Tropical Medicine and Infectious Disease

10 pages, 1409 KB

Open AccessPerspective

Tafenoquine: A Breakthrough Option for Babesiosis Treatment

by Dongxue Ma, Mo Zhou, Shinuo Cao, Eloiza May Galon-Bedonia, Zhiqiang Xu, Chenghui Li, Xu Gao, Shujiang Xue and Shengwei Ji

Trop. Med. Infect. Dis. 2026, 11(5), 141; https://doi.org/10.3390/tropicalmed11050141 - 19 May 2026

Abstract

Babesiosis is a zoonosis caused by protozoan parasites of the genus Babesia. It has a worldwide distribution and affects many kinds of mammals, principally domestic animals and humans. Because there are no safe and effective vaccines available, the treatment and control for [...] Read more.

Babesiosis is a zoonosis caused by protozoan parasites of the genus Babesia. It has a worldwide distribution and affects many kinds of mammals, principally domestic animals and humans. Because there are no safe and effective vaccines available, the treatment and control for babesiosis continues to involve the use of chemotherapeutics. For years, only a few drugs have been used for clinical treatment, namely atovaquone plus azithromycin or clindamycin plus quinine for human, and imidocarb dipropionate and diminazene aceturate for domestic animals. Although screening and developing alternative drugs are continuously pursued, only a few drugs have been prospected to have clinical applications. Of these, tafenoquine has shown wide and potent antibabesial activity, offering a new option to control babesiosis. This article aims to present the current clinical therapeutic strategies for babesiosis and their limitations, as well as the prospect of tafenoquine as a promising drug to treat babesiosis. Full article

(This article belongs to the Special Issue New Strategies for the Diagnosis, Treatment and Risk Assessment of Parasitic Disease)

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15 pages, 1125 KB

Open AccessArticle

Unveiling Clinical Phenotypes in Chronic Chikungunya Disease: Insights from a Brazilian Observational Study

by Karen Santos Lima, Adriane Paz Rocha, Alice Lanna Damásio Castro, Anna Carolina Faria Moreira Gomes Tavares, Flávia Patrícia Sena Teixeira Santos, Gilda Aparecida Ferrreira, Livia Barbara Cordeiro Alves, Josiane Lino dos Santos Frattari, Juliana Froeseler Fittipaldi, Lucas Borba Paulino Coelho, Maria Fernanda Brandão de Resende Guimarães, Pedro Ribeiro de Jesus Almeida, Último Libânio Costa, Cristina Costa Duarte Lanna, Gustavo Gomes Resende and Mauro Martins Teixeira

Trop. Med. Infect. Dis. 2026, 11(5), 140; https://doi.org/10.3390/tropicalmed11050140 - 19 May 2026

Abstract

Chronic chikungunya disease (CCD) affects approximately 30–50% of infected individuals and is associated with persistent inflammatory arthritis, chronic pain, and long-term functional disability. We conducted a prospective observational cohort study including 584 patients with laboratory-confirmed chikungunya infection, evaluated between 3 and 12 months [...] Read more.

Chronic chikungunya disease (CCD) affects approximately 30–50% of infected individuals and is associated with persistent inflammatory arthritis, chronic pain, and long-term functional disability. We conducted a prospective observational cohort study including 584 patients with laboratory-confirmed chikungunya infection, evaluated between 3 and 12 months after acute infection, to better understand the natural history, risk factors, clinical presentation, and treatment patterns of CCD. Here, we present a cross-sectional analysis derived from this cohort. Older age, female sex, and higher body mass index were identified as major risk factors for CCD. Four distinct clinical phenotypes were identified: Axial (12.2%), defined by inflammatory axial pain regardless of peripheral manifestations; Oligoarthritis (18.1%), defined by fewer than four swollen joints; Polyarthritis (10.6%), defined by four or more swollen joints; and Pain without Swelling (70.4%), characterized by myalgia and/or arthralgia in the absence of objective inflammatory findings on physical examination. The axial phenotype could overlap with peripheral phenotypes, whereas oligoarthritis, polyarthritis, and pain without swelling were mutually exclusive categories. These phenotypes differed substantially in symptom burden and clinical impact. Patients with the Pain without Swelling phenotype had longer symptom duration, whereas Axial and Polyarthritis phenotypes were associated with greater functional impairment and higher disease burden. These findings reinforce the clinical heterogeneity of CCD and support the potential value of phenotype-based approaches for clinical management and future therapeutic research. Full article

(This article belongs to the Special Issue Arboviral Infections: Pathogenesis and Immunity)

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4 pages, 164 KB

Open AccessEditorial

Biomarkers and Diagnostic and Therapeutic Approaches for Mycobacterial Diseases

by Arshad Rizvi and Yash Gupta

Trop. Med. Infect. Dis. 2026, 11(5), 139; https://doi.org/10.3390/tropicalmed11050139 - 19 May 2026

Abstract

Mycobacterial diseases, particularly tuberculosis (TB), continue to impose a substantial global health burden, disproportionately affecting populations in low- and middle-income countries [...] Full article

(This article belongs to the Special Issue Biomarkers, Diagnostic, and Therapeutic Approaches for Mycobacterial Diseases)

9 pages, 492 KB

Open AccessCase Report

First Usutu Virus Infection in an Asymptomatic Blood Donor in Greece

by Anna Papa, Katerina Tsioka, Styliani Pappa, Danai Pervanidou, Constantina Politis, Kostas Stamoulis and Vassiliki Bakaloudi

Trop. Med. Infect. Dis. 2026, 11(5), 138; https://doi.org/10.3390/tropicalmed11050138 - 18 May 2026

Abstract

Usutu virus (USUV) is a mosquito-borne flavivirus, widely distributed in Central Europe, where it causes avian outbreaks with large-scale mortality. Although most human infections are asymptomatic or mild, the reports of USUV neurologic infections are increasing, especially among immunocompromised patients. Cross-reactivity in serological [...] Read more.

