Viruses

14 pages, 2734 KiB

Open AccessArticle

Isolation and Pathogenicity of a Natural Recombinant Pig Reproductive and Respiratory Syndrome Virus in Northeast China

by Zhixin Tian, Qiwei Li, Luxiang Xu, Dexin Liang, Yuan Li, Ziqi Shi, Lingzhi Luo, Jiechao Jin, Xiaoyi Huo, Xiumei Dong and Han Zhou

Viruses 2025, 17(5), 729; https://doi.org/10.3390/v17050729 (registering DOI) - 19 May 2025

Abstract

First reported in 1987, the porcine reproductive and respiratory syndrome virus (PRRSV) has significantly disrupted the major regions affected by PRRSV in the pig breeding industry. Recently, outbreaks of disease caused by recombinant PRRSV strains in China have raised serious concerns. Effective immunization [...] Read more.

First reported in 1987, the porcine reproductive and respiratory syndrome virus (PRRSV) has significantly disrupted the major regions affected by PRRSV in the pig breeding industry. Recently, outbreaks of disease caused by recombinant PRRSV strains in China have raised serious concerns. Effective immunization and infection control in pig populations is critical, as the virus frequently undergoes mutation and recombination. This study characterized a novel recombinant PRRSV strain, BX/CH/22, isolated from Northeast China. Genetic analysis revealed that BX/CH/22 is a recombinant of JXA1, NADC 30-like, and NADC 34-like strains. Phylogenetic analysis of the non-structural protein (NSP) 2 region classified BX/CH/22 as JXA1 PRRSV-like, with a characteristic deletion of 30 discontinuous amino acids in NSP2. However, Open Reading Frame (ORF) 5 analysis classified it as NADC 30-like PPRSV, while whole-genome phylogenetic analysis classified it as NADC 34-like PPRSV. Recombination analysis revealed that BX/CH/22 contains an NADC 34-like PRRSV backbone, an NSP-coding region from NADC 30-like PRRSV, and an ORF2-ORF6 region from NADC 34-like PRRSV. The strain was isolated from serum samples obtained from commercial swine farms undergoing active PRRS outbreaks. In animal experiments, all BX/CH/22-challenged piglets exhibited persistent fever, with peak temperatures >40.5 °C at 4–9 dpi resolving by 11 dpi, accompanied by cough, anorexia, and lethargy. A significant reduction in daily weight gain was observed in infected groups compared to asymptomatic controls, with a 100% survival rate. Our findings provide early warning for PRRSV immune control strategies. Full article

(This article belongs to the Special Issue Porcine Viruses 2024)

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16 pages, 4545 KiB

Open AccessArticle

Transcriptomic Analysis of the Spleen from Asian Seabass (Lates calcarifer) Infected with Infectious Spleen and Kidney Necrosis Virus

by Hong-Yi Xin, Lim Xin Ying, Lee Ching Pei Carmen and Mookkan Prabakaran

Viruses 2025, 17(5), 728; https://doi.org/10.3390/v17050728 (registering DOI) - 19 May 2025

Abstract

Infectious spleen and kidney necrosis virus (ISKNV) is an emerging viral pathogen with an expanding host range, posing a significant threat to economically important fish species. In this study, we isolated the ISKNV strain responsible for disease outbreaks in Asian seabass (Lates [...] Read more.

Infectious spleen and kidney necrosis virus (ISKNV) is an emerging viral pathogen with an expanding host range, posing a significant threat to economically important fish species. In this study, we isolated the ISKNV strain responsible for disease outbreaks in Asian seabass (Lates calcarifer) and analyzed the transcriptomic profile of spleen tissues from experimentally infected fish. The phylogenetic analysis confirmed that the virus belongs to clade I of ISKNV. Next-generation sequencing identified differentially expressed genes, providing a comprehensive overview of the transcriptional landscape in the spleen of ISKNV-infected fish. The pathway analysis revealed complex host–virus interactions, impacting immune regulation, endocytosis, cell communication, cell cycle arrest, and programmed cell death. To further investigate these interactions, we analyzed relevant pathways in the Reactome database for Asian seabass, humans, and zebrafish, constructed a protein–protein interaction (PPI) network using STRING database, and identified hub genes using six different algorithms. This analysis revealed 69 key genes, including 41 hub genes and 28 key genes that connect different pathways or clusters within the PPI network. These findings provide new insights into the molecular mechanisms driving ISKNV infection in Asian seabass. Future research should focus on elucidating the regulatory functions of these key genes and their roles in ISKNV pathogenesis. Full article

