Emerging and Re-emerging Infectious Diseases: Global and Local Burden, Surveillance, and Response Strategies

A special issue of Tropical Medicine and Infectious Disease (ISSN 2414-6366). This special issue belongs to the section "Infectious Diseases".

Deadline for manuscript submissions: 31 January 2026 | Viewed by 12597

Special Issue Editors

Institute of Hygiene and Tropical Medicine, Universidade NOVA de Lisboa, 1349-008 Lisbon, Portugal
Interests: phlebotomine sand fly-borne pathogens: epidemiology; diagnosis; vector-pathogen-host interactions; vector-borne agents with zoonotic or veterinary importance

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Guest Editor
Department of Health Sciences, University of Florence, 50134 Florence, Italy
Interests: vector-borne diseases; global health; vaccines; artificial intelligence; health promotion

Special Issue Information

Dear Colleagues,

Emerging and re-emerging diseases, amplified by the increasingly rapid evolution of factors such as globalisation, urbanisation, migration and travel, represent a growing burden on global public health, not only for humans, but also for animals, with significant impacts on global economies being made as a result. Pathogens that emerge for the first time in a population, or that spread rapidly after having been under control, pose an evolving threat, making the development of coordinated and effective preventive strategies and interventions essential.

Recent examples of emerging diseases, such as SARS-CoV-2 and Monkeypox, together with re-emerging diseases, such as certain arboviruses, avian influenza or oropouche fever, highlight the need for coordinated international surveillance and timely response to these global threats.

The aim of this Special Issue is to explore the complexity of these diseases, analysing recent developments, trends and case studies both locally and globally. Contributions may range from new discoveries on emerging pathogens to changes in disease patterns and factors favouring the return of previously under-control infections. It will be focused on epidemiological studies, innovative control and prevention strategies and the impacts of several factors such as climate change, urbanisation and migration.

The ultimate goal of this collection is to create a platform for dialogue between researchers, health professionals and policymakers, promoting collaborations and effective strategies to mitigate the impact of these diseases locally and globally.

Dr. Marco Del Riccio
Dr. Carla Maia
Dr. Claudia Cosma
Guest Editors

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Keywords

  • emerging and re-emerging infectious diseases
  • viruses
  • bacteria
  • parasites
  • health emergency
  • health preparedness
  • global and local surveillance
  • global and local prevention
  • global and local control

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Published Papers (8 papers)

