Pathogens

21 pages, 7314 KB

Open AccessArticle

List of Hard Ticks (Acari: Ixodida: Ixodidae) in Subterranean Habitats in Croatia

by Stjepan Krčmar and Roman Ozimec

Pathogens 2026, 15(3), 343; https://doi.org/10.3390/pathogens15030343 - 23 Mar 2026

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Between 1993 and 2024, a total of 274 hard ticks (Ixodidae) were collected from 138 subterranean localities in Croatia. This study represents the most extensive survey of hard tick fauna in subterranean habitats in Croatia to date. The collected specimens were classified into [...] Read more.

Between 1993 and 2024, a total of 274 hard ticks (Ixodidae) were collected from 138 subterranean localities in Croatia. This study represents the most extensive survey of hard tick fauna in subterranean habitats in Croatia to date. The collected specimens were classified into three genera and seven taxa, including two taxa that could not be identified to the species level (one from the genus Ixodes and one from Haemaphysalis). The genus Ixodes was the most abundant, comprising five taxa, whereas Haemaphysalis and Hyalomma were each represented by a single taxon. The highest diversity of hard ticks was recorded in subterranean habitats in Dalmatia, followed by north-western Croatia and Slavonia. Ixodes vespertilionis Koch, 1844 was the dominant species in the collected sample, representing 81.0% of all specimens, and was recorded in all studied regions. This species was present throughout the entire year, whereas I. hexagonus Leach, 1815 was recorded during nine months, I. frontalis (Panzer, 1798) during four months, and the remaining taxa during shorter periods. The largest number of I. vespertilionis specimens was collected in spring (33.2%), while the lowest number was recorded in winter (16.6%). The record of I. frontalis represents the first documented occurrence of this species in subterranean habitats in Croatia. Full article

(This article belongs to the Special Issue Ticks and Tick-Borne Diseases―Pathogens, Parasites, People and Practices)

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14 pages, 245 KB

Open AccessArticle

HBV and HCV Burden in a Greek Hospital Population (2018–2024): Trends and Correlates of HBsAg and Anti-HCV Positivity

by Nikolaos Georgiadis, Christina Seitopoulou, Maria Kimouli, Theodoros N. Sergentanis, Apostolos Beloukas and Georgina Tzanakaki

Pathogens 2026, 15(3), 342; https://doi.org/10.3390/pathogens15030342 - 23 Mar 2026

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Abstract

Background: Hepatitis B and C remain a major public health challenge in Greece, particularly amid demographic shifts, migration, and evolving socioeconomic conditions. Updated epidemiological data are essential to guide public health planning and prevention strategies. Methods: A repeated cross-sectional study was [...] Read more.

Background: Hepatitis B and C remain a major public health challenge in Greece, particularly amid demographic shifts, migration, and evolving socioeconomic conditions. Updated epidemiological data are essential to guide public health planning and prevention strategies. Methods: A repeated cross-sectional study was conducted among adults (n = 36,085) attending the General Hospital of Nikaia “Agios Panteleimon”, Piraeus, Greece, from 2018 to 2024. Participants consisted of inpatients and outpatients, including recognized high-risk groups. Serological markers assessed current hepatitis B infection (HBsAg) and past or recent hepatitis C exposure (anti-HCV). Associations were examined using univariate and multivariate logistic regression, reporting adjusted odds ratios (aORs) and 95% confidence intervals (CIs). Results: Overall prevalence was 4.65% for HBsAg (n = 1677) and 6.6% for anti-HCV (n = 2378). Females had significantly lower odds compared to males for both markers (HBsAg aOR = 0.24, anti-HCV aOR = 0.77, both p < 0.001). Anti-HCV prevalence declined with age, with the ≥70 group showing the lowest odds (aOR = 0.24, p < 0.001). For HBsAg, older age groups also showed reduced odds, particularly ages 60–69 (aOR = 0.49, p < 0.001) and ≥70 (aOR = 0.75, p = 0.005). Compared to Attica region, most regions had significantly lower odds of both infections, including Thrace (HBsAg aOR = 0.08; anti-HCV aOR = 0.32, both p < 0.001), Crete (HBsAg aOR = 0.13; anti-HCV aOR = 0.35, both p < 0.001), and Macedonia (HBsAg aOR = 0.37; anti-HCV aOR = 0.64, both p < 0.001). Compared to 2018, the odds were markedly higher in 2023 and peaked in 2024 for both infections (anti-HCV aOR = 1.78; HBsAg aOR = 3.10, both p < 0.001 for 2024). High-risk social groups demonstrated substantially elevated odds of anti-HCV (aORs 3.9–5.51, all p < 0.001), but had lower odds of HBsAg (aORs 0.32–0.60, all p ≤ 0.001). Conclusions: Increasing prevalence trends, regional disparities, and pronounced differences among vulnerable groups highlight the urgent need for strengthened screening, vaccination, and targeted hepatitis B and C prevention strategies, particularly among healthcare-attending and high-risk populations in Greece. Full article

20 pages, 3075 KB

Open AccessArticle

Multi-Epitope DNA-Based Feline Immunodeficiency Virus Vaccine Construct Designed by Immunoinformatic and Machine Learning Tools as a Surrogate Model for HIV Vaccine Development

by Tyler Michalka, Abid Ullah Shah, Tiffany Liang and Maged Gomaa Hemida

Pathogens 2026, 15(3), 341; https://doi.org/10.3390/pathogens15030341 - 23 Mar 2026

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Abstract

Feline immunodeficiency virus (FIV) is a lentivirus that exhibits significant structural and pathological similarities to human immunodeficiency virus (HIV), establishing it as a valuable model for HIV vaccine development. In this study, artificial intelligence (AI) and immunoinformatics were employed to design a novel [...] Read more.

Feline immunodeficiency virus (FIV) is a lentivirus that exhibits significant structural and pathological similarities to human immunodeficiency virus (HIV), establishing it as a valuable model for HIV vaccine development. In this study, artificial intelligence (AI) and immunoinformatics were employed to design a novel multi-epitope DNA vaccine targeting conserved regions of the FIV gag, pol, and env genes. Predicted B-cell and T-cell epitopes were evaluated for their capacity to induce strong immune responses while minimizing allergenic or toxic effects and were linked to the immune adjuvant PADRE. Structural analysis indicated that the vaccine construct is stable, soluble, and biocompatible, with a well-folded tertiary structure that binds Toll-like receptor 9 (TLR9) and elicits robust humoral and cellular immune responses. These findings identify a promising FIV vaccine candidate and provide insights for the development of next-generation HIV vaccines. Full article

(This article belongs to the Section Immunological Responses and Immune Defense Mechanisms)

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15 pages, 6452 KB

Open AccessArticle

Diseases Caused by Parasites with Invertebrate Hosts in China: Burden and Trends of Leishmaniasis and Schistosomiasis

by Cun-Chen Wang, Shu-Jing Wang, Rui Han, Gui-Zhi Xu, Hai-Ting Zhang, Xin-Xue Zhu, Qi-Long Wu, Yi-Xue Zhao, Yu-Jie Zhou, Zhen-Zhong Feng, Miao Liu and Sheng-Qun Deng

Pathogens 2026, 15(3), 340; https://doi.org/10.3390/pathogens15030340 - 23 Mar 2026

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Abstract

Parasitic diseases involving invertebrate hosts, notably leishmaniasis (transmitted by sandflies) and schistosomiasis (transmitted via aquatic snails), remain public health concerns in China. Based on the Global Burden of Disease 2021 data, the age-standardized prevalence, mortality, and disability-adjusted life years (DALY) rates for both [...] Read more.

Parasitic diseases involving invertebrate hosts, notably leishmaniasis (transmitted by sandflies) and schistosomiasis (transmitted via aquatic snails), remain public health concerns in China. Based on the Global Burden of Disease 2021 data, the age-standardized prevalence, mortality, and disability-adjusted life years (DALY) rates for both diseases declined significantly from 1990 to 2021. Men consistently experienced a higher burden than women. The age distribution of disease burden differed between the two conditions. Projections to 2036 suggest a continued decrease in schistosomiasis burden and in leishmaniasis mortality and DALYs, but a potential slight rise in leishmaniasis prevalence. Sustained control efforts have been effective, yet challenges persist due to demographic disparities, climate-related invertebrate host/intermediate host expansion, and imported cases. Future strategies require enhanced surveillance, targeted interventions, and multi-sectoral collaboration to advance toward elimination. Full article

(This article belongs to the Special Issue Epidemiology and Molecular Diagnosis of Vector-Borne Diseases)

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14 pages, 2101 KB

Open AccessArticle

Identification and Biological Features of Sesame Phyllody-Associated Phytoplasmas in Western Iran

by Samira Pakbaz, Ehsan Hasanvand, Assunta Bertaccini and Sara Gharouni-Kardani

Pathogens 2026, 15(3), 339; https://doi.org/10.3390/pathogens15030339 - 23 Mar 2026

Cited by 1 | Viewed by 933

Abstract

Sesame is an oilseed crop threatened by a phyllody disease associated with the presence of phytoplasmas, which can reduce yields by up to 80%. The molecular identification of these bacteria in crops located in Western Iran was achieved from samples showing symptoms of [...] Read more.

