Pathogens

12 pages, 881 KB

Open AccessArticle

Persistence and Transmission Dynamics of Babesia ovis After Imidocarb Dipropionate Treatment: Evaluation via Blood Transfusion and Tick Infestation

by Recep Firat, Mehmet Can Ulucesme, Arda Eyvaz, Mehmet Alatas, Munir Aktas, Onur Ceylan, Ferda Sevinc and Sezayi Ozubek

Pathogens 2026, 15(1), 7; https://doi.org/10.3390/pathogens15010007 (registering DOI) - 20 Dec 2025

Abstract

Babesia ovis is a significant tick-borne parasite of sheep, capable of causing both acute disease and long-lasting, low-grade infections. Imidocarb dipropionate (IMDP) is commonly used against babesiosis, yet whether it can completely eliminate B. ovis remains uncertain. In this study, we examined whether [...] Read more.

Babesia ovis is a significant tick-borne parasite of sheep, capable of causing both acute disease and long-lasting, low-grade infections. Imidocarb dipropionate (IMDP) is commonly used against babesiosis, yet whether it can completely eliminate B. ovis remains uncertain. In this study, we examined whether the parasite persists after treatment and whether such residual infections can still be transmitted. Three sheep were experimentally infected, treated with IMDP once clinical signs appeared, and then monitored for 180 days by microscopy, nested PCR, and iELISA. Fever and microscopic parasitemia resolved soon after treatment, but nPCR intermittently detected parasite DNA for several weeks. By day 180, all treated sheep were negative by nPCR and microscopy, while two still showed detectable antibodies. Blood collected at this time was transfused into naïve sheep. Two of the three recipients showed nPCR positivity at scattered time points and later seroconverted while showing no clinical signs. In contrast, Rhipicephalus bursa ticks that fed on the treated donors neither acquired the parasite nor transmitted it to recipients, likely because post-treatment parasitemia remained below the acquisition threshold. Overall, these results indicate that IMDP controls clinical disease but may not fully clear B. ovis, allowing silent transmission through blood despite negative routine tests. Full article

(This article belongs to the Topic Ticks and Tick-Borne Pathogens: 2nd Edition)

► Show Figures

Figure 1

29 pages, 1427 KB

Open AccessReview

Influenza A Virus H5N1 Subtype: Resurgent Interspecies and Intercontinental Transmission, and a New Host

by Matloob Husain

Pathogens 2026, 15(1), 6; https://doi.org/10.3390/pathogens15010006 (registering DOI) - 20 Dec 2025

Abstract

It has been more than 25 years since the avian influenza A virus (IAV) H5N1 subtype emerged in humans in 1997. Since then, this virus has become endemic in poultry and wild birds and has been causing sporadic infections in humans. Furthermore, the [...] Read more.

It has been more than 25 years since the avian influenza A virus (IAV) H5N1 subtype emerged in humans in 1997. Since then, this virus has become endemic in poultry and wild birds and has been causing sporadic infections in humans. Furthermore, the H5N1 subtype has undergone numerous reassortment events with other avian IAVs, resulting in the emergence of various H5Nx subtypes. Furthermore, the original H5 hemagglutinin (HA) has evolved genetically and antigenically and diversified into multiple lineages, phylogenetic clades, and subclades. In 2020, clade 2.3.4.4b H5N1 emerged in Europe and spread intercontinentally. Lately, H5N1 has exhibited a resurgence in transmission across the continents in different avian and mammalian species. Importantly, to the surprise of influenza virologists, H5N1 has recently been found to infect a new host, the cow, and has been detected in cow milk. Furthermore, spillover infections of H5N1 have also been detected in dairy farm workers. This review summarizes the recent transmission of clade 2.3.4.4b H5N1 across the globe and its pathogenesis and adaptation in different hosts. Also, this review discusses the susceptibility of the H5N1 subtype to anti-IAV drugs and vaccines and the public health response and measures that are undertaken and can be taken in the future to contain its further spread. Full article

(This article belongs to the Section Viral Pathogens)

16 pages, 1370 KB

Open AccessArticle

Peptide MegaPools Approach to Evaluate the Dengue-Specific CD4 and CD8 T-Cell Response

by Marta Tiberi, Linda Petrone, Andrea Salmi, Valentina Vanini, Gilda Cuzzi, Alessandra D’Abramo, Patrizia De Marco, Alba Grifoni, Daniela Weiskopf, Alessandro Sette, Emanuele Nicastri and Delia Goletti

Pathogens 2026, 15(1), 5; https://doi.org/10.3390/pathogens15010005 (registering DOI) - 20 Dec 2025

Abstract

Background: Being central players in the adaptive immunity, the study of T-cell responses is crucial in both natural infections and vaccine-induced immunity. In this study, we assessed the antigen-specific T-cell responses to dengue virus (DENV) to identify the most immunogenic antigen for evaluating [...] Read more.

