Emerging Microbes & Infections

African swine fever virus (ASFV) causes a lethal haemorrhagic fever in pigs and spread of this disease threatens many pig species (Suidae) globally. By contrast, ASFV infections in the natural evolved hosts, the warthog and bushpig, are subclinical. The macrophage (M{varphi}) is the primary target of ASFV and species-dependent responses in M{varphi}s are presumed to influence disease susceptibility. In an attempt to model these differences in vitro, we generated transgene-regulated induced pluripotent stem cells (iPSCs) from domestic pig, wild boar, red river hog and warthog, and confirmed that their corresponding iPSC-derived M{varphi}s (iPSCdMs) supported infection and replication of ASFV. In contrast to the other species, however, warthog iPSCdMs did not induce interferon upon infection by either virulent or attenuated ASFV. iPSCdMs may therefore represent an experimental system to understand how ASFV infection of M{varphi}s contributes to disease and aid development of strategies to combat this economically and environmentally devastating pathogen.

The majority of emerging infectious diseases are zoonotic, having their origin in wildlife before spilling over into the human population. While small mammals are recognized as critical reservoirs for these viruses, their viral diversity remains largely uncharacterized across many African countries. We conducted molecular surveillance of synanthropic rodents and shrews in the Kibera informal settlement in Nairobi and the rural Taita Hills region of Kenya to detect and characterize potential zoonotic viruses. Tissue samples from 228 rodents and shrews were screened for six viral families using PCR assays. Rat hepatitis E virus (HEV) (Rocahepevirus ratti), a rodent-associated virus with potential for human spillover, was identified in Mus musculus and Rattus norvegicus from Kibera. NGS was conducted for the HEV positive samples, and we obtained two near-complete HEV genomes from Rattus norvegicus, which clustered within rodent-associated HEV genotypes in the phylogenetic analysis. The two sequences from the Rattus norvegicus cluster together, indicating a close genetic relationship. Paramyxoviruses belonging to the genera Jeilongvirus and Parahenipavirus were detected both from Taita and Kibera in nine different samples from Rattus norvegicus, Mus minutoides, Crocidura sp and Acomys ignitus. One paramyxovirus positive sample (Acomys ignitus) from Taita was selected for further sequencing with NGS, and a complete genome of a new jeilongvirus was assembled. Phylogenetic analysis of the detected viruses confirmed the close relation to previously known rodent-borne jeilongviruses but also revealed potentially novel jeilong- and parahenipavirus species. Our findings highlight the circulation of potentially zoonotic viruses in both urban and rural small mammals in Kenya. It emphasizes the necessity of continued genomic surveillance of zoonotic viruses to mitigate risks of their spillover into human populations. HighlightsO_LISurveillance reveals diverse rodent-borne viruses circulating in Kenya. C_LIO_LIRat-HEV was detected in Rattus norvegicus and Mus musculus from an urban low-income area. C_LIO_LIParamyxoviruses were detected across multiple rodent and shrew species, including novel Acomys ignitus jeilongvirus. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/719784v1_ufig1.gif" ALT="Figure 1"> View larger version (66K): org.highwire.dtl.DTLVardef@194e81eorg.highwire.dtl.DTLVardef@11342cdorg.highwire.dtl.DTLVardef@186ad97org.highwire.dtl.DTLVardef@eeb516_HPS_FORMAT_FIGEXP M_FIG C_FIG

Respiratory virus infections affect both humans and livestock, causing considerable mortality and morbidity. While respiratory pathogens such as swine influenza A virus (pH1N1) and porcine respiratory coronavirus (PRCV) often present with overlapping clinical symptoms, their pathological trajectories and outcomes differ. Given the propensity for pathogen spillover and the use of pigs as a physiologically relevant large-animal translational model, we aimed to characterise host serum protein signatures that detect and differentiate pH1N1 from PRCV, enabling improved disease monitoring and control. Using high-resolution mass spectrometry- based proteomics, we identified 162 serum proteins that were significantly dysregulated across 3 infection timepoints (1, 5, and 12 days post-infection (DPI)), with signatures correlating with viral shedding and lung pathology as early as 1 DPI. Notably, multiplexed targeted analysis of a subset of proteins in an independent cohort from a different breed and geographic location demonstrated detection, femtomole-level targeted quantitation, and validation of SRGN as a diagnostic marker for pH1N1 and PRCV (AUC=0.85). Further, SOD1 was validated as an early marker for PRCV, increasing as early as 1 DPI (AUC= 0.9). Finally, a multi-peptide signature composed of SRGN, SOD1, and RAN demonstrated reasonable predictive power for pH1N1 (AUC=0.75) and PRCV (AUC=0.65) at 1 DPI. Our data validate the proteomic screening, provide insights into the role of early protein markers in distinguishing respiratory viral infections, and pave the way for the development of point-of-care diagnostics and targeted prevention strategies, enhancing preparedness against emerging zoonotic threats.