Usutu virus (USUV) is a mosquito-borne flavivirus, widely distributed in Central Europe, where it causes avian outbreaks with large-scale mortality. Although most human infections are asymptomatic or mild, the reports of USUV neurologic infections are increasing, especially among immunocompromised patients. Cross-reactivity in serological and molecular assays is often seen between USUV and the genetically and antigenically related West Nile virus (WNV). Here, we report the first USUV infection in Greece in an asymptomatic blood donor who tested positive in the automated nucleic acid test during screening for WNV, which is endemic in the country. Following the blood donation surveillance plan, a serum sample taken two weeks post-donation was tested for WNV IgM and IgG antibodies. The borderline index of the IgM antibodies, combined with negative result for IgG antibodies, raised the suspicion of molecular cross-reactivity with USUV. Although the USUV-specific PCR in donor’s plasma was negative, its result was positive following amplification of the virus in cell culture, as USUV RNA was detected in the culture supernatant confirming the USUV infection. Whole genome sequence was taken using an Ion Torrent next-generation sequencing platform. Phylogenetic analysis showed that the Greek strain clusters within the USUV Europe 2A genetic lineage. The detection of USUV human infection in Greece prompts for surveillance studies to elucidate its epidemiology and ecology in the country. Full article

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21 pages, 1624 KB

Open AccessArticle

Impact of Insecticide-Treated Nets on Plasmodium falciparum Infection Rates: A Meta-Analysis

by Nevra Karaca Biçakçi, Ayşe Çalmaz, Merve Ayyildiz Akin, Ching Siang Tan, Jayanthi Barasarathi, Babatunji E. Oyinloye, Annaev Umidjon, Kuvonchbek Egamberdiyev and Intizor Avazmetova

Trop. Med. Infect. Dis. 2026, 11(5), 137; https://doi.org/10.3390/tropicalmed11050137 - 18 May 2026

Abstract

Insecticide-treated nets (ITNs), particularly long-lasting insecticide-treated nets (LLINs), are important for malaria control; however, the rise of insecticide resistance, behavioral adaptations in mosquito vectors, and diminishing net durability may affect their efficacy. The objective of this systematic literature review and meta-analysis to synthesize [...] Read more.

Insecticide-treated nets (ITNs), particularly long-lasting insecticide-treated nets (LLINs), are important for malaria control; however, the rise of insecticide resistance, behavioral adaptations in mosquito vectors, and diminishing net durability may affect their efficacy. The objective of this systematic literature review and meta-analysis to synthesize recent epidemiological evidence (2021–2025) on the correlation between ITN/LLIN use and Plasmodium falciparum infection prevalence and to explore sources of heterogeneity across populations, settings, and type of nets. Searches across PubMed, Scopus, and Web of Science yielded 3151 records, of which 10 met the inclusion criteria. Two separate meta-analyses were performed for crude and adjusted effect estimates using random-effects models. The crude-effects meta-analysis included six studies comprising 7466 participants and yielded a pooled odds ratio of 0.67 (95% CI: 0.42–1.07; p = 0.078), indicating no statistically significant association between ITN/LLIN use and P. falciparum infection. Significant heterogeneity was observed (I² = 79.8%), which was partially explained by population type (59.3%) and study design (36.1%). Subgroup analysis revealed comparable infection prevalence–based associations for ITNs (OR = 0.72) and LLINs (OR = 0.59) use. Assessment of publication bias indicated slight asymmetry; however, the trim-and-fill adjustment did not significantly change the conclusions. The adjusted-effects meta-analysis, comprising nine studies, yielded a non-significant pooled effect (aOR = 0.88; 95% CI: 0.42–1.86; p = 0.71) with substantial heterogeneity (I² = 88.7%). Meta-regression analyses indicated that effect estimates varied by population group and country, with statistically significant modifiers observed for children under five years (p = 0.0098) and for studies conducted in Uganda (p = 0.0378). The type of net contributed to variation between studies, with insecticide-treated nets (ITNs) exhibiting lower pooled odds than long-lasting insecticide-treated nets (LLINs) (p = 0.0415). Overall, this meta-analysis found no conclusive evidence of a statistically significant association between ITN/LLIN use and P. falciparum infection in contemporary epidemiological studies. The substantial heterogeneity across settings underscores the context-dependent nature of observed associations and highlights the need for integrated vector-control strategies and continued evaluation of net technologies under conditions of increasing resistance. Full article

(This article belongs to the Special Issue The Global Burden of Malaria and Control Strategies, 2nd Edition)

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20 pages, 1231 KB

Open AccessArticle

Knowledge, Attitudes and Practices Regarding Rift Valley Fever Among Livestock Traders in the Alaotra Mangoro Region, Madagascar

by Félix Alain, Botovola Miraimila, Véronique Chevalier and Peter N. Thompson

Trop. Med. Infect. Dis. 2026, 11(5), 136; https://doi.org/10.3390/tropicalmed11050136 - 16 May 2026

Abstract

Rift Valley fever (RVF) is a viral zoonosis endemic in Madagascar, threatening human and animal health as well as the economy. Trade-related livestock movements are a major factor in the spread of RVF virus. While previous RVF research in Madagascar has focused on [...] Read more.

