Test, version 2.0. HCV genotyping was performed using an in-house sequencing protocol targeting the NS5B central region. Genotypic HCV prevalence was correlated with patient geographic location, sociodemographic, behavioral, lifestyle, and clinical factors.</div></div><div><h3>Results</h3><div>HCV genotype 4 was detected in 99.3% of the patients, while genotype 3 was identified in 0.7%. A total of eight (8) HCV subtypes were detected, with 4k being the predominant subtype nationwide (49.5%), followed by subtypes 4r (21.2%), 4q (16.2%), 4v (7.9%), 4b (2.0%), 4l (1.8%), 4c and 3h represent 0.7% each. Our findings reveal subtype distribution variations among provinces. Subtype 4k was prevalent across regions, particularly in Kigali (64.0%) and the Eastern Province (61.6%). Subtype 4q was more common in the northern province (40.7%), 4r in the southern (43.9%) and western provinces (37.1%), and 4v in the eastern province (17.8%). Farmers exhibit a distinct infection profile compared to other occupations, showing a lower prevalence of subtype 4k but a higher prevalence of subtype 4r.</div></div><div><h3>Conclusions</h3><div>Our study revealed that HCV infection is unevenly distributed in Rwanda, dominated by HCV genotype 4, with considerable heterogeneity in the repartition of the different subtypes. We found potential associations between rural/urban lifestyles and HCV subtype profiles. Determined HCV distribution and diversity can serve as basis not only for HCV infection awareness and prevention campaigns, but also success and guidance for personalized treatment.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142492795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A quantitative and systematic analysis of Anopheles stephensi bionomics and control approaches","authors":"","doi":"10.1016/j.actatropica.2024.107431","DOIUrl":"10.1016/j.actatropica.2024.107431","url":null,"abstract":"<div><div><em>Anopheles stephensi</em> is a mosquito endemic to South Asia and the Arabian Peninsula that has recently been detected in eight African countries, posing a significant threat to global malaria control efforts. A challenge with <em>An. stephensi</em> is that it requires unique surveillance and control tools when compared to other malaria vectors. Through a systematic literature review, we investigated the efficacy of trapping methods and controls for <em>An. stephensi</em> mosquitoes, with a focus on studies of its behavior and biology. Data from 83 articles (native range: Afghanistan, India, Iran, Iraq, Pakistan, and Qatar; invasive range: Djibouti, Ethiopia, Sri Lanka, Saudi Arabia, and Sudan) met our study inclusion criteria. Data from these studies revealed that using host-seeking animal baited traps increased the number of mosquitoes collected per trap per day in the native range when compared to host-seeking human baited traps. However, these differences were not present in data collection rate assessments from the invasive range. We also found that <em>An. stephensi</em> equally used a large variety of breeding habitats in the native range, but that it tended to prefer water reservoirs and wastewater in the invasive range. Finally, we found that temephos, fenthion, <em>Bacillus thuringiensis israelensis</em>, and <em>Beauveri bassiana</em> were more effective at reducing larvae in their native range compared to the approaches found in our systematic literature search, but the relative effectiveness of these approaches in the invasive range was less clear. Understanding proven historical surveillance and control approaches is essential to the advancement of invasive <em>An. stephensi</em> mitigation efforts, but continued investigations in the invasive range are critical to reducing the impacts of malaria morbidity and mortality.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142455623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crimean Congo hemorrhagic fever virus exposure among febrile patients, cattle herders, and cattle herds in Cameroon","authors":"","doi":"10.1016/j.actatropica.2024.107432","DOIUrl":"10.1016/j.actatropica.2024.107432","url":null,"abstract":"<div><h3>Problem addressed</h3><div>Crimean Congo hemorrhagic fever (CCHF) is a tick-borne disease with high fatality rates and an expansive geographic distribution, yet disease prevalence data in Cameroon is lacking.</div></div><div><h3>Objective</h3><div>This study aimed to determine CCHF virus (CCHFV) seroprevalence and tick distribution among cattle herders and febrile patients in West and Centre Cameroon.</div></div><div><h3>Methods and approach</h3><div>Two cross-sectional serological studies of human and cattle were conducted from October to December 2021 and from June to July 2022, which included the collection of ticks. Enzyme-linked immunosorbent assay (ELISA) were used to detect anti-CCHFV antibodies, while a knowledge, attitudes, and practice (KAP) survey assessed tick and tickborne disease related knowledge and behaviors among herders. Tick identification used morphological keys.</div></div><div><h3>Results</h3><div>The KAP survey showed adequate tick knowledge (94.5 %) among herders but poor understanding of disease transmission, with favorable attitudes towards tick control (24.7 %) but inadequate implementation. <em>Rhipicephalus annulatus</em> (64.1 %) predominated among the 1,296 ticks collected during each rainy season. Among cattle, 27.4 % were seropositive, and seropositivity was associated with specific villages, cattle age (&gt;4 years), and female sex. Herders had a 17.8 % seroprevalence, while febrile patients had 8.3 %, with higher rates in those &gt;20 years old for both groups. Self-reported tick removal by herders after contact and grazing may increase CCHFV exposure.</div></div><div><h3>Conclusions</h3><div>This study confirms CCHFV circulation in rural West Cameroon and unexpected exposure risk in Yaounde, highlighting the need for active entomological surveillance and preventive measures in transhumance and cattle market activities. Establishing an occupation-based surveillance system can help identify CCHFV hotspots to prevent outbreaks.