Sesame is an oilseed crop threatened by a phyllody disease associated with the presence of phytoplasmas, which can reduce yields by up to 80%. The molecular identification of these bacteria in crops located in Western Iran was achieved from samples showing symptoms of diverse intensity and types. For biological characterization, the pathogen was also dodder-transmitted to periwinkle plants. After nucleic acid extraction and nested PCR using phytoplasma-specific primer pairs amplifying part of the 16S rRNA gene, it was possible to amplify DNA fragments from both symptomatic sesame samples and dodder-inoculated periwinkle plants. The virtual RFLP pattern from the 16S rRNA gene sequences using iPhyClassifier indicated the presence of phytoplasma strains in 16SrII-D and 16SrIX-C subgroups. The identity percentage values of the obtained amplified sequences corroborated by the phylogenetic analysis identified them as ‘Candidatus Phytoplasma australasiaticum’ and ‘Ca. P. phoenicium’, respectively. The two phytoplasma strains were detected in different sesame samples collected in the same field. The coexistence of two phytoplasmas may influence the observed differences in disease severity and suggests appropriate management strategies, since diverse insect vectors were reported alongside diverse phytoplasmas associated with this disease. Moreover, the widespread disease presence strongly suggests the breeding of resistant varieties. Full article

(This article belongs to the Special Issue Next-Gen Sequencing Advances Pathogen Research in Health, Agriculture & Environment)

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11 pages, 1176 KB

Open AccessArticle

Molecular Epidemiology of Toscana Virus in Northern and Central Italy Using Metagenomic Next-Generation Sequencing

by Giulia Alessandri, Giada Beligni, Gianni Gori Savellini, Alessandra Mistral De Pascali, Federica Gobbo, Fabrizio Montarsi, Davide Mileto, Letizia Rizzo and Maria Grazia Cusi

Pathogens 2026, 15(3), 338; https://doi.org/10.3390/pathogens15030338 - 21 Mar 2026

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Abstract

Toscana virus (TOSV) is an arthropod-borne virus, transmitted by sandflies, which represents a major cause of aseptic meningitis in Mediterranean countries during summer months. Despite its epidemiological importance, recent genomic data on circulating Italian strains remain limited. We performed comprehensive phylogenetic and genotypic [...] Read more.

Toscana virus (TOSV) is an arthropod-borne virus, transmitted by sandflies, which represents a major cause of aseptic meningitis in Mediterranean countries during summer months. Despite its epidemiological importance, recent genomic data on circulating Italian strains remain limited. We performed comprehensive phylogenetic and genotypic characterization of 34 TOSV isolates (32 obtained from human biological samples and 2 from sandfly homogenates) collected between 2022 and 2025 from Northern/Central Italy. All the sequenced isolates clustered within Lineage A, with strains circulating in Tuscany showing significantly lower intra group genetic divergence (p < 0.05), indicative of compartmentalized local circulation. Both S and M segments exhibited negative selection and identified non-synonymous mutations deserving functional investigation. This study documents stable Lineage A predominance across Italian regions, with Tuscany showing distinct phylogeographic structuring. mNGS proves effective for TOSV genomic surveillance, supporting refined public health strategies, including targeted sandfly control in endemic foci. Full article

(This article belongs to the Section Viral Pathogens)

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17 pages, 664 KB

Open AccessArticle

Clinical Features and Outcomes of Treatment for Effusive Feline Infectious Peritonitis with GS-441524 in Seventeen Retrovirus-Positive Cats

by Marilize Van der Walt, Sarah E. Jones, Julie K. Levy, Emma Hart, Rosa Negash, Wendy M. Novicoff, Nicole Jacque and Samantha J. M. Evans

Pathogens 2026, 15(3), 337; https://doi.org/10.3390/pathogens15030337 - 21 Mar 2026

Viewed by 2316

Abstract

Background: There is limited information about treatment success and outcomes in retrovirus-positive cats diagnosed with feline infectious peritonitis (FIP). Methods: A survey was distributed to caretakers of cats with feline leukemia virus (FeLV) and/or feline immunodeficiency virus (FIV) that were treated with GS-441524 [...] Read more.

Background: There is limited information about treatment success and outcomes in retrovirus-positive cats diagnosed with feline infectious peritonitis (FIP). Methods: A survey was distributed to caretakers of cats with feline leukemia virus (FeLV) and/or feline immunodeficiency virus (FIV) that were treated with GS-441524 for presumptive effusive FIP based on survey responses. Results: Cats with FIV developed FIP at an older age and longer after retrovirus infection than cats with FeLV. The average starting dosage (7 mg/kg/d) was increased in 65% of cats, and treatment was extended in 35%. Three cats relapsed (18%). There was a 94% (16/17) twelve-week survival rate and 82% (14/17) one-year survival rate. Seven cats were alive at follow-up, a median of 1306 days (range 983–2069) after FIP diagnosis, but many cats succumbed to neoplasia. Conclusions: Treatment success for retrovirus-positive cats with presumptive FIP was similar to previously reported outcomes for FIP alone. This could support current evidence of successful antiviral therapy for similar populations, if noncurrent, unstandardized protocols and unlicensed product use are considered. Additional studies are needed to determine ideal protocols for rapid resolution of FIP, good long-term survival, and limited relapse in retrovirus-positive cats, and the impact of the FeLV proviral load. Full article

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14 pages, 762 KB

Open AccessArticle

First Detection of Human- and Dog-Associated Demodex Mites (Acari, Arachnida) in Southern European Wolves (Canis lupus)

by Natalia Sastre, Manena Fayos, Luca Rossi, Olga Francino, Roser Velarde, Sebastian E. Ramos-Onsins and Lluís Ferrer

Pathogens 2026, 15(3), 336; https://doi.org/10.3390/pathogens15030336 - 21 Mar 2026

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Abstract

Demodex mites are common commensals of mammalian skin, but under certain conditions, they can cause severe skin diseases. This study analyzed the presence, diversity, and phylogenetic relationships of Demodex species in two wolf subspecies from southern Europe to determine whether species-level differences exist [...] Read more.

Demodex mites are common commensals of mammalian skin, but under certain conditions, they can cause severe skin diseases. This study analyzed the presence, diversity, and phylogenetic relationships of Demodex species in two wolf subspecies from southern Europe to determine whether species-level differences exist between wild and domestic canids after thousands of years of divergence. A total of 1400 hair samples from 140 wolves were analyzed using a real-time PCR (qPCR) targeting mitochondrial 16S rRNA and nuclear 18S rRNA genes. Overall, 37.1% (52/140; 95% CI: 29.0–45.9%) of wolves were positive for Demodex DNA, with a higher prevalence in Italian (46%) than in Iberian (36%) wolves. The lip and chin areas were the most reliable sampling sites. Four Demodex species were identified in wolves: D. injai and D. canis (associated with dogs), and D. folliculorum and D. brevis (associated with humans). Co-infestations involving multiple Demodex species were recorded for the first time in wild canids. These results challenge the long-held belief of strict host specificity in Demodex mites. The discovery of Demodex species associated with both humans and dogs in wolves supports the idea that host-switching and ecological interactions have occurred throughout the evolution of canids and humans. Such cross-species transfers may have taken place during the early domestication of dogs, representing a plausible scenario compatible with our data. However, given the isolated history of the two southern wolf populations, it is more probable that these findings result from recent interspecific transmission events, likely facilitated by ecological overlap with domestic animals and human environments. Future genomic studies will be essential for clarifying the evolutionary relationships within the genus Demodex and its host associations. Full article

(This article belongs to the Special Issue Parasitic Infections in Animals)

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31 pages, 340 KB

Open AccessReview

Insights into Arcanobacterium haemolyticum: A Narrative Review of an Emerging Pathogen Revisited

by Alessandra Consonni, Elena Briozzo, Chiara Giubbi, Silvia Tonolo, Francesco Luzzaro and Carola Mauri

Pathogens 2026, 15(3), 335; https://doi.org/10.3390/pathogens15030335 - 21 Mar 2026

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Abstract

Arcanobacterium haemolyticum is a facultative anaerobic, Gram-positive bacillus that has garnered attention due to its role in human infections, particularly among adolescents and young adults. Traditionally associated with pharyngitis, this organism is increasingly recognized for its involvement in systemic infections, including bacteremia, central [...] Read more.