Background: Being central players in the adaptive immunity, the study of T-cell responses is crucial in both natural infections and vaccine-induced immunity. In this study, we assessed the antigen-specific T-cell responses to dengue virus (DENV) to identify the most immunogenic antigen for evaluating dengue-specific T-cell responses. Methods: Patients with dengue disease and subjects vaccinated with the QDENGA (TAK-003) vaccine (before and three months after vaccination) were enrolled. The T-cell-specific response was measured by ELISPOT and Activation Induced Markers (AIM) assay following PBMC stimulation either with DENV1-4 CD4 and CD8 MegaPools (MP) or serotype-specific DENV peptide pools at different concentrations. Results: We found that both DENV1-4 CD4 MP (at 1 µg/mL) and CD8 MP (at 5 µg/mL), which encompass all four DENV serotypes, elicited specific T-cell responses in patients with dengue infection independent of the infecting serotype. In contrast, selected serotype-specific DENV peptide pools have a lower ability to induce a measurable T-cell response. Moreover, DENV1-4 CD4 and CD8 MPs, at the highest concentrations, are suitable candidates to evaluate the dengue-specific T-cell response in vaccinated subjects. Conclusions: These findings support the use of the MP approach to investigate dengue-specific T-cell response to monitor the response during the infection and after vaccine administration. Full article

(This article belongs to the Special Issue Arboviruses Infections and Pathogenesis)

► Show Figures

Figure 1

11 pages, 246 KB

Open AccessArticle

Geohelminthiasis and Malaria Co-Infection in Pregnant Women in Kinshasa: Case of Lisungi and Lukunga Hospitals in Democratic Republic of the Congo

by Clarisse Dianzenza, Japhet Kabalu Tshiongo, Lise Kuseke, Francine Muswele, Gustave Kasereka, Daddy Mangungulu, Eddy Kakiese Laken, Vivi Maketa Tevuzula, Kassoum Kayentao and Hypolite Muhindo Mavoko

Pathogens 2026, 15(1), 4; https://doi.org/10.3390/pathogens15010004 (registering DOI) - 20 Dec 2025

Abstract

Background: Geohelminthiasis and malaria are major public health problems in Kinshasa. Pregnant women are particularly vulnerable to these conditions due to their weakened immunity, with severe complications such as maternal anemia and low birth weight. This study assessed the prevalence and associated factors [...] Read more.

Background: Geohelminthiasis and malaria are major public health problems in Kinshasa. Pregnant women are particularly vulnerable to these conditions due to their weakened immunity, with severe complications such as maternal anemia and low birth weight. This study assessed the prevalence and associated factors of geohelminth–malaria co-infection. Methods: A cross-sectional study was conducted in two hospitals in Kinshasa, Democratic Republic of the Congo, which included 336 pregnant women. The lab analyses included thick smears for malaria, stool examinations for geohelminths, and hemoglobin measurements. Multivariate logistic regression was used to identify associated variables, with a significance level set at p < 0.05. Results: Geohelminth–malaria co-infection was observed in 5.7% of pregnant women, while the prevalence of geohelminthiasis alone was 7.7%. Ascaris lumbricoides was the most frequent parasite (6.3%), followed by Trichuris trichiura (1.5%) and Ancylostoma duodenale (0.3%). The third trimester was associated with a significantly increased risk of co-infection and geohelminthiasis (ORa = 5.8; 95% CI: 1.36–9.23; p = 0.0077). No significant association was found between co-infection and maternal anemia. Conclusions: Although co-infection prevalence was low in Kinshasa, the third trimester is a risk period. Systematic screening and integrated management during pregnancy are recommended. Full article

(This article belongs to the Special Issue Parasitic Helminths and Control Strategies)

12 pages, 860 KB

Open AccessArticle

Autonomic Dysfunction in Patients with Acute Infection with Coxiella burnetii

by Branislav Milovanović, Nikola Marković, Elizabeta Ristanović, Sonja Atanasievska Kujović, Nikoleta Đorđevski, Masa Petrovic, Milica Milošević, Sulin Bulatovic and Milovan Bojić

Pathogens 2026, 15(1), 3; https://doi.org/10.3390/pathogens15010003 - 19 Dec 2025

Abstract

Background: Coxiella burnetii is a common zoonotic pathogen that can lead not only to acute or chronic Q fever but also to post-infectious syndromes, where autonomic nervous system (ANS) dysfunction has been suggested as a contributing mechanism. This study aimed to assess [...] Read more.

Background: Coxiella burnetii is a common zoonotic pathogen that can lead not only to acute or chronic Q fever but also to post-infectious syndromes, where autonomic nervous system (ANS) dysfunction has been suggested as a contributing mechanism. This study aimed to assess autonomic function in patients presenting with polymorphic symptoms, dysautonomia, or ME/CFS who had serological evidence of acute infection with Coxiella burnetii. Methods: A total of 156 participants were evaluated, including 100 seropositive patients and 56 matched controls. All subjects underwent standardized cardiovascular reflex tests (CART), beat-to-beat analysis of heart rate and blood pressure with baroreflex indices, 24 h Holter ECG with HRV assessment, and, in the Coxiella group, head-up tilt testing (HUTT). Results: A significantly higher prevalence of autonomic dysfunction was observed in the Coxiella group, predominantly affecting parasympathetic regulation, with abnormal CART scores, reduced LF power and baroreflex effectiveness, and a high rate of positive HUTT findings characterized by extreme blood pressure variability. Although long-term HRV measures did not differ significantly between groups, short-term indices consistently indicated ANS impairment. Conclusions: These findings suggest that Coxiella burnetii infection may trigger persistent autonomic dysfunction, potentially contributing to the development of ME/CFS and syncope in affected individuals. Further longitudinal studies are needed to clarify pathophysiological mechanisms and clinical implications. Full article

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

► Show Figures

Figure 1

14 pages, 1065 KB

Open AccessArticle

Babesia and Bartonella Species DNA in Blood and Enrichment Blood Cultures from People with Chronic Fatigue and Concurrent Neurological Symptoms

by Edward B. Breitschwerdt, Ricardo G. Maggi, Janice C. Bush and Emily Kingston

Pathogens 2026, 15(1), 2; https://doi.org/10.3390/pathogens15010002 - 19 Dec 2025