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Research

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12 pages, 2429 KB  
Article
The Construction and Characterization of an Infectious Clone of the Asian Genotype Chikungunya Virus from Yunnan, China
by Xinhang Ning, Binghui Xia, Zimeng Cheng, Liuyi Zhang, Fengfeng Mo, Hao Ren and Hailin Tang
Trop. Med. Infect. Dis. 2025, 10(10), 278; https://doi.org/10.3390/tropicalmed10100278 - 26 Sep 2025
Abstract
Chikungunya fever (CHIKF), which is caused by the Chikungunya virus (CHIKV), has rapidly spread across the globe in recent years, leading to its listing as a public health concern by the World Health Organization. In 2019, the first local outbreak of Asian-type CHIKF [...] Read more.
Chikungunya fever (CHIKF), which is caused by the Chikungunya virus (CHIKV), has rapidly spread across the globe in recent years, leading to its listing as a public health concern by the World Health Organization. In 2019, the first local outbreak of Asian-type CHIKF was reported in Xishuangbanna, Yunnan Province, China, with 88 CHIKV nucleic acid-positive cases detected from clinical specimens. To further investigate the biological characteristics of the virus strain responsible for this outbreak, we reconstructed the 625D6h strain using reverse genetics and tested its growth kinetics in different cell lines. The results showed a strong replication capacity in the Aedes albopictus C6/36 insect cell line but a weaker one in mammalian cell lines. The virus’s high replication capacity in mosquito cells is an interesting phenotype that warrants further study to determine if it influences vector adaptation and transmission dynamics in endemic settings. The study also found that two DHODH inhibitors, ML390 and vidofludimus, could effectively inhibit CHIKV replication in vitro. The infectious clone created in this study provides a useful tool for studying the recently prevalent Asian-type strain in China, supporting the subsequent development of prevention and treatment methods. Full article
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18 pages, 3997 KB  
Article
Identification of Statewide Hotspots for Respiratory Disease Targets Using Wastewater Monitoring Data
by Dustin Servello, Purnima Chalasani, Erica Leasure, Krysta Danielle LeMaster, Justin Kellar, Jill Stiverson, Michelle White and Zuzana Bohrerova
Trop. Med. Infect. Dis. 2025, 10(9), 241; https://doi.org/10.3390/tropicalmed10090241 - 28 Aug 2025
Viewed by 548
Abstract
As wastewater monitoring networks continue to expand the monitoring of various targets, it is important to ensure these networks remain both representative of their monitored populations and flexible enough to accurately predict shifts in an expanding list of targets. In this study, we [...] Read more.
As wastewater monitoring networks continue to expand the monitoring of various targets, it is important to ensure these networks remain both representative of their monitored populations and flexible enough to accurately predict shifts in an expanding list of targets. In this study, we analyzed the levels of SARS-CoV-2, influenza A (InfA), and influenza B (InfB) detected in untreated wastewater during the 2023–2024 respiratory season at 70 locations participating in the Ohio Wastewater Monitoring Network. Locations with the first detection that are seasonal hotspots and sites reaching peak concentration for each target were compared and analyzed for dependence on healthcare access and population characteristics, such as population size and density, county traffic, and demographic and socioeconomic factors. The trends in these three respiratory viruses were found to closely mirror trends in clinical indicators including the number of cases and positive tests with wastewater levels providing a two-week lead for SARS-CoV-2 and no lead for influenza on these clinical indicators. InfA was first detected in more affluent sewersheds that were less racially and ethnically diverse and had higher traffic counts, while none of the parameters tested had an effect on InfB first detects. The seasonal hotspots varied for all three respiratory viruses, where InfA hotspots were exclusively in the northeast, InfB was in the southeast and east border areas, and SARS-CoV-2 wastewater hotspots concentrated around central and northwestern Ohio. While wastewater monitoring networks may not offer full coverage of all populous areas, we have shown that a spatially distributed and highly diverse network is needed for early detection of various respiratory targets. Full article
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17 pages, 753 KB  
Article
Seroprevalence of West Nile Virus in Blood Donors in Mainland Portugal
by Rafael Rocha, Elif Kurum, Rémi Charrel, Nazli Ayhan and Carla Maia
Trop. Med. Infect. Dis. 2025, 10(8), 229; https://doi.org/10.3390/tropicalmed10080229 - 15 Aug 2025
Viewed by 630
Abstract
The genus Orthoflavivirus includes several mosquito-borne pathogenic viruses, notably West Nile virus (WNV), which is endemic to the Mediterranean region. In Portugal, WNV circulation has been documented in equines, birds and mosquitoes, however human cases remain rare and no recent human seroprevalence studies [...] Read more.
The genus Orthoflavivirus includes several mosquito-borne pathogenic viruses, notably West Nile virus (WNV), which is endemic to the Mediterranean region. In Portugal, WNV circulation has been documented in equines, birds and mosquitoes, however human cases remain rare and no recent human seroprevalence studies have been conducted. This study aimed to estimate the national and regional seroprevalence of WNV among blood donors in mainland Portugal and explore associations with sociodemographic factors. A cross-sectional study conducted in 2022 included 3593 blood donors from across mainland Portugal. Serum samples were tested for WNV immunoglobulin G (IgG) by enzyme-linked immunosorbent assay (ELISA) and positive and borderline samples were confirmed using a virus neutralization test. Sociodemographic data were collected through a structured paper questionnaire. Statistical analyses, including multivariate logistic regression, identified factors associated with seropositivity. A total of 55 samples (1.5%) tested positive, and 21 samples (0.6%) were classified as borderline for WNV antibodies by ELISA. Of these, 47 were confirmed by viral neutralization, giving an estimated national seroprevalence of 1.4%. Significant regional variation was noted, with higher seroprevalence observed in the Beira Baixa, Grande Lisboa and Médio Tejo regions. Some seropositive individuals were identified in northern coastal regions such as Ave, Cávado and Área Metropolitana do Porto. In multivariate analysis, geographical area of residence was the only factor associated with seropositivity. This study highlights regions at potential higher risk for human WNV exposure, primarily in the southern half of Portugal. Continued and integrated surveillance is crucial to inform public health strategies to mitigate WNV transmission risks in these regions, as well as in other regions where WNV may be emerging as a relevant One Health concern. Implementing preventive measures for both animals and humans is critical to minimizing exposure and infection, and further confirmatory studies using virus neutralization tests will be important for refining these estimates. Full article
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12 pages, 376 KB  
Article
Molecular Assays on Cutaneous Swabs as an Effective, Non-Invasive Diagnostic Technique for Cutaneous Leishmaniasis: Results from a Retrospective Study Conducted in Italy
by Anna Barbiero, Andrea Aiello, Nunziata Ciccone, Simona Pollini, Francesca Malentacchi, Maria Grazia Colao, Gian Maria Rossolini, Costanza Fiorelli, Daniela Massi, Alberto Antonelli, Sara Cuffari, Trentina Di Muccio, Alessandro Bartoloni, Michele Spinicci and Lorenzo Zammarchi
Trop. Med. Infect. Dis. 2025, 10(6), 158; https://doi.org/10.3390/tropicalmed10060158 - 9 Jun 2025
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Abstract
Background: The case confirmation of CL relies on the direct demonstration of the parasite in clinical specimens from skin tissues. Despite most research efforts focusing on biopsy samples as the preferred diagnostic specimen for the detection of Leishmania spp., the use of non-invasive [...] Read more.
Background: The case confirmation of CL relies on the direct demonstration of the parasite in clinical specimens from skin tissues. Despite most research efforts focusing on biopsy samples as the preferred diagnostic specimen for the detection of Leishmania spp., the use of non-invasive sampling, such as cutaneous swabs, combined with the use of molecular assays, has shown promising results. Methods: We conducted a retrospective study aimed at comparing the performance of different invasive and non-invasive diagnostic techniques, employed for the diagnosis of CL, in an Italian tertiary care center. Results: We observed 29 cases of CL between 2008 and June 2024. Considering the demonstration of Leishmania spp. on culture, biopsy PCR, histology, or smear microscopy as the reference diagnostic test for CL, molecular assays on cutaneous swabs showed a sensitivity of 100% (95% C.I. 73.5–100). Overall, PCR performed on swab specimens allowed for the detection of three cases that biopsy histology (in two cases) and microscopic examination of cutaneous smear (in three cases) would have failed to identify. Conclusion: Non-invasive swab sampling, combined with molecular analysis, can be a valuable tool for a more accessible and patient-friendly diagnostic approach for CL. Should our preliminary results be confirmed, this test could become the first-line diagnostic tool for CL, reserving biopsy as a second-level test or for cases in which the differential diagnosis includes malignancy or other concerning diseases. Further studies aimed at defining the efficiency of this diagnostic method and providing standardized diagnostic protocols would be needed to provide stronger evidence supporting its recommendation. Full article
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12 pages, 657 KB  
Article
Epidemiological Dynamics and Trends of Dengue Outbreaks in Sao Tome and Principe: A Comprehensive Retrospective Analysis (2022–2024)
by Sousa Lazaro, Vilfrido Santana Gil, Ivando Carvalho Viegas de Ceita, Isaulina Neto Viegas Barreto, Eula Carvalho Batista Sousa Maquengo, Andreza Batista de Sousa, Bakissy da Costa Pina, Tieble Traore, Alimuddin Zumla and John Otokoye Otshudiema
Trop. Med. Infect. Dis. 2025, 10(2), 34; https://doi.org/10.3390/tropicalmed10020034 - 24 Jan 2025
Viewed by 1524
Abstract
Background: Dengue has emerged as a significant public health concern in Sao Tome and Principe, with the first documented outbreak occurring between 2022 and 2024. This study examined the epidemiological patterns, environmental determinants, and demographic characteristics of dengue transmission during this period. Methods: [...] Read more.
Background: Dengue has emerged as a significant public health concern in Sao Tome and Principe, with the first documented outbreak occurring between 2022 and 2024. This study examined the epidemiological patterns, environmental determinants, and demographic characteristics of dengue transmission during this period. Methods: We conducted a comprehensive retrospective analysis of laboratory-confirmed dengue cases using national surveillance data, clinical records, and environmental monitoring data. Statistical analyses included demographic profiling, temporal trend assessment, and environmental correlation studies using multiple regression modeling. Results: Among 1264 laboratory-confirmed cases, we observed distinct age-specific vulnerability patterns, with the highest incidence rate in the 70–79 age group (829.6 per 100,000) despite most cases occurring in younger adults. Rainfall emerged as the strongest predictor of dengue transmission (r = 0.96, p < 0.001), explaining 92% of case variance in the regression model. Case distribution showed marked temporal variation, with 91.9% of cases reported in 2022, coinciding with exceptional rainfall (3205 mm). The overall case fatality rate was 0.71% (95% CI: 0.33–1.35), with significant quarterly variations. Geographical analysis revealed concentration in the Água Grande district (68.2% of cases). Conclusions: This first comprehensive analysis of dengue in Sao Tome and Principe demonstrates the crucial role of rainfall in disease transmission and reveals important age-specific vulnerability patterns. These findings provide an evidence base for developing targeted interventions, particularly during high-rainfall periods, and suggest the need for age-stratified clinical protocols in similar island settings. Full article