Arcanobacterium haemolyticum is a facultative anaerobic, Gram-positive bacillus that has garnered attention due to its role in human infections, particularly among adolescents and young adults. Traditionally associated with pharyngitis, this organism is increasingly recognized for its involvement in systemic infections, including bacteremia, central nervous system abscesses, and Lemierre’s syndrome. The pathogenicity of A. haemolyticum is attributed to its production of hemolysins and neuraminidase, facilitating tissue invasion and immune evasion. Clinically, infections often present with sore throat, fever, and a characteristic scarlatiniform rash, which can lead to their misdiagnosis as streptococcal pharyngitis. Severe manifestations, though rare, have been documented, particularly in immunocompromised individuals. Diagnosis is challenging due to the organism’s slow growth and potential misidentification as diphtheroids in cultures. Accurate identification necessitates specific culture conditions and biochemical testing. Treatment typically involves beta-lactam antibiotics; however, the emergence of resistance patterns necessitate susceptibility testing to guide therapy. This review aims to consolidate current knowledge on A. haemolyticum, emphasizing its clinical presentations, diagnostic challenges, and management strategies, thereby enhancing recognition and treatment of infections caused by this emerging pathogen. Full article

(This article belongs to the Section Bacterial Pathogens)

15 pages, 3126 KB

Open AccessArticle

Green Tea Catechins Significantly Reduce Zika Virus in RBCs Through Viral Inactivation

by Xipeng Yan, Jinlian Li, Xiaoqiong Duan, Limin Chen, Yujia Li and Chunhui Yang

Pathogens 2026, 15(3), 334; https://doi.org/10.3390/pathogens15030334 - 20 Mar 2026

Cited by 1 | Viewed by 873

Abstract

Background: Despite significant improvements in blood safety, the risk of transfusion-transmitted infections persists, particularly from emerging and re-emerging viruses. For red blood cell (RBC) products, this risk is exacerbated by the fact that there is no routine testing for many of these pathogens, [...] Read more.

Background: Despite significant improvements in blood safety, the risk of transfusion-transmitted infections persists, particularly from emerging and re-emerging viruses. For red blood cell (RBC) products, this risk is exacerbated by the fact that there is no routine testing for many of these pathogens, and effective, commercially available pathogen inactivation technologies specifically for RBCs are still lacking. This gap in the safety framework means that viruses capable of establishing an asymptomatic viremia—a characteristic of many arboviruses like Zika, dengue, and West Nile virus—present a tangible threat to the blood supply, highlighting the need for broad-spectrum countermeasures. Study Design and Methods: This study aims to investigate the antiviral activity of green tea extract (GTE) and its key catechins, epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), against ZIKV in both cellular models and red blood cell (RBC) products. In vitro antiviral activity was assessed using A549 cells treated with GTE (150 μg/mL) or purified EGCG/ECG (20 μM). Mechanistic studies focused on viral attachment inhibition. Additionally, ZIKV-spiked RBC products were co-incubated with GTE (300 μg/mL) for 1 h to evaluate virucidal effects. Erythrocyte integrity was confirmed via hemolysis assays. Results: Co-treatment with GTE or catechins suppressed ZIKV replication by ≥3.64 logs (p < 0.001) in A549 cells. GTE and catechins primarily inhibited viral attachment. In RBCs, GTE reduced viral infectivity by 99.99% (4-log reduction) without compromising erythrocyte membrane integrity or cellular viability. Furthermore, RBCs with added GTE demonstrated a lower hemolysis rate during storage for up to 60 days. Conclusions: GTE exhibits potent virucidal activity against ZIKV in blood matrices, highlighting its potential as a pathogen reduction agent to enhance transfusion safety. Further development of GTE-based additive solutions or technologies is warranted. Full article

(This article belongs to the Special Issue Emerging Arboviruses and Novel Viral Threats: Detection, Surveillance, and Mitigation Strategies)

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28 pages, 3943 KB

Open AccessArticle

Practical Real-Time Quaking-Induced Conversion for Detecting Classical Bovine Spongiform Encephalopathy and Classical and Atypical Scrapie Prions

by Akio Suzuki, Kazuhei Sawada, Taku Nakashima, Toyotaka Sato, Kohtaro Miyazawa, Yuichi Matsuura, Keigo Ikeda, Yoshifumi Iwamaru and Motohiro Horiuchi

Pathogens 2026, 15(3), 333; https://doi.org/10.3390/pathogens15030333 - 20 Mar 2026

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Abstract

Real-time quaking-induced conversion (RT-QuIC) is highly sensitive for prion detection; however, inhibitory factors present in tissue homogenates readily interfere with the assay. We previously reported that recombinant cervid prion protein (rCerPrP) enabled the establishment of practical RT-QuIC for detecting chronic wasting disease and [...] Read more.

Real-time quaking-induced conversion (RT-QuIC) is highly sensitive for prion detection; however, inhibitory factors present in tissue homogenates readily interfere with the assay. We previously reported that recombinant cervid prion protein (rCerPrP) enabled the establishment of practical RT-QuIC for detecting chronic wasting disease and atypical bovine spongiform encephalopathy (BSE) prions, i.e., detecting low levels of prions in high concentration of brain tissue homogenates. Accordingly, the present study aimed to establish RT-QuIC for detecting classical BSE (C-BSE) and classical and atypical scrapie (C- and A-scrapie, respectively). A single-step lipid extraction using a 3:1 mixture of 2-butanol and methanol was effective as a pretreatment to remove inhibitors from brain homogenates. Among three rPrPs extensively evaluated, recombinant sheep PrP (rShPrP) was the most suitable substrate for practical detection of C-BSE prions. rCerPrP-173S/177N and rCerPrP-98S/173S/177N, which carry sheep-type amino acid substations at codons 173 and 177 and at codons 98, 173, and 177, showed excellent performance for detecting C-scrapie prions. Moreover, rCerPrP-98S/173S/177N, but not rCerPrP-173S/177N, was identified as an optimal substrate for detecting A-scrapie prions. These results suggested that combining inhibitor-removal pretreatment with the optimization of rPrP substrate for each animal prions further enhanced of RT-QuIC performance. Full article

(This article belongs to the Collection Prions and Chronic Wasting Diseases)

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24 pages, 11367 KB

Open AccessArticle

Potential Activity of 6-Pentyl-α-pyrone as an Antiviral for Bovine Coronavirus

by Luca Del Sorbo, Rosa Giugliano, Clementina Acconcia, Maria Michela Salvatore, Alessia Staropoli, Violetta Iris Vasinioti, Maria Stella Lucente, Paolo Capozza, Francesco Vinale, Annamaria Pratelli, Luigi Russo, Rosa Iacovino and Filomena Fiorito

Pathogens 2026, 15(3), 332; https://doi.org/10.3390/pathogens15030332 - 20 Mar 2026

Cited by 1 | Viewed by 1071

Abstract

During infection in vitro with the strain 438/06 of bovine coronavirus (BCoV), a β-coronavirus similar to severe acute respiratory syndrome (SARS) CoV-2, treatment with 6-pentyl-α-pyrone (6PP), a fungal metabolite obtained from Trichoderma atroviride, was recently shown to influence viral load by reducing [...] Read more.

During infection in vitro with the strain 438/06 of bovine coronavirus (BCoV), a β-coronavirus similar to severe acute respiratory syndrome (SARS) CoV-2, treatment with 6-pentyl-α-pyrone (6PP), a fungal metabolite obtained from Trichoderma atroviride, was recently shown to influence viral load by reducing viral entry. Herein, the ability of 6PP to counteract the BCoV infection was further investigated both in vitro and in silico. Following the BCoV (strain 282/23) infection in bovine (MDBK) cells, the 6PP in co-treatment increased cell viability, reduced morphological signs of cell death, and significantly inhibited viral yield, by lessening the expression of the viral spike (S) protein, as well as the gene transcription of the viral nucleocapsid (NP) protein. In addition, a noticeable down-regulation in the expression of aryl hydrocarbon receptor (AhR) signaling, a strategic modulator of CoVs infection, was found. Molecular docking studies were performed to evaluate the potential interaction between 6PP and AhR involved in the BCoV infection. The docking 3D structural model showed that 6PP fits into a binding pocket positioned between the PASB and TAD domains of bovine AhR (bAhR), where the ligand is stabilized through hydrophobic interactions. In addition, the obtained computational data strongly suggest that the bAhR binding mechanism of 6PP is principally mediated by a well-conserved hydrophobic cavity playing a key role in the modulation of the receptor functions. Overall, our findings showed an antiviral action of 6PP versus BCoV infection in vitro and in silico. Full article

(This article belongs to the Special Issue Emerging/Re-Emerging Viruses and Antiviral Drug Design)

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14 pages, 1750 KB

Open AccessArticle

Meningitis Mortality in U.S. Adults Aged ≥25 Years: Demographic and Geographic Insights from the CDC WONDER Database (1999–2024)

by Hassaan Abid, Muhammad Jawad, Muhammad Vazaym, Gaaitri Lohano, Syed Mohamin Abbas Shah, Naveed Ahmed Khan, Abdullah Afridi and Muhammad Mohid Haroon

Pathogens 2026, 15(3), 331; https://doi.org/10.3390/pathogens15030331 - 19 Mar 2026

Viewed by 1930

Abstract

Meningitis remains a significant cause of morbidity and mortality in the United States despite advances in vaccination, antimicrobial therapy, and critical care. However, long-term national mortality patterns across demographic and geographic subgroups remain incompletely characterized. This study evaluated temporal trends in meningitis-associated mortality [...] Read more.