Rift Valley fever (RVF) is a viral zoonosis endemic in Madagascar, threatening human and animal health as well as the economy. Trade-related livestock movements are a major factor in the spread of RVF virus. While previous RVF research in Madagascar has focused on farmers or general ecology, this study is the first to specifically target livestock traders, the primary drivers for long-distance viral spread, in the Alaotra Mangoro endemic hotspot. This study aimed to assess the level of knowledge, prevailing attitudes and current practices regarding RVF among people engaged in livestock trade in the Alaotra Mangoro region, as well as the factors associated with these KAPs. A descriptive and analytical cross-sectional survey was conducted among 406 livestock traders in five districts of the Alaotra Mangoro region, using a structured questionnaire. A multi-stage sampling approach was employed, utilising purposive selection of markets followed by snowball sampling to reach informal traders often missed by traditional surveys. Generalised linear mixed models were used to analyse factors associated with KAPs regarding RVF. Awareness of RVF was very low (only 18.5% respondents had heard of it), with significant regional disparities (0% in Anosibe An’Ala versus 51.6% in Moramanga). Veterinarians (15.5%), family (12.8%), radio (9.6%) and neighbours (9.6%) were the main sources of information. Understanding of symptoms and modes of transmission (particularly mosquito bites) was limited. Higher levels of education (OR = 181.6; 95% CI: 29.9–1123.7; p < 0.001) and older age (50–60 years) were associated with better knowledge. Proactive attitudes were scarce (21.4%), although more than half (53.4%) believed that RVF is a real disease. Perception of personal risk and the contribution of livestock trade to the spread of the disease was low. However, confidence in animal vaccination was relatively high (60.3%). Preventive practices were highly inadequate. The majority did not wear protective equipment when handling sick animals (94.6%) and rarely avoided touching aborted foetuses (12.6%). Less than half (48.3%) expressed a willingness to report sick or dead animals, and nearly half admitted to having sold or purchased sick livestock (49.5%). Cooking meat (95.1%) and using mosquito nets (74.1%) were the only well-established practices. More than half of respondents (57.9%) lived more than 5 km from veterinary services, and cost was the most frequently cited barrier to consultation. Participation in awareness campaigns was virtually non-existent (5.4%). Results revealed critical gaps in KAP that may contribute to the persistence of RVF. A “One Health” approach is imperative, integrating human, animal and environmental health. Full article

(This article belongs to the Section One Health)

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15 pages, 6365 KB

Open AccessArticle

Human Metapneumovirus G Protein Immunogenicity and Safety Explored via Carrier Protein Fusion

by Tian Ren, Kailun Ma, Xinmiao Lai, Jizheng Chen and Changgui Li

Trop. Med. Infect. Dis. 2026, 11(5), 135; https://doi.org/10.3390/tropicalmed11050135 - 15 May 2026

Abstract

Human metapneumovirus (HPMV) is a significant pathogen that causes lower respiratory tract infections. Given the weak immunogenicity thereof, and the few relevant studies, the utility of the viral membrane protein G as a vaccine remains controversial. In this study, the G extracellular domain [...] Read more.

Human metapneumovirus (HPMV) is a significant pathogen that causes lower respiratory tract infections. Given the weak immunogenicity thereof, and the few relevant studies, the utility of the viral membrane protein G as a vaccine remains controversial. In this study, the G extracellular domain (RMG) of HMPV was expressed either alone or fused with the cholera toxin B subunit (CTB) and “cross-reacting material 197” (CRM197) carrier proteins (giving G-CTB/G and CRM197), to enhance immunogenicity. The non-glycosylated G protein (REG) expressed in Escherichia coli served as a control. SDS-PAGE and anti-His tag Western blotting verified that each protein was successfully expressed and correctly identified. BALB/c mice were immunized with each protein and subjected to challenge with HMPV. The results showed that, although immunization with RMG alone failed to induce potent neutralizing antibodies, it modestly reduced viral loads in the lungs of mice. However, the pathological damage caused by lung inflammation was more aggravated than that of the control challenge group. The level of specific IgG antibody induced by the recombinant G-CTB was significantly higher than that elicited by RMG. Compared to the RMG group, the viral load in the lungs of the G-CTB group tended to be reduced. Also, the damage caused by lung inflammation was significantly alleviated. Our study proves that HMPV G may be a valuable antigen in terms of HMPV vaccine development and offers a promising strategy for modulating the immunogenicity and safety thereof. Full article

(This article belongs to the Special Issue Immune Responses in Respiratory Infections)

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22 pages, 1113 KB

Open AccessArticle

Oviposition Deterrent and Larvicidal Activity of Salvia munzii Essential Oil Against Susceptible and Insecticide-Resistant Aedes aegypti

by Selene M. Gutierrez-Rodriguez, Ivan Cordova-Guerreo, Laura Diaz-Rubio, Jesus A. Davila-Barboza, Iram P. Rodriguez-Sanchez, Beatriz Lopez-Monroy, Sergio A. Galindo-Rodriguez and Adriana E. Flores

Trop. Med. Infect. Dis. 2026, 11(5), 134; https://doi.org/10.3390/tropicalmed11050134 - 15 May 2026

Abstract

The increasing prevalence of insecticide resistance in Aedes aegypti threatens the effectiveness of chemical vector control and highlights the need for alternative approaches targeting mosquito behavior. This study evaluated the oviposition deterrent and larvicidal activity of Salvia munzii essential oil against insecticide-susceptible (New [...] Read more.