Orthoparamyxoviruses such as human parainfluenza virus type-3 (HPIV3) and measles virus (MeV), are a major health threat. We discovered an orally efficacious broad-spectrum inhibitor of orthoparamyxovirus polymerases. However, here we found that tolerability in higher mammals was limited. We report development of clinical candidate analog GHP-88310 (EIDD-3608), which combines improved oral efficacy with favorable tolerability in non-rodents (ferrets and dogs). GHP-88310 was active against HPIV3, Sendai virus (SeV), MeV, and related canine distemper virus (CDV). In 7-day tolerability studies, daily doses of 2,000 mg/kg were well tolerated. Pharmacokinetic analysis revealed altered plasma exposure of GHP-88310 compared to the original hit. In HPIV3-infected cotton rats, GHP-88310 lowered respiratory tract viral load. Dosing of ferrets infected with CDV, causing lethal measles-like disease, resulted in complete survival, reduction of viremia and shed viral load, and alleviated lymphocytopenia. Once-daily GHP-88310 was efficacious in the CDV-ferret and HPIV3-cotton rat models. The compound was sterilizing against HPIV3 at physiological concentrations in human airway epithelium organoids.

A multiplex diagnostic test is evaluated for self-reported long COVID associated persistent symptoms and a poor recovery from a SARS-CoV-2 infection. A mass-standardised concentration of total antibodies (AC), high-quality (HQ) antibodies and percentage of HQ antibodies (HQ%) is assessed against a spectrum of spike proteins to the SARS-CoV-2 variants: Wuhan, , {delta}, and the Omicron variants BA.1, BA.2, BA.2.12.1, BA.2.75, BA.5, CH.1.1, BQ.1.1 and XBB.1.5 in three cohorts. A cohort of control patients (n = 46) recovered (CC) and a cohort of self-declared long COVID patients (n = 113) (LCC). A nested Receiver Operating Characteristic (ROC) analysis, performed for the variant with lowest HQ concentration in the spectrum, produced an area under the curve and AUC = 0.61 (0.53-0.70) for the CC vs LCC cohorts. For the LCC cohort, the cut-off thresholds for AC = 0.8 mg/L, HQ = 1.5 mg/L and HQ% of 34% were determined, leading to a 71% sensitivity and 66% specificity derived by the Youden metric. The cohorts may be fully classified based on ROC and outlier analysis to give an incidence of persistent virus 62% (95% CI 52% - 71%), hyperimmune 12% (95% CI 7% - 20%) and unclassified, 26% (95% CI 18% - 35%). The overall diagnostic accuracy for both the hyper and hypo immune is 69%. All clinical interventions can now be tailored for the heterogenous long COVID patient cohort.

Arthropod-borne pathogens, many of which are neurotropic, can disseminate beyond the central nervous system to infect peripheral organs. In recent years, an increasing number of cardiac dysfunctions have been reported following arthropod-borne viral infections; however, the mechanism underlying these cardiac manifestations remains poorly understood. In this study, we investigated the impact of Venezuelan Equine Encephalitis Virus (VEEV) TC-83 infection on cardiac function and immune-response of human induced-pluripotent stem cell (hIPSC)-derived cardiomyocytes (hIPSC-CMs). We first confirmed the successful differentiation of hIPSCs into spontaneously beating hIPSC-CMs. We then demonstrated that these cells are highly susceptible to VEEV TC-83 infection, which induced pronounced arrhythmias and complete cessation of beating within 24 hours post-infection. To quantify these functional changes, we developed a segmentation-free computational pipeline that converts frame-to-frame motion in brightfield time-lapse movies into a one-dimensional signal reflecting contractile activity and extracts beat timing, beat rate, and rhythm-regularity features in the time and frequency domains. This analysis revealed progressive disruption of beating dynamics following VEEV TC-83 infection, with early rhythm instability and complete loss of coordinated beating by 24 hours post-infection. Furthermore, mass spectrometry analysis of VEEV TC-83-infected hIPSC-CMs supernatants revealed the presence of biomarkers typically associated with heart failure in patients, underscoring a virus-induced cardiac functional impairment. Together, these findings provide new insight into cardiac complications associated with arthropod-borne viral infections and may support advances in preventive medicine.

Arenaviruses are divided into Old World (OW) and New World (NW) groups. OW arenaviruses enter cells through a pH-dependent receptor switch from a plasma-membrane factor to an endolysosomal receptor for subsequent membrane fusion, whereas clade B NW arenaviruses use transferrin receptor 1 without a secondary receptor. Using a vesicular stomatitis virus (VSV) chimera expressing the glycoprotein complex (GPC) of the clade A NW arenavirus Pichinde virus, we performed a genome-wide CRISPR loss-of-function screen and identified the endolysosomal sialomucin CD164 as an essential host factor. CD164 knockout cells were resistant to VSV chimeras bearing the GPCs of Pichinde, Parana, and Flexal viruses, and to authentic Pichinde and Parana virus, with susceptibility restored by complementation. The requirement mapped to the cysteine-rich domain of CD164, which bound GP1 in a pH-dependent manner through main-chain interactions. These findings define CD164 as an endolysosomal receptor for clade A NW arenaviruses expanding the receptor switching paradigm.

West Nile virus (WNV) is the causative agent of fatal West Nile encephalitis. To date, no human vaccine against WNV has been approved. Adjuvants are important for developing effective and affordable vaccines that enhance the immunogenicity and decrease the required antigen doses. In this study, we assessed the efficacy of AddaS03, a synthetic adjuvant analogous to AS03, in a WNV subunit vaccine composed of soluble recombinant envelope protein (sEnv). Using a passive immunization mouse model, we defined the neutralizing antibody titer threshold required for protection against lethal WNV infections and applied this threshold as a surrogate marker to evaluate adjuvant efficacy. AddaS03-adjuvanted formulations elicited markedly higher neutralizing antibody titers compared to Alhydrogel adjuvant 2% (Alhydrogel), even at suboptimal antigen doses, and consistently exceeded the defined protective threshold titer. Moreover, in a sequential challenge mouse model, AddaS03-adjuvanted vaccines completely protected mice from symptomatic WNV infections, whereas Alhydrogel-adjuvanted vaccines failed to confer full protection. Collectively, these findings demonstrate that AddaS03 is a promising adjuvant for WNV subunit vaccine development and highlights the utility of a passive immunization model for defining protective antibody thresholds as a surrogate marker for vaccine evaluation.

Fusobacterium nucleatum is an anaerobic bacterium strongly associated with the development and progression of colorectal cancer (CRC). Its pathogenic mechanisms involve the LuxS/AI-2 quorum sensing (QS) system, which regulates biofilm formation, virulence factor expression, and host immune evasion. Targeting LuxS represents a promising anti-virulence strategy that could disrupt bacterial communication without inducing selective pressure for antibiotic resistance. In this study, we employed a computational drug repurposing pipeline to identify FDA-approved drugs capable of inhibiting the LuxS enzyme in F. nucleatum. We performed structure-based virtual screening of 9,466 compounds from DrugBank using AutoDock Vina against the AlphaFold-predicted LuxS structure (UniProt: A0A133NIU3). From 1,082 initial hits (binding energy [&le;] - 7.0 kcal/mol), we applied ADMET filtering and composite scoring to select the top 5 candidates. Molecular dynamics simulations (10 ns each) using OpenMM with the AMBER14 force field confirmed the stability of all five protein-ligand complexes (RMSD < 2.0 [A]). The most promising candidates include Tubocurarine ({Delta}G = -16.97 kcal/mol, RMSD = 1.87 [A]), Docetaxel ({Delta}G = -13.22 kcal/mol, RMSD = 1.81 [A]), Metyrosine ({Delta}G = -13.78 kcal/mol, RMSD = 1.97 [A]), and Ergometrine ({Delta}G = -13.22 kcal/mol, RMSD = 1.92 [A]). These results constitute an exploratory computational basis that requires subsequent experimental validation through in vitro and in vivo assays, and provide candidates for testing as anti-quorum sensing agents against F. nucleatum, with potential implications for CRC prevention and treatment.

Understanding the dynamics of HIV epidemics is important to control them effectively. Classical methods that mainly rely on occurrence data are limited by the fact that an unknown part of the epidemic eludes sampling. Since the early 2000s, phylodynamic methods have enabled the estimation of key epidemiological parameters from virus genetic sequence data. These methods have the advantage of being less sensitive to partial sampling and to provide insights about epidemic history that even predates the first samples. In this study, we analysed 2,205 HIV sequences from the French ANRS PRIMO C06 cohort. We identified and were able to reconstruct the temporal dynamics of two large clades that represent the HIV-1 epidemics in the country. Using Bayesian phylodynamic inference models, we found that the first clade, from subtype B, originated in the end of 1970s, grew rapidly during the 80s before decreasing from 2000 to 2015 and stagnating since then. The second clade, from circulating recombinant form CRF02_AG, emerged and spread in the 80s, grew again in the early 2000s, before declining slightly. We also estimated key epidemiological parameters associated with each clade. Finally, using numerical simulations, we investigated prospective scenarios and assessed the possibility to meet the 2030 UNAIDS targets. This is one of the rare studies to analyse the HIV epidemic in France using molecular epidemiology methods. It highlights the value of routine HIV sequence data for studying past epidemic trends or designing public health policies.

BackgroundScrub typhus is a major yet neglected vector-borne disease in Thailand, where it has been nationally notifiable for over two decades. However, long-term changes in its epidemiology, including reporting rates, transmission intensity, disease severity, and seasonal patterns, have not been comprehensively characterised at the national level. MethodologyWe analysed 22 years of national surveillance data for scrub typhus in Thailand (2003-2024) using a latent process model that jointly fits reported cases with published nationwide seroprevalence data and antibody kinetics to estimate reporting rates and underlying transmission dynamics across all 77 provinces of Thailand. FindingsOver the 22-year study period, 143096 cases and 119 deaths were reported nationally. Estimated reporting proportion broadly mirrored transmission intensity, being higher in high-burden regions and lower elsewhere. A synchronous decline in detection was observed across all regions during the COVID-19 pandemic, followed by rapid rebound by 2024. After accounting for these reporting dynamics, the force of infection was highest in the northern provinces but also substantial in the northeast and south, with upward trends in some provinces. Susceptibility among older adults aged 65 and above increased progressively over the study period, reversing the pattern observed two decades earlier. Case-fatality in the 25-35-year reference group was low and declined from 0.14% (95% Credible Interval [CrI]: 0.06-0.29%) to 0.06% (95% CrI: 0.02-0.12%), but relative case-fatality remained consistently highest among adults above 65 across all periods. Three geographically distinct seasonal patterns were identified, all stable over time. ConclusionOver two decades, scrub typhus transmission in Thailand has been shown to extend well beyond its traditionally recognised northern focus, with substantial burden in previously underappreciated regions, while the demographic profile of those most affected has shifted progressively toward older adults. These findings support the need for regionally tailored surveillance, age-targeted clinical preparedness, and sustained investment in understanding the ecological drivers of transmission. Key messagesScrub typhus is a common but neglected cause of fever in Thailand, where it has been reported through the national surveillance system for over two decades. However, trends in reported cases can be misleading because they reflect not only true changes in transmission but also variation in diagnosis and reporting over time and across regions. We developed a model that combines surveillance data with seroprevalence surveys and antibody kinetics to separate true changes in transmission from variation in reporting, allowing us to estimate how transmission intensity, disease severity, and seasonal patterns have evolved from 2003 to 2024 across all 77 provinces. We found that substantial transmission occurs not only in the well-studied northern provinces but also in the northeast and south, where the disease has received less attention. Susceptibility has progressively shifted toward older adults, who also face the highest case-fatality, while three distinct seasonal patterns vary by region but have remained stable over time. These findings suggest that scrub typhus control in Thailand requires a shift from a predominantly northern focus toward regionally tailored strategies that account for local transmission timing, an ageing at-risk population, and the ecological drivers that sustain transmission in each setting.

Metataxonomic analysis targeting the V4 region of the 18S rDNA gene, combined with molecular phylogenetic inference, was applied to detect nematode DNA of public health relevance in environmental matrices. A total of 25 mOTUs corresponding to six nematode taxa were detected in environmental samples from the Andean region of Colombia. Analysis of 12 water and sludge samples from wastewater treatment plants, 5 artisanal agricultural bioinputs, and 3 food samples revealed multiple species of public health significance: Trichuris trichiura, Enterobius vermicularis, Ascaris spp., and Necator americanus. We also confirmed zoonotic species, including Angiostrongylus cantonensis and Trichinella spp. These findings demonstrate that combining metataxonomics with molecular phylogeny provides a scalable molecular framework for the environmental surveillance of parasitic nematodes, overcoming the limitations of traditional morphological identification methods. This approach offers a replicable model for strengthening control and monitoring programs for parasitism in human populations.

Lyme disease, caused by Borrelia burgdorferi and transmitted by Ixodes scapularis ticks, remains a significant vector-borne illness in the United States. Small mammal reservoirs, particularly Peromyscus leucopus, play a critical role in B. burgdorferi maintenance. Here we conducted a five-year, randomized, double-blinded, placebo-controlled field trial deploying an oral OspA-based reservoir targeted vaccine (RTV) across seven Maryland sites. Bayesian modeling provided estimates of vaccine impact on mouse anti-OspA antibody levels, nymphal tick infection prevalence (NIP), mouse infection rates, and seroconversion to B. burgdorferi in hunting dogs. RTV sites exhibited an estimated 10.5% proportional increase in protective murine anti-OspA antibody levels and a 15.4% reduction in NIP by year five. We also found a lower infection prevalence in mouse blood fed nymphal ticks (9.8%). RTV sites exhibited modest decreases in mouse infection prevalence and dog seroconversion rates were similar between groups. Our results indicate that anti-OspA antibody in vaccinated-infected P. leucopus reduced B. burgdorferi summertime larval infection prevalence, measured as NIP reductions the following spring. This suggests that OspA-based oral RTV reduces B. burgdorferi transstadial transmission within tick populations. Our findings advance development of reservoir targeted solutions for Lyme disease prevention. Further evaluation of impacts on incidental hosts is needed.

BackgroundAnimal bites represent a significant public health concern due to the risk of injuries and transmission of zoonotic diseases such as Rabies, particularly in low and lower- middle-income countries (LMICs). Understanding the epidemiological characteristics of animal bite incidents is essential for improving the prevention and control strategies. This study aimed to characterize the epidemiological patterns and characteristics of animal bite cases in Sylhet, Bangladesh. Methodology/Principal findingsWe conducted a retrospective analysis of 6,565 animal bite cases reported between January 1 and December 31, 2024, in Sylhet, Bangladesh. Data on demographic characteristics, type of biting animal, site of bite, and exposure category were collected and analyzed to determine associations using correlation analyses and chi-square tests. Among the victims, 3,917 (60%) were male and 2,648 (40%) were female and young adults aged 20-39 years comprised the largest group (39% of cases). The majority of cases (88.1%) originated from urban areas within Sylhet City Corporation. Cats were the leading cause of bites (56.6%), followed by dogs (35.0%) and monkeys (7.5%), suggesting a shift from the traditional dog-dominated pattern. The most frequently affected anatomical sites were the legs (50.3%) and hands (40.9%). Most exposures were classified as World Health Organization (WHO) Category II (98.2%). Bite incidents showed moderate seasonal variation, with peaks in spring and early autumn. A significant declining temporal trend was observed for monkey bites (R = -0.59, p = 0.044), whereas cat and dog bite patterns remained relatively stable throughout the year. Significant associations were identified between bite site and age group, as well as between biting animal and demographic characteristics (p < 0.05). Conclusion/SignificanceThese findings highlight the epidemiological patterns of animal bites in Sylhet and emphasize the need for strengthened public awareness, surveillance, and preventive strategies to reduce animal bite incidents and associated zoonotic disease risks. SynnopsisO_LIA large-scale retrospective analysis of 6,565 animal bite cases revealed a cat-dominant bite pattern (56.6%), contrasting with the traditional dog-dominant paradigm in South Asia. C_LIO_LIYoung adults (20-39 years) and males (60%) were disproportionately affected, reflecting occupational and behavioral exposure risks. C_LIO_LIUrban residents (88.1%) accounted for the majority of cases, highlighting the growing public health burden of animal bites in rapidly urbanizing settings. C_LIO_LIThe most frequently affected anatomical sites were the legs (50.3%) and hands (40.9%). Bite incidents showed moderate seasonal variation, with peaks in spring and early autumn. C_LIO_LICategory II exposures (98.2%) predominated, indicating a high burden of seemingly minor injuries that may be underestimated in rabies prevention strategies. C_LI

Endosymbiosis of phytoplankton in heterotrophic hosts is ecologically important and has led to key evolutionary innovations. However, the dynamic molecular processes underlying endosymbiosis establishment remain poorly understood. Here, using large-particle sorting and liquid chromatography-tandem mass spectrometry, we unravel heterogeneous changes in proteomes of the cosmopolitan ciliate Paramecium and algal endosymbiont Chlorella from engulfment to stable endosymbiosis. The initial digestion sees a sharp decline of intracellular Chlorella cells, along with host cellular reorganization involving a reduction of the cortex-localized defensive organelles, trichocysts, and proteins for intracellular transport and recycling. The remaining Chlorella cells enter a bottleneck stage characterized by energy production and cell cycle commitment before active proliferation. Comparison of Paramecium with successful and failed endosymbiosis further identifies a solute carrier transporter that potentially mediates metabolic homeostasis of the endosymbiotic system. Our study reveals inter-organismal coordination during the transition from predator-prey to host-endosymbiont relationships. The approach of time-course single-cell dual proteomics can be useful for investigating diverse interactions between microbial eukaryotes.

The detection and monitoring of bat species using non-invasive sampling and molecular techniques has become increasingly popular in recent years. In Europe, these approaches have been applied to identify horseshoe bats of the genus Rhinolophus, which includes five species: R. hipposideros, R. ferrumequinum, R. euryale, R. mehelyi and R. blasii. While species-specific real-time PCR assays exist for R. ferrumequinum and R. hipposideros, no unified panel of real-time PCR assays currently enables the identification of all five European Rhinolophus species from non-invasively collected samples. Here, we developed five species-specific real-time PCR assays, each targeting interspecies nucleotide variation within the mitochondrial cytochrome b gene. To enhance single-base discrimination, RNase H-dependent PCR (rhPCR) primers were employed, incorporating cleavable blocked primers that require perfect complementarity for extension. The assays were applied to droppings non-invasively collected from 18 caves and one church in Serbia and Romania. Of the 149 samples analysed, 131 (88%) yielded successful amplification of Rhinolophus DNA. Detection probabilities for the three species identified in the field ranged from 0.49 to 0.82. Occupancy estimates varied, with R. euryale showing the highest (0.86; UI: 0.69-0.97) and R. mehelyi the lowest (0.23; UI: 0.08-0.43). The assays were capable of detecting up to three species concurrently within a single pooled sample (approximately 15 droppings). These assays are especially valuable for detecting R. mehelyi, given its rarity and uncertain distribution, and offer a robust tool for monitoring Rhinolophus populations across Europe.

Background: Although the hemagglutination inhibition (HAI) titer remains the gold standard correlate of protection against influenza, it does not fully capture the broader antibody responses that contribute to immunity. Methods: We analyzed immune responses in paired pre-infection and convalescent sera from 306 RT-PCR-confirmed A/H3N2 infections from two household studies (2014-18) in Managua, Nicaragua. Antibody responses were measured by HAI and enzyme-linked immunosorbent assays (ELISAs) against full-length hemagglutinin (HA), the HA stalk, and neuraminidase (NA). Participants were classified as HAI responders ([&ge;]4-fold HAI rise), alternate responders (no HAI rise but [&ge;]4-fold boost in [&ge;]1 ELISA), or no-response individuals (no [&ge;]4-fold rise in any assay). We compared demographic, clinical, and pre-infection antibody characteristics across these groups. We also analyzed predictors of an NA response. Results: Overall, 77% of participants had HAI seroconversion or a 4-fold rise. Among the 23% HAI non-responders, 62% had alternate antibody responses. No-response individuals had the highest pre-infection HAI and full-length HA titers (p < 0.0001), the lowest viral loads, and the fewest fever or influenza like illness (ILI) symptoms (p < 0.01). An NA response was more common among symptomatic individuals (p = 0.0483) and those with low or high baseline NA titers. Conclusions: High baseline HAI titers can limit detectable 4-fold rises and are associated with milder illness. Evaluating additional immune responses may capture a more complete picture of the host response to infection, thereby improving surveillance and informing vaccine development. Keywords: Influenza A/H3N2; Hemagglutination inhibition (HAI); Neuraminidase antibodies; symptomatic vs asymptomatic infection; correlates of protection.

Candidiasis pose a serious health threat, stimulating efforts to develop new antifungal agents and alternative therapies. Given the high mortality of fungal infections and the historical use of natural remedies, there is a growing interest in integrating natural substances into modern treatments. It is particularly important to explore interactions between home remedies and clinically approved antifungals to avoid harmful combinations or enhance beneficial effects. In this study, the chemical composition of the ethanolic extract of propolis (EEP) using UHPLC-DAD-QqTOF-MS was analyzed. The interactions of this extract with several antifungal agents against four yeast pathogens causing candidiasis: Candida albicans, Nakaseomyces glabratus, Pichia kudriavzevii, and Candida auris were investigated using Checkerboard Titration Assay, Growth Kinetics, and Disc-diffusion assay. Also, a novel simulated infection model was proposed. The results showed synergistic interactions between EEP and amphotericin B, and additive effects with nystatin. Synergy and additivity with fluconazole and voriconazole were observed, but limited to C. albicans and N. glabratus. In contrast, antagonistic interactions were noted with caspofungin, clotrimazole, and ketoconazole, which may have clinical relevance. Additionally, positive interactions with 2-phenoxyethanol and silver nanoparticles (AgNPs) suggest potential practical applications. Propoliss synergistic properties could expand antifungal strategies and support the development of multi-target, resistance-preventing therapies.

Mycobacterium tuberculosis (Mtb) subverts host immune responses via modulation of host epigenome and metabolism. In this study, we underscore a role for the epigenetic modifier, Lysine Specific Demethylase 1 (LSD1), in regulating macrophage metabolism to support mycobacterial pathogenesis. In ex vivo and in vivo infection models, LSD1 inhibition reduced mycobacterial CFU alleviating lung pathology. Metabolomic analysis of Mtb infected, LSD1 deficient macrophages revealed increased levels of alpha-ketoglutarate (AKG), a crucial TCA cycle metabolite via regulating genes implicated in glutamine breakdown. Moreover, exogenous addition of AKG resulted in reduced oxidative stress and attenuated lipid peroxidation (LPO) with a consequent decrease in Mtb survival. Blocking glutamine breakdown in LSD1 deficient macrophages failed to reduce LPO and promoted Mtb intracellular survival, highlighting the role of LSD1-AKG axis in this immunomodulation. Dietary supplementation of AKG to Mtb infected mice improved lung pathology, limited Mtb dissemination and reduced the levels of oxidative Malondialdehyde adducts. Therefore, we highlight a host protective role of AKG during Mtb pathogenesis through suppression of lipid peroxidation and uncover an epigenetic-metabolic axis exploited by Mtb, thereby positing dietary supplementation of AKG as a potential therapeutic strategy against Tuberculosis.

Immunocastration, a non surgical strategy based on active immunization against gonadotropin-releasing hormone (GnRH), effectively suppresses steroidogenesis and spermatogenesis. However, peptide vaccines targeting poorly immunogenic antigens such as GnRH often fail to elicit robust adaptive immune responses, requiring adjuvants or carrier proteins. Previously, we introduced Coated Bacterial Vaccines (CBVs), a platform that uses chemically inactivated Gram-positive bacteria to display recombinant antigens fused to the SlpA carboxy terminal domain (dSLPA) on their surface. This system leverages natural pathogen associated molecular patterns (PAMPs) to enhance immunogenicity without additional adjuvants. In this work, we extended the application of the CBVs platform to enhance the immune response against a poorly immunogenic GnRH-based peptide vaccine. GnRH-CBVs were formulated using inactivated Bacillus subtilis var. natto coated with a recombinant GnRH tandem repeat dSLPA fusion protein and administered to male BALB/c mice. A chitosan-adjuvanted GnRH dSLPA formulation served as a positive control. GnRH-CBVs induced a strong Th2-biased humoral response, characterized by predominant IgG1 levels comparable to those achieved with chitosan. The resulting antibodies effectively neutralized endogenous GnRH, reducing steroidogenesis and spermatogenesis and inducing marked testicular histological alterations. These findings support CBVs as a promising strategy to enhance peptide vaccine immunogenicity for veterinary immunocastration.