Pathogens

11 pages, 2391 KiB

Open AccessArticle

A Major Facilitator Superfamily Transporter Is Critical for the Metabolism and Biogenesis of the Apicoplast

by Yumeng Liang, Wei Qi, Jiawen Fu and Honglin Jia

Pathogens 2025, 14(8), 763; https://doi.org/10.3390/pathogens14080763 (registering DOI) - 1 Aug 2025

The apicoplast is a highly specialized organelle in the biosynthesis of essential metabolites in most of the apicomplexan protozoa. This organelle is surrounded by four layers of membranes. However, the molecular mechanisms mediating transmembrane transport are not yet fully understood. In this study, [...] Read more.

The apicoplast is a highly specialized organelle in the biosynthesis of essential metabolites in most of the apicomplexan protozoa. This organelle is surrounded by four layers of membranes. However, the molecular mechanisms mediating transmembrane transport are not yet fully understood. In this study, we conducted a phenotypic analysis to investigate the role of a major facilitator superfamily transporter (TgApMFS1) in the survival of the parasite. The results indicated that TgApMFS1 is critical for the survival of Toxoplasma gondii in cell culture conditions. Further analysis indicated that these transporters are crucial for the biogenesis of organelles and the metabolic processes of parasite. Full article

(This article belongs to the Section Parasitic Pathogens)

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46 pages, 1120 KiB

Open AccessReview

From Morphology to Multi-Omics: A New Age of Fusarium Research

by Collins Bugingo, Alessandro Infantino, Paul Okello, Oscar Perez-Hernandez, Kristina Petrović, Andéole Niyongabo Turatsinze and Swarnalatha Moparthi

Pathogens 2025, 14(8), 762; https://doi.org/10.3390/pathogens14080762 (registering DOI) - 1 Aug 2025

Abstract

The Fusarium genus includes some of the most economically and ecologically impactful fungal pathogens affecting global agriculture and human health. Over the past 15 years, rapid advances in molecular biology, genomics, and diagnostic technologies have reshaped our understanding of Fusarium taxonomy, host–pathogen dynamics, [...] Read more.

The Fusarium genus includes some of the most economically and ecologically impactful fungal pathogens affecting global agriculture and human health. Over the past 15 years, rapid advances in molecular biology, genomics, and diagnostic technologies have reshaped our understanding of Fusarium taxonomy, host–pathogen dynamics, mycotoxin biosynthesis, and disease management. This review synthesizes key developments in these areas, focusing on agriculturally important Fusarium species complexes such as the Fusarium oxysporum species complex (FOSC), Fusarium graminearum species complex (FGSC), and a discussion on emerging lineages such as Neocosmospora. We explore recent shifts in species delimitation, functional genomics, and the molecular architecture of pathogenicity. In addition, we examine the global burden of Fusarium-induced mycotoxins by examining their prevalence in three of the world’s most widely consumed staple crops: maize, wheat, and rice. Last, we also evaluate contemporary management strategies, including molecular diagnostics, host resistance, and integrated disease control, positioning this review as a roadmap for future research and practical solutions in Fusarium-related disease and mycotoxin management. By weaving together morphological insights and cutting-edge multi-omics tools, this review captures the transition into a new era of Fusarium research where integrated, high-resolution approaches are transforming diagnosis, classification, and management. Full article

(This article belongs to the Special Issue Current Research on Fusarium: 2nd Edition)

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25 pages, 7784 KiB

Open AccessArticle

Diversity in the Common Fold: Structural Insights into Class D β-Lactamases from Gram-Negative Pathogens

by Clyde A. Smith and Anastasiya Stasyuk

Pathogens 2025, 14(8), 761; https://doi.org/10.3390/pathogens14080761 (registering DOI) - 1 Aug 2025

Abstract

Class D β-lactamases (DBLs) represent a major threat to antibiotic efficacy by hydrolyzing β-lactam drugs, including last-resort carbapenems, thereby driving antimicrobial resistance in Gram-negative bacteria. The enzymes share a structurally conserved two-domain α/β architecture with seven active-site motifs and three flexible extended loops [...] Read more.

Class D β-lactamases (DBLs) represent a major threat to antibiotic efficacy by hydrolyzing β-lactam drugs, including last-resort carbapenems, thereby driving antimicrobial resistance in Gram-negative bacteria. The enzymes share a structurally conserved two-domain α/β architecture with seven active-site motifs and three flexible extended loops (the P-loop, Ω-loop, and newly designated B-loop) that surround the active site. While each of these loops is known to influence enzyme function, their coordinated roles have not been fully elucidated. To investigate the significance of their interplay, we compared the sequences and crystal structures of 40 DBLs from clinically relevant Gram-negative pathogens and performed molecular dynamics simulations on selected representatives. Combined structural and dynamical analyses revealed a strong correlation between B-loop architecture and carbapenemase activity in the pathogens Klebsiella and Acinetobacter, particularly regarding loop length and spatial organization. These findings emphasize the B-loop’s critical contribution, in concert with the P- and Ω-loops, in tuning active site versatility, substrate recognition, catalytic activity, and structural stability. A deeper understanding of how these motifs and loops govern DBL function may inform the development of novel antibiotics and inhibitors targeting this class of enzymes. Full article

(This article belongs to the Special Issue Virulence and Resistance Mechanisms in Multidrug-Resistant Gram-Negative Bacteria)

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25 pages, 9193 KiB

Open AccessArticle

Antibiotic-Loaded Bioglass 45S5 for the Treatment and Prevention of Staphylococcus aureus Infections in Orthopaedic Surgery: A Novel Strategy Against Antimicrobial Resistance

by Humera Sarwar, Richard A. Martin, Heather M. Coleman, Aaron Courtenay and Deborah Lowry

Pathogens 2025, 14(8), 760; https://doi.org/10.3390/pathogens14080760 (registering DOI) - 1 Aug 2025

Abstract

This study explores the potential of biodegradable Bioglass 45S5 formulations as a dual-function approach for preventing and treating Staphylococcus aureus infections in orthopaedic surgery while addressing the growing concern of antimicrobial resistance (AMR). The research focuses on the development and characterisation of antibiotic-loaded [...] Read more.