The increasing prevalence of insecticide resistance in Aedes aegypti threatens the effectiveness of chemical vector control and highlights the need for alternative approaches targeting mosquito behavior. This study evaluated the oviposition deterrent and larvicidal activity of Salvia munzii essential oil against insecticide-susceptible (New Orleans; NO) and insecticide-resistant (Escobedo) Ae. aegypti strains. The essential oil, dominated by camphor (29.6%), 1,8-cineole (20.8%), and limonene (16.7%), was assessed through laboratory and semi-field bioassays. Larvicidal activity yielded LC₅₀ values of 184.38 µg mL⁻¹ for the susceptible strain and 305.04 µg mL⁻¹ for the resistant strain, with a resistance ratio of 1.65, indicating susceptibility. Oviposition deterrence was quantified using the Oviposition Activity Index (OAI), and median repellent concentrations (RC₅₀) were estimated. Under laboratory conditions, RC₅₀ values were 1.65 µg mL⁻¹ for the NO strain and 1.73 µg mL⁻¹ for the Escobedo strain. Under semi-field conditions, the RC₅₀ for the Escobedo strain decreased to 0.62 µg mL⁻¹. Deterrent activity increased with concentration and persisted for up to 40 days, particularly at higher doses. These results demonstrate that S. munzii essential oil exhibits both larvicidal and oviposition deterrent activity against Ae. aegypti, including a pyrethroid-resistant population, under laboratory and semi-field conditions. The findings support further evaluation of S. munzii essential oil as a potential complementary tool for integrated vector management strategies. Full article

(This article belongs to the Special Issue Insecticide Resistance and Vector Control, 2nd Edition)

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9 pages, 2108 KB

Open AccessCase Report

Strongyloides stercoralis Hyperinfection Presenting as Diffuse Alveolar Hemorrhage in an Endemic Region: A Case Report

by Juan Camilo Motta, Manuel Alejandro Delgado and Jacqueline Mugnier-Quijano

Trop. Med. Infect. Dis. 2026, 11(5), 133; https://doi.org/10.3390/tropicalmed11050133 - 14 May 2026

Abstract

Background: Strongyloides stercoralis is a soil-transmitted helminth capable of establishing chronic infection through an autoinfective cycle, with the potential to progress to life-threatening hyperinfection, particularly in immunocompromised individuals. Case Presentation: We report the case of a 70-year-old man from an endemic region in [...] Read more.

Background: Strongyloides stercoralis is a soil-transmitted helminth capable of establishing chronic infection through an autoinfective cycle, with the potential to progress to life-threatening hyperinfection, particularly in immunocompromised individuals. Case Presentation: We report the case of a 70-year-old man from an endemic region in Colombia with metastatic urothelial carcinoma who developed hyperinfection syndrome following corticosteroid therapy for spinal cord compression. The patient presented with progressive respiratory failure and diffuse alveolar hemorrhage. Chest imaging showed bilateral ground glass opacities, and bronchoalveolar lavage revealed numerous larvae consistent with S. stercoralis, confirming the diagnosis. Despite supportive care and broad-spectrum antimicrobial therapy, the patient experienced rapid clinical deterioration and died. Conclusions: This case highlights the importance of considering strongyloidiasis in the differential diagnosis of diffuse alveolar hemorrhage in endemic settings, particularly in patients receiving corticosteroids. Early recognition and timely treatment are essential to reduce the high associated mortality. Preventive strategies, including targeted screening or empiric ivermectin administration prior to immunosuppression, should be considered in high-risk populations. Full article

(This article belongs to the Special Issue Advances in Strongyloidiasis: Celebrating the Tenth Anniversary of Tropical Medicine and Infectious Disease and a Special Tribute in Memory of Professor Rick Speare (1946–2016))

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11 pages, 235 KB

Open AccessCase Report

Clinical Experience of Therapeutic Plasma Exchange (TPE) in Severe Leptospirosis: A Case Series from Sri Lanka

by Manana Dewage Sankani Vishvara Kularathna and Senanayake Abeysinghe Mudiyanselage Kularatne

Trop. Med. Infect. Dis. 2026, 11(5), 132; https://doi.org/10.3390/tropicalmed11050132 - 12 May 2026

Abstract

Background: Leptospirosis is a globally prevalent zoonosis with significant morbidity and mortality, especially in tropical regions like South Asia. In its severe form, the disease often leads to multiorgan dysfunction, with pulmonary haemorrhage being a major cause of death. Evidence supporting specific treatments [...] Read more.

Background: Leptospirosis is a globally prevalent zoonosis with significant morbidity and mortality, especially in tropical regions like South Asia. In its severe form, the disease often leads to multiorgan dysfunction, with pulmonary haemorrhage being a major cause of death. Evidence supporting specific treatments for severe leptospirosis with pulmonary involvement remains limited. Recent studies suggest that immunomodulatory therapies, such as therapeutic plasma exchange (TPE), may offer survival benefits. This case series explores the application and outcomes of TPE in patients with severe leptospirosis at a tertiary care hospital in Sri Lanka. Methods: We studied a case series involving nine patients with confirmed severe leptospirosis and multiorgan involvement from September 2021 to October 2022. All patients received standard care, including intravenous antibiotics and methylprednisolone. TPE was initiated in all nine patients based on clinical severity, particularly in the presence of pulmonary haemorrhage. Clinical, laboratory, and radiological data were collected from patient records and follow-up. Leptospirosis diagnosis was confirmed through ELISA IgM testing. TPE decisions were made by a multidisciplinary team. Results: Of the nine patients who received TPE, seven survived (78%). Pulmonary haemorrhage was the primary indication for TPE in all cases. All patients had multiorgan involvement: renal failure (89%), hepatic dysfunction (55%), and myocarditis (67%). Mortality was associated with inotropic-dependent myocarditis and mechanical ventilation at TPE initiation. Patients requiring intubation had a 50% mortality rate, compared to 14% in those who were not intubated. Non-survivors also had significantly elevated lactate levels (>4 mmol/L) and worsening acid–base status. Four patients required dialysis: three survived. Conclusions: Early initiation of TPE may be safe and beneficial in severe leptospirosis, and future randomised controlled studies are necessary to examine its benefits further. These findings are hypothesis-generating for further research, particularly on patient selection for TPE. Full article

(This article belongs to the Section Infectious Diseases)

15 pages, 8098 KB

Open AccessSystematic Review

Spatiotemporal Patterns and Historical Overview of Aedes Mosquitoes in Iran: A Systematic Review

by Jalil Nejati, Abedin Saghafipour, Mahsa Sarvi and Rubén Bueno-Marí

Trop. Med. Infect. Dis. 2026, 11(5), 131; https://doi.org/10.3390/tropicalmed11050131 - 12 May 2026

Abstract

Aedes mosquitoes are among the most important vectors of arboviral diseases such as dengue, Zika, and chikungunya. Mapping their geographic and temporal patterns is essential for understanding disease risk and guiding vector control. This systematic review provides an updated synthesis of the spatial [...] Read more.