Abstract

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a medical condition characterized by extreme fatigue lasting at least 6 months. Based upon case reports, patients infected with Babesia or Bartonella spp. have reported a history of chronic fatigue and concurrent neurological symptoms. In this study, [...] Read more.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a medical condition characterized by extreme fatigue lasting at least 6 months. Based upon case reports, patients infected with Babesia or Bartonella spp. have reported a history of chronic fatigue and concurrent neurological symptoms. In this study, 50 study participants reporting fatigue lasting from six months to 19 years and one or more neurological symptoms were selected. PCR assays were used to amplify Babesia and Bartonella spp. DNA from blood and enrichment blood cultures. Using targeted qPCR amplification and DNA sequencing, infection with Babesia spp., Bartonella spp. or both genera was confirmed in 10, 11, and 2 individuals, respectively. Of 50 participants, 12 (24%, 95% CI: 12–36%) were infected with a Babesia species, while Bartonella species infection was documented in 13/50 individuals (26%, 95% CI: 13.8–38.2%). This study provides documentation supporting a potential role for Babesia and Bartonella infection in patients with presentations consistent with ME/CFS. Prospective case–control studies, using highly sensitive direct pathogen detection techniques, are needed to determine whether or the extent to which infection with members of these two genera contributes to or causes ME/CFS. Full article

(This article belongs to the Special Issue Zoonotic Vector-Borne Infectious Diseases: The One Health Perspective)

► Show Figures

Figure 1

15 pages, 254 KB

Open AccessArticle

Successful Brachyspira hyodysenteriae Eradication Through a Combined Approach of a Zinc Chelate Treatment and Adapted Management Measures

by Frédéric A. C. J. Vangroenweghe

Pathogens 2026, 15(1), 1; https://doi.org/10.3390/pathogens15010001 - 19 Dec 2025

Abstract

Brachyspira hyodysenteriae is the primary cause of swine dysentery, characterized by bloody to mucoid diarrhea due to mucohaemorhagic colitis in pigs. The disease primarily affects pigs during the growth and finishing stage. The control and prevention of B. hyodysenteriae consists of the administration [...] Read more.

Brachyspira hyodysenteriae is the primary cause of swine dysentery, characterized by bloody to mucoid diarrhea due to mucohaemorhagic colitis in pigs. The disease primarily affects pigs during the growth and finishing stage. The control and prevention of B. hyodysenteriae consists of the administration of antimicrobial drugs, in addition to management and adapted feeding strategies. A worldwide re-emergence of the disease has recently been reported with an increasing number of isolates demonstrating decreased susceptibility to several crucially important antimicrobials in the control of swine dysentery. This compromises the possibilities to eradicate B. hyodysenteriae from infected pig farms. A novel non-antibiotic zinc chelate has been reported to demonstrate positive effects on fecal quality and consistency, general clinical signs, average daily weight gain, and B. hyodysenteriae excretion during and after a 6-day oral treatment. The objective of the present study was to evaluate the zinc chelate (IntraDysovinol^® 499 mg/mL; IntraCare) within an eradication schedule with naturally occurring swine dysentery due to B. hyodysenteriae resistant to pleuromutilins under field conditions in Belgium. We evaluated a 14-day treatment schedule combined with alternative management measures (including partial depopulation of post-weaning facilities and improved external and internal biosecurity measures) and thorough cleaning and disinfection (including 2% NaOH) of the buildings and the sows from day 7 of treatment onwards. This alternative approach for B. hyodysenteriae eradication was evaluated on 18 pig farms over a 5-year period. All enrolled eradication programs were evaluated as successful at least 6–9 months after the finalization of the protocol. In conclusion, the zinc chelate product has an excellent potential for application within an eradication protocol of B. hyodysenteriae that are diagnosed as resistant to pleuromutilins. The combined approach of zinc chelate treatment and alternative management measures is demonstrated to be successful in the eradication of farrow-to-wean, farrow-to-finish, and finishing pig farms under field conditions in Belgium. Full article

(This article belongs to the Special Issue Swine Infectious Diseases: Diagnostics, Pathogenesis, and Control Strategies)

24 pages, 4265 KB

Open AccessArticle

Prevalence and Intensity of Perkinsus sp. Infection in Mizuhopecten yessoensis and Its Impact on the Immune Status of Bivalves

by Elizaveta Tsoy, Ayna Tumas, Mariia Mokrina, Andrei Grinchenko, Vadim Kumeiko, Daria Lanskikh and Yulia Sokolnikova

Pathogens 2025, 14(12), 1303; https://doi.org/10.3390/pathogens14121303 - 18 Dec 2025

Abstract

Despite the economic importance of Mizuhopecten yessoensis, little is known about their parasites and immunity. This study, the first to examine the prevalence and intensity of Perkinsus across three age groups of scallops from four locations in the Sea of Japan, revealed [...] Read more.

Despite the economic importance of Mizuhopecten yessoensis, little is known about their parasites and immunity. This study, the first to examine the prevalence and intensity of Perkinsus across three age groups of scallops from four locations in the Sea of Japan, revealed that the gills, mantle, and digestive glands of one-year-old specimens from mariculture farms are heavily colonized. The cases of infection were notably higher in older specimens (mostly hemolymph and shell), suggesting that they act as carriers of Perkinsus. An immunological analysis indicated that when the pathogen is found only in the hemolymph and mantle, there is an increase in plasma protein concentrations, which likely plays a crucial role in resisting infection. However, when hypnospores were present in the mantle and gills, a decrease in reactive oxygen species and granulocytes occurred, accompanied by an increase in hemoblasts and agranulocytes. Phagocytic activity increased only when the pathogen appeared in the digestive gland. This evidence highlights the heightened vulnerability of young scallops, emphasizing the necessity for preventive measures against infection. The current troubling epidemiological situation regarding scallop diseases in the region suggests a rise in epizootics, raising doubts about the sustainability of the scallop farming industry unless timely interventions are implemented. Full article

(This article belongs to the Special Issue Aquatic Pathogens and Host Immune Responses)