Meningitis remains a significant cause of morbidity and mortality in the United States despite advances in vaccination, antimicrobial therapy, and critical care. However, long-term national mortality patterns across demographic and geographic subgroups remain incompletely characterized. This study evaluated temporal trends in meningitis-associated mortality among U.S. adults aged ≥25 years from 1999 to 2024 using the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) Multiple Cause of Death database. Death certificates listing meningitis as either the underlying cause or a contributing cause of death were identified using ICD-10 codes to capture meningitis-associated mortality. Age-adjusted mortality rates (AAMRs) per 100,000 population were calculated using the 2000 U.S. standard population. Temporal trends were assessed using Joinpoint regression to estimate annual percent change (APC) and average annual percent change (AAPC). Across the study period, meningitis-associated mortality demonstrated an early decline followed by stabilization and more recent increases in several subgroups. AAMRs decreased significantly from 1999 to 2001 (APC: −14.09%; p = 0.0029) and from 2001 to 2013 (APC: −4.74%; p < 0.000001), followed by a significant increase from 2013 to 2024 (APC: 1.78%; p = 0.0059). Despite these later increases, the overall AAPC across the full study period remained significantly negative (AAPC: −2.73%; p < 0.000001). Earlier analyses using shorter observation windows did not demonstrate a statistically significant overall trend; the significance observed in the present analysis reflects the inclusion of extended mortality data through 2024. Mortality rates were consistently higher among males and adults aged ≥65 years. Non-Hispanic Black individuals experienced increasing mortality after 2013, while Hispanic individuals demonstrated a sustained increase across the entire study period. Regional analyses showed recent increases in the Northeast, South, and West, while non-metropolitan areas did not experience statistically significant improvement through 2020. In summary, meningitis-associated mortality among U.S. adults declined significantly during the early study years but has shown stabilization and recent increases in several demographic and geographic subgroups since approximately 2013. Although overall mortality across the full study period remains lower than baseline levels, these emerging disparities highlight the importance of continued surveillance and targeted public health interventions. Full article

(This article belongs to the Special Issue Epidemiology of Infectious Diseases and Prevention Strategies in Clinical Populations)

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20 pages, 3752 KB

Open AccessArticle

Exploring the Antibacterial Properties of a Newly Isolated Microviridae Phage Against Multidrug-Resistant Escherichia coli

by Yoana Kizheva, Maria Pandova, Zoltan Urshev, Yoana Gladicheva, Tsvetelina Paunova-Krasteva, Sergei Ivanov and Petya Hristova

Pathogens 2026, 15(3), 330; https://doi.org/10.3390/pathogens15030330 - 19 Mar 2026

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Abstract

In response to the alarming rise in antimicrobial resistance, bacteriophages have re-emerged as a promising alternative to conventional antibiotic therapy. The main objective of this paper was to characterize a newly isolated phage (vB_SEC_3) in the context of its suitability for phage therapy [...] Read more.

In response to the alarming rise in antimicrobial resistance, bacteriophages have re-emerged as a promising alternative to conventional antibiotic therapy. The main objective of this paper was to characterize a newly isolated phage (vB_SEC_3) in the context of its suitability for phage therapy against MDR E. coli, which is considered a priority pathogen. The phage was characterized at the morphological, genomic, and biological levels relevant to phage therapy. TEM analyses revealed a non-enveloped icosahedral capsid lacking tail structure. Phylogenetic and tANI analyses placed the phage within the α3 phages (genus Alphatrevirus) of the less-studied family Microviridae and revealed <95% similarity to its closest relatives, suggesting vB_SEC_3 is a putative novel species within this genus. The genome (6085 bp, GC content 45.3%) displayed the conserved organization typical for these phages, including overlapping genes. No known genes associated with lysogeny, antibiotic resistance, or virulence were detected. Briefly, vB_SEC_3 was able to effectively lyse two MDR strains of E. coli (S1 and B5, EOP 0.735 and 0.961, respectively). Tolerance to a wide pH range (4–10.5) and to temperatures up to 80 °C was established. Six-month storage of the crude lysate at 4 °C resulted in a slight decrease (<0.16 log₁₀ PFU/mL) in phage titer. This study provides additional insights into the biology and diversity of Microviridae phages and offers a basis for future investigations into their potential relevance in the context of combating MDR bacteria. Full article

(This article belongs to the Special Issue Current Progress on Bacterial Antimicrobial Resistance)

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22 pages, 3195 KB

Open AccessArticle

Profile of Priority Antimicrobial-Resistant Pathogens and the Behavior of Multidrug-Resistant Tuberculosis in the Santiago de Cali District, Colombia

by Alejandra Mondragón Quiguanas, Jorge Iván Montoya Salazar, Juan Camilo Mosquera-Hernandez, Margareth Zuluaga Aricapa, Carlos Eduardo Pinzón Flórez, German Escobar Morales, Johana Alejandra Moreno-Drada, Bruno Gutiérrez and Lucy Marcela Díaz Rivadeneira

Pathogens 2026, 15(3), 329; https://doi.org/10.3390/pathogens15030329 - 19 Mar 2026

Viewed by 970

Abstract

Background: Antimicrobial resistance is a threat that increases morbidity and mortality. This cross-sectional study aimed to describe the profile of priority antimicrobial-resistant pathogens and to analyze the behavior of multidrug-resistant tuberculosis (MDR-TB) in the Santiago de Cali District, Colombia. Methods: researchers compiled information [...] Read more.

Background: Antimicrobial resistance is a threat that increases morbidity and mortality. This cross-sectional study aimed to describe the profile of priority antimicrobial-resistant pathogens and to analyze the behavior of multidrug-resistant tuberculosis (MDR-TB) in the Santiago de Cali District, Colombia. Methods: researchers compiled information from data provided by healthcare institutions, the National Public Health Surveillance System, and laboratory-based surveillance using the World Health Organization’s WHONET v.5.6 software. Univariate statistical analysis described trends in pathogen resistance, and multivariate analysis analyzed the behavior of MDR-TB. Results: Among Gram-negative bacteria, high levels of carbapenem resistance were observed in A. baumannii (84% aztreonam resistance) and in K. pneumoniae (63%). P. aeruginosa exhibited elevated multidrug resistance, consistent with extensive antimicrobial selective pressure. MDR-TB exhibited a high burden of resistance, reaching 96%, with projections indicating a potential increase driven by monoresistance and resistance to rifampicin. Patients with drug-resistant tuberculosis who were HIV-positive or experiencing homelessness had a significantly higher likelihood of hospitalization (OR 5.59; 95% CI 3.09–10.11 and OR 2.94; 95% CI 1.48–5.81, respectively) and mortality (OR 3.34; 95% CI 1.72–6.49 and OR 2.59; 95% CI 1.16–5.79, respectively). Conclusions: The expansion of resistance mechanisms suggests sustained selective pressure, underscoring the need for strategies to optimize antibiotics. Full article

(This article belongs to the Special Issue Advanced Antimicrobial Agents: Combatting Multi-Drug Resistant Bacterial Infections)

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16 pages, 1219 KB

Open AccessArticle

Epidemiological Features and Environmental Factors of Severe Fever with Thrombocytopenia Syndrome Patients in a Highly Endemic Region: A 12-Year Surveillance Study

by Xin Yang, Cheng-Juan Liu, Hong-Han Ge, Chun-Hui Li, Li-Fen Hu, Xiao-Ai Zhang, Ming Yue, Pei-Jun Guo and Wei Liu

Pathogens 2026, 15(3), 328; https://doi.org/10.3390/pathogens15030328 - 18 Mar 2026

Viewed by 826

Abstract

Background: Severe fever with thrombocytopenia syndrome (SFTS) has become an increasing public health threat in China, with Yantai City representing a major endemic focus. A fine-scale, long-term epidemiological analysis integrating human case data with vector surveillance is essential for understanding local transmission dynamics. [...] Read more.