Aedes mosquitoes are among the most important vectors of arboviral diseases such as dengue, Zika, and chikungunya. Mapping their geographic and temporal patterns is essential for understanding disease risk and guiding vector control. This systematic review provides an updated synthesis of the spatial and temporal distribution of Aedes species across Iran. A comprehensive search of international (PubMed, Scopus, Web of Science) and national (SID, IranMedex, Magiran) databases was performed for studies published between 1980 and 2025. Eligible publications reporting the occurrence or distribution of Aedes mosquitoes were screened according to PRISMA guidelines. Data were extracted and analyzed descriptively to identify long-term spatial and temporal trends. Sixty-six studies met the inclusion criteria, covering more than 20 provinces and examining over 390,000 mosquito specimens. Aedes caspius was the dominant species nationwide, reflecting its high ecological adaptability. Invasive vectors, Ae. aegypti and Ae. albopictus, were recorded mainly in southern coastal provinces and, more recently, in the humid northern regions. Over time, surveys have evolved from scattered faunistic reports to systematic nationwide monitoring, revealing clear patterns of ecological expansion driven by climatic and environmental factors. Increasing reports, broader geographic distribution, and adaptability to diverse ecological settings indicate an ongoing expansion of Aedes mosquitoes in Iran. While these developments reflect successful entomological surveillance and public health efforts, enhanced preparedness and continuous monitoring are essential to manage potential Aedes-borne outbreaks effectively. Full article

(This article belongs to the Special Issue Global Perspectives on the Role of Invasive Mosquito Species and Emerging Vector-Borne Diseases)

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18 pages, 1500 KB

Open AccessArticle

Time-Series Analysis and Age-Stratified Forecasting of Diarrheal Disease in Rwanda Using SARIMA Models

by Theos Dieudonne Benimana, Martin Habimana, Jean de Dieu Harerimana, Eric Mugabo, Thierry Sebakunzi, Patrick Niyonshuti, Valens Rwema, Muhammed Semakula and Seung-sik Hwang

Trop. Med. Infect. Dis. 2026, 11(5), 130; https://doi.org/10.3390/tropicalmed11050130 - 11 May 2026

Abstract

Background: Diarrheal disease remains a major and persistent cause of morbidity and mortality in Rwanda, with substantial seasonal surges that strain routine services; however, transparent and operationally interpretable national forecasting has been underused for age-stratified burden. Methods: We analyzed the Rwanda Health Management [...] Read more.

Background: Diarrheal disease remains a major and persistent cause of morbidity and mortality in Rwanda, with substantial seasonal surges that strain routine services; however, transparent and operationally interpretable national forecasting has been underused for age-stratified burden. Methods: We analyzed the Rwanda Health Management Information System (HMIS) monthly diarrhea case counts (January 2015–December 2025), stratified by age group (under-five and five-and-above), and developed validated Seasonal Autoregressive Integrated Moving Average (SARIMA) forecasts for January 2026–December 2027. Stationarity was assessed using the Augmented Dickey–Fuller test and addressed through differencing. Candidate models were selected via rolling 5-fold cross-validation: Root Mean Square Error (RMSE), Mean Absolute Error (MAE), Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC), and Mean Absolute Percentage Error (MAPE) and confirmed via Ljung–Box residual diagnostics, and benchmarked against seasonal naïve, Exponential Smoothing State-Space (ETS), and Seasonal-Trend decomposition using Loess (STL) + drift reference models. Results: Rwanda recorded 6,309,098 diarrhea cases during 2015–2025, with 49.2% among under-fives; while absolute counts were higher in those aged ≥5 years, risk remained consistently higher in under-fives (91.7–229.5 per 1000) than in those ≥5 years (17.9–34.3 per 1000). Both series showed strong annual seasonality with recurrent peaks in August–November, and forecasts suggest this pattern will persist through 2026–2027. Conclusions: These findings suggest a provisional seasonal (pre-peak, peak, and post-peak) preparedness framework and age-differentiated planning signals, underscoring that burden and risk are not inter changeable across age groups. Full article

(This article belongs to the Special Issue Spatial Epidemiology and Infectious Diseases in the Context of Changing Climate)

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16 pages, 5602 KB

Open AccessArticle

Tailoring Prevention and Control Strategies for Childhood Tuberculosis: From a Global Analysis of Burden Trends and Inequalities Across Three Age Groups (1990–2021) to Prevention and Control Strategies

by Xiaoming Liu, Howard Takiff, Hui Jiang and Weimin Li

Trop. Med. Infect. Dis. 2026, 11(5), 129; https://doi.org/10.3390/tropicalmed11050129 - 9 May 2026

Abstract

Background: Childhood tuberculosis (TB) is a major but underappreciated threat to human health. Because diagnosis of tuberculosis in children is difficult, there are a lack of accurate global statistics. This study aimed to comprehensively assess the long-term global, regional, and age-specific burden [...] Read more.

