Search Results (810)

Cutaneous leishmaniasis (CL) is a vector-borne parasitic disease caused by protozoa of the Leishmania genus. Once confined to endemic regions such as the Middle East, Americas, North Africa, and Central Asia, CL is increasingly emerging in non-endemic areas due to a multitude of drivers, including population displacement, environmental disruption, and political instability. These overlapping drivers contribute to expanding sand fly habitats, degrading living conditions, and weakening health systems, increasing transmission. Rising global temperatures further facilitate vector expansion into new regions, where clinical unfamiliarity often leads to misdiagnosis, delayed treatment, increased morbidity, and greater financial burden. Despite its rising incidence and global spread, CL remains a neglected tropical disease since it is seldom fatal, with scant interest by public health authorities and financial donors, limiting activities that further research and prevent spread of the disease. This review synthesizes current evidence on how geopolitical instability, forced migration, and climate-driven ecological changes collectively reshape CL epidemiology and complicate diagnosis, treatment, and surveillance. As CL extends beyond traditional geographic boundaries, it requires integrated strategies that address its multifaceted drivers through strengthened cross-border surveillance, provider education, and international coordination—focusing on prevention, diagnosis, and equitable access to diagnostics and therapeutics, especially among displaced and underserved populations. Full article

Hepatitis B virus (HBV) infection remains a global public health concern, with perinatal transmission as the primary route in endemic populations. Ayacucho is a priority region due to its high incidence (second nationally between 2019 and 2024) and the significant decline in vaccination coverage (~15%). This study aims to synthesize existing epidemiological evidence on HBV seroprevalence in Ayacucho, Peru, emphasizing temporal changes observed before and after the implementation of vaccination programs to inform control strategies. This review was conducted, integrating data from diverse population groups, including children, pregnant women, blood donors, high-risk individuals (military personnel, female sex workers, prisoners), and household contacts, to identify transmission patterns and evaluate the impact of immunization efforts. Historically, Ayacucho was hyperendemic, with an HBsAg prevalence of 20% in Huanta (1985–1986) and a high mortality from liver diseases. The introduction of a vaccination in the 1990s led to a drastic reduction in infection rates among children, from 24.4–30.4% (1994) to 2.3–5.1% (1997), and improved overall Expanded Program on Immunization (EPI) coverage. However, recent data (2000–2024) reveal a concerning increase in HBV cases since 2012, with peaks in 2016 and 2023, correlating with a decline in vaccination rates post-2021. HBV prevalence remains elevated among high-risk populations—including military personnel, female sex workers, and prisoners—as well as among blood donors (HBsAg: 3.73–5.0%; anti-HBc: 21–33%). In addition, significant knowledge gaps and low adherence to EPI strategies were observed. Despite initial vaccination success, Ayacucho faces a resurgence of HBV infection, exacerbated by declining vaccine coverage and vulnerabilities in high-risk populations. Reinforcing immunization programs and screening strategies is urgent to control and eventually eliminate HBV cases in the region. Full article

Schmallenberg virus (SBV) is a negative-sense RNA virus transmitted by insect vectors, causing arthrogryposis-hydranencephaly syndrome in newborn ruminants. Since its discovery in Germany and the Netherlands in 2011, SBV has rapidly spread across multiple European countries, resulting in significant economic losses in the livestock industry. With the increasing global animal trade and the expanded range of insect transmission, the risk of SBV introduction into non-endemic regions is also rising. As the gold standard for serological testing, the virus neutralization test (VNT) is crucial for tracking the spread of SBV and evaluating the efficacy of vaccines. However, in non-endemic regions, the lack of local viral strains and the biosafety risks associated with introducing foreign strains pose challenges to the implementation of VNT. In this study, we employed reverse genetics techniques using vesicular stomatitis virus (VSV) to substitute the VSV G protein with the envelope glycoproteins of SBV, thereby successfully generating and rescuing the recombinant virus rVSVΔG-eGFP-SBVGPC. The recombinant virus was then thoroughly characterized in terms of SBV Gc protein expression, viral morphology, and growth kinetics. Importantly, rVSVΔG-eGFP-SBVGPC exhibited SBV-specific cell tropism and was capable of reacting with SBV-positive serum, enabling the measurement of neutralizing antibody titers. The results suggest that this recombinant virus can serve as a feasible alternative for SBV neutralization tests, with promising potential for application in serological screening and vaccine evaluation. Full article

In this study, we formulate and analyze a deterministic mathematical model describing the transmission dynamics of pneumonia. A comprehensive stability analysis is conducted for both the disease-free and endemic equilibrium points. The disease-free equilibrium is locally and globally asymptotically stable when the basic reproduction number R₀ < 1, while the endemic equilibrium is locally and globally asymptotically stable when R₀ > 1. To evaluate effective intervention strategies, an optimal control problem is formulated by introducing time-dependent control variables representing awareness campaigns, screening of carriers, and treatment of infected individuals. Applying Pontryagin’s Maximum Principle, the simulation results confirm the effectiveness of the proposed control strategies in reducing the number of infections and mitigating the overall disease burden. The findings offer valuable insights into the control of pneumonia and highlight the potential impact of strategic public health interventions. Full article