(This article belongs to the Special Issue Iridoviruses, 2nd Edition)

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11 pages, 2000 KiB

Open AccessArticle

HTLV-I Basic Leucine Zipper Factor (sHBZ) Actively Associates with Nucleophosmin (B23) in the Nucleolus

by Nahid Moghadam, Yong Xiao, Francois Dragon and Benoit Barbeau

Viruses 2025, 17(5), 727; https://doi.org/10.3390/v17050727 (registering DOI) - 19 May 2025

Abstract

Human T cell leukemia virus type 1 (HTLV 1) is an oncogenic retrovirus responsible for the development of adult T cell leukemia (ATL). The minus strand of HTLV-1 provirus encodes an oncoprotein named HTLV-1 bZIP factor (HBZ), which plays a pivotal role in [...] Read more.

Human T cell leukemia virus type 1 (HTLV 1) is an oncogenic retrovirus responsible for the development of adult T cell leukemia (ATL). The minus strand of HTLV-1 provirus encodes an oncoprotein named HTLV-1 bZIP factor (HBZ), which plays a pivotal role in viral replication and T cell proliferation. Of particular interest is the spliced HBZ isoform (sHBZ), which is predominantly expressed in ATL cells and localizes within the nucleolus, conferring immortalizing properties to T cells. Our previous study has shown that sHBZ colocalizes and associates with Nucleophosmin/B23, a nucleolar phosphoprotein with multiple functions. In this study, through an optimized nucleolar isolation method, we first confirmed sHBZ’s nucleolar localization via Western blotting in transfected HEK293T cells, chronically HTLV-1-infected T cell lines, and freshly infected HeLa cells. We further demonstrated that the sHBZ/B23 association predominantly occurs in the nucleolus by co-immunoprecipitation of cell fractions. Our study highlights the nucleolar localization of sHBZ and its possibly essential interaction with this nucleolar-residing protein, leading to cell immortalization. Full article

(This article belongs to the Special Issue Virus-Host Protein Interactions)

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17 pages, 3699 KiB

Open AccessArticle

Uncovering SARS-CoV-2 Molecular Epidemiology Across the Pandemic Transition: Insights into Transmission in Clinical and Environmental Samples

by Vrushali D. Patil, Rashmi Chowdhary, Anvita Gupta Malhotra, Jitendra Singh, Debasis Biswas, Rajnish Joshi and Jagat Rakesh Kanwar

Viruses 2025, 17(5), 726; https://doi.org/10.3390/v17050726 (registering DOI) - 19 May 2025

Abstract

Background: Respiratory droplets are the main way in which the COVID-19 pandemic’s causal agent, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), spreads. Angiotensin-converting enzyme 2 (ACE2) receptors, especially in lung cells, allow the virus to enter host cells. However, ACE2 expression in intestinal cells [...] Read more.

Background: Respiratory droplets are the main way in which the COVID-19 pandemic’s causal agent, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), spreads. Angiotensin-converting enzyme 2 (ACE2) receptors, especially in lung cells, allow the virus to enter host cells. However, ACE2 expression in intestinal cells has sparked worries about possible fecal transfer, particularly in poor-sanitation areas like India. Methods: Between July 2021 and July 2024, clinical (nasopharyngeal, saliva, and stool samples) and sewage samples were collected from outpatient departments and sewage treatment plants (STPs), respectively, from the high-population-density area under study in order to investigate SARS-CoV-2 transmission. Results: This proof-of-concept study analyzed clinical samples from n = 60 COVID-19-positive patients at a central Indian tertiary care hospital and n = 156 samples from hospital STPs. Variants of SARS-CoV-2 were found using qRT-PCR and Next-Generation Sequencing (NGS). Of the n = 37 qRT-PCR-positive patients who gave their assent, 30% had stool samples that tested positive for viral RNA. In 70% of positive NP and 65% of positive saliva samples, along with two stool samples from immunocompromised patients, the live virus was identified using Vero E6 cell lines. Although 18% of the tests reported qRT-PCR-positive results, no live virus was detected in sewage samples despite NGS validation. The detection of SARS-CoV-2 in the absence of confirmed clinical cases may indicate the silent circulation of the virus within the community, suggesting that sewage surveillance can serve as an early warning system before an outbreak occurs. Conclusions: These findings provide critical insights into the importance of continuous environmental surveillance, silent virus circulation, changes in viral epidemiology throughout the years, and strategies to mitigate coronavirus outbreaks. Full article