► Show Figures

Figure 1

25 pages, 360 KB

Open AccessReview

Detection, Isolation, and Identification of Mycobacteria That Cause Nontuberculous Mycobacterial Disease and Tuberculosis

by Lyudmila Severova, Dmitrii Giller, Inga Enilenis, Patimat Gadzhieva, Galina Shcherbakova, Oleg Kesaev, Vadim Koroev, Olga Frolova, Anna Popova, Alexandr Ilyukhin, Valeria Basangova, Elena Belova, Elham Pahlevani Gazi, Irina Taushkanova and Ivan Martel

Pathogens 2025, 14(12), 1302; https://doi.org/10.3390/pathogens14121302 - 18 Dec 2025

Abstract

Pulmonary diseases caused by nontuberculous mycobacteria are increasingly becoming common worldwide and are occurring more frequently alongside pulmonary tuberculosis. Given that pulmonary diseases resulting from nontuberculous mycobacteria and pulmonary tuberculosis display similar features—such as clinical manifestations, imaging findings, and laboratory results—the accurate differentiation [...] Read more.

Pulmonary diseases caused by nontuberculous mycobacteria are increasingly becoming common worldwide and are occurring more frequently alongside pulmonary tuberculosis. Given that pulmonary diseases resulting from nontuberculous mycobacteria and pulmonary tuberculosis display similar features—such as clinical manifestations, imaging findings, and laboratory results—the accurate differentiation of each disease type is highly challenging. Mycobacterial culture, as a gold standard method, cannot be considered completely trustworthy because of low bacterioexcretion rates among nontuberculous mycobacterial pulmonary patients. Additional problems result from poor diagnosis. The treatment of lung diseases caused by nontuberculous mycobacteria is also difficult. This could be due to the wide spectrum of bacteria belonging to nontuberculous mycobacteria, as well as low bacterioexcretion. Therefore, bacterial sensitivity to drugs is insufficient. As a result, in this article, our intention is to explain the diagnostic difficulties of pulmonary diseases caused by nontuberculous mycobacteria and the Mycobacterium tuberculosis complex. The review seeks to outline promising directions for the development of novel diagnostic approaches in order to improve clinical decision-making and ultimately treatment outcomes. Full article

(This article belongs to the Special Issue Mycobacterial Infection: Pathogenesis and Drug Development)

21 pages, 282 KB

Open AccessArticle

Bacterial Contaminants in Ambulances from a Tertiary Care Hospital as Potential Threats to Patients and Medical Staff in Al-Qassim Region, Saudi Arabia—Effect of Decontamination

by Ahmed E. Taha, Ahmad R. Alharbi, Omar N. Alharbi, Alaaeldin M. Komila, Abdullah Almushawwah, Solaiman Aldeghaim, Ahmed N. Algefary, Majed Allahim, Khalid Alzaben and Faisal M. Alharbi

Pathogens 2025, 14(12), 1301; https://doi.org/10.3390/pathogens14121301 - 18 Dec 2025

Abstract

Bacterial contaminants in ambulances could have a major impact on morbidities, mortalities, and healthcare resources, especially if these bacteria are antimicrobial-resistant. As far as we know, this is the first study in Al-Qassim region to evaluate the prevalence of bacterial contaminants in swab [...] Read more.

Bacterial contaminants in ambulances could have a major impact on morbidities, mortalities, and healthcare resources, especially if these bacteria are antimicrobial-resistant. As far as we know, this is the first study in Al-Qassim region to evaluate the prevalence of bacterial contaminants in swab samples obtained from ambulances from Alqwarah General Hospital, Al-Qassim region, Saudi Arabia as an indicator for evaluation of the implemented infection control measures, and screen the antibiotics profiles of the isolates against the most regularly used antimicrobials. In total, 204 samples were collected from the ambulances following patient transport. To evaluate the effect of vehicle decontamination, 204 swabs were collected from the same sites of the ambulances immediately after cleaning and disinfection. The isolates were identified using standard bacteriological and biochemical methods, as recommended by the Clinical Laboratory Standard Institute (CLSI). The antibiotic susceptibility patterns were assessed using the Kirby–Bauer disc diffusion method. The prevalence of bacterial contamination in the samples collected following patient transport was 46.08%. In total, 83.33%, 75.00%, and 66.66% of the samples collected from DC shock apparatuses, ceilings, and emergency personnel seats, respectively, were contaminated. Furthermore, ceilings, DC shock apparatuses, emergency personnel seats, cervical collars, and monitors were found to harbor 10.8%, 9.8%, 7.8%, 6.8%, and 6.8% of the 102 bacterial isolates, respectively. Gram-positive organisms represented 96.1% of all bacterial isolates. Bacillus spp. was the most common isolate, accounting for 60.8% of all bacterial isolates. Although Pseudomonas aeruginosa and Proteus spp. isolates were sensitive to all the tested antimicrobials, many Gram-positive bacterial isolates were resistant to some antibiotics in variable frequencies. After 48 h of aerobic incubation (with or without 5–10% CO₂) on nutrient, blood, chocolate, and MacConkey agar plates at 37 °C, no bacterial growth was detected in the samples collected immediately following cleaning and disinfection. This is the second Saudi study to evaluate the prevalence of bacterial contaminants in Saudi Arabian ambulances, and it could help health policy makers in improving the implemented infection prevention and control measures in Saudi Arabian ambulances. The samples taken after patient transport revealed bacterial contaminants with varying rates of antimicrobial resistance. Policies ensuring the optimal cleaning and disinfection of ambulances can minimize the potential of bacterial infection for high-risk patients, their relatives, and healthcare providers. Full article