This study explores the potential of biodegradable Bioglass 45S5 formulations as a dual-function approach for preventing and treating Staphylococcus aureus infections in orthopaedic surgery while addressing the growing concern of antimicrobial resistance (AMR). The research focuses on the development and characterisation of antibiotic-loaded BG45S5 formulations, assessing parameters such as drug loading efficiency, release kinetics, antimicrobial efficacy, and dissolution behaviour. Key findings indicate that the F2l-BG45S5-T-T-1.5 and F2l-BG45S5-T-V-1.5 formulations demonstrated controlled antibiotic release for up to seven days, with size distributions of D(10): 7.11 ± 0.806 µm, 4.96 ± 0.007 µm; D(50): 25.34 ± 1.730 µm, 25.20.7 ± 0.425 µm; and D(90): 53.7 ± 7.95 µm, 56.10 ± 0.579 µm, respectively. These formulations facilitated hydroxyapatite formation on their surfaces, indicative of osteogenic potential. The antimicrobial assessments revealed zones of inhibition against methicillin-susceptible Staphylococcus aureus (MSSA, ATCC-6538) measuring 20.3 ± 1.44 mm and 24.6 ± 1.32 mm, while for methicillin-resistant Staphylococcus aureus (MRSA, ATCC-43300), the inhibition zones were 21.6 ± 1.89 mm and 22 ± 0.28 mm, respectively. Time-kill assay results showed complete bacterial eradication within eight hours. Additionally, biocompatibility testing via MTT assay confirmed cell viability of >75%. In conclusion, these findings highlight the promise of antibiotic-loaded BG45S5 as a multifunctional biomaterial capable of both combating bone infections and supporting bone regeneration. These promising results suggest that in vivo studies should be undertaken to expedite these materials into clinical applications. Full article

(This article belongs to the Special Issue Antimicrobial Resistance in the Post-COVID Era: A Silent Pandemic)

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18 pages, 1587 KiB

Open AccessArticle

Urban Mangroves Under Threat: Metagenomic Analysis Reveals a Surge in Human and Plant Pathogenic Fungi

by Juliana Britto Martins de Oliveira, Mariana Barbieri, Dario Corrêa-Junior, Matheus Schmitt, Luana Lessa R. Santos, Ana C. Bahia, Cláudio Ernesto Taveira Parente and Susana Frases

Pathogens 2025, 14(8), 759; https://doi.org/10.3390/pathogens14080759 (registering DOI) - 1 Aug 2025

Abstract

Coastal ecosystems are increasingly threatened by climate change and anthropogenic pressures, which can disrupt microbial communities and favor the emergence of pathogenic organisms. In this study, we applied metagenomic analysis to characterize fungal communities in sediment samples from an urban mangrove subjected to [...] Read more.

Coastal ecosystems are increasingly threatened by climate change and anthropogenic pressures, which can disrupt microbial communities and favor the emergence of pathogenic organisms. In this study, we applied metagenomic analysis to characterize fungal communities in sediment samples from an urban mangrove subjected to environmental stress. The results revealed a fungal community with reduced richness—28% lower than expected for similar ecosystems—likely linked to physicochemical changes such as heavy metal accumulation, acidic pH, and eutrophication, all typical of urbanized coastal areas. Notably, we detected an increase in potentially pathogenic genera, including Candida, Aspergillus, and Pseudoascochyta, alongside a decrease in key saprotrophic genera such as Fusarium and Thelebolus, indicating a shift in ecological function. The fungal assemblage was dominated by the phyla Ascomycota and Basidiomycota, and despite adverse conditions, symbiotic mycorrhizal fungi remained present, suggesting partial resilience. A considerable fraction of unclassified fungal taxa also points to underexplored microbial diversity with potential ecological or health significance. Importantly, this study does not aim to compare pristine and contaminated environments, but rather to provide a sanitary alert by identifying the presence and potential proliferation of pathogenic fungi in a degraded mangrove system. These findings highlight the sensitivity of mangrove fungal communities to environmental disturbance and reinforce the value of metagenomic approaches for monitoring ecosystem health. Incorporating fungal metagenomic surveillance into environmental management strategies is essential to better understand biodiversity loss, ecological resilience, and potential public health risks in degraded coastal environments. Full article

(This article belongs to the Section Fungal Pathogens)

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17 pages, 812 KiB

Open AccessArticle

Association Between ABO Blood Groups and SARS-CoV-2 RNAemia, Spike Protein Mutations, and Thrombotic Events in COVID-19 Patients

by Esra’a Abudouleh, Tarek Owaidah, Fatimah Alhamlan, Arwa A. Al-Qahtani, Dalia Al Sarar, Abdulrahman Alkathiri, Shouq Alghannam, Arwa Bagasi, Manal M. Alkhulaifi and Ahmed A. Al-Qahtani

Pathogens 2025, 14(8), 758; https://doi.org/10.3390/pathogens14080758 (registering DOI) - 31 Jul 2025

Abstract

Background: COVID-19 is associated with coagulopathy and increased mortality. The ABO blood group system has been implicated in modulating susceptibility to SARS-CoV-2 infection and disease severity, but its relationship with viral RNAemia, spike gene mutations, and thrombosis remains underexplored. Methods: We analyzed 446 [...] Read more.