(This article belongs to the Special Issue Molecular Epidemiology of SARS-CoV-2, 4th Edition)

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25 pages, 2300 KiB

Open AccessArticle

Discovery and Genome Characterization of Three New Rhabdoviruses Infecting Passiflora spp. in Brazil

by Andreza Henrique Vidal, Ana Clara Rodrigues Abreu, Jorge Flávio Sousa Dantas-Filho, Monique Jacob Xavier Vianna, Cristiano Lacorte, Emanuel Felipe Medeiros Abreu, Gustavo Pereira Felix, Dione Mendes Teixeira Alves-Freitas, Bruna Pinheiro-Lima, Isadora Nogueira, Fabio Gelape Faleiro, Raul Castro Carriello Rosa, Onildo Nunes Jesus, Marcio Martinello Sanches, Yam Sousa Santos, Rosana Blawid, José Leonardo Santos Jiménez, Maite Freitas Silva Vaslin, Elliot Watanabe Kitajima, Magnolia de Araujo Campos, Rafaela Salgado Fontenele, Arvind Varsani, Fernando Lucas Melo and Simone Graça Ribeiro Show full author list Hide full author list

Viruses 2025, 17(5), 725; https://doi.org/10.3390/v17050725 (registering DOI) - 19 May 2025

Abstract

This study aimed to explore the RNA viruses affecting Passiflora species in Brazil. Our results enhance the understanding of the viruses that infect Passiflora plants by identifying and characterizing three previously unrecognized viruses: Passiflora cytorhabdovirus (PFCV), Passiflora nucleorhabdovirus 1 (PaNV1), and Passiflora nucleorhabdovirus [...] Read more.

This study aimed to explore the RNA viruses affecting Passiflora species in Brazil. Our results enhance the understanding of the viruses that infect Passiflora plants by identifying and characterizing three previously unrecognized viruses: Passiflora cytorhabdovirus (PFCV), Passiflora nucleorhabdovirus 1 (PaNV1), and Passiflora nucleorhabdovirus 2 (PaNV2). These rhabdoviruses were identified through high-throughput sequencing and validated by reverse transcription-polymerase chain reaction (RT-PCR) in various Passiflora species. PFCV has a genome organization 3′-N-P-P3-P4-M-G-P7-L-5′ and was classified as a novel member of the Gammacytorhabdovirus genus. A particularly noteworthy feature of PFCV is its glycoprotein, as the genomes of other gammarhabdoviruses do not contain this gene. PFCV has a high incidence across multiple locations and was identified in plants from Northeastern, Central, and Southeastern Brazil. PaNV1 with genome structure 3′-N-P-P3-M-G-L-5′ and PaNV2 with genome organization 3′-N-X-P-Y-M-G-L-5′ are new members of the Alphanucleorhabdovirus genus and have a more restricted occurrence. Importantly, all three viruses were found in mixed infections alongside at least one other virus. In situ observations confirmed mixed infections, with PaNV2 particles co-located in tissues with a potyvirus and a carlavirus. Phylogenetic and glycoprotein sequence similarity network analysis provided insights into their evolutionary placement and potential vector associations. These findings expand the known diversity of rhabdoviruses in Passiflora and contribute to the understanding of their evolution and epidemiology. Full article

(This article belongs to the Section Viruses of Plants, Fungi and Protozoa)

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13 pages, 281 KiB

Open AccessReview

The Role of TDP-43 in SARS-CoV-2-Related Neurodegenerative Changes

by Dong-Hwi Kim, Jae-Hyeong Kim, Min-Tae Jeon, Kyu-Sung Kim, Do-Geun Kim and In-Soo Choi

Viruses 2025, 17(5), 724; https://doi.org/10.3390/v17050724 (registering DOI) - 19 May 2025

Abstract

The coronavirus disease 2019 (COVID-19) pandemic has been linked to long-term neurological effects with multifaceted complications of neurodegenerative diseases. Several studies have found that pathological changes in transactive response DNA-binding protein of 43 kDa (TDP-43) are involved in these cases. This review explores [...] Read more.