Background: Severe fever with thrombocytopenia syndrome (SFTS) has become an increasing public health threat in China, with Yantai City representing a major endemic focus. A fine-scale, long-term epidemiological analysis integrating human case data with vector surveillance is essential for understanding local transmission dynamics. Methods: We conducted a retrospective analysis using 12-year (2013–2024) county-level SFTS surveillance data from Yantai City. Temporal trends were analyzed by Joinpoint regression. Concurrent field surveillance of Haemaphysalis longicornis (2019–2024) was used to quantify local SFTSV infection rates in ticks. Associations between SFTS incidence and environmental/livestock factors were evaluated using Spearman’s correlation and multivariable negative binomial regression. Results: A total of 1964 SFTS cases were reported. The annual incidence rate increased from 0.65 to 5.12 per 100,000 population, with an average annual percentage change (AAPC) of 13.56% 2013–2024, showing the most substantial rise among the elderly. Marked spatial heterogeneity was observed, with county-level mean incidence ranging from 0.30 to 5.23 per 100,000. The SFTSV infection rate in ticks surged from 0.54% in 2019 to 3.24% in 2024, and showed a strong positive correlation with human incidence both seasonally (ρ = 0.998) and across counties (ρ = 0.79), a pattern likely driven by shared environmental factors. Multivariable analysis identified grassland coverage (adjusted IRR [aIRR] = 1.21), woodland coverage (aIRR = 2.31), goat density (aIRR = 1.49), and tick infection rate (aIRR = 1.65) as independent risk factors, while urban land was protective (aIRR = 0.83). The overall case fatality rate was 8.86%, showing a declining trend, but was significantly higher in males (10.90%) than in females (7.04%), particularly among the elderly. Conclusions: SFTS incidence in Yantai increased significantly over the past decade, characterized by a heightened burden on the elderly and strong spatiotemporal clustering. Risk is independently mediated by ecological interfaces, notably woodland/grassland habitats and goat rearing. These findings delineate high-risk areas and populations, offering crucial insights for developing targeted public health strategies. Full article

(This article belongs to the Section Viral Pathogens)

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22 pages, 1763 KB

Open AccessArticle

Clinical Manifestations of Lyme Borreliosis in Europe: Burden of Lyme Disease Study (BOLD), 2021–2022

by Kate Halsby, Alexandra Loew-Baselli, Franc Strle, Anna Moniuszko-Malinowska, Johan Sanmartin Berglund, Viliam Cibik, Dagmar Zakova, Ye Tan, Frederick J. Angulo, Juanita Edwards, Andreas Pilz, Brad D. Gessner, Elizabeth Begier, James H. Stark and on behalf of the BOLD Study Group

Pathogens 2026, 15(3), 327; https://doi.org/10.3390/pathogens15030327 - 18 Mar 2026

Cited by 1 | Viewed by 1672

Abstract

Lyme borreliosis (LB), the most common European tick-borne disease, can manifest as an erythema migrans (EM) rash or as disseminated LB. The prospective Burden of Lyme Disease (BOLD) study evaluated the frequency of LB clinical manifestations, including signs, symptoms, and treatment patterns in [...] Read more.

Lyme borreliosis (LB), the most common European tick-borne disease, can manifest as an erythema migrans (EM) rash or as disseminated LB. The prospective Burden of Lyme Disease (BOLD) study evaluated the frequency of LB clinical manifestations, including signs, symptoms, and treatment patterns in 14 healthcare practices in endemic regions of six European countries: the Czech Republic, Germany, Poland, Slovakia, Slovenia, and Sweden. Between April 2021 and December 2022, patients with suspected LB were evaluated using predefined case definitions that were applied by investigators to identify medically attended LB cases. Enrolled cases were interviewed about their symptoms. Among the 797 LB cases, 615 (77.2%) had EM and 182 (22.8%) had disseminated disease; 154 of the disseminated cases had Lyme arthritis (LA), five had Lyme neuroborreliosis, and three had Lyme carditis. Geographically, the proportion of disseminated disease varied by country, from 1.1% in Slovenia to 78.0% in Slovakia. Overall, 76.3% of all LB cases in Slovakia were LA. Antibiotic use varied by country, although every country prescribed doxycycline. The frequency of LB manifestations varied substantially between countries. EM was the most common manifestation in all countries except Slovakia, where LA was most common. This study underscores the need for improved prevention strategies. Full article

(This article belongs to the Special Issue Tick-Borne Threats in Europe: From Epidemiology to the Impact of Vaccination)

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12 pages, 488 KB

Open AccessArticle

The Resurgence of Pertussis in Tuscany (Italy): A Six-Year Retrospective Epidemiological Analysis

by Sara Boccalini, Manuela Chiavarini, Alice Dell’Acqua, Beatrice Conti, Zhanna Tumanova, Alessandra Picelli, Vanessa Verniani, Daniele Borchi, Lorenzo Latella, Saverio Checchi, Matteo Bastiani, Barbara Rita Porchia, Daniela Senatore, Giovanna Bianco, Paolo Bonanni and Angela Bechini

Pathogens 2026, 15(3), 326; https://doi.org/10.3390/pathogens15030326 - 18 Mar 2026

Cited by 1 | Viewed by 972

Abstract

Pertussis, caused by Bordetella pertussis, remains a public health concern despite long-standing vaccination programs. After a marked decline during the COVID-19 pandemic, a resurgence was observed in Europe and Italy, with a sharp increase in 2024. This study describes pertussis epidemiological trends [...] Read more.

Pertussis, caused by Bordetella pertussis, remains a public health concern despite long-standing vaccination programs. After a marked decline during the COVID-19 pandemic, a resurgence was observed in Europe and Italy, with a sharp increase in 2024. This study describes pertussis epidemiological trends in the Tuscany Region (Italy) from 2019 to 2024 to identify high-risk groups and inform prevention strategies. A retrospective population-based analysis was conducted using cases reported to the national surveillance system (PREMAL). Incidence rates were calculated using ISTAT population data, and demographic, temporal, and clinical characteristics were analyzed. Overall, 669 cases were reported (mean annual incidence rate: 3.03/100,000 (IC 95% 2.47–3.59; period incidence rate: 18.2/100,000 (IC 95% 16.81–19.56)), with 89% occurring in 2024 (16.34/100,000 (IC 95% 15.03–17.65)). No sex differences were observed, and most cases were reported in Central Tuscany (64%). Children under 15 years accounted for 87% of cases. The highest incidence was observed among 10–14-year-olds, while infants < 1 year, particularly those under 4 months, showed the highest burden in narrower age strata. Hospitalizations occurred in 12.6% of cases, decreasing substantially in 2024. The 2024 resurgence likely reflects waning immunity, disruptions to routine vaccinations during the pandemic, and reduced pathogen circulation in previous years due to containment and isolation measures related to the pandemic. Strengthening surveillance and improving booster and maternal vaccination coverage are essential to protect vulnerable populations. Full article

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19 pages, 1704 KB

Open AccessReview

Research Progress on Heavy Metals as Regulators of Bacterial Virulence in a Caenorhabditis elegans Infection Model

by Yiying Zhang, Xuanheng Tai, Kelan Wang, Ying Zhao, Xin Zhao and Wei Zou

Pathogens 2026, 15(3), 325; https://doi.org/10.3390/pathogens15030325 - 18 Mar 2026

Viewed by 1027

Abstract

Heavy metal pollution is increasingly recognized, not merely as a source of static toxicity, but also as a driver of dynamic microbial regulation. At sublethal concentrations, these pollutants function as critical environmental cues that reshape microbial evolutionary trajectories. This review elucidates how low-dose [...] Read more.