16 pages, 600 KB

Open AccessArticle

Ceftazidime-Avibactam Regimens for the Treatment of Bacteremic and Non-Bacteremic Episodes of Carbapenemase-Producing Enterobacterales Infections in Immunosuppressed Patients

by Fabián Herrera, Diego Torres, María Leone, Maximiliano Gabriel Castro, Jorge López Camelo, Elena Temporiti, Natalin Grippo, Silvia Relloso and Pablo Bonvehí

Pathogens 2025, 14(12), 1300; https://doi.org/10.3390/pathogens14121300 - 18 Dec 2025

Abstract

Ceftazidime-avibactam (CA) and CA plus aztreonam (ATM) are the preferred treatment options for KPC and MBL carbapenemase-producing Enterobacterales infections (CPEis). All episodes of monomicrobial CPEis in immunosuppressed patients (IPs) admitted from May 2019 to November 2024, who received definitive antibiotic therapy (AT) with [...] Read more.

Ceftazidime-avibactam (CA) and CA plus aztreonam (ATM) are the preferred treatment options for KPC and MBL carbapenemase-producing Enterobacterales infections (CPEis). All episodes of monomicrobial CPEis in immunosuppressed patients (IPs) admitted from May 2019 to November 2024, who received definitive antibiotic therapy (AT) with CA or CA + ATM for at least 72 h, were prospectively included. Bacteremic episodes (BEs) and non-bacteremic episodes (NBEs) were compared. Logistic regressions adjusted by propensity score were used to identify variables associated with 30-day overall mortality. In total, 82 CPEis were included (38 NBEs and 44 BEs). BEs more frequently occurred in hematological malignancies (52.3% vs. 15.8%, p = 0.0006), while NBEs were more commonly observed in solid organ transplantation (73.7% vs. 34.1%, p = 0.001). K. pneumoniae was the main isolated microorganism; KPC-CPE was the most common resistance mechanism in both groups, followed by MBL-CPE. The 7-day clinical response, 30-day overall and infection-related mortality between NBEs and BEs were 92.1% vs. 88.6%, p = 0.59, 10.5% vs. 27.3%, p = 0.09, and 2.6% vs. 13.6%, p = 0.11. Septic shock, OR 6.5, 95% CI, 1.58–26.72 (p = 0.01), and refractory malignancy, OR 5.6, 95% CI, 1.03–30.14 (p = 0.046), were associated with 30-day mortality, whereas BEs were not, OR 1.5, 95% CI, 0.36–6.2 (p = 0.56). CPEis in both NBE and BE IPs who received definitive AT with CA or CA + ATM correlated with a high rate of 7-day clinical response and low 30-day infection-related mortality. Underlying malignancy and disease severity were associated with 30-day overall mortality. Regional knowledge of bacterial antibiotic resistance enables the implementation of individualized AT to improve patient survival. Full article

(This article belongs to the Special Issue Emerging Infectious Diseases: A Perpetual Challenge)

► Show Figures

Figure 1

13 pages, 1100 KB

Open AccessArticle

Pentraxin 3 Levels Reflect Inflammatory and Parasitic Activity in Human Visceral Leishmaniasis

by Lucyo Flávio Bezerra Diniz, Milena Xavier Silva Barbosa, Samuel Ricarte de Aquino, Anderson da Costa Armstrong, Carlos Dornels Freire de Souza and Rodrigo Feliciano Carmo

Pathogens 2025, 14(12), 1299; https://doi.org/10.3390/pathogens14121299 - 18 Dec 2025

Abstract

Visceral leishmaniasis (VL) is a severe zoonotic disease characterized by high mortality and a pronounced systemic inflammatory response. Although Pentraxin 3 (PTX3) has been implicated in infectious and inflammatory disorders, its role in human VL remains poorly defined, and host-derived indicators that simultaneously [...] Read more.

Visceral leishmaniasis (VL) is a severe zoonotic disease characterized by high mortality and a pronounced systemic inflammatory response. Although Pentraxin 3 (PTX3) has been implicated in infectious and inflammatory disorders, its role in human VL remains poorly defined, and host-derived indicators that simultaneously reflect inflammatory and parasitic activity are limited. This study investigated the association between plasma PTX3 levels, parasite load, and PTX3 gene polymorphisms (rs1840680 and rs2305619) in patients with VL. An observational study was conducted between 2017 and 2021, including 36 patients with confirmed VL and 45 healthy controls matched by age and sex. Plasma PTX3 concentrations were determined by ELISA, parasite load by quantitative PCR (qPCR), and cytokines (IL-2, IL-6, IL-10, IL-17A, IFN-γ and TNF-α) by flow cytometry. PTX3 levels were significantly higher in VL patients than in controls (23.2 ng/mL vs. 0.80 ng/mL; p < 0.0001) and correlated positively with parasite load (r = 0.39; p = 0.02) and cytokines IL-6, IL-10 and IFN-γ. No associations were observed between PTX3 polymorphisms and disease susceptibility. These findings suggest that PTX3 reflects both inflammatory responses and parasitic burden in VL and may serve as a potential indicator of disease activity. Full article

(This article belongs to the Special Issue Diagnosis, Prevention, and Treatment of Leishmaniasis and Chagas Disease: Focus on Latin American Context)

► Show Figures

Figure 1

11 pages, 1172 KB

Open AccessArticle

Development of a Novel Sandwich ELISA Test for the Detection of Antibodies Against Rickettsia

by Marco Quevedo-Diaz, Semen Kaliukanov, Frantisek Csicsay, Diana Hopkova and Ludovit Skultety

Pathogens 2025, 14(12), 1298; https://doi.org/10.3390/pathogens14121298 - 18 Dec 2025

Abstract

Diagnosis of rickettsial infections is challenging due to nonspecific clinical symptoms and limitations of current diagnostic methods. Molecular assays allow early detection but are limited by cost and technical demands, whereas conventional serological tests often exhibit cross-reactivity and low sensitivity during the early [...] Read more.