The coronavirus disease 2019 (COVID-19) pandemic has been linked to long-term neurological effects with multifaceted complications of neurodegenerative diseases. Several studies have found that pathological changes in transactive response DNA-binding protein of 43 kDa (TDP-43) are involved in these cases. This review explores the causal interactions between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and TDP-43 from multiple perspectives. Some viral proteins of SARS-CoV-2 have been shown to induce pathological changes in TDP-43 through its cleavage, aggregation, and mislocalization. SARS-CoV-2 infection can cause liquid−liquid phase separation and stress granule formation, which accelerate the condensation of TDP-43, resulting in host RNA metabolism disruption. TDP-43 has been proposed to interact with SARS-CoV-2 RNA, though its role in viral replication remains to be fully elucidated. This interaction potentially facilitates viral replication, while viral-induced oxidative stress and protease activity accelerate TDP-43 pathology. Evidence from both clinical and experimental studies indicates that SARS-CoV-2 infection may contribute to long-term neurological sequelae, including amyotrophic lateral sclerosis-like and frontotemporal dementia-like features, as well as increased phosphorylated TDP-43 deposition in the central nervous system. Biomarker studies further support the link between TDP-43 dysregulation and neurological complications of long-term effects of COVID-19 (long COVID). In this review, we presented a novel integrative framework of TDP-43 pathology, bridging a gap between SARS-CoV-2 infection and mechanisms of neurodegeneration. These findings underscore the need for further research to clarify the TDP-43-related neurodegeneration underlying SARS-CoV-2 infection and to develop therapeutic strategies aimed at mitigating long-term neurological effects in patients with long COVID. Full article

(This article belongs to the Section Coronaviruses)

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Graphical abstract

13 pages, 15467 KiB

Open AccessArticle

Evaluating Neutralizing Antibodies in Hantavirus-Infected Patients Using Authentic Virus and Recombinant Vesicular Stomatitis Virus Systems

by Punya Shrivastava-Ranjan, Jamie A. Kelly, Laura K. McMullan, Deborah Cannon, Laura Morgan, Payel Chatterjee, Shilpi Jain, Joel M. Montgomery, Mike Flint, César G. Albariño and Christina F. Spiropoulou

Viruses 2025, 17(5), 723; https://doi.org/10.3390/v17050723 (registering DOI) - 19 May 2025

Abstract

Hantaviruses, including the Sin Nombre virus (SNV) and Andes virus (ANDV), are associated with severe global health risks, causing high mortality rates in hantavirus pulmonary syndrome (HPS) patients. Neutralizing antibodies are essential for virus clearance and survival, making neutralization assays critical for understanding [...] Read more.

Hantaviruses, including the Sin Nombre virus (SNV) and Andes virus (ANDV), are associated with severe global health risks, causing high mortality rates in hantavirus pulmonary syndrome (HPS) patients. Neutralizing antibodies are essential for virus clearance and survival, making neutralization assays critical for understanding immunity and evaluating therapeutic strategies. In this study, we developed a recombinant vesicular stomatitis virus (VSV)-based surrogate system expressing SNV and ANDV glycoproteins (GPCs), enabling neutralization studies under biosafety level 2 conditions. The neutralization titers obtained with the VSV-based system closely matched the findings from authentic hantavirus assays performed under biosafety level 3 conditions, confirming its potential as a useful tool for determining immune responses and advancing hantavirus research. Full article

(This article belongs to the Special Issue Hantavirus 2024)

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17 pages, 2391 KiB

Open AccessReview

Evolution of Antiviral Drug Resistance in SARS-CoV-2

by Roy Dinata, Piyush Baindara and Santi M. Mandal

Viruses 2025, 17(5), 722; https://doi.org/10.3390/v17050722 (registering DOI) - 18 May 2025

Abstract

The COVID-19 pandemic has had a significant impact and continues to alarm the entire world due to the rapid emergence of new variants, even after mass vaccinations. There is still an urgent need for new antivirals or strategies to combat the SARS-CoV-2 infections; [...] Read more.