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15 pages, 518 KB  
Article
Multidrug-Resistant Acinetobacter baumannii: Risk Factors for Mortality in a Tertiary Care Teaching Hospital
by Kristina Černiauskienė and Astra Vitkauskienė
Trop. Med. Infect. Dis. 2025, 10(1), 15; https://doi.org/10.3390/tropicalmed10010015 - 6 Jan 2025
Cited by 2 | Viewed by 3160
Abstract
Background and objectives: Due to resistance and the lack of treatment options, hospital-acquired Acinetobacter baumannii (A. baumannii) infections are associated with high mortality. This study aimed to analyze the characteristics of patients with infections caused by multidrug-resistant (MDR) A. baumannii and patients’ clinical [...] Read more.
Background and objectives: Due to resistance and the lack of treatment options, hospital-acquired Acinetobacter baumannii (A. baumannii) infections are associated with high mortality. This study aimed to analyze the characteristics of patients with infections caused by multidrug-resistant (MDR) A. baumannii and patients’ clinical outcomes as well as determine the risk factors for mortality in a tertiary care teaching hospital. Materials and methods: A retrospective cohort study including 196 adult patients with A. baumannii strains isolated from different clinical specimens in the Hospital of the Lithuanian University of Health Sciences in 2016, 2017, 2020, and 2021 was conducted. Data on patients’ characteristics, comorbid diseases, treatment, length of hospital and ICU stay, and outcome were collected. Carbapenemase-producing isolates were detected phenotypically. To determine risk factors for in-hospital mortality, logistic regression analysis was performed. Results: There were 60 (30.6%) women and 136 (69.4%) men with a mean age of 61.7 ± 16.6 years (range, 52–74). More than three-fourths (76.5%, n = 150) of the patients had at least one comorbid disease. The highest number of A. baumannii strains were isolated from patients hospitalized in ICUs (43.4%, n = 85). A. baumannii strains producing three types of β-lactamases were more frequently isolated from women than men (77.8% vs. 22.2%, p = 0.006). Infections caused by A. baumannii strains producing two types of β-lactamases were significantly more often treated with combination therapy than infections caused by strains producing one type of β-lactamase (78.9% vs. 60.0%, p = 0.019). Patients with A. baumannii strains producing two different types of β-lactamases (AmpC plus KPC, AmpC plus ESBL, or ESBL plus KPC) stayed significantly shorter at the ICU compared to patients with A. baumannii strains with no detected β-lactamases (median of 9, IQR 2–18, vs. median of 26, IQR 7–38, p = 0.022). Death occurred in 58.7% (n = 115) of patients. Logistic regression analysis showed that a duration of the effective antibiotic treatment of ≤6 days, invasive mechanical ventilation, combination therapy, aged >58 years, and the absence of co-infection were independent predictors of in-hospital mortality. Conclusions: MDR A. baumannii infections pose a significant threat to human health not only due to multidrug resistance but also due to high mortality. The mortality rate of patients with MDR A. baumannii infection was high and was associated with age, invasive mechanical ventilation, the duration of effective antibiotic treatment, no co-infection, and combination therapy. Therefore, it is of utmost importance to reduce the prevalence of MDR A. baumannii infections in healthcare facilities by applying preventive measures and to administer timely effective treatment once A. baumannii infection is detected. Full article
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16 pages, 1881 KB  
Article
From Paper to Digital: Performance and Challenges of the Electronic Hepatitis B Surveillance System in Ninh Binh, Northern Vietnam (2017–2022)
by Hien T. Nguyen, Thai Q. Pham, Duc M. Hoang, Quang D. Tran, Giang T. Chu, Thuong T. Nguyen, Nam H. Le, Huyen T. Nguyen, Khanh C. Nguyen and Florian Vogt
Trop. Med. Infect. Dis. 2024, 9(12), 299; https://doi.org/10.3390/tropicalmed9120299 - 5 Dec 2024
Viewed by 4067
Abstract
Hepatitis B remains a major public health issue in Vietnam. Mandatory reporting to the national electronic communicable disease surveillance system (eCDS) has been required since July 2016. We conducted an evaluation of the hepatitis B surveillance system in Ninh Binh, the province with [...] Read more.
Hepatitis B remains a major public health issue in Vietnam. Mandatory reporting to the national electronic communicable disease surveillance system (eCDS) has been required since July 2016. We conducted an evaluation of the hepatitis B surveillance system in Ninh Binh, the province with the highest reported burden of hepatitis B in Northern Vietnam, between 2017 and 2022. Using the CDC’s guidelines for evaluating public health surveillance systems, we assessed four key attributes: simplicity, timeliness, data quality, and acceptability. This retrospective evaluation included document reviews, analysis of hepatitis B data, and in-depth interviews with provincial-level healthcare staff involved in the reporting of hepatitis B cases. The results showed that the eCDS improved reporting frequency, provided more detailed case information, and enhanced data accessibility compared to the previous paper-based system. However, the system faced several challenges, including unclear objectives, difficulties in distinguishing acute from chronic cases, insufficient training for staff, lack of supervision for data quality, and technical software issues. Despite these challenges, stakeholders found the system acceptable but emphasized the need for improvements, including revising the system’s objectives, automating case classification, enhancing training, securing funding for maintenance, and implementing regular data review processes. Full article
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Review