Diagnosis of rickettsial infections is challenging due to nonspecific clinical symptoms and limitations of current diagnostic methods. Molecular assays allow early detection but are limited by cost and technical demands, whereas conventional serological tests often exhibit cross-reactivity and low sensitivity during the early stages of infection. This study aimed to develop and evaluate a recombinant-antigen sandwich ELISA for improved antibody detection against Rickettsia spp. Three Rickettsia akari proteins, rGroEL, rDnaK, and rA8GP63 (uncharacterized protein), were produced and validated for immunogenicity. The assay was evaluated using 94 patient serum samples, including those with positive, negative, and unknown clinical course. The optimized ELISA demonstrated high reproducibility, with IgG sensitivity of 89.47–95.39% and specificity of 90%. IgM detection, also assessed, showed lower sensitivity (42.11–82.89%) but maintained strong specificity (83.33%). The diagnostic performance was comparable to that of a commercial indirect immunofluorescence assay, with no cross-reactivity detected in sera from patients with unrelated infections. rDnaK and rA8GP63 represent newly explored diagnostic candidates. These findings highlight the potential of this recombinant protein-based ELISA as an accessible, sensitive and specific diagnostic tool, with a meaningful clinical impact for improving the early and accurate detection of rickettsial infections. Full article

(This article belongs to the Special Issue New Insights into Host-Vector-Pathogen Interactions)

► Show Figures

Figure 1

22 pages, 438 KB

Open AccessArticle

Antimicrobial Resistance in Urinary Tract Infections Among Patients with and Without Renal Comorbidities: A Retrospective Study from Al-Baha, Saudi Arabia

by Shazia Shaheen Mir, Eman Ali, Samiyah Ahmad Abdullah Alghamdi, Nora Mohamed Alghamdi, Raed A. Alharbi, Abdulmajeed A. A. Sindi and Ali A. Zaeri

Pathogens 2025, 14(12), 1297; https://doi.org/10.3390/pathogens14121297 - 17 Dec 2025

Abstract

Urinary tract infections are among the most common bacterial infections worldwide, with increasing antimicrobial resistance posing a significant public health challenge. This study aimed to determine the demographic distribution, antimicrobial susceptibility patterns of uropathogens, and the clinical implications of UTIs in patients with [...] Read more.

Urinary tract infections are among the most common bacterial infections worldwide, with increasing antimicrobial resistance posing a significant public health challenge. This study aimed to determine the demographic distribution, antimicrobial susceptibility patterns of uropathogens, and the clinical implications of UTIs in patients with renal comorbidities in the Al-Baha region of Saudi Arabia. A retrospective, cross-sectional study was conducted at King Fahad Hospital, Al-Baha, from January 2021 to September 2022. A total of 1126 culture-positive UTI cases were included. Patient demographics, uropathogen distribution, antimicrobial resistance profiles, and clinical characteristics were extracted from hospital records. Subgroup analysis was performed for 32 patients with renal comorbidities, including end-stage renal disease (ESRD), glomerulonephritis (GN), and kidney transplant recipients (KTs). Statistical analysis was performed using SPSS version 25. Most cases occurred in patients aged >70 years (43.2%) and females (68.29%). Escherichia coli (38.09%) and Klebsiella pneumoniae (14.02%) were the leading pathogens. High resistance to ampicillin (47–67%), cotrimoxazole (35–37%), and third-generation cephalosporins (34–47%) was observed, whereas carbapenems and aminoglycosides remained largely effective. Among the 32 patients with renal comorbidities, E. coli (43.8%), Staphylococcus aureus (25%), and Enterococcus spp. (18.8%) were the most common isolates. Dysuria (46.87%) and fever (31.25%) were the most frequent clinical presentations. Treatment regimens in this subgroup often required multidrug combinations, reflecting higher resistance burdens. Uropathogens in the Al-Baha region shows rising resistance to first-line antibiotics, with vulnerable populations such as patients with renal comorbidities experiencing distinct pathogen distributions and treatment challenges. Continuous surveillance, prudent antibiotic use, and targeted strategies for high-risk patients are essential to mitigate the impact of multidrug-resistant UTIs in Saudi Arabia. Full article

(This article belongs to the Special Issue Advances in the Epidemiology of Human Infectious Diseases)

► Show Figures

Figure 1

13 pages, 279 KB

Open AccessArticle

Genetic Characterization of Hepatitis C Virus Among People Who Use Crack Cocaine: A Study Conducted on the Brazilian Amazon Coast

by João Alphonse A. Heymbeeck, Wilker Leite do Nascimento, Marina Cristina S. Freitas, Leticia de Sousa Rocha, Franciane Ferreira Costa, Jocilena Pamela Q. de Queiroz, Diego Simeone, Luísa Caricio Martins, Luiz Fernando A. Machado, Benedikt Fischer, Emil Kupek and Aldemir B. Oliveira-Filho

Pathogens 2025, 14(12), 1296; https://doi.org/10.3390/pathogens14121296 - 17 Dec 2025

Abstract

People who use crack cocaine (PWUCC) constitute a key population due to vulnerability and marginalization, especially in a socio-ecologically diverse, relatively isolated region with limited public health infrastructure. This study aimed to perform a genetic characterization of circulating HCV among PWUCC in the [...] Read more.