Background: Hansen’s disease or leprosy is one of the 21 neglected tropical diseases (NTDs). In Ecuador, leprosy is considered eliminated as a public health problem; however, new cases are reported annually. Additionally, Mycobacterium leprae infection was detected in nine-banded armadillos across the country, suggesting a potential zoonotic reservoir. This literature review aims to provide an updated overview of the epidemiological situation of leprosy in Ecuador, identify knowledge gaps, and outline research priorities to support the development of a comprehensive national strategy for achieving zero autochthonous cases. Methods: This article analyses the current situation of leprosy in Ecuador based on international and national publications. A retrospective literature search using five international, regional, and national publications on leprosy published between 1954 and 2024 (70 years) with no restriction on language or publication date, was performed. Findings: Our review identified 28 publications with the earliest article dating back to 1954. Of these, 14 were published in international journals, 15 (53.6%) were in Spanish. Four nationwide studies documented leprosy cases across Ecuador’s three continental regions (Coast, Andes, and Amazon) with a predominance in the tropical coast. No cases have been reported from the Galápagos Islands. From 1983, Ecuador started multi-drug therapy. Data from the Ministry of Public Health (MoH) system identified 1539 incident cases, showing a significant decline in new cases from 2000 to 2024, with no cases in children. New cases detection rate by 100,000 inhabitants was 0.51 in 2019 according to the World Health Organization (WHO). No study has genotyped the Mycobacterium spp. in human cases, other animal species, or environment. According to the MoH, multibacillary leprosy accounts for 78.95% of diagnosed cases, with confirmation based on Ziehl–Neelsen staining and histopathology. No survey has assessed disabilities, knowledge, attitudes, and practices (KAP) or stigma related to leprosy. Research is needed on transmission routes, Mycobacterium genotyping, genetic susceptibility, and antibiotic resistance. BCG vaccination coverage fell to 75.3% in 2021. Cases are currently diagnosed and treated on an outpatient basis in large hospitals. Conclusions: This comprehensive review highlights persistent gaps in leprosy research and critical information, despite seven decades of documented cases in Ecuador. The disease is still endemic across the country, particularly at subnational level in the subtropics and tropics of the Pacific coast and the Amazon. There is a need for nationwide epidemiological research on reservoirs and the environment applying the One Health concept. Increased laboratory facilities and readily available official data are required to improve our understanding of leprosy in Ecuador. Strengthening community-level efforts is essential for Ecuador to meet the targets of the “WHO’s Towards Zero Leprosy: Strategy 2021–2030.” Full article

Helicobacter pylori (H. pylori) and intestinal helminthes are common in low- and middle-income countries, where co-infection is endemic due to similar modes of transmission and poor sanitation. Whereas H. pylori are recognized gastric pathogens that induce gastritis, ulcers, and gastric carcinoma, helminths possess systemic immunomodulatory functions. The immunological, epidemiological, and clinical features of H. pylori and helminth co-infections will be discussed in this review. Key findings include that helminths induce a Th2-biased and regulatory immune response, potentially counteracting the Th1/Th17 H. pylori-induced inflammation and therefore limiting gastric tissue damage and cancer risk. Certain human studies and animal models concluded that co-infection would be protective against extreme gastric pathology by modulating immunity, altering gut microbiota, and by helminth-secreted extracellular vesicles. Epidemiologic data show large regional heterogeneity in co-infection prevalence with higher rates in children and rural socioeconomically disadvantaged populations. Much of the research mechanisms, however, are limited to models in the lab, and few human studies exist. Lastly, helminth co-infection is also potentially immunoprotective against H. pylori-associated illnesses, but greater translational research and human clinical trials are necessary. Public health policy in endemic regions must consider the complex relationships between co-infecting parasites when developing control. Full article

Identifying the diversity of wildlife hosts for malaria parasites in wildlife is crucial for understanding transmission dynamics in endemic regions where humans, vectors, and wildlife heavily overlap. We examined the presence of Plasmodium parasites in free-ranging ring-tailed coatis (Nasua nasua, n = 44) and nine-banded armadillos (Dasypus novemcinctus, n = 66) from an Indigenous community in the Peruvian Amazon. Nested PCR targeting the mitochondrial cytb gene detected Plasmodium spp. DNA in two coatis (4.7%). Sequencing revealed one lineage identical to Plasmodium vivax/P. simium and another to P. malariae/P. brasilianum. A subset of samples was reanalyzed using cox3-based PCR and sequencing in an independent laboratory, confirming P. malariae/P. brasilianum in one coati. No infections were observed in armadillos. These results indicate that coatis in the wild may host diverse Plasmodiidae parasites and that coatis may even carry Plasmodium spp., likely as incidental hosts. Expanding surveillance to additional non-primate mammals will help clarify their role in sylvatic malaria ecology and evaluate potential zoonotic risks. Full article