Background: Childhood tuberculosis (TB) is a major but underappreciated threat to human health. Because diagnosis of tuberculosis in children is difficult, there are a lack of accurate global statistics. This study aimed to comprehensively assess the long-term global, regional, and age-specific burden of childhood TB from 1990 to 2021, to examine its temporal trends and socioeconomic inequalities, and to project future patterns through 2045. Methods: We used incidence and mortality data from the GBD 2021 database for TB in children ages 0–14 years from 1990 to 2021. Children were stratified into three age groups—<5, 5–9 and 10–14 years—and classified by region and Socio-Demographic Index (SDI). Multiple statistical approaches were employed, including average annual percentage change and Bayesian age-period-cohort models, to analyze spatiotemporal trends in disease burden and generate projections for the next 20 years. We used decomposition analysis to separate demographic from epidemiological drivers and concentration indices to quantify socioeconomic inequalities. Results: In 2021 there were, globally, an estimated 759,300 incident cases of childhood TB and 70,659 deaths. Since 1990, childhood TB incidence and mortality rates have declined at average annual rates of 2.61% and 4.48%, respectively. The SDI showed a significant negative correlation with both incidence and mortality of childhood TB (p < 0.05). In 2021, 78.01% of childhood TB deaths were in children under 5 years of age, and over 80% of global childhood TB deaths occurred in Sub-Saharan Africa. Epidemiological interventions were partly offset by rapid population growth in low-SDI regions. The trends show that the incidence and mortality will continue to decline through 2045, but not enough to meet the goal of eliminating childhood TB by 2035. Conclusions: Global efforts should adopt an age-specific framework that prioritizes universal preventive treatment to eliminate mortality in children under 5 years, and implements active case finding to reduce transmission chains among children 5–14 years. Sustaining the decrease in the TB burdens of low-SDI regions requires international financing strategies attuned to expanding populations to ensure epidemiological success is not erased by demographic growth. Full article

(This article belongs to the Special Issue Innovative Tools and Strategies for Tuberculosis (TB) Detection: Advancing Diagnosis Through Technology, Integration, and Equity)

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15 pages, 3574 KB

Open AccessReview

Dengue NS1 as a Driver of Immune-Mediated Pathogenesis

by Upeksha S. Wanigarathna, Senaka Rajapakse, Sisira L. Pathirana, Shiroma M. Handunnetti, Andreas Nitsche and Narmada Fernando

Trop. Med. Infect. Dis. 2026, 11(5), 128; https://doi.org/10.3390/tropicalmed11050128 - 8 May 2026

Abstract

Dengue infection remains a major global health concern, with a subset of patients progressing from self-limited dengue fever to severe disease characterised by plasma leakage, shock, and organ dysfunction. The dengue non-structural protein 1 (NS1), a multifunctional glycoprotein expressed on infected cells and [...] Read more.

Dengue infection remains a major global health concern, with a subset of patients progressing from self-limited dengue fever to severe disease characterised by plasma leakage, shock, and organ dysfunction. The dengue non-structural protein 1 (NS1), a multifunctional glycoprotein expressed on infected cells and secreted into circulation, has emerged as a key mediator linking viral infection to immune-driven vascular pathology. This review synthesises experimental, animal, and human clinical evidence on NS1-driven immunopathogenesis, focusing on mechanisms leading to endothelial dysfunction and increased vascular permeability. NS1 modulates the complement system in a context-dependent manner, contributing to immune evasion by inhibiting terminal complement complex formation, while also promoting antibody-dependent complement activation associated with severe disease. Additionally, NS1 directly disrupts endothelial barrier integrity through disruption of adherens and tight junction architecture, Ang-2/Tie2 imbalance, activation of RhoA/ROCK (RhoA/Rho-associated coiled-coil-containing protein kinase) signalling, and enzymatic degradation of the endothelial glycocalyx, with further amplification through inflammatory mediators. In addition, evidence shows that NS1 activates innate immune signalling, perturbs platelet biology and haemostasis, and forms pro-inflammatory complexes with lipoproteins. Moreover, anti-NS1 antibodies may be both protective and pathogenic. Collectively, these data position NS1-linked pathways as rational targets for adjunctive therapies and next-generation vaccines aimed at preventing vascular leakage and severe dengue infection. Full article

(This article belongs to the Special Issue Arboviral Infections: Pathogenesis and Immunity)

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15 pages, 2069 KB

Open AccessArticle

Sentinel Surveillance of Influenza A in Libya: Subtyping and Genomic Analysis During Recent Seasons (2022–2024)

by Mahmud Azbida, Sana Ferjani, Omar Elahmer, Rmadhan Osman, Salem Shenaisheh, Amal Barakat, Salma Abid, Adem Eljerbi, Abdulwahab Kammon, Ameni Sallemi, Haider El-Saeh, Ilhem Boutiba-Ben Boubaker and Ibrahim Eldaghayes

Trop. Med. Infect. Dis. 2026, 11(5), 127; https://doi.org/10.3390/tropicalmed11050127 - 8 May 2026

Abstract

Influenza sentinel surveillance in Libya was formally established in 2022 by the Libyan National Center for Disease Control (NCDC). Between 2022 and 2024, a total of 1864 nasopharyngeal specimens were collected from patients presenting with influenza-like illness and tested using the GeneXpert for [...] Read more.