Background: COVID-19 is associated with coagulopathy and increased mortality. The ABO blood group system has been implicated in modulating susceptibility to SARS-CoV-2 infection and disease severity, but its relationship with viral RNAemia, spike gene mutations, and thrombosis remains underexplored. Methods: We analyzed 446 hospitalized COVID-19 patients between 2021 and 2022. SARS-CoV-2 RNAemia was assessed via RT-qPCR on whole blood, and spike gene mutations were identified through whole-genome sequencing in RNAemia-positive samples. ABO blood groups were determined by agglutination testing, and thrombotic events were evaluated using coagulation markers. Statistical analyses included chi-square tests and Kruskal–Wallis tests, with significance set at p < 0.05. Results: RNAemia was detected in 26.9% of patients, with no significant association with ABO blood group (p = 0.175). Omicron was the predominant variant, especially in blood group A (62.5%). The N501Y mutation was the most prevalent in group O (53.2%), and K417N was most prevalent in group B (36.9%), though neither reached statistical significance. Thrombotic events were significantly more common in blood group A (OR = 2.08, 95% CI = 1.3–3.4, p = 0.002), particularly among RNAemia-positive patients. Conclusions: ABO blood group phenotypes, particularly group A, may influence thrombotic risk in the context of SARS-CoV-2 RNAemia. While no direct association was found between blood group and RNAemia or spike mutations, the observed trends suggest potential host–pathogen interactions. Integrating ABO typing and RNAemia screening may enhance risk stratification and guide targeted thromboprophylaxis in COVID-19 patients. Full article

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12 pages, 1678 KiB

Open AccessArticle

Molecular Surveillance of Plasmodium spp. Infection in Neotropical Primates from Bahia and Minas Gerais, Brazil

by Luana Karla N. S. S. Santos, Sandy M. Aquino-Teixeira, Sofía Bernal-Valle, Beatriz S. Daltro, Marina Noetzold, Aloma Roberta C. Silva, Denise Anete M. Alvarenga, Luisa B. Silva, Ramon S. Oliveira, Cirilo H. Oliveira, Iago A. Celestino, Maria E. Gonçalves-dos-Santos, Thaynara J. Teixeira, Anaiá P. Sevá, Fabrício S. Campos, Bergmann M. Ribeiro, Paulo M. Roehe, Danilo Simonini-Teixeira, Filipe V. S. Abreu, Cristiana F. A. Brito and George R. Albuquerque Show full author list Hide full author list

Pathogens 2025, 14(8), 757; https://doi.org/10.3390/pathogens14080757 (registering DOI) - 31 Jul 2025

Abstract

In Brazil, Plasmodium infections in non-human primates (NHPs) have been associated with P. simium and P. brasilianum, which are morphologically and genetically similar to the human-infecting species P. vivax and P. malariae, respectively. Surveillance and monitoring of wild NHPs are crucial [...] Read more.

In Brazil, Plasmodium infections in non-human primates (NHPs) have been associated with P. simium and P. brasilianum, which are morphologically and genetically similar to the human-infecting species P. vivax and P. malariae, respectively. Surveillance and monitoring of wild NHPs are crucial for understanding the distribution of these parasites and assessing the risk of zoonotic transmission. This study aimed to detect the presence of Plasmodium spp. genetic material in Platyrrhini primates from 47 municipalities in the states of Bahia and Minas Gerais. The animals were captured using Tomahawk-type live traps baited with fruit or immobilized with tranquilizer darts. Free-ranging individuals were chemically restrained via inhalation anesthesia using VetBag^® or intramuscular anesthesia injection. Blood samples were collected from the femoral vein. A total of 298 blood and tissue samples were collected from 10 primate species across five genera: Alouatta caraya (25), Alouatta guariba clamitans (1), Callicebus melanochir (1), Callithrix geoffroyi (28), Callithrix jacchus (4), Callithrix kuhlii (31), Callithrix penicillata (175), Callithrix spp. hybrids (15), Leontopithecus chrysomelas (16), Sapajus robustus (1), and Sapajus xanthosthernos (1). Molecular diagnosis was performed using a nested PCR targeting the 18S small subunit ribosomal RNA (18S SSU rRNA) gene, followed by sequencing. Of the 298 samples analyzed, only one (0.3%) from Bahia tested positive for Plasmodium brasilianum/P. malariae. This represents the first detection of this parasite in a free-living C. geoffroyi in Brazil. These findings highlight the importance of continued surveillance of Plasmodium infections in NHPs to identify regions at risk for zoonotic transmission. Full article

(This article belongs to the Section Parasitic Pathogens)

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18 pages, 3030 KiB

Open AccessArticle

Morphometric and Molecular Insights into Hepatozoon spp. in Wild and Synanthropic Rodents from Southern and Southeastern Brazil

by Tatiana Pádua Tavares de Freitas, Bernardo Rodrigues Teixeira, Eduarda de Oliveira Silva Lima Machado, Isaac Leandro Lira Pinto, Laís da Silva de Oliveira, Karina Varella, Huarrisson Azevedo Santos, Fernando de Oliveira Santos, Liliani Marilia Tiepolo, Carlos Luiz Massard and Maristela Peckle

Pathogens 2025, 14(8), 756; https://doi.org/10.3390/pathogens14080756 (registering DOI) - 31 Jul 2025

Abstract

Small rodents are known hosts of various pathogens, including Hepatozoon, but until now, in Brazil, only Hepatozoon milleri has been described in these animals. In this study, liver samples and blood smears were obtained from 289 rodents belonging to 14 Cricetidae and [...] Read more.