Heavy metal pollution is increasingly recognized, not merely as a source of static toxicity, but also as a driver of dynamic microbial regulation. At sublethal concentrations, these pollutants function as critical environmental cues that reshape microbial evolutionary trajectories. This review elucidates how low-dose heavy metals bypass acute cellular damage to instead engage bacterial chemical-sensing networks, systematically upregulating virulence factors, biofilm architecture, and the co-selection of antibiotic resistance. By leveraging the Caenorhabditis elegans (C. elegans) infection model (a platform defined by its evolutionarily conserved innate immune architecture), we dissect the tripartite interplay between environmental metal flux, bacterial pathogenic output, and host immunological defense. We synthesize empirical evidence from the C. elegans model to highlight how heavy metals modulate bacterial virulence and host defense mechanisms, thereby providing new insights into the indirect health risks of environmental pollutants and their implications for redefining public health exposure thresholds and infectious disease control in the Anthropocene. Full article

(This article belongs to the Section Bacterial Pathogens)

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17 pages, 5935 KB

Open AccessArticle

Antiviral Activity of Pyrazolopyrimidine and Triazolopyrimidine Derivatives Against SARS-CoV-2 In Vitro: Identifying PZP25 as a Promising Scaffold

by Saiqa Sardar, Jessica S. C. C. Martins, Thiago C. Sousa, Andreon S. M. Silva, Marcelo A. Pinto, Flávia F. Silveira, Thais B. Silva, Rodolfo R. F. França, Luiz C. S. Pinheiro, Nubia Boechat, Marilda M. Siqueira, Aline R. Matos and Leonardo J. M. Carvalho

Pathogens 2026, 15(3), 324; https://doi.org/10.3390/pathogens15030324 - 18 Mar 2026

Cited by 1 | Viewed by 761

Abstract

Prior molecular docking and dynamics studies indicated a pyrazolopyridine–sulfonamide derivative (L87/PPS2, or simply PPS2) as a potential interactant with SARS-CoV-2 protein targets. The in vitro anti-SARS-CoV-2 activity and cytotoxicity profile of PPS2 were screened alongside a series of pyrazolopyrimidine (PZP) and triazolopyrimidine (TZP) [...] Read more.

Prior molecular docking and dynamics studies indicated a pyrazolopyridine–sulfonamide derivative (L87/PPS2, or simply PPS2) as a potential interactant with SARS-CoV-2 protein targets. The in vitro anti-SARS-CoV-2 activity and cytotoxicity profile of PPS2 were screened alongside a series of pyrazolopyrimidine (PZP) and triazolopyrimidine (TZP) derivatives. PPS2 demonstrated only partial inhibition of SARS-CoV-2 growth in Vero E6 cells at 100 µM. Crucially, however, four out of five PZPs and eight out of fourteen TZPs exhibited potent in vitro inhibitory activity against SARS-CoV-2 at 100 µM, with none of the tested compounds displaying cytotoxicity against Vero E6 cells at this concentration. Further characterization of one compound, PZP25, revealed an inhibitory concentration (IC50) of 8.2 µM, combined with low cytotoxicity (CC50 > 800 µM), yielding a selectivity index greater than 100. Time of addition assays indicated that PZP25’s antiviral effects were most pronounced when administered post-infection. While cellular pre-treatment provided a partial reduction in virus growth, modest virucidal activity was also observed at warmer temperatures (20 °C and 37 °C). Collectively, our findings demonstrate that PZP and TZP derivatives possess potent inhibitory activity of SARS-CoV-2 replication in vitro and highlight such compounds as promising chemical scaffolds for the development of novel antiviral agents targeting coronaviruses. Full article

(This article belongs to the Special Issue Advances in Virus-Host Interactions, Viral Pathogenicity and Antiviral Drug Development)

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18 pages, 2867 KB

Open AccessArticle

Evaluation of a Commercial Ozonated Olive Oil Product (800 mEq O₂/Kg) Against Methicillin-Resistant Staphylococcus pseudintermedius (MRSP) Using an Ex Vivo Canine Skin Model

by Hilke Oltmanns, Aimara Bello Suarez-Kupka, Christina Puff, Jessica Meißner and Andrea Vanessa Volk

Pathogens 2026, 15(3), 323; https://doi.org/10.3390/pathogens15030323 - 18 Mar 2026

Viewed by 747

Abstract

Background: Methicillin-resistant Staphylococcus pseudintermedius (MRSP) represents an emerging challenge in veterinary dermatology. Commercially available ozonated oils promise antibacterial activity, but their efficacy under physiologically relevant conditions remains unexplored. Objective: We aimed to evaluate the efficacy of commercial ozonated olive oil product (800 mEq [...] Read more.

Background: Methicillin-resistant Staphylococcus pseudintermedius (MRSP) represents an emerging challenge in veterinary dermatology. Commercially available ozonated oils promise antibacterial activity, but their efficacy under physiologically relevant conditions remains unexplored. Objective: We aimed to evaluate the efficacy of commercial ozonated olive oil product (800 mEq O₂/kg) against MRSP using an established in vitro model and a newly presented ex vivo canine skin model. Materials and Methods: In vitro susceptibility testing determined minimum inhibitory concentrations (MIC) and time–kill kinetics. Subsequently, canine skin samples were mounted in Franz diffusion cells, inoculated with MRSP (~10⁶ colony-forming units [CFU]), and treated for 8 h with ozonated or placebo olive oil. Bacterial viability was assessed by quantitative culture and histopathology. Results: In vitro testing demonstrated antibacterial activity for ozonated oil (MIC < 20% v/v) compared to placebo oil (90% v/v), with ozonation-specific bactericidal effects. However, ex vivo testing showed no MRSP reduction for either oil versus untreated controls, with bacterial localization in superficial dermis unchanged. Conclusions: Despite in vitro activity, this ozonated olive oil failed to reduce MRSP in ex vivo skin, revealing that tissue barriers prevent antibacterial delivery. These findings demonstrate that in vitro screening cannot predict topical efficacy and emphasize the necessity of tissue-based validation before clinical use. Full article

(This article belongs to the Section Bacterial Pathogens)

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24 pages, 829 KB

Open AccessArticle

Assessment of the Microbiological Quality of Raw Milk Sold Through Vending Machines at the Farm Level in Switzerland

by Thomas Paravicini, Marc J. A. Stevens, Karen Barmettler, Nicole Cernela and Roger Stephan

Pathogens 2026, 15(3), 322; https://doi.org/10.3390/pathogens15030322 - 17 Mar 2026

Viewed by 1957

Abstract

The sale of raw milk via vending machines represents a well-established distribution model in many European countries, including Switzerland. As part of this study, data on the microbiological quality of raw milk sold via vending machines in Switzerland were collected. A total of [...] Read more.

The sale of raw milk via vending machines represents a well-established distribution model in many European countries, including Switzerland. As part of this study, data on the microbiological quality of raw milk sold via vending machines in Switzerland were collected. A total of 124 raw milk samples from 124 raw milk vending machines across Switzerland were analysed. In addition to standard hygiene parameters (TVC and E. coli), the scope of the investigation particularly included foodborne pathogens as well as methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase (ESBL)-producing Enterobacterales. Isolates were further characterised by whole-genome sequencing. Shiga toxin-producing Escherichia coli (STEC) were detected in 3.2%, Staphylococcus aureus was detected in 12.1%, Listeria monocytogenes was detected in 2.4%, Campylobacter spp. were detected in 1.6%, Yersinia enterocolitica was detected in 29.8%, and Salmonella spp. were detected in 0% of the samples. MRSA and ESBL-producing Enterobacterales were each detected in 0.8% of samples. The results highlight the potential risk of foodborne infections associated with the consumption of untreated raw milk, as well as hygiene deficiencies linked to several raw milk vending machines. Based on the generated data, the importance of the requested heat treatment of raw milk in Switzerland is clearly underscored. Furthermore, more precise and binding guidelines for self-monitoring and the management of raw milk vending machines appear necessary. Full article

(This article belongs to the Special Issue Dairy Cattle Health: Mastitis, Milk Quality, and Antimicrobial Resistance from a One Health Perspective)

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8 pages, 733 KB

Open AccessCase Report

A Fatal Case of Puumala Virus Infection with Pulmonary and Renal Syndrome in Moscow Region, Russia

by Ekaterina Blinova, Tamara Dzagurova, Galina Gopatsa, Natalya Pshenichnaya, Evgeny Morozkin and Vasiliy Akimkin

Pathogens 2026, 15(3), 321; https://doi.org/10.3390/pathogens15030321 - 17 Mar 2026

Viewed by 1229

Abstract

Hemorrhagic fever with renal syndrome (HFRS) is the most common zoonotic disease in Russia, with about a 98% abundance of Puumala virus in all HFRS cases. We report clinical manifestations and genomic characteristics of the Puumala virus strain that caused an unconventional course [...] Read more.