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25 pages, 596 KB  
Review
AmpC β-Lactamase-Producing Microorganisms in South American Hospitals: A Meta-Regression Analysis, Meta-Analysis, and Review of Prevalence
by Valmir Nascimento Rastely-Junior, Hosanea Santos Nascimento Rocha and Mitermayer Galvão Reis
Trop. Med. Infect. Dis. 2025, 10(10), 280; https://doi.org/10.3390/tropicalmed10100280 - 29 Sep 2025
Abstract
AmpC β-lactamases are class C enzymes that hydrolyze penicillins, cephalosporins, and monobactams. The WHO recently classified third-generation cephalosporin-resistant and carbapenem-resistant Enterobacterales as critical pathogens. We conducted a systematic review and meta-analysis to evaluate AmpC prevalence in hospital isolates across South America. We searched [...] Read more.
AmpC β-lactamases are class C enzymes that hydrolyze penicillins, cephalosporins, and monobactams. The WHO recently classified third-generation cephalosporin-resistant and carbapenem-resistant Enterobacterales as critical pathogens. We conducted a systematic review and meta-analysis to evaluate AmpC prevalence in hospital isolates across South America. We searched PubMed/MEDLINE, SciELO, and Google Scholar. We included 69 observational studies that phenotypically or genotypically identified AmpC producers. A random-effects generalized linear mixed model with logit transformation estimated pooled prevalence; heterogeneity and moderators were explored through subgroup analyses and meta-regression. Seventy studies, including 48,801 isolates, were eligible. AmpC β-lactamases were detected in 11.7% of isolates (95% CI 11.4–12.0), with extreme heterogeneity (I2 ≈ 97%). Enterobacter species showed the highest prevalence (~46%), whereas Escherichia spp. had the lowest (~4.5%) prevalence of AmpC positivity within each genus. Meta-regression indicated that studies focusing on a single genus reported higher prevalence and that including pediatric patients was associated with a lower prevalence of AmpC-positive microorganisms among isolates. Quality of evidence was rated low due to inconsistency, moderate risk of bias, and indirectness of data. AmpC producers are entrenched in South American hospitals, and species-aware surveillance and harmonized detection are critical to guide empiric therapy and antimicrobial stewardship. Full article
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