This study presents a mathematical model to describe the transmission dynamics of asthma, explicitly accounting for the impact of dust waves and airborne particulate matter in the environment, recognized as key triggers of asthma exacerbations. The model incorporates a single endemic equilibrium point, which is shown to be locally asymptotically stable. To mitigate the burden of asthma, we employed the Pontryagin Maximum Principle within an optimal control framework, incorporating three time-dependent intervention strategies: vaccination, treatment, and avoidance of environmental triggers such as dust exposure. The model was numerically solved using the fourth-order Runge–Kutta method in conjunction with a forward–backward sweep algorithm to investigate the effects of various control combinations on the prevalence of asthma. Additionally, a comprehensive cost-effectiveness analysis was conducted to evaluate the economic viability of each strategy. The results indicate that the combined application of vaccination and treatment is the most cost-effective approach among the strategies analyzed, significantly reducing the number of asthma cases at minimal cost. All simulations and numerical experiments were performed to validate the theoretical findings and quantify the effectiveness of the proposed interventions under realistic environmental conditions driven by dust activity. The model highlights the importance of integrated medical and environmental control policies in mitigating asthma outbreaks, particularly in regions frequently exposed to dust storms. Full article

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

Co-infection of Orientia tsutsugamushi and influenza A virus complicates diagnosis and treatment in endemic regions because of overlapping clinical features and potential synergistic inflammation. We describe a 68-year-old woman from Hainan, China, who presented with five days of high fever (39.2 °C), nonproductive cough, eschar formation, lymphadenopathy, cytopenias, elevated liver enzymes, and raised inflammatory markers. On the day of admission, influenza A was confirmed by rapid antigen test and Orientia tsutsugamushi IgM/IgG was detected via colloidal-gold immunochromatography, prompting concurrent oseltamivir and doxycycline therapy. Quantitative PCR on day 2 measured an Orientia tsutsugamushi load of 2.85 × 10⁴ copies/mL (Cq 28.86), and targeted next-generation sequencing on day 3 revealed a high H1N1pdm09 viral burden (>1 × 10⁶ copies/mL) with low-level human herpesvirus 1 co-detection. Nested PCR and Sanger sequencing assigned Orientia tsutsugamushi to the Karp_A lineage and influenza A to clade 6B.1A.5a.2a. The patient defervesced by hospital day 2, laboratory indices normalized by day 3, and radiographic abnormalities resolved by day 6. This first documented Orientia tsutsugamushi–influenza A co-infection in China highlights the value of integrating rapid serology, qPCR quantification, nested PCR genotyping, and tNGS for early, precise dual-pathogen identification. Systematic multi-pathogen screening during overlapping transmission seasons is recommended to guide timely combination therapy and enhance epidemiological surveillance. Full article

Human brucellosis is a zoonotic, bacterial infection caused by the intracellular, Gram-negative Brucella spp., which is common globally but rare in the United Kingdom, with approximately 20 imported cases per annum following travel to countries with high endemicity. Transmission typically occurs via the ingestion of infected animal products, including unpasteurised dairy products. Human-to-human transmission is rare, and routes include postpartum vertical transmission through breastfeeding. We report here on a familial cluster of three cases within a single UK-based Kurdish household of four, including a 11-month-old infant infected through the consumption of breast milk. Four months prior to presentation, the family had travelled together to northern Iraq for a 5-week holiday and all consumed local dairy products except for the children, including the 11-month-old, who was exclusively breastfed at the time. All three patients, including one adult male with complicated brucellosis, had a favourable outcome with medical therapy.: Brucellosis is an important differential diagnosis in returning travellers and specialist advice should be obtained early to prevent sequelae. It is also important for active case-finding, especially in family units with shared exposure. Paediatricians and adult physicians who may manage brucellosis should consider the possibility of vertical transmission in breastfeeding mothers. Full article