People who use crack cocaine (PWUCC) constitute a key population due to vulnerability and marginalization, especially in a socio-ecologically diverse, relatively isolated region with limited public health infrastructure. This study aimed to perform a genetic characterization of circulating HCV among PWUCC in the municipality of Bragança, situated on the Brazilian Amazon coast, identifying viral genotypes, subtypes, resistance-associated substitutions (RAS)—naturally occurring mutations in the viral genome that can reduce the efficacy of direct-acting antiviral (DAA) agents—and predictions of phenotypic resistance. Methods: Between 2016 and 2018, biological samples and epidemiological data were obtained from 165 PWUCC. Viral detection was performed using RT-PCR, while genotyping, subtyping, and RAS profiling were conducted through nucleotide sequencing and fragment analysis. Results: In 165 PWUCC, 22 (13.3%) tested positive for HCV RNA. Most of them had not had access to public health services (91.5%), and more than half (57.0%) reported living in unstable housing conditions. HCV subtypes 1a (27.3%), 1b (40.9%), and 3a (31.8%) were detected. Evidence of resistance associated with DAAs, such as daclatasvir and dasabuvir, was detected in five PWUCC with HCV (22.7%). Conclusions: The high prevalence of HCV infection, predominantly subtype 1b, and significant levels of resistance are very concerning. This demonstrates the urgent need for targeted public health interventions to expand access to testing, treatment, and effective antiviral therapy in this vulnerable population of the Brazilian Amazon. Full article

(This article belongs to the Special Issue Viral Hepatitis Among Specific Populations: Epidemiology, Transmission, Treatment, and Prevention)

10 pages, 423 KB

Open AccessReview

Diagnostic Approaches for Measles Virus: Methods, Advances, and Ongoing Challenges

by Yuan-Chao Xue and Ping Ren

Pathogens 2025, 14(12), 1295; https://doi.org/10.3390/pathogens14121295 - 17 Dec 2025

Abstract

Measles, also known as rubeola, is a highly contagious and potentially life-threatening disease caused by the measles virus. It classically presents with fever, cough, coryza, conjunctivitis, and a maculopapular rash. Despite the availability of an effective vaccine for decades, measles outbreaks continue to [...] Read more.

Measles, also known as rubeola, is a highly contagious and potentially life-threatening disease caused by the measles virus. It classically presents with fever, cough, coryza, conjunctivitis, and a maculopapular rash. Despite the availability of an effective vaccine for decades, measles outbreaks continue to occur globally, largely driven by declining vaccination coverage and increased international travel. With no specific antiviral therapy available, rapid and accurate diagnosis remains essential for timely clinical management and effective outbreak control. Diagnostic methods have evolved from traditional virus isolation in cell culture to serologic assays and, more recently, to molecular techniques such as real-time reverse transcriptase polymerase chain reaction (rRT-PCR). Each diagnostic method has unique advantages and limitations influenced by specimen type, timing of collection, and laboratory capacity. This minireview summarizes the progress of measles virus diagnostics, outlines current laboratory detection strategies, and discusses emerging technologies and ongoing challenges amid global measles resurgence and increasing public health demands. Full article

(This article belongs to the Special Issue Emerging Viral Pathogens: Diagnosis, Treatment, and Public Health Interventions)

► Show Figures

Figure 1

22 pages, 3013 KB

Open AccessArticle

Identification of Oral Microbiome Biomarkers Associated with Lung Cancer Diagnosis and Radiotherapy Response Prediction

by Xiaoqian Shi, Nan Bi, Wenyang Liu, Liying Ma, Mingyang Liu, Tongzhen Xu, Xingmei Shu, Linrui Gao, Ranjiaxi Wang, Yinan Chen, Li Li, Yu Zhu and Dan Li

Pathogens 2025, 14(12), 1294; https://doi.org/10.3390/pathogens14121294 - 16 Dec 2025

Abstract

The oral cavity acts as the anatomical gateway to the respiratory tract, sharing both microbiological and pathophysiological links with the lower airways. Although radiotherapy is a cornerstone treatment for lung cancer, reliable oral microbiome biomarkers for predicting patient outcomes remain lacking. We analyzed [...] Read more.

The oral cavity acts as the anatomical gateway to the respiratory tract, sharing both microbiological and pathophysiological links with the lower airways. Although radiotherapy is a cornerstone treatment for lung cancer, reliable oral microbiome biomarkers for predicting patient outcomes remain lacking. We analyzed the oral microbiome of 136 lung cancer patients and 199 healthy controls across discovery and two validation cohorts via 16S rRNA sequencing. Healthy controls exhibited a significantly higher abundance of Streptococcus compared to patients (p = 0.049, p < 0.001, p < 0.001, respectively). The structure of the microbial community exhibited substantial dynamic changes during treatment. Responders showed enrichment of Rothia aeria (p = 0.027) and Prevotella salivae (p = 0.043), associated with prolonged overall survival (OS) and progression-free survival (PFS), whereas non-responders exhibited elevated Porphyromonas endodontalis (p = 0.037) correlating with shorter OS and PFS. According to Analysis of Compositions of Microbiomes with Bias Correction 2 (ANCOM-BC2) analysis, Akkermansia and Alistipes were nearly absent in non-responders, while Desulfovibrio and Moraxella were virtually absent in responders. A diagnostic model based on Streptococcus achieved area under the curve (AUC) values of 0.85 (95% CI: 0.78–0.91) and 0.99 (95% CI: 0.98–1) in the validation cohorts, and a response prediction model incorporating Prevotella salivae and Neisseria oralis yielded an AUC of 0.74 (95% CI: 0.58–0.90). Furthermore, in small cell lung cancer, microbiota richness and diversity were inversely correlated with Eastern Cooperative Oncology Group (ECOG) performance status (p = 0.008, p < 0.001, respectively) and pro-gastrin-releasing peptide (ProGRP) levels (p = 0.065, p = 0.084, respectively). These results demonstrate that lung cancer-associated oral microbiota signatures dynamically reflect therapeutic response and survival outcomes, supporting their potential role as non-invasive biomarkers for diagnosis and prognosis. Full article