Small rodents are known hosts of various pathogens, including Hepatozoon, but until now, in Brazil, only Hepatozoon milleri has been described in these animals. In this study, liver samples and blood smears were obtained from 289 rodents belonging to 14 Cricetidae and two Muridae species that had been captured in municipalities of the states of Paraná and Rio de Janeiro. Smears were stained with Giemsa, and gametocytes were detected via microscopy in 10.72% (n = 31/289) of samples, with these individuals representing three rodent species. Significant morphometric differences were observed in gametocyte measurements in Akodon rodents. Using conventional PCR, Hepatozoon spp. 18S rDNA fragments were amplified in 24.91% (n = 72/289) of samples, with those individuals representing seven rodent species. Phylogenetic analyses clustered 41 sequences from this study into a subclade with other sequences from small mammals in Brazil, identifying four distinct haplotypes, and, for the first time, a relationship between Hepatozoon haplotype and gametocyte length was observed. Based on phylogenetic analysis, this study reinforces the trophic relationship between rodents and reptiles as a possible link in the Hepatozoon transmission cycle in South America. Furthermore, our findings expand knowledge on Hepatozoon spp. hosts, describing Oxymycterus nasutus and Oxymycterus quaestor as new host species and identifying two novel circulating haplotypes in rodents from Paraná State, southern Brazil. Full article

(This article belongs to the Special Issue Vector Control and Parasitic Infection in Animals)

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16 pages, 4439 KiB

Open AccessArticle

Baseline Assessment of Taeniasis and Cysticercosis Infections in a High-Priority Region for Taenia solium Control in Colombia

by Carlos Franco-Muñoz, María Camila Jurado Guacaneme, Sonia Dayanni Castillo Ayala, Sofia Duque-Beltrán, Adriana Arévalo, Marcela Pilar Rojas Díaz, Julián Trujillo Trujillo, Luz Elena Borras Reyes, Luis Reinel Vásquez Arteaga, Julio César Giraldo Forero and Mario J. Olivera

Pathogens 2025, 14(8), 755; https://doi.org/10.3390/pathogens14080755 (registering DOI) - 31 Jul 2025

Abstract

Coyaima is a town in the department of Tolima, Colombia, that was prioritized in a pilot program under Colombia’s National Plan for the Control of the Taeniasis/Cysticercosis Complex, focusing on this neglected health issue. The project engaged local indigenous communities, promoting education and [...] Read more.

Coyaima is a town in the department of Tolima, Colombia, that was prioritized in a pilot program under Colombia’s National Plan for the Control of the Taeniasis/Cysticercosis Complex, focusing on this neglected health issue. The project engaged local indigenous communities, promoting education and outreach within the One Health framework. The study included 444 randomly selected volunteers, who filled a Knowledge, Attitudes, and Practices (KAP) survey on the taeniasis/cysticercosis complex. The baseline study found no Taenia spp. eggs via microscopy on 383 stool samples examined, and no T. solium DNA was detected on human stool and soil samples by Copro-qPCR. However, seroprevalence was 8.5% for human cysticercosis and 14% for porcine cysticercosis, as detected by in-house ELISA testing for T. solium. Moreover, 57.9% of participants who provided a stool sample were positive for at least one parasite. Following the sampling and characterization activities, local health workers implemented mass treatment with Niclosamide, based on evidence of ongoing transmission, high porcine seroprevalence, poor basic sanitation, and the presence of free-roaming pigs reported in the KAP survey. These findings provide scientific evidence to apply national public health policies for controlling taeniasis/cysticercosis complex in Coyaima. Full article

(This article belongs to the Special Issue Recent Advances in Taeniasis and Cysticercosis)

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14 pages, 3364 KiB

Open AccessArticle

Microbial Load and Diversity of Bacteria in Wild Animal Carcasses Sold as Bushmeat in Ghana

by Daniel Oduro, Winnifred Offih-Kyei, Joanita Asirifi Yeboah, Rhoda Yeboah, Caleb Danso-Coffie, Emmanuel Boafo, Vida Yirenkyiwaa Adjei, Isaac Frimpong Aboagye and Gloria Ivy Mensah

Pathogens 2025, 14(8), 754; https://doi.org/10.3390/pathogens14080754 (registering DOI) - 31 Jul 2025

Abstract

The demand for wild animal meat, popularly called “bushmeat”, serves as a driving force behind the emergence of infectious diseases, potentially transmitting a variety of pathogenic bacteria to humans through handling and consumption. This study investigated the microbial load and bacterial diversity in [...] Read more.

