Search Results (311)

In May 2022, an expedition was conducted in the Gobi Desert, Mongolia, to investigate the viral diversity of bats, recognized as reservoirs of emerging zoonotic viruses. Bats were captured in six oases using mist nets and were identified morphologically and molecularly. Fecal samples were collected and screened using molecular protocol targeting viral agents of relevance to human and animal health, including coronaviruses, orthoreoviruses, herpesviruses, adenoviruses, flaviviruses, phleboviruses, paramyxoviruses, pestiviruses, and Influenza A viruses. In total, 74 bats were sampled. The most represented bat genus was Plecotus, followed by Hypsugo, Vespertilio, and Myotis. Coronavirus RNA was detected in eleven samples (14.86%), Mammalian orthoreovirus RNA in two samples (2.70%), and herpesvirus DNA in three samples (4.05%). No other targeted viruses were detected. These data expand our understanding of viral circulation in bats from previously unstudied regions. By expanding our understanding of the viral diversity harbored by bats, this study contributes to ongoing efforts to better characterize their role in the ecology and evolution of emerging zoonotic viruses. Continuous surveillance in remote and biodiverse areas is essential to identify potential threats to public and animal health and to improve preparedness for future viral emergence. Full article

Replication-defective adenoviruses are widely used as vectors for vaccines, but their efficacy may be compromised by the prevalence of pre-existing neutralizing antibodies from natural infections or prior vaccination with adenovirus-based vaccines. To overcome these limitations, less common human adenovirus (HAdV) types and simian adenoviruses (SAdV) have been explored as alternative vectors to the widely prevalent HAdV-C5. Despite their importance, there is limited information on the epidemiology of adenovirus immunity in many countries and geographical regions, including Mexico. In this study, we analyzed 2488 serum samples from healthy adults across all 32 states of Mexico to assess the prevalence of both total and neutralizing antibodies against various HAdV types from species A-F, and three related SAdVs. Our findings indicate a high prevalence of neutralizing antibodies against HAdV-C5 and HAdV-C6, with significant cross-reactivity observed among related adenoviruses. Notably, HAdV-D26 exhibited a lower prevalence of neutralizing antibodies, suggesting its potential suitability as a vector for vaccine development in populations with high pre-existing immunity to more common HAdV types. These results provide critical insights for optimizing adenovirus-based vaccine strategies in Mexico. Full article

Wild carnivores can harbor pathogens affecting wildlife conservation and domestic animal health. This study surveyed major viral pathogens in free-ranging wolves, red foxes, stone martens, and Eurasian badgers in Northwestern Italy. Duodenal samples from 140 carcasses were screened by consensus PCR for members of the species Protoparvovirus carnivoran1 and for canine adenoviruses (CAdV-1/2). PCR-positive samples underwent sequence-independent amplification and Oxford Nanopore sequencing. Canine parvovirus type 2 (CPV-2) and feline panleukopenia virus (FPV) DNAs were identified in three wolves (6.4%) and one badger (4.3%), whereas CAdV-1 was detected in one red fox (1.8%). Nanopore sequencing yielded near-complete genomes of two CPV-new 2a, one CPV-2c, and one FPV strains, along with partial CAdV-1 sequences. Furthermore, the complete genome of a canine circovirus (CaCV) strain in co-infection with a CPV-2c-positive wolf and partial sequences of a canine kobuvirus (CaKoV) strain were also obtained. Phylogenetic analysis placed these viruses within known European lineages and linked them to domestic and wild hosts. These findings revealed the circulation of multiple viral pathogens among wild carnivores, reflecting ongoing cross-species spillover. Continuing molecular surveillance at the wildlife–domestic interface is recommended. Full article

Over 35 years of history, the field of gene therapy has undergone much progress. The initial concept—the replacement of dysfunctional genes with correct ones—has advanced to the next stage and reached the level of precise genome editing. Dozens of gene therapy products based on viral and non-viral delivery platforms have been approved, marking the dawn of the gene therapy era. These viral vector strategies rely on adenoviruses, adeno-associated viruses, lentivirus-derived tools, and so on. From the middle of the gene therapy transition, despite the challenges and serious negative consequences, the lentiviral vector has emerged as a cornerstone and demonstrated benefits in fields ranging from basic science to gene therapy. Therefore, we outline the importance of lentiviral vectors in the gene therapy era by focusing on their roles in the clinical usage, derivation, and development of next-generation platforms, as well as their pseudotyping. Full article