Influenza sentinel surveillance in Libya was formally established in 2022 by the Libyan National Center for Disease Control (NCDC). Between 2022 and 2024, a total of 1864 nasopharyngeal specimens were collected from patients presenting with influenza-like illness and tested using the GeneXpert for influenza A virus, influenza B virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and respiratory syncytial virus (RSV). Influenza A virus was detected in 21.1% (393/1864) of samples and influenza B virus was detected in 5.4% of samples (100/1864). SARS-CoV-2 and RSV were identified in 11.6% (216/1864) and 4.1% (77/1864) of specimens, respectively. A subset of 22 influenza A-positive samples was selected based on sample availability and sufficient remaining volume after the initial test for confirmatory testing and further molecular characterization. Real-time RT-PCR subtyping identified 11 A(H1N1)pdm09 and four A(H3N2) viruses. Whole-genome sequencing was successfully performed for 11 isolates, followed by phylogenetic analysis. Genetic characterization revealed that all A(H1N1)pdm09 viruses belonged to clade 6B.1A.5a.2a (5a.2a), while A(H3N2) viruses clustered within clade 3C.2a1b.2a.2a.3a.1 (2a.3a.1) were based on hemagglutinin gene mutations. No neuraminidase mutations associated with antiviral resistance were detected. This study represents the first molecular and phylogenetic characterization of circulating human influenza viruses in Libya, with sequence data submitted to the Global Initiative on Sharing All Influenza Data (GISAID) to establish baseline genetic data for influenza viruses in Libya. Full article

(This article belongs to the Section Infectious Diseases)

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14 pages, 3580 KB

Open AccessArticle

New Data on Ixodid Ticks and Their Infection with Borrelia and Coxiella burnetii in Vietnam

by Nguyen Van Hiep, Tatiana A. Bondarenko, Le Thi Lan Anh, Olga A. Stukolova, Luong Thi Mo, Kseniia A. Sycheva, Vien Chinh Chien, Alex L. Viskontene, Nguyen Thi Dung, Dmitriy V. Dubrovskiy, Truong Xuan Toan, Marina I. Sokolova, Truong Thi Ngan, Irina P. Lisyukova, Daria D. Skripnichenko, Viktoria P. Bulanenko, Yulia V. Fedakova, Vasily G. Akimkin and Marat T. Makenov

Trop. Med. Infect. Dis. 2026, 11(5), 126; https://doi.org/10.3390/tropicalmed11050126 - 6 May 2026

Abstract

The distribution of medically significant ticks in Vietnam requires ongoing monitoring. This study presents data on tick distribution and molecular screening for Borrelia spp. and Coxiella burnetii DNA. Ticks were collected from domestic animals and vegetation in four provinces over the period of [...] Read more.

The distribution of medically significant ticks in Vietnam requires ongoing monitoring. This study presents data on tick distribution and molecular screening for Borrelia spp. and Coxiella burnetii DNA. Ticks were collected from domestic animals and vegetation in four provinces over the period of 2024–2025. Species identification was performed based on morphology and confirmed by sequencing mitochondrial COI and 16S rRNA genes. A total of 2347 ticks were collected, representing eight species from the genera Haemaphysalis, Rhipicephalus, and Amblyomma. The study provides new distribution records for H. bispinosa, H. cornigera, A. integrum, and several rarely reported species (H. lagrangei, H. hystricus, and H. wellingtoni). PCR screening revealed a relatively high detection rate of Borrelia DNA in H. cornigera from Cao Bang province. Sequencing identified the pathogen as B. theileri, the agent of bovine borreliosis. Borrelia theileri was also detected in R. microplus in other regions, indicating wider circulation. PCR screening for Coxiella burnetii was positive for 13 ticks from cattle in Cao Bang province. To rule out false-positive results due to detection of DNA from Coxiella-like endosymbionts, we sequenced a fragment of the IS1111 element for three positive samples. The sequences confirmed that the DNA belongs to bacteria of the genus Coxiella, but the data do not allow confident assignment to C. burnetii at the species level. These positive ticks originated from eight neighboring households, suggesting a potential localized focus that requires further assessment in livestock and humans to determine the epidemiological significance. This research enhances the understanding of Vietnam’s tick fauna and associated pathogens of medical and veterinary importance. Full article

(This article belongs to the Section Vector-Borne Diseases)

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11 pages, 259 KB

Open AccessArticle

Knowledge, Attitudes, and Preparedness Regarding Marburg Virus Disease Among Healthcare Workers in Awi Zone Public Hospitals, Northwest Ethiopia: A Multicenter Cross-Sectional Study

by Ayenew Genet Kebede, Zewdu Bishaw Aynalem, Aragaw Egziabherfenta Tadele, Belachew Tegegne, Asrat Yazew, Betelhem Mekonnen Alem, Lalem Tilahun, Tamene Fetene Terefe, Getachew Amare, Atsedemariam Andualem, Sewunet Ademe and Yonas Wondie

Trop. Med. Infect. Dis. 2026, 11(5), 125; https://doi.org/10.3390/tropicalmed11050125 - 6 May 2026

Abstract

Background: An outbreak of Marburg virus in Jinka Town, Southern Ethiopia, has raised significant concern regarding the potential spreading of disease throughout the country. Healthcare workers play a crucial role in early prevention and control of such an outbreak. However, the knowledge, attitudes, [...] Read more.

Background: An outbreak of Marburg virus in Jinka Town, Southern Ethiopia, has raised significant concern regarding the potential spreading of disease throughout the country. Healthcare workers play a crucial role in early prevention and control of such an outbreak. However, the knowledge, attitudes, and preparedness of healthcare workers regarding Marburg virus disease have not been assessed yet, despite these factors being critical for early prevention and control of an outbreak. This study aimed to assess the knowledge, attitude, and preparedness regarding Marburg virus disease among healthcare workers in Awi Zone public hospitals, northwest Ethiopia, in 2026. Methods: An institutional-based cross-sectional study was conducted among healthcare workers in Awi Zone public hospitals from 26 December 2025 to 10 January 2026. A simple random sampling technique was used to select 394 participants. The data were collected using a pre-tested, structured self-administered questionnaire. The data were entered into Epi-data version 4.6 and analyzed using SPSS version 25. Results: A total of 394 healthcare workers participated in this study. The mean age of the participants was 32.9 ± 4.87 years. The study revealed that 47.7% (95% CI: 42.78–52.62%) and 61.2% (95% CI: 56.4–66%) of participants had good knowledge and a positive attitude towards Marburg virus disease, respectively. However, only 20.3% (95% CI: 16.34–24.26%) demonstrated good preparedness for the Marburg virus outbreak. Conclusions: The study revealed that the majority of healthcare workers had positive attitudes and suboptimal knowledge but critically low preparedness regarding Marburg virus disease prevention and control in Awi Zone public hospitals, northwest Ethiopia. Hence, healthcare workers who are frontline staff for outbreak prevention and control, Awi zone health departments and hospital administrators should be provided with targeted training preparation, training for implementing emergency preparedness plans, and essential infection prevention protocols to improve readiness for a potential outbreak. Full article