Hemorrhagic fever with renal syndrome (HFRS) is the most common zoonotic disease in Russia, with about a 98% abundance of Puumala virus in all HFRS cases. We report clinical manifestations and genomic characteristics of the Puumala virus strain that caused an unconventional course of HFRS with sudden death. The patient was admitted to the hospital on the third day from fever onset with hyperthermia, cough, shortness of breath, and severe weakness, and died 28 h after hospitalization despite intensive care. Further analyses of autopsy samples led to Puumala virus detection. The viral genome was sequenced, followed by phylogenetic and similarity plot analyses. The genomic sequences of three viral segments were identified as endemic for the Moscow region strain. Phylogenetic and similarity plot analysis revealed the reassortant origin of the strain via M segment exchange. This finding increases the explored molecular diversity of Puumala virus in the Central Federal District and underscores the need for heightened awareness of HFRS manifestations that deviate from regular clinical presentation. Full article

(This article belongs to the Section Viral Pathogens)

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17 pages, 943 KB

Open AccessArticle

Whole-Genome Sequencing and Phenotypic Drug Susceptibility Testing of Bedaquilin, Delamanid, Pretomanid, and Linezolid in Drug-Resistant Mycobacterium tuberculosis from a Single Institute in South Korea

by Hyun-Woo Choi, Yoo-Ree Kang, Eun-Soon Son, Kyungsik Choi, Myungsun Cho, Young Jin Kim, Seo A Lee, Jin Young Lee, Jee Hey Kim, Seon Joo Kang, Seung-Jung Kee, Jong Seok Lee and Hee Joo Lee

Pathogens 2026, 15(3), 320; https://doi.org/10.3390/pathogens15030320 - 16 Mar 2026

Cited by 1 | Viewed by 1426

Abstract

Multidrug-resistant tuberculosis is a major global health concern. Newer agents, including bedaquiline (BDQ), delamanid (DLM), pretomanid (PMD), and linezolid (LZD), are essential for treatment; however, the resistance mechanisms of these drugs remain poorly understood in South Korea. This study aimed to investigate correlations [...] Read more.

Multidrug-resistant tuberculosis is a major global health concern. Newer agents, including bedaquiline (BDQ), delamanid (DLM), pretomanid (PMD), and linezolid (LZD), are essential for treatment; however, the resistance mechanisms of these drugs remain poorly understood in South Korea. This study aimed to investigate correlations between phenotypic and genotypic resistance to these drugs using 49 clinical Mycobacterium tuberculosis isolates collected in South Korea between 2017 and 2022. The minimum inhibitory concentrations were determined using the 7H9 broth microdilution method, and whole-genome sequencing (WGS) results were compared with the May 2024 World Health Organization (WHO) mutation catalogue. Phenotypic drug susceptibility testing (pDST) revealed elevated MICs to BDQ in 12 isolates (24.5%), DLM in nine (18.4%), and PMD and LZD in two each (4.1%). No Group 1 or 2 resistance-associated mutations were detected in BDQ-, PMD-, or LZD-elevated-MIC isolates. A Group 2 mutation (fbiC_LoF) was observed in one DLM-elevated-MIC isolate, whereas fbiC_p.Ala855fs (WHO Group 2) mutations occurred in four susceptible isolates. These findings suggest resistance mechanisms beyond the current WHO catalog. Discrepancies between pDST and WGS highlight the need for integrated diagnostics and reinforce the importance of ongoing surveillance and refinement of mutation classification systems to improve genotypic resistance prediction. Full article

(This article belongs to the Section Bacterial Pathogens)

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17 pages, 3401 KB

Open AccessReview

Host Immune Response Mechanisms Against Herpes Simplex Virus Type 2 Infection

by Yongming Mei, Hong Teng and Jianbin Wang

Pathogens 2026, 15(3), 319; https://doi.org/10.3390/pathogens15030319 - 16 Mar 2026

Viewed by 2762

Abstract

Herpes simplex virus type 2 (HSV-2) is the primary pathogen responsible for genital herpes. Predominantly transmitted via sexual contact, HSV-2 not only poses significant physical and psychological burdens on infected individuals but also substantially elevates the risk of HIV acquisition and represents a [...] Read more.

Herpes simplex virus type 2 (HSV-2) is the primary pathogen responsible for genital herpes. Predominantly transmitted via sexual contact, HSV-2 not only poses significant physical and psychological burdens on infected individuals but also substantially elevates the risk of HIV acquisition and represents a potentially fatal threat to newborns. Following primary infection, HSV-2 establishes lifelong latent infection within the sacral ganglia. Currently, there are no vaccines or therapeutics capable of eradicating this latent virus reservoir or effectively preventing initial infection. The core impediment to developing such interventions lies in the incomplete elucidation of the protective immune mechanisms against HSV-2 and its precise molecular pathogenesis. The host immune response against HSV-2 hinges critically on the coordinated interplay between innate and adaptive immunity. The innate immune system, serving as the first line of defense, acts to curtail early viral replication and initiate adaptive responses. This is achieved through mechanisms, including the genital mucosal barrier, activation of Toll-like receptors (TLRs), the cGAS-STING signaling pathway, interferon (IFN)-mediated antiviral effector functions, and activation of innate immune cells such as natural killer (NK) cells and dendritic cells (DCs). Crucially, however, HSV-2 counteracts these host defenses by expressing immune modulatory proteins (e.g., ICP0, ICP27, ICP35) that target key host antiviral signaling pathways, thereby affecting immune evasion. Within the adaptive immune response, neutralizing antibodies generated by the humoral immunity can provide localized protection at mucosal sites, but their protective efficacy is limited due to sophisticated viral immune evasion mechanisms. Cellular immunity, particularly mediated by CD4+ T cells, constitutes the core mechanism for viral clearance and suppression of recurrent outbreaks. Notably, tissue-resident memory T cells (TRMs) play a pivotal role in controlling the reactivation of latent HSV-2 within the ganglia. This review integrates current research advances to delineate the innate and adaptive immune mechanisms engaged during HSV-2 infection from the perspective of the dynamic host–virus interplay, with an ultimate aim to provide a theoretical foundation informing the rational development of preventive vaccines and therapeutic agents against HSV-2. Full article

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23 pages, 3032 KB

Open AccessArticle

A Compact Closed Genome of Orientia tsutsugamushi from Hainan Island, China Provides a TA763_A Reference and Reveals Repeat-Driven Remodeling

by Yi Niu, Yijia Guo, Zhao Xu, Siqi Chen, Liyuan Zhang, Xiuji Cui, Dachuan Lin, Kwok-Yung Yuen, Jasper Fuk-Woo Chan, Chuanning Tang and Feifei Yin

Pathogens 2026, 15(3), 318; https://doi.org/10.3390/pathogens15030318 - 16 Mar 2026

Cited by 1 | Viewed by 1267

Abstract

Scrub typhus, caused by the obligate intracellular bacterium Orientia tsutsugamushi (O. tsutsugamushi), remains a major public-health concern in the Asia–Pacific region. Genome-wide inference is complicated by extensive repetitive DNA and frequent genome rearrangement. We isolated O. tsutsugamushi HMU_001 from a scrub [...] Read more.

Scrub typhus, caused by the obligate intracellular bacterium Orientia tsutsugamushi (O. tsutsugamushi), remains a major public-health concern in the Asia–Pacific region. Genome-wide inference is complicated by extensive repetitive DNA and frequent genome rearrangement. We isolated O. tsutsugamushi HMU_001 from a scrub typhus patient on Hainan Island, China. Intracellular morphology was examined and replication was quantified in endothelial cells. Using long-read sequencing with short-read polishing, we generated a closed circular genome and performed standardized comparative analyses across all available complete O. tsutsugamushi genomes. HMU_001 assembled as a 1,895,724 bp genome and, among the 17 complete genomes analyzed in this study, represented the most compact genome. Repeats comprised 873,550 bp (46.08%) and included 72 RAGE loci (4 relatively complete) and 283 insertion sequences (54 intact). Repeat content varied widely and largely explained genome size differences. A core-gene phylogeny resolved four clades with partial geographic structure, while tsa56 genotypes were only partly congruent with it. Genome synteny was generally limited across strains but markedly higher among the closest relatives, consistent with ongoing rearrangement. HMU_001 expands representation of complete O. tsutsugamushi genomes by adding a TA763_A lineage strain from a high-incidence island setting. Comparative analyses support a model in which repeat proliferation and decay drive genome evolution and structural remodeling. Full article

(This article belongs to the Special Issue New Insights into Rickettsia and Related Organisms)

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15 pages, 2887 KB

Open AccessArticle

Survey of Antimicrobial-Resistant Bacteria Isolated from Rivers in Japan, Indonesia and Nepal

by Kayo Osawa, Ryohei Nomoto, Takashi Suzuki, Taishi Maeda, Ganesh Rai, Shouhiro Kinoshita, Noriko Nakanishi, Dadik Raharjo, Masanori Kameoka, Masato Fujisawa, Shiba Kumar Rai, Kuntaman Kuntaman and Toshiro Shirakawa

Pathogens 2026, 15(3), 317; https://doi.org/10.3390/pathogens15030317 - 15 Mar 2026

Viewed by 1147

Abstract

The threat of antimicrobial resistance in aquatic environments, particularly riverine systems, is escalating, in part due to effluents discharged from healthcare facilities. This issue has been recognized not only in Japan but also in other Asian countries such as Indonesia and Nepal. Nevertheless, [...] Read more.