Adenovirus is an important respiratory virus that causes severe diseases in immunocompromised patients. Data on its impact in immunocompetent patients are relatively limited. We conducted a territory-wide retrospective study on adult patients hospitalized for respiratory tract infections caused by adenovirus or influenza viruses in Hong Kong between 1 January 2016 and 30 June 2023. Inpatient mortality, severe respiratory failure (SRF), secondary bacterial pneumonia and acute kidney injury (AKI) were compared. The risk factors for these outcomes in patients hospitalized for adenovirus respiratory tract infections were assessed. Overall, 41,206 and 528 patients were hospitalized for influenza and adenovirus respiratory tract infections, respectively. Patients with respiratory tract infections due to adenoviruses showed significantly higher risk of inpatient mortality, SRF, secondary bacterial pneumonia and AKI compared to seasonal influenza. Medical comorbidities including cardio-pulmonary diseases, end-stage kidney disease requiring dialysis, and a lower estimated glomerular filtration rate were robust independent risk factors for inpatient mortality and serious respiratory outcomes in adenovirus respiratory tract infections. Adults hospitalized for adenoviruses respiratory tract infections had a significantly higher risk of inpatient mortality and adverse outcomes than adults infected with seasonal influenza. Medical comorbidities are important risk factors for severe adenovirus infections in adult patients. Full article

Over the past decade, diseases associated with fowl adenoviruses (FAdVs) have exhibited a new epidemic trend worldwide. The presence of numerous FAdVs serotypes, combined with the virus’s broad host range, positions it as a significant pathogen in the poultry industry. In the current context of intensive poultry production and global trade, co-infections involving multiple FAdVs serotypes, as well as co-infections with FAdVs alongside infectious bursal disease or infectious anemia virus, may occur within the same region or even on the same farm. The frequency of these outbreaks complicates the prevention and control of FAdVs. Therefore, the development of effective, targeted vaccines is essential for providing technical support in the management of FAdVs epidemics. Ongoing vaccine research aims to improve vaccine efficacy and address the challenges posed by emerging FAdVs outbreaks. This review focuses on vaccines developed and studied worldwide for various serotypes of FAdVs in the past decade. It encompasses inactivated vaccines, live attenuated vaccines, e.g., host-adapted attenuated vaccines and gene deletion vaccines, viral vector vaccines, and subunit vaccines (including VLP proteins and chimeric proteins). The current limitations and future development directions of FAdVs vaccine development are also proposed to provide a reference for new-generation vaccines and innovative vaccination strategies against FAdVs, as well as for the rapid development of highly effective vaccines. Full article

Human adenoviruses (HAdVs) are pathogens causing different illnesses, particularly in pediatric and immunocompromised patients in developed countries. The clinical spectrum of HAdV-infections ranges from mild to severe, and the clinical presentation varies widely. Certain HAdVs types, including types B3, E4, B7, B14, B21, G55, and B66, may be associated with lower respiratory tract infections and thus lead to higher hospitalization, increased morbidity, as well as lethality rates. The aim of this article is to synthesize and analyze the prevalence of specific HAdV types in pediatric patients worldwide. A systematic literature search was performed using MEDLINE, Scopus, and Web of Science. In total, n = 1167 titles and abstracts were screened, and 105 full-text articles were assessed for eligibility. Screening, data extraction, and appraisal were analyzed by reviewers, in accordance with PRISMA guidelines and JBI recommendations. We included studies reporting on currently circulating HAdV types (n = 16). Based on a systematic and narrative approach, relevant types of HAdV biology and infections in children are presented. In detail, HAdV-B3 and HAdV-B7 were commonly associated with severe respiratory tract infections, while HAdV-F40 and HAdV-F41 caused acute gastroenteritis. Moreover, detailed research revealed the critical role of HAdV-C2 and the necessity for particular attention to HAdVs in acute neurological infections. This comprehensive analysis highlights the significant global distribution and diverse clinical implications of different HAdV types in children, pointing out the need for continued surveillance to better understand HAdVs epidemiology and its implications for public health, and future preventive measures, in particular among vulnerable patients. Full article

Background/Objectives: While adenovirus (Ad) therapies have been proven to be effective in local administration, systemic Ad treatments have shown limited success due to pre-existing antibodies in the human blood that neutralize the virus. We developed a liposome coating procedure that protects the Ad from pre-existing neutralizing antibodies in human blood. To assess the in vivo stability of the liposomes, the present study used a novel in vivo method to quantitatively assess the protective capabilities of liposome-encapsulated Ad (DfAd) from neutralizing antibodies. Methods: The assay systemically administers DfAd with a green fluorescent protein transgene (DfAd-GFP) into pre-immunized mice and allows it to circulate in the presence of neutralizing antibodies; the infected blood is extracted and used to transduce HEK293 cells, which emits fluorescence in the presence of protected, un-neutralized Ad. Results: The PEGylated liposome formulation provides 12× protection in vivo relative to unencapsulated Ads. In vitro optimization of the liposome coating reveals a strong correlation between the structural stability of liposomes and protection against anti-Ad neutralizing antibodies, where DSPE-PEG2000-carboxylic acid (DSPE-PEG2000-CA) is a critical component for liposome stability and increasing protection against antibody neutralization of the encapsulated Ad. Conclusions: The findings in the present study confirm that the DfAd liposome can protect against neutralizing antibodies in blood circulation. The novel in vivo assay for liposome protection against neutralizing antibodies and in vitro experiments in the present study provide new tools and insights toward designing liposome–Ad complexes for the systemic treatment of cancer. Full article

Wastewater-based epidemiology (WBE) offers valuable insight into viral circulation at the community level. In this study, we combined digital PCR (dPCR) with molecular typing to investigate the prevalence and diversity of human adenoviruses (HAdVs) in untreated wastewater samples collected throughout Italy. HAdV genomes were detected in over 93% of the 168 samples analyzed, with concentrations up to 4.5 × 10⁶ genome copies per liter. For genotypic characterization, we used nested PCR followed by Sanger and Oxford Nanopore Technologies (ONTs) long-read sequencing. While Sanger sequencing identified three dominant genotypes (HAdV-A12, HAdV-B3, and HAdV-F41), ONT sequencing provided enhanced resolution, confirming all previously identified types and revealing seven additional genotypes: HAdV-B21, HAdV-C5, HAdV-D45, HAdV-D46, HAdV-D49, HAdV-D83, and HAdV-F40. This comprehensive approach highlights the added value of ONT long-read sequencing in uncovering the genetic complexity of adenoviruses in wastewater, particularly in detecting rare or low abundance types that conventional methods may miss. Our findings highlight the value of integrating quantitative and high-resolution molecular tools in WBE to improve surveillance and better understand the epidemiology of viral pathogens circulating in the human population. Full article

Background: adenoviruses (AdVs) are DNA viruses that typically cause mild infections in immunocompetent children, and typically involve the respiratory and gastrointestinal tract. Adenoviral pharyngitis is a common paediatric illness, particularly in children under 4 years old. The aim of our 7-year retrospective study, conducted at a tertiary care paediatric emergency department (ED), was to describe the clinical and laboratory characteristics and management of patients with pharyngeal AdV infections. Specifically, we examined how the management of patients with adenoviral pharyngitis has evolved following the introduction of a rapid antigen nasopharyngeal swab test for AdVs, which has been performed directly in the ED since 2023. Methods: in this single-centre retrospective observational study, the demographic and clinical information for children discharged from the ED who had been diagnosed with a pharyngeal AdV infection between 1 January 2017 and 31 December 2023 were retrospectively reviewed. Moreover, we compared data before and after the introduction of rapid AdV antigenic swabs, which have been directly performed in the ED since the beginning of 2023. Statistical analysis was undertaken using the Student’s t-test and Pearson and Fisher’s exact test, as appropriate. Significance was set at p-value < 0.05. Results: during the study period, 172 children were diagnosed with adenoviral pharyngitis based on a positive swab. All patients were febrile, with a median duration of fever of 4 days. Blood tests were requested for 84.9% of patients at admission, resulting in a mean WBC count of 13,250/mmc and a mean CRP of 70.6 mg/L. The highest CRP median values were found on the third day of fever. Out of 383 swabs performed during 2017–2022, 13.6% were positive vs a 32% positive rate for the 372 swabs performed in 2023. The mean duration of observation in the ED before 2023 was 31.4 h vs. 10.4 h in 2023. Similarly, 9% of patients with adenoviral pharyngitis were admitted to a paediatric ward before 2023 and only 0.8% in 2023. Conclusions: the primary reason for ED admission in cases of adenoviral pharyngitis is fever lasting several days due to hyperinflammation. Differential diagnosis with bacterial infection is essential to limit the number of hospitalisations and inappropriate antibiotic therapy. The introduction of the rapid antigen nasopharyngeal swab has simplified the diagnosis of adenoviral pharyngitis, enabling timely and accurate differentiation from bacterial causes. Full article

Fowl adenoviruses (FAdVs) are important emerging pathogens affecting the poultry industry in Egypt as they are the primary etiology of inclusion body hepatitis–hydropericardium syndrome (IBH-HPS) associated with severe economic losses. This study aims to identify the circulating FAdVs from cases of IBH-HPS in 5 Egyptian provinces during the period from October 2020 through September 2022. Out of the 210 examined flocks, liver samples from 66 flocks were positive for FAdVs (31.4%) using conventional polymerase chain reaction targeting loop 1 of the major hexon gene, with varying rates of mortality (1% to 14%). In the positive samples detected during the study, the histopathological examination revealed pathognomonic lesions of FAdVs, including basophilic and eosinophilic intra-nuclear inclusion bodies (INIBs). The percentage of FAdV positivity increased with the flock age; from samples collected at ages 1 to10, 11 to 20, 21 to 30, and >30 days of age, 10% (5/50), 25.6% (11/43), 34.3% (23/67), and 54% (27/50) were found positive for FAdVs, respectively. Notably, the positivity percentages among the flocks reared in cages were higher than for those reared in the deep litter system of housing. The gene sequencing and phylogenetic analysis of 19 strains revealed clustering into FAdV species D serotype 2/11, demonstrating that serotype 2/11 is most prevalent in the targeted Egyptian provinces during the period of the study. Several point mutations in the sequenced region among different strains were reported. These findings underscore the prevalence of FAdV and provide a basis for further research on circulating strains to develop effective control strategies. Full article

The concerns regarding Fowl Adenoviruses have gained significance in the poultry industry due to their association with various diseases, including Inclusion Body Hepatitis, Hepatitis-Hydropericardium Syndrome, and Adenoviral Gizzard Erosion (AGE). AGE is an emerging disease reported in several countries, particularly in Asia and Europe, causing significant economic losses in the poultry industry. In 2001, Fowl Adenovirus Serotype 1 was identified as the etiological agent of AGE in Japan. Since then, it has been spreading to other countries due to its transmission mode. Although Adenoviral Gizzard Erosion has been mostly described in broilers, it has also been observed in layers and pullets. This review offers a comprehensive analysis of Fowl Adenovirus Serotype 1, encompassing various key aspects of the virus. We also examine the pathogenesis and epidemiology of the virus, providing an overview of its distribution and prevalence in avian populations worldwide. Highlighting the most recent developments in serological and molecular techniques for virus detection, quantification, and genotyping and comparing them to conventional tests, this review aims to contribute to the understanding of the diagnostic workflow for this virus. Lastly, this review sheds light on some vaccine strategies to prevent Adenoviral Gizzard Erosion. Full article

Human enteric adenoviruses (HAdV-F40/41) play a crucial role as causative agents of acute gastroenteritis (AGE), particularly affecting children in low-and middle-income countries. This study investigated the prevalence, genetic diversity, and molecular characteristics of HAdV-F40/41 in AGE cases reported in Brazil from 2021 to 2023, a period after the COVID-19 pandemic. A total of 1980 stool samples collected from medically attended AGE patients from nine states were analyzed by TaqMan-based qPCR. Overall, HAdV was detected in 16.6% (n = 328/1980) of cases, with the highest prevalence observed in children under five years of age. The positive HAdV samples were genotyped through partial sequencing of the hexon and/or fiber genes followed by phylogenetic analysis. Enteric HAdVs (HAdV-F40/41) were detected in 3.2% (n = 63/1980) of samples, with HAdV-F41 (44.1%) being the most common genotype. Among the non-enteric types, HAdV-C (29.4%) was the most prevalent, followed by HAdV-B (13.2%), HAdV-A (10.3%), and HAdV-D (2.9%). Phylogenetic analysis of the hexon (HVR1–HVR6) and fiber (Shaft) gene regions identified two major clusters, H-GTC1 and F-GTC2, showing close genetic relationships with global strains. HAdV-F40/41 demonstrated significantly higher viral loads compared to non-enteric HAdVs. These findings highlight the importance of continued surveillance of HAdV-F to better understand its role in AGE cases and support public health strategies, including potential vaccine development. Full article

The insertion of a transgene downstream of the L3-23K or L5-Fiber region was reported as a vital strategy for arming E3 non-deleted oncolytic adenoviruses. However, depending on the percentage of codons with G/C at the third base position (GC3%) and the type of splicing acceptor, an insert downstream of the L5-Fiber region may substantially affect virus fitness. Since the insertion of transgenes downstream of the L3-23K and L5-Fiber regions has never been compared in terms of their expression levels and impact on virus fitness, we assessed the total virus yield, cytolytic efficacy, and plaque size of Ad5-delta-24-RGD (Ad5Δ24RGD) armed with EGFP, FLuc, the suppressor of RNA silencing p19, soluble wild-type human/mouse and high-affinity human programmed cell death receptor-1 (PD-1/PDCD1) ectodomains, and soluble human hyaluronidase PH20/SPAM1. The insertion of transgenes downstream of the L3-23K region ensures their production at considerably higher levels. However, the insertion of transgenes downstream of either region differentially and unpredictably affects the oncolytic potency of Ad5Δ24RGD, which cannot be explained by GC3% or expression level alone. Surprisingly, the expression of the human and mouse PD-1 ectodomains with 83.1% and 70.1% GC3%, respectively, does not affect cytolytic efficacy but increases the plaque size in a cell line-dependent manner. Full article

Inflammatory cardiomyopathy is a condition that is characterised by the presence of inflammatory cells in the myocardium, which can lead to a significant deterioration in cardiac function. The etiology of this condition involves multiple factors, both infectious and non-infectious causes. While it is primarily associated with viral infections, other potential causes include bacterial, protozoal, or fungal infections, as well as a wide variety of toxic substances and drugs, and systemic immune-mediated pathological conditions. In spite of comprehensive investigation, the presence of inflammatory cardiomyopathy accompanied by left ventricular dysfunction, heart failure or arrhythmia is indicative of an unfavourable outcome. The reasons for the occurrence of either favourable outcomes, characterised by the absence of residual myocardial injury, or unfavourable outcomes, marked by the development of dilated cardiomyopathy, in patients afflicted by the condition remain to be elucidated. The relative contributions of pathogenic agents, genomic profiles of the host, and environmental factors in disease progression and resolution remain subjects of ongoing discourse. This includes the determination of which viruses function as active inducers and which merely play a bystander role. It remains unknown which changes in the host immune profile are critical in determining the outcome of myocarditis caused by various viruses, including coxsackievirus B3 (CVB3), adenoviruses, parvoviruses B19 and SARS-CoV-2. The objective of this review is unambiguous: to provide a concise summary and comprehensive assessment of the extant evidence on the pathogenesis, diagnosis and treatment of myocarditis and inflammatory cardiomyopathy. Its focus is exclusively on virus-induced and virus-associated myocarditis. In addition, the extant lacunae of knowledge in this field are identified and the extant experimental models are evaluated, with the aim of proposing future directions for the research domain. This includes differential gene expression that regulates iron and lipid and metabolic remodelling. Furthermore, the current state of knowledge regarding the cardiovascular implications of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is also discussed, along with the open questions that remain to be addressed. Full article