The demand for wild animal meat, popularly called “bushmeat”, serves as a driving force behind the emergence of infectious diseases, potentially transmitting a variety of pathogenic bacteria to humans through handling and consumption. This study investigated the microbial load and bacterial diversity in bushmeat sourced from a prominent bushmeat market in Kumasi, Ghana. Carcasses of 61 wild animals, including rodents (44), antelopes (14), and African civets (3), were sampled for microbiological analysis. These samples encompassed meat, intestines, and anal and oral swabs. The total aerobic bacteria plate count (TPC), Enterobacteriaceae count (EBC), and fungal counts were determined. Bacterial identification was conducted using MALDI-TOF biotyping. Fungal counts were the highest across all animal groups, with African civets having 11.8 ± 0.3 log₁₀ CFU/g and 11.9 ± 0.2 log₁₀ CFU/g in intestinal and meat samples, respectively. The highest total plate count (TPC) was observed in rodents, both in their intestines (10.9 ± 1.0 log₁₀ CFU/g) and meat (10.9 ± 1.9 log₁₀ CFU/g). In contrast, antelopes exhibited the lowest counts across all categories, particularly in EBC from intestinal samples (6.1 ± 1.5 log₁₀ CFU/g) and meat samples (5.6 ± 1.2 log₁₀ CFU/g). A comprehensive analysis yielded 524 bacterial isolates belonging to 20 genera, with Escherichia coli (18.1%) and Klebsiella spp. (15.5%) representing the most prevalent species. Notably, the detection of substantial microbial contamination in bushmeat underscores the imperative for a holistic One Health approach to enhance product quality and mitigate risks associated with its handling and consumption. Full article

(This article belongs to the Section Bacterial Pathogens)

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25 pages, 1990 KiB

Open AccessArticle

Fecal and Environmental Shedding of Influenza A Virus in Brazilian Swine: Genomic Evidence of Recent Human-to-Swine Transmission

by Nágila Rocha Aguilar, Beatriz Senra Alvares da Silva Santos, Bruno Zinato Carraro, Brenda Monique Magalhães Rocha, Jardelina de Souza Todao Bernardino, Ana Luiza Soares Fraiha, Alex Ranieri Jeronimo Lima, Gabriela Ribeiro, Alessandra Silva Dias, Renata Rezende Carvalho, Bruna Ferreira Sampaio Ribeiro, Marta Giovanetti, Luiz Carlos Júnior Alcântara, Sandra Coccuzzo Sampaio, Maria Carolina Quartim Barbosa Elias Sabbaga, Rafael Romero Nicolino, Zélia Inês Portela Lobato, Maria Isabel Maldonado Coelho Guedes, Cesar Rossas Mota Filho, Vincent Louis Viala, Bruna Coelho Lopes and Erica Azevedo Costa Show full author list Hide full author list

Pathogens 2025, 14(8), 753; https://doi.org/10.3390/pathogens14080753 (registering DOI) - 31 Jul 2025

Abstract

Surveillance of swine influenza A virus (swIAV) traditionally focuses on respiratory matrices, yet emerging evidence suggests that fecal shedding and secondary environmental contamination may also contribute to viral dissemination. In this study, we collected and analyzed nasal, rectal, environmental, milk, and colostrum samples [...] Read more.

Surveillance of swine influenza A virus (swIAV) traditionally focuses on respiratory matrices, yet emerging evidence suggests that fecal shedding and secondary environmental contamination may also contribute to viral dissemination. In this study, we collected and analyzed nasal, rectal, environmental, milk, and colostrum samples from naturally infected pigs in a commercial farm in Minas Gerais, Brazil. IAV RNA was detected in 25% of samples, including 42% from asymptomatic animals, with nasal swabs showing higher detection rates (30%) than rectal swabs (20%), though rectal Ct values were consistently higher, indicative of lower viral loads. We successfully isolated viable viruses from feces and effluent samples. Whole-genome sequencing revealed co-circulation of enzootic pH1N1 clade #2 (HA) and pN1 clade #4 (NA), alongside human-origin H3N2 sequences clustering within clade 3C.2a1b.2a.2a.1, and N2 segments related to pre-3C human lineages from 2001 to 2002. Phylogenetic and p-distance analyses support both recent reverse zoonosis and historical transmission events. Detection of complete HA/NA sequences from rectal swabs and treated effluent further emphasizes the surveillance value of non-respiratory matrices. The integration of respiratory and fecal/environmental sampling appears important to achieve more comprehensive IAV monitoring in swine herds and may have significant implications for One Health strategies in Brazil and beyond. Full article

(This article belongs to the Special Issue Pathogenesis, Epidemiology, and Control of Animal Influenza Viruses—2nd Edition)

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9 pages, 6176 KiB

Open AccessCase Report

Concurrent Leydig and Sertoli Cell Tumors Associated with Testicular Mycosis in a Dog: A Case Report and Literature Review

by Mirosław Kuberka, Przemysław Prządka and Stanisław Dzimira

Pathogens 2025, 14(8), 752; https://doi.org/10.3390/pathogens14080752 (registering DOI) - 31 Jul 2025

Abstract

Mycosis is caused by, among other factors, filamentous fungi, ubiquitous molds belonging to Aspergillus spp. which are often opportunistic pathogens. Over 100 species of Aspergillus have been described. The most common species responsible for diseases in humans and animals are Aspergillus fumigatus and [...] Read more.