► Show Figures

Figure 1

16 pages, 2931 KB

Open AccessArticle

Immune Responses and Protective Efficacy of Nanoemulsion-Adjuvanted Monkeypox Virus Recombinant Vaccines Against Lethal Challenge in Mice

by Congcong Zhang, Nuo Liu, Yanqi Zhao, Zhendong Pan, Dawei Wang, Wanda Tang, Yanhua He, Xu Zheng, Zhongtian Qi, Xinxin Zhang and Ping Zhao

Pathogens 2025, 14(12), 1293; https://doi.org/10.3390/pathogens14121293 - 16 Dec 2025

Abstract

The ongoing global monkeypox outbreak since 2022 has highlighted the urgent need for vaccine development. Current vaccination strategies rely on cross-protective immunity provided by orthopoxvirus-based live-attenuated vaccines. However, these vaccines not only exhibit suboptimal efficacy against monkeypox virus (MPXV) but also raise safety [...] Read more.

The ongoing global monkeypox outbreak since 2022 has highlighted the urgent need for vaccine development. Current vaccination strategies rely on cross-protective immunity provided by orthopoxvirus-based live-attenuated vaccines. However, these vaccines not only exhibit suboptimal efficacy against monkeypox virus (MPXV) but also raise safety concerns, particularly given the significant global overlap between MPXV infections and HIV. Owing to their superior safety profile and accessibility, recombinant subunit vaccines represent a highly promising platform for monkeypox vaccine development. In this study, we developed a subunit vaccine comprising A29L, B6R, and M1R antigens formulated with a proprietary nanoemulsion adjuvant and evaluated its immunogenicity and protective efficacy. In mice immunized with a prime-boost regimen of the three individual antigens combined with the nanoemulsion adjuvant, comparable serum IgG levels against each antigen were elicited. Both A29 and M1 formulations induced serum antibodies with potent neutralizing activity against MPXV and Vaccinia virus Western Reserve strain (VACV-WR). Notably, M1 antiserum exhibited stronger neutralization than A29 antiserum, whereas B6R immune serum showed no significant neutralizing activity. Splenocytes from B6R-immunized mice mounted a robust IFN-γ response, which was markedly lower in those immunized with A29 or M1. All three monovalent vaccines conferred complete survival following an intranasal lethal MPXV challenge, with M1 providing the strongest protection. In a lethal VACV-WR challenge model, only M1 immunization conferred significant protection. Histopathological analysis of lung tissues on day 5 post-infection revealed more pronounced inflammatory features in B6R-immunized mice compared to the nanoemulsion adjuvant control group. Furthermore, the nanoemulsion-adjuvanted bivalent A29L + B6R formulation induced significantly higher IgG and neutralizing antibody titers and demonstrated superior protective efficacy compared to the aluminum hydroxide-adjuvanted formulation. This comparative preclinical evaluation provides important evidence to support the development of a safe and effective subunit vaccine against monkeypox. Full article

(This article belongs to the Special Issue Emerging Viral Pathogens: Diagnosis, Treatment, and Public Health Interventions)

► Show Figures

Figure 1

17 pages, 2991 KB

Open AccessArticle

Interplay Between NLRP3 Activation by DENV-2 and Autophagy and Its Impact on Lipid Metabolism in HMEC-1 Cells

by Giovani Visoso-Carvajal, Julio García-Cordero, Yandy Ybalmea-Gómez, Margarita Diaz-Flores, Moisés León-Juárez, Rosaura Hernández-Rivas, Porfirio Nava, Nicolás Villegas-Sepúlveda and Leticia Cedillo-Barrón

Pathogens 2025, 14(12), 1292; https://doi.org/10.3390/pathogens14121292 - 16 Dec 2025

Abstract

Dengue Virus (DENV) induces assembly of the NOD-like receptor (NLR) family pyrin domain containing-3 (NLRP3) inflammasome and autophagy, which are closely interconnected processes playing crucial roles in lipid metabolism and DENV replication. However, the autophagy–NLRP3 activation interplay during DENV infection in human endothelial [...] Read more.

Dengue Virus (DENV) induces assembly of the NOD-like receptor (NLR) family pyrin domain containing-3 (NLRP3) inflammasome and autophagy, which are closely interconnected processes playing crucial roles in lipid metabolism and DENV replication. However, the autophagy–NLRP3 activation interplay during DENV infection in human endothelial cells remains incompletely understood. We aimed to elucidate effects of NLRP3 activation on autophagy during DENV-2 infection. We investigated how autophagy-related molecules are altered by NLRP3 inhibition and how this regulation affects lipid metabolism, through the master lipid transcription factors SREBP-1 and 2, which increase the expression of their target lipid-synthesizing genes such as fatty acid synthase (FAS) in a model of microvascular endothelial cells (HMEC-1). We demonstrated a dynamic interplay between inflammasome activity and autophagy in DENV-infected HMEC-1 cells: autophagy increases early during infection and decreases as inflammasome activity increases. NLRP3 inflammasome inhibition affects viral replication. Glyburide (an inflammasome inhibitor) treatment partially inhibited DENV-induced NLRP3 inflammasome activation. Non-structural viral protein expression (NS3 and NS5) and infectious viral-particle formation were significantly reduced. NLRP3 inhibition also downregulated SREBP-1 and SREBP-2 activation. These findings provide new insights into the modulation of the interconnected NLRP3 inflammasome, autophagy, and lipid metabolism pathways, presenting a promising therapeutic strategy for severe clinical forms of dengue. Full article

► Show Figures

Graphical abstract

Journal Description

Pathogens

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI