The hepatitis E virus (HEV) is the leading cause of enterically transmitted acute hepatitis worldwide. It can have a zoonotic origin through the consumption of infected meat. Pigs are the main reservoir of zoonotic HEV, and pork livers are frequently contaminated by HEV. In the present study, we investigated the use of high-pressure processing (HPP) to inactivate HEV-3 in pork liver. This study is the first to identify HPP treatment parameters that can be applied to pork liver to reduce HEV infectivity. Additionally, it is the first study to demonstrate the feasibility of processing HPP-treated pork liver into food products, such as dry liver sausage.

Recurrence of coronavirus outbreaks and zoonotic origins of human coronaviruses underscore the importance of developing pan-coronavirus antivirals. The highly conserved 3C-like protease (3CLpro) in coronaviruses, together with the well-established druggability, makes it an ideal target for broad-spectrum antiviral therapeutics. Here, the inhibitory activity of approved 3CLpro inhibitors, including nirmatrelvir, ensitrelvir, and simnotrelvir, against fifteen 3CLpros is first reported by enzymatic assays. Despite their potent inhibition toward 3CLpros of β-CoVs, these inhibitors show reduced potency against 3CLpros from the other three genera, particularly against two newly identified human coronaviruses (α-CCoV-HuPn-2018 and δ-PDCoV). In this context, continued efforts in structure-based optimization of nirmatrelvir lead to the identification of compound 8 that potently inhibits a panel of 32 3CLpros across all subgenera (IC50s: 19-146nm), with an IC50 value of 61 and 81nm against α-CCoV-HuPn-2018 and δ-PDCoV 3CLpros, respectively. Moreover, it effectively inhibits nirmatrelvir-resistant 3CLpro mutants and demonstrates broad-spectrum antiviral efficacy in cells. These findings suggest an important rule that a small, non-cyclic P2 segment and a P4 segment with a suitable size are preferred by the design of ultra-broad-spectrum 3CLpro inhibitors, and provide a proof-of-concept guide for developing broad-spectrum antivirals as potential pan-CoV therapeutics.

Squirrel reservoirs of monkeypox virus are sister species separated by the Sanaga River (Cameroon), as are the two main viral clades.

The mpox outbreak in august 2024 in central Africa, together with the mpox pandemic in 2022 associated with the emergence of new viral lineages in urban areas highlighted that this historically neglected zoonotic tropical disease caused by mpox virus (MPXV) is of public health concern. The majority of mpox infections are of zoonotic origin, but knowledge on the animal reservoir of MPXV is still extremely limited. Non-human primate (NHP) samples (n=1,571) from 29 different species, collected across Cameroon and the Democratic Republic of the Congo (DRC) were tested for the presence of IgG antibodies with a peptide-based multiplex mpox serological assay. According to stringent or less-stringent cut-off used, 17 to 85 animals (1.1-5.4%) had antibodies to at least one of the three peptides used. Seropositive samples were observed in seven to fifteen species, including Cercopithecus sp (C.ascanius, C.cephus, C.mitis, C.nictitans, C.neglectus, C.pogonias), Cercocebus sp (C.torquatus, C.agilis), Colobus sp (C.angolensis, C.guereza), Papio anubis, Lophocebus albigena, Mandrillus sphinx, Allenopithecus nigroviridis and Pan troglodytes. Mpox seroprevalence was higher in Cameroon than in DRC, i.e. 1.7-8.5% versus 0.2-0.9% (p<0.01 - p<0.001), respectively. Seroprevalence differed also according to sampling sites. In several sites, more than one NHP species was seropositive. Mpox seroprevalence differed, but not significantly in arboreal (1.2-5.4%; 15-69/1,267), semi-terrestrial (1.1-4.3%; 1-4/92) and terrestrial species (0.5-5.7%; 1-12/212). The low overall seroprevalence suggests that NHPs are most likely intermediate hosts and may be infected by other species, including reservoirs. However, they remain a potential source of human infection.

Background: Human adenovirus type 4 (HAdV-4), the sole member of species Human mastadenovirus E (HAdV-E), is of zoonotic origin and has established stable human transmission through recombination, conferring distinctive host adaptation and pathogenicity. It causes respiratory and ocular diseases, with a significant risk of severe pneumonia in children. No targeted antivirals are approved for routine use, leaving supportive care as the primary management. China bears a relatively high HAdV-4 disease burden in Asia. Methods: To generate neutralizing nanobodies (Nbs) against HAdV-4, we employed an alpaca immunization strategy using hexon protein from Ad4-RI67 strain, followed by the isolation of hexon-specific nanobodies. The epitope competition and molecular docking was employed to analysis the binding site of the Nbs’. We engineered VHH-Fc fusions by conjugating VHH domains to human IgG1 Fc. The lead candidate, NVA17, showed efficacy in both in vitro and in vivo (Stat1+/− mouse model). Flow cytometric analysis was employed to assess the downstream immune effects of NVA17 in vivo. Its intracellular neutralization mechanism was further investigated through confocal microscopy by examining co-localization in TRIM21-overexpressing and knockdown cells. Results: The isolated nanobodies revealed epitopes distinct from those targeted by known antibodies. The lead candidate NVA17 demonstrated potent neutralizing activity in vitro (IC50 < 10 ng/mL). In the Stat1+/− mouse model, NVA17 provided complete protection against lethal challenge, significantly reduced viral load in the lungs, and ameliorated pathological damage. NVA17 treatment dose-dependently reversed the virus-induced reduction in immune cell counts and enhanced cytotoxicity, suggesting a systemic immunomodulatory effect. Mechanistic studies indicated that the antiviral activity of NVA17 partly depends on the TRIM21-mediated antibody-dependent intracellular neutralization (ADIN) pathway, whereby TRIM21 terminates the viral life cycle by promoting viral degradation via K48-linked ubiquitination. Conclusions: We have identified multiple antibody candidates, particularly NVA17, with significant therapeutic potential for developing antibody-based treatments against HAdV-4. This offers a targeted intervention strategy to counter the current lack of specific antiviral therapies.

The porcine origin rotavirus A (RVA) G5 genotype is notable for its unique and sustained human circulation in Brazil, primarily as G5P[8] during the 1980s–2000s. This study aimed to characterize and investigate the full genome of a rare G5P[6] strain detected in 2013 (RVA/Human-wt/BRA/IAL-R406/2013/G5P[6]) to elucidate its evolutionary origin throughout RT-PCR, sequencing, and phylogenetic analysis. Whole-genome assessment revealed an atypical G5-P[6]-I1-R1-C1-M1-A8-N1-T7-E1-H1 constellation. The IAL-R406 VP7 (classified in Lineage I) was closely related to G5 strains that have circulated in both humans and pigs in Brazil for nearly three decades, showing no evidence of recent variant introduction. The VP4 P[6] (assigned as Lineage I) was genetically similar to Paraguayan and Argentinian G4P[6] porcine-like strains, indicating a regional swine reservoir and zoonotic RVA spillover in South America. The remaining nine segments support the animal–human reassortant origin of IAL-R406, showing broad similarity to porcine-like human and porcine strains described worldwide, with additional relationships to bovine (Republic of Korea, USA), feline-like human (Brazil), equine (UK), simian (Caribbean), wild boar/fox (Croatia), and classical human (Japan, USA) strains. In particular, the NSP1-A8 and NSP3-T7 genotypes, extremely rare in humans yet widespread in animals, especially swine, strongly indicate interspecies reassortment, likely resulting from porcine-to-human transmission. Together, these findings reinforce swine as a persistent reservoir for zoonotic RVA infections and highlight the importance of a One Health approach integrating human and animal surveillance to better understand RVA cross-species transmission and evolution.

Emerged SARS-CoV-2 intermediate hosts: The missing links from One Health perspective

Abstract Background West Nile virus (WNV) and Dengue virus (DENV), are mosquito-borne human pathogens of zoonotic origin that belong to Flavivirus genus. They usually cause asymptomatic infections but may present with clinical symptoms ranging from mild acute febrile illness (AFI) to severe life-threatening conditions such as encephalitis, hemorrhage, or shock. WNV has been endemic in the Nile valley since its isolation, and recent outbreaks of DENV have been reported in Upper Egypt and Red Sea regions. However, their prevalence in Cairo remains unclear and requires further investigation. This study aimed to detect acute WNV and DENV infections among AFI patients in Cairo. Methods A Cross-sectional study was conducted over nine months on 34 AFI patients with clinical findings suggestive of flaviviral infection, admitted to Abbassia fever hospital (AFH), Cairo, Egypt. Detection of flaviviral infection was performed using anti-WNV and anti-DENV IgM enzyme-linked immunosorbent assay and panflavi- and/or DENV reverse transcriptase polymerase chain reaction. Relevant sociodemographic data, recent travel history, clinical manifestations and laboratory investigations were evaluated for potential association. Results Among the 34 AFI patients, none tested positive by panflavi-/DENV RT-PCR. However eight (23.5%) had probable flaviviral infections: four (11.8%) tested positive for anti-WNV IgM, three (8.8%) for anti-DENV IgM and one (2.9%) for both. Two (5.9%) cases were borderline for anti-WNV IgM. There was no statistically significant difference between positive and negative cases as regards sociodemographic, clinical or potential exposure data, though there was an increased likelihood of positivity with recent travel (p-value= 0.0928). Conclusion Low rates of WNV and DENV infections are detected in Cairo. While recent travel history remains an important factor in detecting imported cases, local autochthonous transmission of WNV/DENV in Egypt is also plausible. Continuous surveillance of AFI patients admitted to tertiary referral and quarantine hospitals, such as AFH, is essential to monitor the epidemiology of flaviviral infections.

Biodiversity and human infectious diseases of zoonotic origin Or the science of trompe-l’œil!

Reoviruses are non-enveloped viruses with segmented double-stranded RNA (dsRNA) genomes that are members of the Reoviridae family. These viruses may infect a wide range of hosts, including people, mammals, birds, and reptiles, and are widely known for their diversity and zoonotic potential. Bangladesh announced the first verified cases of Reovirus infection in humans in January 2025, which might be a public health concern. Five patients were confirmed to be infected with Reovirus. All exhibited mild to moderate symptoms, with full recovery observed in each case. Epidemiological analysis suggests a zoonotic origin, with potential transmission linked to exposure to raw date palm sap, a known reservoir for bat-borne viruses. The identification highlights the need for more monitoring, better diagnostic tools, and public health awareness, especially in rural regions where close animal-human interaction is more prevalent, even though the clinical results were not severe and not dangerous. Bangladesh Journal of Infectious Diseases, June 2025;12(1):181-184

ABSTRACTBackground and AimsFollowing the end of the COVID‐19 global emergency, concern has shifted to “Disease X,” a hypothetical, highly transmissible, and deadly pathogen, and Middle East Respiratory Syndrome Coronavirus (MERS‐CoV) is a prime candidate for this. This review explores its epidemiology, mutations, transmission, and potential to become a pandemic‐capable pathogen, aiming to support future research and public health preparedness against the disease.MethodsA comprehensive search of major databases was conducted for peer‐reviewed English articles (2000–2025) focusing on virology, outbreaks, treatments, and public health using relevant but definite keywords. Studies met strict inclusion criteria and standardized methods to ensure quality, reproducibility, and transparency.ResultsSince it was identified in 2012, MERS‐CoV has spread across 27 countries, presenting a high case fatality rate (~34.5%) and zoonotic origin. It is primarily linked to dromedary camels, but shows limited human‐to‐human transmission (R₀ < 1). Unlike SARS‐CoV‐2, MERS‐CoV's spread is confined to close contact and healthcare settings, largely in the Middle East and parts of Africa. Its pathogenesis involves severe respiratory illness, driven by immune evasion and systemic inflammation, especially in individuals with comorbidities. While MERS‐CoV lacks pandemic‐level transmissibility, its genetic plasticity poses a risk for future evolution. Vaccine and therapeutic development remain limited due to sporadic outbreaks and low global urgency.ConclusionDespite not currently fitting the Disease X archetype, MERS‐CoV's high mortality, zoonotic spillover potential, and possibility for increased transmissibility warrant continued surveillance, targeted research, and strengthened public health infrastructure to prevent localized outbreaks from escalating into broader crises.

Bronze Age Yersinia pestis genome from sheep sheds light on hosts and evolution of a prehistoric plague lineage.

The ferret model is widely used to study influenza A viruses (IAVs) isolated from multiple avian and mammalian species, as IAVs typically replicate in the respiratory tract of ferrets without the need for prior host adaptation. During standard IAV risk assessments, tissues are routinely collected from ferrets at a fixed time point post-inoculation to assess the capacity for systemic spread. Here, we describe a data set of virus titers in tissues collected from both respiratory tract and extrapulmonary sites 3 days post-inoculation from over 300 ferrets inoculated with more than 100 unique IAVs (inclusive of H1, H2, H3, H5, H7, and H9 IAV subtypes, both mammalian and zoonotic origin). All experiments were conducted by a single research group under a uniform experimental protocol, making it the largest well-controlled publicly available data set to date of discrete tissue titers reported on a per-ferret level. Analysis of these tissues revealed spatial variation in infectious virus load across different tissues, coupled with different interdependence of infectious viral titers throughout the ferret respiratory tract, dependent on the subtype and sequence identity of the IAV. Collectively, this data set enhances our understanding of the diverse heterogeneity exhibited by IAV strains that pose a threat to human health, as observed in tissues collected during the acute phase of infection in mammals, and enables subsequent in-depth analyses spanning a wide array of data science, statistical, and modeling approaches.IMPORTANCEThe three Rs (reduction, refinement, and replacement, which govern ethical and humane use of animals in scientific research) compel investigators to consider ways to maximize value and impact of in vivo experimentation using a minimum number of animals. One way to achieve this is to aggregate and share publicly results from multiple studies for subsequent investigation. This resource report describes such a data set, reporting infectious virus titers detected in multiple tissues from influenza A virus-infected ferrets, day 3 post-inoculation, aggregated from studies conducted over multiple decades by one research group. We provide usage notes for best practices to inform analysis of these data by other investigators and report results of exploratory studies that illustrate conclusions that can be informed by analyses of this nature. Future public release of like data sets by other groups with similar historical archives may be informed by the practices and formatting described herein.

BackgroundOn September 27, 2024, Rwanda reported an outbreak of Marburg virus disease (MVD), after a cluster of cases of viral hemorrhagic fever was detected at two urban hospitals.MethodsWe report key aspects of the epidemiology, clinical manifestations, and treatment of MVD during this outbreak, as well as the overall response to the outbreak. We performed a retrospective epidemiologic and clinical analysis of data compiled across all pillars of the outbreak response and a case-series analysis to characterize clinical features, disease progression, and outcomes among patients who received supportive care and investigational therapeutic agents.ResultsAmong the 6340 patients with suspected MVD who underwent testing, 66 had laboratory-confirmed MVD, 51 (77%) of whom were health care workers. The median estimated incubation period was 10 days (interquartile range, 8 to 13), and symptom onset occurred a median of 2 days (interquartile range, 1 to 3) before hospital admission. The results of epidemiologic investigations were highly suggestive of a zoonotic origin of the outbreak: an index patient was identified who had been exposed to Egyptian fruit bats at a mining site. The case fatality rate in the outbreak was 23% (15 deaths among 66 patients). Remdesivir and the monoclonal antibody MBP091 were used under expanded access and clinical trial protocols. In addition, 1710 frontline workers and high-risk contacts received the chimpanzee adenovirus 3–vectored vaccine ChAd3-MARV under emergency use authorization in a phase 2 clinical trial.ConclusionsImplementation of containment measures, advanced supportive care, and access to investigational countermeasures may have contributed to reduced mortality from MVD in this outbreak. Enhancing surveillance, improving infection prevention and control in health care settings, and ensuring timely deployment of medical countermeasures will be critical for mitigating the effects of future filovirus disease outbreaks.

Human organoid models to study coronavirus infections of the respiratory tract.

The COVID-19 pandemic is primarily caused by SARS-CoV-2, with significantly higher morbidity and mortality worldwide. More than 3.78 million individuals have been killed, affecting almost all regions worldwide. The SARS-CoV-2 is a positive sense ssRNA, a zoonotic origin virus that commonly habitats in horseshoe bats. Since the advent of this pandemic, the major agencies worldwide have started research for developing therapeutics and medicine against this disease. Many medicines have been repurposed for their effective treatment. However, clinical trials for many drugs are currently being conducted. In this review, we propose the use of RNAi technology to silence the genome of the virus once it gets inside the cells and for its site-specific delivery. Artificial cells and a nanotechnology technique to use micelleplexes have been proposed to deliver siRNA to susceptible cells. Site-specific delivery could be achieved by harnessing the antigenic peptide of the viral spike protein. The proposed delivery system may help to elicit an immune response against the virus and provide a protection tool against the COVID-19 infection.

Emerging infectious diseases, particularly those of zoonotic origin, often originating from wildlife reservoirs represent a growing threat to global health. Human-driven environmental changes such as habitat fragmentation, climate change, and urban expansion have intensified interactions at the wildlife-domestic animal-human interface, facilitating cross-species viral transmission. Despite their epidemiological importance, systematic virological surveillance of wildlife remains challenging. In this study, we employed shotgun metagenomic sequencing to characterize the virome of wild animals rescued in the Pisa area and hospitalized at the "Mario Modenato" Veterinary Teaching Hospital (VTH) at the University of Pisa. Fecal samples collected from injured wildlife admitted between September 2020 and September 2021 were analyzed to detect both known and novel viruses. This approach builds upon previous PCR-based investigations of the same biological material, enabling a more comprehensive assessment of viral diversity. We adopted a shotgun approach for analyzing six sample pools-four were positive for at least one viral target-identifying diverse viral families, including Astroviridae, Circoviridae, Picornaviridae, Adenoviridae, and Retroviridae, in asymptomatic wildlife admitted to a veterinary hospital, highlighting their potential role as reservoirs. Our findings provide insights into the influence of environmental and anthropogenic factors on wildlife virome composition and highlight the value of hospital-based sampling strategies for urban viral surveillance. The results contribute to the development of integrated monitoring and prevention strategies within a One Health framework.

Introduction Monkeypox (Mpox) is a growing public health concern in Africa, driven by its zoonotic origin and increasing human-to-human transmission. However, existing mechanisms face significant challenges that limit effective outbreak control. This scoping review maps the current landscape of Mpox surveillance in endemic African regions, evaluates the effectiveness of current strategies, and identifies key gaps needing urgent attention. Methods A scoping review methodology was adopted, following the guidelines recommended by Arksey and O’Malley. We conducted a comprehensive search of peer reviewed articles, grey literature, and policy reports from January 2010 to December 2022, utilizing databases such as PubMed, Scopus, and Web of Science. Studies and reports that focused on surveillance strategies, diagnostic technologies, outbreak response, and Mpox-related challenges in endemic African countries were included. In total, 25 relevant studies from six African nations, including the Democratic Republic of the Congo, Nigeria, and Cameroon, were analyzed. Results Mpox surveillance systems in the region suffer from major limitations such as delayed outbreak reporting, limited laboratory capacity, and weak data management systems. While some countries employed active case finding and mobile health tools, most relied on passive surveillance, resulting in delayed outbreak detection. Diagnostic capacity—especially access to PCR testing—was particularly poor in rural areas. Additional barriers included logistical constraints, poor inter-agency data sharing, and limited integration of community-based surveillance. Conclusion Strengthening Mpox surveillance in endemic regions requires expanded diagnostic infrastructure, integration of digital surveillance tools, and stronger community involvement. Regional and international collaborations are critical for enhancing data sharing and coordinated responses. Addressing these gaps will improve preparedness and help prevent future public health emergencies.

Infectious diseases of zoonotic origin are a serious threat to human health and livelihoods globally. Habitat encroachment and deforestation bring humans and animals into contact, increase potential for disease spread, and foster human-animal conflict. Our aim, using thematic analysis, was to qualitatively examine the zoonotic disease landscape in Nepal from public, policymaker, and healthcare practitioner perspectives, and to describe key human-animal interactions. Community participants at six sites were interviewed or took part in focus groups (n = 73); 20 healthcare practitioner and policymaker representatives were interviewed. Lack of data complicates understanding of the zoonotic disease landscape in Nepal and limits evidence-informed policymaking. Some participants were aware of the potential significance of Nipah virus in Nepal, but insufficient data precluded planning for potential outbreaks. Drivers of some zoonoses, such as leptospirosis, may be difficult to address as they are related to traditional practices, such as consumption of rodents or barefoot paddy planting. Community participants identified rodents as frequently responsible for human-animal conflict in both rural and urban areas. Most participant photographs included evidence of rodent damage or mitigation against rodents. Habitat encroachment and deforestation have increased wild animal sightings and may increase contact between these and domestic animals, and humans. Although community participants reported no longer killing and eating wild animals, some health/policy participants questioned whether communities adhere to relevant regulations. This underlines the importance of involving communities in culturally appropriate policy development and implementation. To strengthen policymaking around zoonotic disease prevention and human-animal conflict, with the aim of reducing spread of zoonoses, we recommend public engagement between affected communities, healthcare practitioners, and policymakers to agree priorities (e.g. rodent damage and potential mitigation); and further research on effects of anthropogenic environmental changes in conjunction with members of communities most likely to be affected by increased contact with wild animals.

ABSTRACTBackground:Coronaviruses are from the family of viruses that cause respiratory illness in humans. Severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and the common cold are examples of coronaviruses that cause illness in humans. COVID-19, the new strain of coronavirus was first reported in Wuhan, China in December 2019. The virus has since spread all over the world creating havoc. The zoonotic origin of the virus has been a significant area of investigation. The infected person spreads the virus to two or three other people in a chain reaction-like pattern. India, like many countries, experienced a significant number of confirmed cases and deaths.Variations in fatality rates were observed globally.Purpose:The aim of the study is to study risk factors, clinical profile, and outcomes in hospitalized elderly (age >60) with COVID-19 and the correlation of disease severity with comorbidities and laboratory and radiological parameters by comparing the differences between young elderly (60-70 years old), old elderly (71-80 years old), and very old elderly (>81 years old). It is important to identify the risk factors and high-risk groups to aid early, aggressive intervention, facilitate equitable hospital resources, and alleviate the critical care crisis that has arisen in the country and the world.Method:This is a retrospective observational study of all the hospitalized elderly patients (>60 years old) who were diagnosed with COVID-19 and admitted to a tertiary care hospital from April 1, 2020, to December 31, 2020. Data such as clinical history along with associated comorbidities, clinical parameters, radiological imaging, signs and symptoms, treatment given and oxygen requirements, and hospital stay including ICU were collected from a computer-based data acquisition system.Conclusion:Out of 654 confirmed hospitalized elderly patients with COVID-19, 60.1% (n = 393) were young adults, 31.2% (n = 204) were old adults and 8.7% (n = 57) were very old adults. Among these, hypertension, diabetes mellitus, hypothyroidism, and chronic artery disease (CAD) were the most common comorbidities in the data collected. The frequent symptoms observed were fever in almost 89% of the patient’s upper respiratory tract infection (which commonly includes sore throat, nasal stuffiness, runny nose, and cough) was observed in more than 60% of the admitted patients, and approximately 20% of the patient’s complaint of shortness of breath (SOB). Adults above 60 years are considered vulnerable group who are more prone to develop severe disease and tend to have more complications as the age increases. The number of ICU admissions is also amplified with age and related comorbidity. It is observed in the study that the duration of hospital stay is reduced significantly with the advent of antiviral use such as Remdesivir and other experimental protocols including plasma therapy and tocilizumab in COVID-19. The clinical parameters such as elevated ferritin, CRP, D-dimers, lymphocytopenia, and CTSS are important to determine the severity of the ongoing disease in the patients.