SARS-CoV and MERS-CoV are two coronaviruses that have received significant attention due to their high pathogenicity and mortality rates in human populations. In this study, we compared their evolutionary dynamics to provide a One Health perspective on their differences in terms of the results of disease control. The phylogenetic network of SARS-CoVs showed that human isolates gathered into a “super-spreader” cluster and were distinct from civet isolates. In contrast, dromedary camel- and human-isolated MERS-CoVs were clustered together. Thus, most clades of MERS-CoV can infect humans, and MERS-CoVs seem to more easily spill over the animal-to-human interface. Additionally, the civet can be easily controlled, while the intermediate host (dromedary camels) of MERS-CoV is an important livestock species, so it is impossible to eliminate all animals. This further leads to difficulties in disease control in MERS. Although MERS-CoVs are endemic to dromedary camels in both the Middle East and Africa, human infections are mainly linked to the Middle East. The nucleotide sequences of the MERS-CoV receptor gen (dipeptidyl peptidase 4 (DPP4)) from 30 Egyptians, 36 Sudanese, and 34 Saudi Arabians showed little difference. These findings suggest that the observed disparities in MERS prevalence between populations in the Middle East and Africa may be more strongly attributed to inadequate disease surveillance and the limited camel-to-human transmission of clade C MERS-CoV in Africa, rather than variations in DPP4 gene. Full article

 Porcine epidemic diarrhea virus (PEDV) continues to circulate globally, causing substantial economic losses to the swine industry. Historically, PEDV strains are classified into the classical G1, epidemic G2, and S-INDEL genotypes. Among these genotypes, the highly virulent and prevalent G2 genotype has been extensively studied. However, recent clinical outbreaks in China necessitate a reevaluation of the epidemiological and evolutionary dynamics of circulating strains. This study analyzed 37 newly sequenced S genes and public sequences to characterize the genetic variations of S-INDEL strains. Our analysis revealed that S-INDEL strains are endemic throughout China, with a phylogenetic analysis identifying two distinct clades: clade 1, comprising early endemic strains, and clade 2, representing a recently dominant, geographically restricted lineage in China. While inter-genotypic recombination has been documented, our findings also demonstrate that intra-genotypic and intra-clade recombination events contributed significantly to the emergence of clade 2, distinguishing its evolutionary pattern from clade 1. A comparative analysis identified 22 clade-specific amino acid changes, 11 of which occurred in the D0 domain. Notably, mutations at positively selected sites—113 and 114 within the D0 domain, a domain associated with pathogenicity—were specific to clade 2. A phylodynamic analysis indicated Germany as the epicenter of S-INDEL dispersal, with China acting as a sink population characterized by localized transmission networks and frequent recombination events. These results demonstrate that contemporary S-INDEL strains, specifically clade 2, exhibit unique recombination patterns and mutations potentially impacting virulence. Continuous surveillance is essential to assess the pathogenic potential of these evolving recombinant variants and the efficacy of vaccines against them.  Full article

Rabies remains a significant global public health concern, causing an estimated 59,000–69,000 human fatalities annually. Despite being entirely preventable through vaccination, rabies continues to impose substantial economic burdens worldwide. This study presents a scoping review of the economic research on rabies to determine overlaps and gaps in knowledge and inform future research strategies. We selected 150 studies (1973–2024) to analyze. The review categorizes the literature based on geographic distribution, species focus, and type of study. Findings indicate that economic studies are disproportionately concentrated in developed countries, such as the United States and parts of Europe, where rabies risk is low, while high-risk regions, particularly in Africa and Asia, remain underrepresented. Most studies focus on dog-mediated rabies, reflecting its dominant role in human transmission, while fewer studies assess the economic impacts of wildlife and livestock-mediated rabies. Case studies and modeling approaches dominate the literature, whereas cost–benefit and cost–effectiveness analyses—critical for informing resource allocation—are limited. The review highlights the need for more economic evaluations in rabies-endemic regions, expanded research on non-dog reservoirs, and broader use of economic methods. Addressing these gaps will be crucial for optimizing rabies control and supporting global initiatives to eliminate dog-mediated rabies by 2030. Full article

Via a One Health approach, this study concomitantly assessed the susceptibility of humans and dogs to Trypanosoma cruzi infections on three islands and in two mainland seashore areas of southern Brazil. Human serum samples were tested using an enzyme-linked immunosorbent assay (ELISA) to detect anti-T. cruzi antibodies, while dog serum samples were tested using indirect fluorescent antibodies in an immunofluorescence assay (IFA). Seropositive human and dog individuals were also tested using quantitative polymerase chain reaction (qPCR) in corresponding blood samples. Overall, 2/304 (0.6%) human and 1/292 dog samples tested seropositive for T. cruzi by ELISA and IFA, respectively, and these cases were also molecularly positive for T. cruzi by qPCR. Although a relatively low positivity rate was observed herein, these cases were likely autochthonous, and the individuals may have been infected as a consequence of isolated events of disturbance in the natural peridomicile areas nearby. Such a disturbance could come in the form of a fire or deforestation event, which can cause stress and parasitemia in wild reservoirs and, consequently, lead to positive triatomines. In conclusion, T. cruzi monitoring should always be conducted in suspicious areas to ensure a Chagas disease-free status over time. Further studies should also consider entomological and wildlife surveillance to fully capture the transmission and spread of T. cruzi on islands and in seashore mainland areas of Brazil and other endemic countries. Full article