Tropical Diseases, Travel Medicine and Vaccines最新文献

Dengue is the most rapidly spreading vector-borne disease worldwide, with over half the global population at risk for an infection. Antibody-dependent enhancement (ADE) is associated with increased disease severity and may also be attributable to the deterioration of disease in vaccinated people. Two dengue vaccines are approved momentarily, with more in development. The increasing use of vaccines against dengue, combined with the development of more, makes a thorough understanding of the processes behind ADE more important than ever. Above that, due to the lack of treatment options, this method of prevention is of great importance. This review aims to explore the impact of ADE in dengue vaccinations, with the goal of enhancing potential vaccination strategies in the fight against dengue.

Purpose: Nocardia is emerging as a common and easily neglected cause of both healthcare- and occupation-associated infections worldwide, however, human vaccines for Nocardia prevention are not yet available. In this study, we aimed to evaluate the immunoprotective effect of the NFA47630 protein, a secreted protein abundant in the N. farcinica IFM10152 supernatant.

Methods: Conservation and characteristics of nfa47630 were analyzed by PCR and bioinformatics. Then recombinant NFA47630 protein was cloned, expressed and purified for further antigenicity analysis. Subsequently, the ability to activate innate immunity was evaluated by examining the phosphorylation status of the MAPK signaling pathway and cytokine levels. Finally, the protective effect was evaluated on rNFA47630-immunized mice.

Results: nfa47630 was conserved in N. farcinica strains with good antigenicity. The rNFA47630 protein was expressed under the optimal conditions of 0.2 mM IPTG, 28 °C, and it can be recognized by anti-N. farcinica and anti-N. cyriacigeorgica sera, but not anti-N. asteroids, anti-N. brasiliensis, anti-N. nova and anti-Mycobacterium bovis sera. It can upregulate the phosphorylation status of ERK, JNK, P38 and the cytokine levels of TNF-α, IL-10, IL-12, and IFN-γ. In addition, mice immunized with rNFA47630 protein exhibited higher antibody titers, greater bacterial clearance ability, milder organ infection, and higher survival rates than PBS-immunized mice.

Conclusions: Our data demonstrate that NFA47630 is a potential vaccine candidate for defending against N. farcinica infection.

Background: Dengue virus remains a major public health problem with one of the hallmark pathologies is the vascular leakage caused by endothelial dysfunction which can lead to Dengue Hemorrhagic Fever (DHF) manifestation. In the status quo, no specific therapy has been discovered but rather heavily relies on judicious and frequent monitoring of intravenous fluids administration. The current guideline has discussed the roles of fluid therapy during the Dengue Shock Syndrome (DSS) stage, however, administration of early fluid intervention for DHF grade I and II remains uncharted territory. In addition, the choice and timing of colloid administration remains underexplored. As one of the widely available colloids, 5% albumin has known physiological properties that potentially minimize plasma leakage. Therefore, this study aimed to evaluate the benefit of early intervention of 5% albumin in adults with DHF in the hope of preventing the lethal progression to DSS and further, shorten the length of stay (LOS) for patients.

Methods: We conducted a multicenter, open-labeled, randomized controlled trial in Jakarta and Banten to compare the effect of early intervention with 5% albumin in adult patients with DHF compared to Ringer's Lactate (RL). Statistical analyses were conducted using unpaired t-test and Mann-Whitney for normally and abnormally distributed data respectively.

Results: Adult patients with a diagnosis of DHF grade I and II that being hospitalized to receive the early intervention of 5% albumin had significantly lower levels of hemoconcentration 4, 12, and 24 h (p = 0.002, 0.001, 0.003, respectively), higher platelet counts 4 h (p = 0.036), higher serum albumin levels 48 h (p = 0.036), lower proteinuria 24 and 48 h post-albumin administration (p < 0.001, < 0.001, respectively), and shorter LOS (p < 0.001) when compared to the RL group.

Conclusion: Early intervention of 5% albumin showed better control on vascular integrity and function compared to ringer lactate in hospitalized adults with grade I & II DHF, thus halting the progression of DHF into DSS and other related complications which leads to faster recovery and shorter length of stay.

Trial registration: The study was registered to www.

Clinicaltrial: gov with trial registration number NCT04076254, and registration date October 31st 2016.

Background: Influenza remains a global public health concern. Understanding the vaccination-induced response in an aging population, which is susceptible and at high risk, is essential for disease prevention and control. Here, we report findings on the safety and immunogenicity of a quadrivalent influenza split-virion vaccine (15 µg/subtype/0.5 ml/dose) (hereinafter referred to as the "quadrivalent influenza vaccine") in a population aged ≥ 60 years.