Mycosis is caused by, among other factors, filamentous fungi, ubiquitous molds belonging to Aspergillus spp. which are often opportunistic pathogens. Over 100 species of Aspergillus have been described. The most common species responsible for diseases in humans and animals are Aspergillus fumigatus and Aspergillus niger, with Aspergillus flavus and Aspergillus clavatus being somewhat rarer. Aspergillus causes a range of diseases, from localized colonization and hypersensitivity reactions, through chronic necrotizing infections, to rapidly progressing angioinvasion and dissemination, leading to death. Testicular mycosis is extremely rarely described in both humans and animals. No studies in the literature report a simultaneous occurrence of testicular tumors and fungal infection of the organ, so the aim of this paper was to describe, for the first time, a case of two independent testicular tumors coexisting with testicular mycosis. A histopathological examination was performed on the left testicle of a male dog, specifically a mixed-breed dog resembling a husky weighing 22 kg and with an age of 8 years. Bilateral orchidectomy was performed for medical reasons due to the altered outline of the left testicle, leading to scrotal deformation. The dog did not show any clinical signs of illness, and the testicles were not painful. The right testicle, according to the operating veterinarian, showed no macroscopic changes, so histopathological verification was not performed. Microscopic imaging of the changes clearly indicated the coexistence of a tumor process involving Leydig cells (Leydigoma, interstitial cell tumor, ICT), Sertoli cells (Sertolioma), and fungal infection of the testis. The case suggests the possibility of the coexistence of tumor processes, which may have impaired local immune response of the tissue, with an infectious, in this case fungal, inflammatory process. Based on the literature, this paper is the first report on the occurrence of two independent histotype testicular tumors and their associated mycosis. Full article

(This article belongs to the Special Issue Rare Fungal Infection Studies)

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23 pages, 4510 KiB

Open AccessArticle

Identification and Characterization of Biosecurity Breaches on Poultry Farms with a Recent History of Highly Pathogenic Avian Influenza Virus Infection Determined by Video Camera Monitoring in the Netherlands

by Armin R. W. Elbers and José L. Gonzales

Pathogens 2025, 14(8), 751; https://doi.org/10.3390/pathogens14080751 - 30 Jul 2025

Abstract

Biosecurity measures applied on poultry farms, with a recent history of highly pathogenic avian influenza virus infection, were monitored using 24 h/7 days-per-week video monitoring. Definition of biosecurity breaches were based on internationally acknowledged norms. Farms of four different production types (two broiler, [...] Read more.

Biosecurity measures applied on poultry farms, with a recent history of highly pathogenic avian influenza virus infection, were monitored using 24 h/7 days-per-week video monitoring. Definition of biosecurity breaches were based on internationally acknowledged norms. Farms of four different production types (two broiler, two layer, two breeder broiler, and one duck farm) were selected. Observations of entry to and exit from the anteroom revealed a high degree of biosecurity breaches in six poultry farms and good biosecurity practices in one farm in strictly maintaining the separation between clean and potentially contaminated areas in the anteroom. Hand washing with soap and water and/or using disinfectant lotion was rarely observed at entry to the anteroom and was almost absent at exit. Egg transporters did not disinfect fork-lift wheels when entering the egg-storage room nor change or properly disinfect footwear. The egg-storage room was not cleaned and disinfected after egg transport by the farmer. Similarly, footwear and trolley wheels were not disinfected when introducing young broilers or ducklings to the poultry unit. Biosecurity breaches were observed when introducing bedding material in the duck farm. This study shows a need for an engaging awareness and training campaign for poultry farmers and their co-workers as well as for transporters to promote good biosecurity practices. Full article

(This article belongs to the Special Issue Pathogenesis, Epidemiology, and Control of Animal Influenza Viruses—2nd Edition)

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12 pages, 1078 KiB

Open AccessArticle

Aerostability of Sin Nombre Virus Aerosol Related to Near-Field Transmission

by Elizabeth A. Klug, Danielle N. Rivera, Vicki L. Herrera, Ashley R. Ravnholdt, Daniel N. Ackerman, Yangsheng Yu, Chunyan Ye, Steven B. Bradfute, St. Patrick Reid and Joshua L. Santarpia

Pathogens 2025, 14(8), 750; https://doi.org/10.3390/pathogens14080750 (registering DOI) - 30 Jul 2025

Abstract

Sin Nombre virus (SNV) is the main causative agent of hantavirus cardiopulmonary syndrome (HCPS) in North America. SNV is transmitted via environmental biological aerosols (bioaerosols) produced by infected deer mice (Peromyscus maniculatus). It is similar to other viruses that have environmental [...] Read more.

Sin Nombre virus (SNV) is the main causative agent of hantavirus cardiopulmonary syndrome (HCPS) in North America. SNV is transmitted via environmental biological aerosols (bioaerosols) produced by infected deer mice (Peromyscus maniculatus). It is similar to other viruses that have environmental transmission routes rather than a person-to-person transmission route, such as avian influenza (e.g., H5N1) and Lassa fever. Despite the lack of person-to-person transmission, these viruses cause a significant public health and economic burden. However, due to the lack of targeted pharmaceutical preventatives and therapeutics, the recommended approach to prevent SNV infections is to avoid locations that have a combination of low foot traffic, receive minimal natural sunlight, and where P. maniculatus may be found nesting. Consequently, gaining insight into the SNV bioaerosol decay profile is fundamental to the prevention of SNV infections. The Biological Aerosol Reaction Chamber (Bio-ARC) is a flow-through system designed to rapidly expose bioaerosols to environmental conditions (ozone, simulated solar radiation (SSR), humidity, and other gas phase species at stable temperatures) and determine the sensitivity of those particles to simulated ambient conditions. Using this system, we examined the bioaerosol stability of SNV. The virus was found to be susceptible to both simulated solar radiation and ozone under the tested conditions. Comparisons of decay between the virus aerosolized in residual media and in a mouse bedding matrix showed similar results. This study indicates that SNV aerosol particles are susceptible to inactivation by solar radiation and ozone, both of which could be implemented as effective control measures to prevent disease in locations where SNV is endemic. Full article