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142455625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Risk factors and control strategies for Brucella spp. and RB51 vaccine shedding in buffalo milk: A cross-sectional study","authors":"","doi":"10.1016/j.actatropica.2024.107436","DOIUrl":"10.1016/j.actatropica.2024.107436","url":null,"abstract":"<div><div>Brucellosis is prevalent in water buffaloes, which serve as significant reservoirs. The disease adversely affects meat and dairy products and can be transmitted to humans through contaminated products. This study aimed to determine the risk factors and control strategies for <em>Brucella</em> spp. and RB51 vaccine shedding in raw buffalo milk. A cross-sectional study was conducted across 261 farms where only 182 out of 261 farms received regular vaccinations through PCR tests and a questionnaire survey. The survey addressed potential risk factors and farm management. Univariable and multivariable logistic regression analyses were used to analyze the associated risk factors, represented as odds ratios (OR) with 95 % confidence intervals. The PCR survey revealed a 35.2 % prevalence of <em>Brucella</em> spp at the household level and 30.8 % at the buffalo level. Significant risk factors for <em>Brucella</em> PCR-positivity included the number of buffaloes in a household (OR = 1.512, 95 %CI: 1.107–2.065, p = 0.009) and the presence of resident dogs (OR = 2.157, 95 %CI: 1.053–4.417, p = 0.036). Regular vaccination practices were identified as a preventive factor (OR = 0.304, 95 %CI: 0.172–0.537, p &lt;0.001). No animal-level risk factors were identified, and reduced-dose brucellosis vaccination showed a protective effect. Higher buffalo numbers in a household correlated with increased vaccine shedding in milk (OR= 2.489, p-value &lt;0.001). Shedding was lower in households with primary education farmers than those without education (OR=14.163, p-value &lt;0.001). Borrowing bulls for insemination also increased shedding (OR=13.266, p-value= 0.015). The study highlights the need for targeted control strategies, emphasizing education, vaccination, and hygiene practices to mitigate brucellosis's impact on buffalo and human populations.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142455628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing the survey design for assessing schistosomiasis at the sub-district for treatment decision making","authors":"","doi":"10.1016/j.actatropica.2024.107422","DOIUrl":"10.1016/j.actatropica.2024.107422","url":null,"abstract":"<div><h3>Background</h3><div>Schistosomiasis control programs typically launch with district-level, school-based preventive chemotherapy (PC). Recent World Health Organization recommendations are to shift to community-wide treatment where schistosomiasis prevalence is &gt;10%. Simultaneously there is a push to move to sub-district PC to prioritize communities in need of treatment and alleviate the pressure on global praziquantel need, but few countries have sub-district prevalence data and no guidelines on how to collect this information.</div></div><div><h3>Methods/Principal findings</h3><div>Data collected from 57,161 school-aged children (SAC) across six countries (Burkina Faso, Ghana, Mali, Senegal, Sierra Leone, and Togo) to generate spatially realistic gold standard datasets that were used to evaluate different numbers of schools per sub-district (1-10) and district (5–30), number of SAC sampled per school (10–50), on accuracy of prevalence estimates. Sampling fewer children in more schools maximized accuracy of prevalence at the sub-district and district level. Surveying three schools per sub-district or 15 schools per district gave precise prevalence estimates. Increasing the number of SAC beyond 30 per school led to negligible improvements in reliably detecting schistosomiasis. Failure to detect schistosomiasis occurred more frequently in low (1–10%) prevalence and larger districts/sub-districts.</div></div><div><h3>Conclusion</h3><div>This study provides guidelines for evaluating sub-district schistosomiasis in a range of transmission settings. Among two-stage cluster surveys for schistosomiasis, our simulations show surveying three schools per sub-district and 20-30 SAC per school optimized cost-efficiency and minimized risk of mistreatment. Population size and endemicity influenced survey estimates, with the probability of misclassification being greater as populations increased or prevalence decreased.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142455627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to: Quality assurance of serologic testing for Chagas disease in a primary care setting of rural Paraguay [Acta Tropica, volume 259 (2024) 107382].","authors":"Juan Carlos Gabaldón-Figueira, Irene Losada-Galvan, Miriam Rolón, Sofía Ardiles-Ruesjas, Lilian Chena, Zully Cubilla, Vidalia Lesmo, Nieves Martínez-Peinado, Celeste Vega, Antonieta Rojas de Arias, Claudia Huber Schill, Joaquim Gascón, María-Jesús Pinazo, Julio Alonso-Padilla","doi":"10.1016/j.actatropica.2024.107408","DOIUrl":"https://doi.org/10.1016/j.actatropica.2024.107408","url":null,"abstract":"","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142455624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Epidemiology characterization and risk factors of brucellosis among older rural populations in northwest China","authors":"","doi":"10.1016/j.actatropica.2024.107437","DOIUrl":"10.1016/j.actatropica.2024.107437","url":null,"abstract":"<div><div>Brucellosis causes significant economic damage and public health problems in northwest China. The older rural population is considered a high-risk group. However, the epidemiological characteristics and risk factors for brucellosis in this population remain unclear. This study investigated these factors within this high-risk group by performing a cross-sectional study in five townships of Wuwei City, Gansu Province. Cases were screened via rose Bengal and serum plate agglutination tests. Risk factors were evaluated using a standard questionnaire form. This study included 1074 participants aged &gt;50 years. Among them, 15 (1.4%) tested positive for <em>Brucella</em>. The most common symptoms were arthralgia/myalgia (n=5, 33.3%), and 10 (66.7%) cases were asymptomatic. Raising lambs artificially (odds ratio, 4.7; 95% CI, 1.3–17.0; <em>P</em>=0.02) increased the risk of brucellosis. The results indicated a high proportion of asymptomatic brucellosis in this group. Raising lambs artificially is a risk factor for brucellosis. The surveillance and health education of brucellosis for older rural populations in endemic areas of northwest China should been attention.</div></div>","PeriodicalId":7240,"journal":{"name":"Acta tropica","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142455629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}