The COVID-19 pandemic has had a significant impact and continues to alarm the entire world due to the rapid emergence of new variants, even after mass vaccinations. There is still an urgent need for new antivirals or strategies to combat the SARS-CoV-2 infections; however, we have success stories with nirmatrelvir. Drug repurposing and drug discovery may lead to a successful SARS-CoV-2 antiviral; however, rapid drug use may cause unexpected mutations and antiviral drug resistance. Conversely, novel variants of the SARS-CoV-2 can diminish the neutralizing efficacy of vaccines, thereby enhancing viral fitness and increasing the likelihood of drug resistance emergence. Additionally, the disposal of antivirals in wastewater also contributes to drug resistance. Overall, the present review summarizes the strategies and mechanisms involved in the development of drug resistance in SARS-CoV-2. Understanding the mechanism of antiviral resistance is crucial to mitigate the significant healthcare threat and to develop effective therapeutics against drug resistance. Full article

(This article belongs to the Special Issue Mechanism of Receptor Recognition in Coronavirus, 2nd Edition)

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14 pages, 7209 KiB

Open AccessArticle

Establishment and Implementation of the Point-of-Care RT-RAA-CRISPR/Cas13a Diagnostic Test for Foot-And-Mouth Disease Virus Serotype O in Pigs

by Ping Meng, Bo Ni, Chenyu Li, Zhou Sha, Chunju Liu, Weijie Ren, Rong Wei, Fuxiao Liu, Jinming Li and Zhiliang Wang

Viruses 2025, 17(5), 721; https://doi.org/10.3390/v17050721 (registering DOI) - 17 May 2025

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Abstract

Foot and mouth disease virus (FMDV) is a highly pathogenic virus that mainly infects cloven hooved animals, such as pigs. The establishment of a rapid, sensitive and accurate point-of-care detection method is critical for the timely identification and elimination of infected pigs for [...] Read more.

Foot and mouth disease virus (FMDV) is a highly pathogenic virus that mainly infects cloven hooved animals, such as pigs. The establishment of a rapid, sensitive and accurate point-of-care detection method is critical for the timely identification and elimination of infected pigs for controlling this disease. In this study, a RT-RAA-CRISPR/Cas13a method was developed for the detection of FMDV serotype O in pigs. Six pairs of RT-RAA primers were designed based on the conserved gene sequence of FMDV serotype O, and the optimal amplification primers and reaction temperatures were screened. The CRISPR-derived RNA (crRNA) was further designed based on the optimal target band sequence and the most efficient crRNA was screened. The results revealed that FMDV-O-F4/R4 was the optimal primer set, and the optimal temperature for the RT-RAA reaction was 37 °C. Moreover, crRNA4 exhibited the strongest detection signal among the six crRNAs. The established RT-RAA-CRISPR/Cas13a method demonstrated high specificity and no cross-reactivity with other common swine pathogens such as Senecavirus A (SVA), porcine reproductive and respiratory virus (PRRSV), porcine epidemic diarrhea virus (PEDV), porcine circovirus type 2 (PCV2), classical swine fever virus (CSFV), and pseudorabies virus (PRV), additionally, it was observed to be highly sensitive, with a detection limit of 19.1 copies/µL. The repeatability of this method was also observed to be good. This method could produce stable fluorescence and exhibited good repeatability when three independent experiments yielded the same results. A validation test using three types of simulated clinical samples (including swab, tissue, and serum samples) revealed a 100% concordance rate. The detection results could be visualized via a fluorescence reader or lateral flow strips (LFSs). Thus, a highly specific and sensitive RT-RAA-CRISPR/Cas13a detection method was developed and is expected to be applied for the rapid detection of FMDV serotype O in situ. Full article

(This article belongs to the Special Issue Advances in Endemic and Emerging Viral Diseases in Livestock)

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12 pages, 388 KiB

Open AccessArticle

Foscarnet Versus Ganciclovir for Severe Congenital Cytomegalovirus Infection: Short- and Long-Term Follow-Up

by Giovanni Nigro, Marta Buzzi, Milena Catenaro, Eleonora Coclite and Mario Muselli

Viruses 2025, 17(5), 720; https://doi.org/10.3390/v17050720 (registering DOI) - 17 May 2025

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Abstract

Background: Cytomegalovirus (CMV) infection is the most common and serious congenital infection, with universal screening in pregnancy, standardized therapy, and a vaccine still lacking. Study design: In the 1990s, we noted that intravenous ganciclovir did not cure some children with severe sequelae due [...] Read more.