(This article belongs to the Special Issue Airborne Transmission of Pathogens)

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15 pages, 1843 KiB

Open AccessArticle

Genotype-Specific HPV mRNA Triage Improves CIN2+ Detection Efficiency Compared to Cytology: A Population-Based Study of HPV DNA-Positive Women

by S. Sørbye, B. M. Falang, M. Antonsen and E. Mortensen

Pathogens 2025, 14(8), 749; https://doi.org/10.3390/pathogens14080749 - 30 Jul 2025

Abstract

Background: Effective triage of women testing positive for high-risk HPV DNA is essential to reduce unnecessary colposcopies while preserving cancer prevention. Cytology, the current standard, has limited specificity and reproducibility. The genotype-specific 7-type HPV E6/E7 mRNA test (PreTect HPV-Proofer’7), targeting HPV types 16, [...] Read more.

Background: Effective triage of women testing positive for high-risk HPV DNA is essential to reduce unnecessary colposcopies while preserving cancer prevention. Cytology, the current standard, has limited specificity and reproducibility. The genotype-specific 7-type HPV E6/E7 mRNA test (PreTect HPV-Proofer’7), targeting HPV types 16, 18, 31, 33, 45, 52, and 58, detects transcriptionally active infections and may enhance risk stratification. Methods: Between 2019 and 2023, 34,721 women aged 25–69 underwent primary HPV DNA screening with the Cobas 4800 assay at the University Hospital of North Norway, within the national screening program. Of these, 1896 HPV DNA-positive women were triaged with liquid-based cytology with atypical squamous cells of undetermined significance or worse (≥ASC-US) and the 7-type HPV mRNA test. Histological outcomes were followed through October 2024. Diagnostic performance for CIN2+ was evaluated overall and by genotype. Results: CIN2+ prevalence was 13.3%. The mRNA test reduced test positivity from 50.3% to 33.4% while maintaining comparable sensitivity (70.6% vs. 72.2%) and improving specificity (72.3% vs. 53.0%) and PPV (28.1% vs. 19.1%). Genotype-specific PPVs were highest for HPV16 mRNA (47.7%), followed by HPV33 (39.2%) and HPV31 (32.2%), all exceeding corresponding DNA-based estimates. Conclusion: Genotype-specific HPV mRNA triage offers superior risk discrimination compared to cytology, supporting more targeted, efficient, and accessible cervical cancer screening. Full article

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20 pages, 732 KiB

Open AccessReview

AI Methods Tailored to Influenza, RSV, HIV, and SARS-CoV-2: A Focused Review

by Achilleas Livieratos, George C. Kagadis, Charalambos Gogos and Karolina Akinosoglou

Pathogens 2025, 14(8), 748; https://doi.org/10.3390/pathogens14080748 - 30 Jul 2025

Abstract

Artificial intelligence (AI) techniques—ranging from hybrid mechanistic–machine learning (ML) ensembles to gradient-boosted decision trees, support-vector machines, and deep neural networks—are transforming the management of seasonal influenza, respiratory syncytial virus (RSV), human immunodeficiency virus (HIV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Symptom-based [...] Read more.

Artificial intelligence (AI) techniques—ranging from hybrid mechanistic–machine learning (ML) ensembles to gradient-boosted decision trees, support-vector machines, and deep neural networks—are transforming the management of seasonal influenza, respiratory syncytial virus (RSV), human immunodeficiency virus (HIV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Symptom-based triage models using eXtreme Gradient Boosting (XGBoost) and Random Forests, as well as imaging classifiers built on convolutional neural networks (CNNs), have improved diagnostic accuracy across respiratory infections. Transformer-based architectures and social media surveillance pipelines have enabled real-time monitoring of COVID-19. In HIV research, support-vector machines (SVMs), logistic regression, and deep neural network (DNN) frameworks advance viral-protein classification and drug-resistance mapping, accelerating antiviral and vaccine discovery. Despite these successes, persistent challenges remain—data heterogeneity, limited model interpretability, hallucinations in large language models (LLMs), and infrastructure gaps in low-resource settings. We recommend standardized open-access data pipelines and integration of explainable-AI methodologies to ensure safe, equitable deployment of AI-driven interventions in future viral-outbreak responses. Full article

(This article belongs to the Section Viral Pathogens)

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28 pages, 1184 KiB

Open AccessReview

Immune Modulation by Microbiota and Its Possible Impact on Polyomavirus Infection

by Giorgia Cianci, Gloria Maini, Matteo Ferraresi, Giulia Pezzi, Daria Bortolotti, Sabrina Rizzo, Silvia Beltrami and Giovanna Schiuma

Pathogens 2025, 14(8), 747; https://doi.org/10.3390/pathogens14080747 - 30 Jul 2025

Abstract

Polyomaviruses are a family of small DNA viruses capable of establishing persistent infections, and they can pose significant pathogenic risks in immunocompromised hosts. While traditionally studied in the context of viral reactivation and immune suppression, recent evidence has highlighted the gut microbiota as [...] Read more.