Methods: This open-label, pragmatic post-marketing trial enrolled 1399 older adults to receive one dose of an approved commercially available quadrivalent influenza vaccine manufactured by Hualan Biological Bacterin Inc. (hereinafter referred to as "Hualan Bio"). Participants with contraindications for the vaccine were excluded, while poor health condition was acceptable. All vaccinated subjects experienced adverse events collection within 30 days and serious adverse events within 180 days post-vaccination. 25% subjects, selected randomly, underwent venous blood sampling pre-vaccination and 30 days after post-vaccination, for detecting antibody titers against each subtype of influenza virus by hemagglutination inhibition assay. The incidences of adverse events and antibody titers against each subtype of influenza virus were statistically analyzed using SAS 9.4.

Results: No grade 3 adverse reactions occurred within 30 days post-vaccination. The incidences of overall adverse reactions, local adverse reactions and systemic adverse reactions were 3.79%, 2.86% and 1.00%, respectively. No serious adverse reactions occurred within 180 days post-vaccination. There were 350 subjects who completed venous blood sampling pre-vaccination, among whom 348 subjects completed venous blood sampling at 30 days post-vaccination for immunogenicity assessment. With respect to hemagglutination inhibition antibodies against influenza viruses H1N1, H3N2, BV and BY subtypes, at 30 days post-vaccination, the seroconversion rates were 87.64%, 75.57%, 73.28% and 78.74%, respectively; the seropositive rates were 93.97%, 98.56%, 79.31% and 95.40%, respectively; and the geometric mean increase (GMI) in post-immunization/pre-immunization antibodies was 24.80, 7.26, 10.39 and 7.39, respectively.

Conclusion: One 15 µg/subtype dose of the vaccine had a good safety profile and elicited favorable immunogenicity among subjects aged ≥ 60 years. The results of this study indicate that Hualan Bio quadrivalent influenza vaccine strike balance between safety and immunogenicity, supporting unnecessity to increase dosage or inoculation frequency for further enhancing immunogenicity.

Trial registration: Registered on ClinicalTrials.gov.

Registration number: NCT06334510. Registered on 28/03/2024 (retrospectively registered).

Background: Chagas disease (CD), triggered by the Trypanosoma cruzi parasite, is originally endemic across Latin America, affecting millions. While cardiac complications are widely recognized, the association between CD and stroke remains underexplored. This systematic review aims to elucidate the relationship between CD and stroke, highlighting the cardioembolic origins of stroke in CD patients and assessing the elevated stroke risk compared to non-infected individuals.

Methodology: Adhering to the PRISMA guidelines, we conducted a comprehensive search in PubMed and Scopus databases without date restrictions, including articles in both Spanish and English. This approach enabled the identification and analysis of relevant studies to understand the interplay between CD and stroke risk.

Results: Our analysis of 25 selected studies indicates that strokes in CD patients predominantly arise from cardioembolic sources. The data underscore a significant increase in stroke risk among individuals infected with T. cruzi compared to uninfected counterparts. Additionally, CD patients face a higher stroke and mortality risk than those with other heart failure etiologies, irrespective of disease severity.

Conclusion: The review establishes CD as a critical contributor to stroke incidence, emphasizing the need for heightened awareness and diagnosis of CD in stroke patients, particularly in regions with high CD prevalence. Recognizing the increased stroke risk associated with T. cruzi infection is crucial for developing targeted educational and preventive strategies in endemic areas.

Background: The benefits of travel for the wellbeing of people of all ages and abilities are well known, though travellers with prostheses have so far been excluded. Limb loss, due to trauma, vascular disease, cancer, or infections requires a prosthesis for cosmesis and functionality. The life-changing event of losing a limb and the considerable psychological adjustment to accept an altered body image influence rehabilitation and self-management as well as the participation in social activities, such as sport and travel. The challenge of travel lies not only in transferring practical impediments encountered at home to another location; familiar coping strategies may require unexpected adjustments. After presenting background information on limb loss and prostheses, the purpose of this paper was to review literature on health advice for travellers with prosthetic limbs.

Method: All major data bases were searched for peer-reviewed literature using a variation of keyword combinations around travel and prosthetics. Relevant journals were searched individually, and selected authors and university departments contacted. No evidence-based results were obtained. The search then moved to grey literature including documents from relevant organisations, professional bodies, government websites, manufacturers, airlines, prosthetic/physiotherapy clinics, sport organisations to approaching amputees, including veterans and athletes, directly.