(This article belongs to the Section Infectious Diseases)

11 pages, 268 KB

Open AccessReview

Ten Years of Congenital Zika Syndrome: From Outbreak to a Decade of Clinical, Therapeutic, and Preventive Advances in a Tropical Disease Context

by Fabrício Silva Pessoa

Trop. Med. Infect. Dis. 2026, 11(5), 124; https://doi.org/10.3390/tropicalmed11050124 - 6 May 2026

Abstract

A decade has elapsed since the first recognized cluster of congenital anomalies associated with Zika virus (ZIKV) was reported in Brazil in 2015, culminating in the formal delineation of Congenital Zika Syndrome (CZS) as a specific pattern of birth defects. This narrative review [...] Read more.

A decade has elapsed since the first recognized cluster of congenital anomalies associated with Zika virus (ZIKV) was reported in Brazil in 2015, culminating in the formal delineation of Congenital Zika Syndrome (CZS) as a specific pattern of birth defects. This narrative review examines the ten-year trajectory of CZS as a tropical infectious disease, from its initial emergence and public health emergency declaration by the World Health Organization (WHO) in February 2016, through evolving epidemiological, clinical, and scientific understanding. CZS is characterized by a spectrum of severe neurological manifestations—including microcephaly, subcortical calcifications, malformations of cortical development, ventriculomegaly, and corpus callosum abnormalities—alongside ophthalmic, auditory, and musculoskeletal complications. Transmitted primarily by Aedes aegypti mosquitoes in tropical and subtropical regions, ZIKV disproportionately affects low- and middle-income countries in Latin America, Africa, and Southeast Asia, underscoring its nature as a quintessential tropical disease linked to poverty, inadequate vector control, and health inequity. Over ten years, substantial advances have been made in understanding ZIKV pathogenesis, neurodevelopmental outcomes, diagnostic criteria, and multidisciplinary clinical management of affected children. In the therapeutic and preventive domain, over 45 vaccine candidates have been identified, with 16 reaching Phase 1 or 2 clinical trials by late 2025, though no licensed vaccine or specific antiviral therapy yet exists. This review contextualizes CZS within the broader framework of neglected tropical diseases, evaluates its global and family-level burden, and critically appraises progress and remaining gaps in clinical care, vaccination, and vector control over the past ten years. Full article

(This article belongs to the Special Issue Emerging Vector-Borne Diseases and Public Health Challenges)

17 pages, 1159 KB

Open AccessArticle

Challenges to ‘Last Mile’ Surveillance: Result of Programmatic Review of Integrated Skin NTDs Surveillance in Three Indonesian Districts

by Agrin Zauyani Putri, Ajib Diptyanusa, Regina Tiolina Sidjabat, Yatinawati Yatinawati, Yety Intarti, Irma Surya Kusuma, Khadijah Qurrata Ayun, Trijoko Yudopuspito, Muhammad Anwar Simanullang, Dwi Martanti, Achmad Naufal Azhari, Herdiana Herdiana and Yullita Evarini Yuzwar

Trop. Med. Infect. Dis. 2026, 11(5), 123; https://doi.org/10.3390/tropicalmed11050123 - 6 May 2026

Abstract

Indonesia is approaching the ‘last mile’ of elimination for several skin-related neglected tropical diseases (skin NTDs): notably, leprosy, yaws and lymphatic filariasis (LF). However, persistent transmission in selected districts highlights systemic weaknesses in surveillance. This paper aimed to analyse the health system, operational [...] Read more.

Indonesia is approaching the ‘last mile’ of elimination for several skin-related neglected tropical diseases (skin NTDs): notably, leprosy, yaws and lymphatic filariasis (LF). However, persistent transmission in selected districts highlights systemic weaknesses in surveillance. This paper aimed to analyse the health system, operational and sociocultural barriers to integrated skin NTDs surveillance in Indonesia. A descriptive analysis of the national programmatic review of integrated skin NTDs was conducted in 2024, using a mixed-methods descriptive evaluation based on routine data and thematic analysis. Comparative case studies of the Belitung, Mimika and Sorong Selatan Districts were conducted using routine data, programme reports, and structured observations at primary health centres, district health offices and laboratories. Qualitative insights from programme managers, health workers and communities were thematically analysed. Integrated surveillance was constrained by fragmented governance, inflexible financing, and uneven workforce capacity, alongside operational challenges like delayed detection and geographic inaccessibility. Furthermore, sociocultural factors such as stigma and population mobility, combined with zoonotic LF transmission in Belitung, significantly undermine effectiveness and long-term programmatic sustainability. Despite strong national policy commitment and substantial progress in disease elimination, significant gaps remain between integration frameworks and operational realities at the district level. Accelerating skin NTDs elimination in Indonesia requires context-adapted integration, strengthened digital surveillance, sustained subnational financing, workforce capacity building and, in zoonotic settings, a One Health approach. Addressing these factors is essential for achieving and sustaining elimination in the last mile. Indonesia has achieved substantial progress across major skin NTDs, while also revealing persistent gaps that threaten the sustainability of elimination gains. Full article

(This article belongs to the Special Issue Surveillance of Eliminated and Near-Eliminated Infectious Disease in the Western Pacific Region)

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