Polyomaviruses are a family of small DNA viruses capable of establishing persistent infections, and they can pose significant pathogenic risks in immunocompromised hosts. While traditionally studied in the context of viral reactivation and immune suppression, recent evidence has highlighted the gut microbiota as a critical regulator of host immunity and viral pathogenesis. This review examines the complex interactions between polyomaviruses, the immune system, and intestinal microbiota, emphasizing the role of short-chain fatty acids (SCFAs) in modulating antiviral responses. We explore how dysbiosis may facilitate viral replication, reactivation, and immune escape and also consider how polyomavirus infection can, in turn, alter microbial composition. Particular attention is given to the Firmicutes/Bacteroidetes ratio as a potential biomarker of infection risk and immune status. Therapeutic strategies targeting the microbiota, including prebiotics, probiotics, and fecal microbiota transplantation (FMT), are discussed as innovative adjuncts to immune-based therapies. Understanding these tri-directional interactions may offer new avenues for mitigating disease severity and improving patient outcomes during viral reactivation. Full article

(This article belongs to the Special Issue The Interplay of Microbiota and Polyomaviruses in Human Health and Disease)

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19 pages, 10978 KiB

Open AccessArticle

Identification of Fungi Causing Root Rot in Oregano Crops in Southern Peru: Morphological and Molecular Analysis

by Rubí Adelin Quispe-Mamani, Liduvina Sulca-Quispe, Wilson Huanca-Mamani, Mirna G. Garcia-Castillo, Patricio Muñoz-Torres and German Sepúlveda-Chavera

Pathogens 2025, 14(8), 746; https://doi.org/10.3390/pathogens14080746 - 29 Jul 2025

Abstract

Oregano (Origanum vulgare) cultivation is of great economic importance in Peru. Tacna stands out as its main producer. However, the presence of phytopathogenic fungi represents a challenge for its production. This study aimed to characterize both the morphological and molecular levels [...] Read more.

Oregano (Origanum vulgare) cultivation is of great economic importance in Peru. Tacna stands out as its main producer. However, the presence of phytopathogenic fungi represents a challenge for its production. This study aimed to characterize both the morphological and molecular levels of the causal agent of crown and root rot in a crop field in the Camilaca district, Candarave, Tacna. To this end, systematic sampling was carried out using the five-gold method, collecting plants with typical symptoms. Fungi were isolated from diseased roots and characterized using macroscopic and microscopic morphological analysis as well as sequencing and multilocus phylogenetic analysis (ITS, 28S, HIS3, TEF1, TUB2). In addition, pathogenicity tests were performed on healthy plants to confirm the infectivity of the isolates. The results demonstrated that root rot was caused by a complex of phytopathogenic fungi through phylogenetic analysis of Dactylonectria torresensis, Fusarium oxysporum, F. iranicum, and F. redolens. These findings represent the first report of these species as causal agents of oregano root rot in Peru, highlighting the need for integrated management strategies that reduce the economic impact of these diseases and contribute to the sustainability of the crop in key producing regions such as Tacna. Full article

(This article belongs to the Special Issue Fungal Infections—Pathogenesis, Diagnosis, and Treatment: From Bench to Bedside and Beyond)

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14 pages, 1132 KiB

Open AccessArticle

Phylogenetic Reclassification of Metarhizium granulomatis and Metarhizium viride Species Complex

by Johanna Würf and Volker Schmidt

Pathogens 2025, 14(8), 745; https://doi.org/10.3390/pathogens14080745 - 29 Jul 2025

Abstract

Metarhizium (M.) granulomatis and M. viride have previously been described as pathogens causing hyalohyphomycosis in various species of captive chameleons and bearded dragons (Pogona vitticeps). Previous studies yielded different genotypes of M. granulomatis and M. viride based on sequencing of the [...] Read more.

Metarhizium (M.) granulomatis and M. viride have previously been described as pathogens causing hyalohyphomycosis in various species of captive chameleons and bearded dragons (Pogona vitticeps). Previous studies yielded different genotypes of M. granulomatis and M. viride based on sequencing of the internal transcribed spacer 1-5.8S rDNA (ITS-1-5.8S) and a fragment of the large subunit of the 28S rDNA (LSU). The aim of this study was to clarify the relationships between these genotypes and obtain a more accurate phylogenetic classification by sequencing two different loci of the RNA polymerase II second largest subunit (NRPB2), referred to as RPB1 and RPB2, and the translation elongation factor 1 alpha (EF1α). A total of 23 frozen isolates from 21 lizards, including the first isolates of M. granulomatis and M. viride from Parson’s chameleons (Calumma parsonii), were available for phylogenetic analysis. A total of 13 isolates belonged to the M. granulomatis complex and 10 isolates belonged to the M. viride complex. Following the amplification and sequencing of the protein-coding genes, the resulting nucleotide sequences were analyzed, trimmed and assembled. These were further analyzed with regard to differences in single-nucleotide polymorphisms (SNPs) and amino acid structure. In consideration of the results of the present analyses, a phylogenetic reclassification is recommended. Three different genotypes of M. granulomatis can be distinguished, which can be phylogenetically addressed as subspecies. Six subspecies can be distinguished regarding M. viride. Full article

(This article belongs to the Special Issue Filamentous Fungal Pathogens: 2nd Edition)

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