The threat of antimicrobial resistance in aquatic environments, particularly riverine systems, is escalating, in part due to effluents discharged from healthcare facilities. This issue has been recognized not only in Japan but also in other Asian countries such as Indonesia and Nepal. Nevertheless, existing research remains limited, prompting an investigation into the prevalence of antimicrobial-resistant bacteria in the upstream and downstream sites of environmental rivers. In 2024, six samples were collected from three rivers in Hyogo Prefecture, Japan; five samples from five river sites in Indonesia; and three samples from downstream sites of rivers in Kathmandu, Nepal. These samples were subjected to selective culture–based Next Generation Sequencing and resistome analyses, based exclusively on the selective culture of bacteria propagated on CHROMagar ESBL plates. In Japan and Indonesia, Pseudomonas, Stenotrophomonas and Acinetobacter were frequently detected, whereas Klebsiella was overwhelmingly predominant in Nepal. Significant differences in the similarity of bacterial community composition among sampling sites across the three countries were observed (p < 0.001). Notably, Nepal exhibited the highest abundance level of antimicrobial resistance genes among the three countries, largely consisting of β-lactam resistance genes. In conclusion, these analyses elucidated substantial differences in bacterial community composition and degrees of environmental contamination. Full article

(This article belongs to the Special Issue New Insights into Antibiotic-Resistant Pathogens Within the One Health Framework: Epidemiology, Mechanisms and Strategies for Eradication)

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13 pages, 251 KB

Open AccessArticle

Different Trends of Immune Activation Markers When Switching to Either Oral or Injectable Dual Antiretroviral Therapy Based on Integrase Inhibitors in People Living with HIV

by Matteo Vassallo, Jacques Durant, Roxane Fabre, Jacqueline Capeau, Soraya Fellahi, Jean-Philippe Bastard, Pierre Corbeau and Christian Pradier

Pathogens 2026, 15(3), 316; https://doi.org/10.3390/pathogens15030316 - 14 Mar 2026

Viewed by 1011

Abstract

Background: Despite improvements in life expectancy, people living with HIV (PWH) continue displaying immune activation and high rates of comorbid conditions. No comparative studies concerning activation markers exist between simplification strategies to either oral or long-acting (LA) dual ART. Methods: We prospectively collected [...] Read more.

Background: Despite improvements in life expectancy, people living with HIV (PWH) continue displaying immune activation and high rates of comorbid conditions. No comparative studies concerning activation markers exist between simplification strategies to either oral or long-acting (LA) dual ART. Methods: We prospectively collected plasma samples from PWH on successful ART, simplifying treatment from triple oral to either oral or LA dual ART based on integrase inhibitors. We measured changes in soluble CD14 (sCD14), soluble CD163 (sCD163), monocyte chemoattractant protein-1, and interleukin-6. Background measurements and markers of microbial translocation and gut integrity (I-FABP, LBP) were also collected. Results: From 2019 to 2023, 38 PWH were analyzed (mean age 52, 87% male, 21 years HIV diagnosis, CD4 730 cells/mm³, nadir CD4 317 cells/mm³, AIDS 13%). After 7.2 months, sCD14 trajectories differed according to regimen (+0.43 ng/mL, p = 0.033 for LA ART, −0.62 ng/mL, p < 0.001 for oral ART) but were not related to I-FABP or to LBP values. In case of CD4 nadir < 200 cc/mm³, AIDS, or very-low-level viremia, sCD163 values significantly increased when switching to oral but not to LA dual ART. Conclusion: We found different trends in immune activation markers and risk factors associated with PWH switching to either oral or LA ART, requiring larger studies. Full article

20 pages, 4104 KB

Open AccessArticle

Design and Characterization of an HRC-Derived Peptide Inhibitor of Canine Coronavirus Spike-Mediated Fusion

by Valentina Iovane, Rosa Giugliano, Antonio Gentile, Roberta Della Marca, Laura Di Clemente, Annalisa Chianese, Serena Montagnaro, Anna De Filippis, Massimiliano Galdiero and Carla Zannella

Pathogens 2026, 15(3), 315; https://doi.org/10.3390/pathogens15030315 - 14 Mar 2026

Cited by 1 | Viewed by 997

Abstract

Canine coronavirus (CCoV), an alphacoronavirus belonging to the Coronaviridae family, is primarily associated with enteric infections in dogs. The ongoing evolution of coronaviruses through genetic recombination and mutation leads to the emergence of novel strains with increased pathogenicity, thereby raising the risk of [...] Read more.

Canine coronavirus (CCoV), an alphacoronavirus belonging to the Coronaviridae family, is primarily associated with enteric infections in dogs. The ongoing evolution of coronaviruses through genetic recombination and mutation leads to the emergence of novel strains with increased pathogenicity, thereby raising the risk of cross-species transmission and spillover events. In this context, viral entry inhibitors represent a promising strategy, as they can serve as pivotal tools to prevent initial infection and subsequent viral replication. The S2 subunit of the spike (S) glycoprotein contains two heptad repeat regions (HRN and HRC), which play essential roles in the conformational changes required for viral fusion. In this study, we describe the design, synthesis, and functional evaluation of a peptide derived from the HRC domain of the CCoV S glycoprotein. First, we assessed the cytotoxicity of the CCoV-HRC peptide in two cell lines, HE293T and A72, and determined CC₅₀ values > 100 μM. At non-toxic concentrations, the peptide effectively blocked membrane fusion mediated by the CCoV S glycoprotein and significantly reduced viral infection, as demonstrated both in cell–cell fusion assays and in live virus experiments. These findings were supported by in silico docking and molecular dynamics simulations, which provided structural insight into the interaction between CCoV-HRC and the S fusion core. Then, molecular analyses were conducted to evaluate the expression of the gene encoding the viral S protein, confirming the antiviral potential of CCoV-HRC peptide. Overall, these findings provide a solid foundation for the development of peptide-based therapeutics to treat or prevent CCoV infections. Full article

(This article belongs to the Special Issue Current Challenges in Veterinary Virology)

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Open AccessArticle

Pyogenic Spondylitis with Epidural Abscess Caused by Streptococcus suis Serotype 2 ST7: Tissue mNGS Confirmation and Whole-Genome Characterization of a Human Isolate

by Peiyan He, Henghui Wang, Ping Li, Yong Yan, Lei Gao and Lu Chen

Pathogens 2026, 15(3), 314; https://doi.org/10.3390/pathogens15030314 - 13 Mar 2026

Viewed by 784

Abstract

Streptococcus suis is an emerging zoonotic pathogen that typically causes bacteremia or meningitis in humans, whereas vertebral osteomyelitis with epidural abscess is exceedingly rare and may be missed. We describe a 65-year-old farmer with fever and severe low back pain after long-term bare-handed [...] Read more.

Streptococcus suis is an emerging zoonotic pathogen that typically causes bacteremia or meningitis in humans, whereas vertebral osteomyelitis with epidural abscess is exceedingly rare and may be missed. We describe a 65-year-old farmer with fever and severe low back pain after long-term bare-handed handling of raw pig lungs. Pre-treatment blood cultures yielded S. suis identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). After transient improvement on empirical therapy, fever recurred with worsening lumbar pain. Contrast-enhanced magnetic resonance imaging (MRI) demonstrated multilevel thoracolumbar pyogenic spondylitis with an epidural abscess and a sub-ligamentous abscess beneath the posterior longitudinal ligament (PLL) extending from L2 to L5. Computed tomography-guided lumbar biopsy followed by tissue metagenomic next-generation sequencing (mNGS) detected S. suis, providing concordant evidence supporting pathogen involvement at the vertebral focus. The bloodstream isolate (SS-JX2025-01) was serotype 2, sequence type 7 (ST7). It remained susceptible to β-lactams and glycopeptides but was resistant to macrolide–lincosamide and tetracycline classes, consistent with erm(B), tet(O), tet(40), and ant(6)-Ia detected by whole-genome sequencing (WGS). Virulence profiling revealed an epf⁺/sly⁺/mrp⁻ pattern with multiple adhesins and immune-evasion factors, whereas canonical 89K pathogenicity island markers were absent. Core-genome phylogeny placed SS-JX2025-01 within the Chinese ST7 lineage associated with previous outbreaks. This biopsy-supported case expands the clinical spectrum of invasive S. suis infection, highlights the value of tissue mNGS as an adjunct for supporting deep-seated foci in zoonotic infections, and underscores the importance of occupational prevention in small-scale farming households. Full article

(This article belongs to the Section Bacterial Pathogens)

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Pathogens, Volume 15, Issue 3 (March 2026) – 104 articles

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