Result: The list of collated travel advice for people with artificial limbs relates to (1) trip preparation, (2) packing (especially considering the mechanical and/or electrical requirements of the prosthesis), (3) travelling by plane as the most covered mode of travel, and (4) navigating airports and airport security, which may be used by travel health practitioners while awaiting evidence-based guidelines.

Conclusion: This is the first paper on travel with a prosthetic limb in any field, including travel medicine. Therefore, travel health practitioners have no evidence-based guidelines at their disposal required for high-quality care for this neglected population. Preliminary recommendations for clinical practice, advice for required updates in education, and suggestions for urgently needed research are provided to replace current hints and tips with evidence so that travellers with prostheses are no longer 'out on a limb'.

Background: Globally, malaria continues to pose a major health challenge, with approximately 247 million cases of the illness and 627,000 deaths reported in 2021. However, the threat is particularly pronounced in sub-Saharan African countries, where pregnant women and children under the age of five face heightened vulnerability to the disease. As a result, the imperative to develop malaria vaccines especially for these vulnerable populations, remains crucial in the pursuit of malaria eradication. However, despite decades of research, effective vaccine development faces technical challenges, including the rapid spread of drug-resistant parasite strains, the complex parasite lifecycle, the development of liver hypnozoites with potential for relapse, and evasion of the host immune system. This review aims to discuss the different malaria vaccine candidates in the pipeline, highlighting different approaches used for adjuvating these candidates, their benefits, and outcomes, and summarizing the progress of these vaccine candidates under development.

Method: A comprehensive web-based search for peer-reviewed journal articles published in SCOPUS, MEDLINE (via PubMed), Science Direct, WHO, and Advanced Google Scholar databases was conducted from 1990 to May 2022. Context-specific keywords such as "Malaria", "Malaria Vaccine", "Malaria Vaccine Candidates", "Vaccine Development", "Vaccine Safety", "Clinical Trials", "mRNA Vaccines", "Viral Vector Vaccines", "Protein-based Vaccines", "Subunit Vaccines", "Vaccine Adjuvants", "Vaccine-induced Immune Responses", and "Immunogenicity" were emphatically considered. Articles not directly related to malaria vaccine candidates in preclinical and clinical stages of development were excluded.

Results: Various approaches have been studied for malaria vaccine development, targeting different parasite lifecycle stages, including the pre-erythrocytic, erythrocytic, and sexual stages. The RTS, S/AS01 vaccine, the first human parasite vaccine reaching WHO-listed authority maturity level 4, has demonstrated efficacy in preventing clinical malaria in African children. However, progress was slow in introducing other safe, and feasible malaria vaccines through clinical trials . Recent studies highlight the potential effectiveness of combining pre-erythrocytic and blood-stage vaccines, along with the advantages of mRNA vaccines for prophylaxis and treatment, and nonstructural vaccines for large-scale production.

Conclusion: Malaria vaccine candidates targeting different lifecycle stages of the parasite range from chemoprophylaxis vaccination to cross-species immune protection. The use of a multi-antigen, multi-stage combinational vaccine is therefore essential in the context of global health. This demands careful understanding and critical consideration of the long-term multi-faceted interplay of immune interference, co-dominance, complement

Background: The Democratic Republic of Congo (DRC) has one of the highest numbers of un and under-vaccinated children as well as number of refugees and internally displaced persons (IDPs) in the world. This study aims to determine and compare the proportion and characteristics of zero-dose (ZD) and under-vaccinated (UV) children among refugees and IDPs in the DRC, as well as the reasons for incomplete vaccination schedules.

Methods: Data from a rolling vaccination coverage survey conducted from September 10, 2022, to July 03, 2023, among refugees and IDPs in 12 provinces of the DRC. ZD was defined as a child aged 12-23 months who had not received any dose of pentavalent vaccine DTP-Hib-Hep B (by card or recall) and UV as a child who had not received the third dose of pentavalent vaccine. The proportions of non and under-vaccination and the associated factors using a logistic regression model are presented for ZD and UV children. The reasons for non-vaccination of these children are described using the WHO-Immunization behavioral and social-drivers-conceptual framework and compared using Pearson's Chi2 test.

Results: Of 692 children aged 12 to 23 months included in the analysis, 9.3% (95% CI: 7.2-11.7%) were ZD and 40.9% (95% CI: 95%: 37.2-44.6%) UV. The Penta1/Penta3 drop-out rate was 34.9%. After adjustment, ZD children had a significant history of home or road birth. And UV children were significantly associated with mothers/caregivers being under 40, uneducated, farmers, ranchers, employed, rural residents, as well as with home or road births. Reasons linked to people's perceptions and feelings were cited much more often for ZD (50.0%) than for UV (38.3%). Those related to social reasons were cited much more often by ZD (40.6%) than by UV (35.7%). Reasons related to "programmatic and practical issues" were cited less for ZD (90.5%) than for UV (97.1%).

Conclusions: ZD and UV children represent significant proportions in refugee and IDPs sites in the DRC. However, the proportion of ZD is less than for the entire country, while the proportion of UV is comparable, reflected in a very high drop-out rate. Similarly to studies in the general population in DRC, the reasons for ZD children were mainly linked to challenges in caregiver motivation to vaccinate, while for UV children, they were more often linked to pro-grammatic and practical problems of the health system.

Background: Tuberculosis (TB) is a major public health concern in the developing countries. Moreover, the emergence of multidrug-resistant tuberculosis is challenging. However, there are no organized data on the trends of pulmonary tuberculosis and rifampicin-resistant Mycobacterium tuberculosis in the study area.

Methods: A retrospective cross-sectional study was conducted to fill the information gap in Central Tigray at St. Mary General Hospital between 2018 and 2023. Data were collected from the GeneXpert™ tuberculosis registration logbooks using standard checklists and analyzed using Statistical Package for Social Science version 22. After performing logistic regression, a p-value < 0.05 with a corresponding 95% confidence interval was considered statistically significant. Moreover, chi square test for trend was performed to assess the percentage of annual detection of pulmonary tuberculosis and rifampicin-resistant Mycobacterium tuberculosis during the study years.

Result: Presumptive pulmonary tuberculosis patients with complete data (n = 3696) were included in the study. The overall prevalence of pulmonary tuberculosis was 11.7%, of which 8.1% were resistant to rifampicin. The study revealed that the incidence of pulmonary tuberculosis has been increasing, mainly in the recent four years. Likewise, an increase in rifampicin-resistant Mycobacterium tuberculosis was observed with considerable fluctuations. Age, human immunodeficiency virus infection, and presumptive rifampicin-resistant Mycobacterium tuberculosis infection were significantly associated with the presence of pulmonary tuberculosis. Moreover, pulmonary tuberculosis was more prevalent among participants in the productive-age group.

Conclusion: Although there have been fluctuations, an increasing of pulmonary tuberculosis and rifampicin-resistant Mycobacterium tuberculosis has been observed in recent years. Hence, prevention and treatment strategies for tuberculosis should be strengthened to alleviate the burden of pulmonary tuberculosis and rifampicin-resistant Mycobacterium tuberculosis in the study area.

Background: International travel exposes individuals to diverse health risks, necessitating proactive pre-travel health preparations. Saudi Arabia has witnessed increased outbound travel. This study addresses a critical gap in knowledge by investigating the utilization and perceptions of pre-travel health consultations among adults in the Eastern Province of Saudi Arabia.

Methods: This cross-sectional study surveyed patients at the Family and Community Medicine Center of Imam Abdulrahman Bin Faisal University during January 2024 to explore perceptions of pre-travel health consultations among the Saudi Arabian population. Adults aged 18 years or older in the waiting area were invited to complete a self-administered questionnaire.

Results: Of the 772 participants, 624 (80.8%) engaged in international travel within the last year. However, 593 (76.8%) had never sought pre-travel health consultations. Age, gender, and education level significantly influenced the pursuit of pre-travel health advice, with older individuals, females, and those with higher educational attainment more likely to seek consultations. Participants perceived vaccination recommendations (597, 77.4%) and disease prevention information (678, 87.8%) as crucial parts of pre-travel health consultations. However, barriers to seeking advice included perceived low risk (445, 74.8%), lack of awareness (215, 36.3%), time constraints (128, 21.6%), and cost concerns (92, 15.5%).

Conclusion: The low prevalence of pre-travel health consultations among travelers highlights the need for targeted educational campaigns and the integration of travel health services into primary healthcare. Addressing the identified barriers and leveraging preferred information sources are crucial steps towards enhancing the uptake of pre-travel health consultations, ultimately improving the health and safety of international travelers from the region.