Background: Cytomegalovirus (CMV) infection is the most common and serious congenital infection, with universal screening in pregnancy, standardized therapy, and a vaccine still lacking. Study design: In the 1990s, we noted that intravenous ganciclovir did not cure some children with severe sequelae due to congenital cytomegalovirus (CMV) infection. Therefore, we performed an open randomized trial using intravenous foscarnet as an alternative to intravenous ganciclovir in 24 infants (12 in each therapy group), all with severe neurological manifestations due to congenital CMV infection. Nine and five infants, belonging to the foscarnet or ganciclovir group, respectively, had abnormal hearing. One infant in each group also had chorioretinitis. Concomitantly, 12 CMV-infected infants with similar manifestations, who did not receive any therapy, were used as controls. The results of short-term (2 years) and long-term (7–29 years, mean 22.2) follow-up are reported herein. Short-term results: Neurological outcomes were normal in five of the twelve children who were treated with foscarnet, compared to nine of the twelve children given ganciclovir. None of the untreated children were healthy. There was a statistically significant difference (p = 0.023) between the treated and untreated children. Hearing was normal in four of the twelve children treated with foscarnet, seven of the twelve children treated with ganciclovir, and two untreated children. Long-term-results: Two children in both therapy groups died before the age of 17 years, and six untreated children died between 7 and 26 years of age. Neurological outcomes were normal in three of the ten children treated with foscarnet, in two of the ten treated with ganciclovir, and in none of the untreated children. Hearing was normal in two children treated with foscarnet, in six children treated with ganciclovir, and in one untreated child. Conclusions: Intravenous ganciclovir and foscarnet were found to be safe at long-term follow-up and appeared to be capable of mitigating the neurological and auditory consequences of congenital CMV disease at the short-term follow-up. However, there was progressive worsening of the symptomatology in all three groups, with a statistically significant increase in the number of deaths (p = 0.035) among 4 of the 24 children in the therapy groups and 6 of the 12 untreated children. Full article

(This article belongs to the Special Issue Congenital Cytomegalovirus Infection: Volume II)

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15 pages, 2900 KiB

Open AccessArticle

Characterization of Papillomatous Lesions and Genetic Diversity of Bovine Papillomavirus from the Amazon Region

by Fernanda dos Anjos Souza, Cíntia Daudt, André de Medeiros Costa Lins, Igor Ribeiro dos Santos, Lorena Yanet Cáceres Tomaya, Agnes de Souza Lima, Eduardo Mitke Brandão Reis, Rafael Augusto Satrapa, David Driemeier, Audrey Bagon, Cláudio Wageck Canal, Felipe Masiero Salvarani and Flavio Roberto Chaves da Silva

Viruses 2025, 17(5), 719; https://doi.org/10.3390/v17050719 (registering DOI) - 16 May 2025

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Abstract

Bovine papillomaviruses (BPVs) have been widely characterized from cutaneous warts in cattle worldwide. However, there are still limited studies addressing the geographic distribution of viral types and their potential associations with the histopathological characteristics of lesions, particularly in the vast and ecologically diverse [...] Read more.

Bovine papillomaviruses (BPVs) have been widely characterized from cutaneous warts in cattle worldwide. However, there are still limited studies addressing the geographic distribution of viral types and their potential associations with the histopathological characteristics of lesions, particularly in the vast and ecologically diverse Amazon region. This study aimed to histologically and phylogenetically characterize cutaneous papillomatous lesions in cattle from the Vale do Guaporé, located in the Brazilian Western Amazon. A total of 54 wart samples were collected from 44 cattle clinically diagnosed with cutaneous papillomatosis. Histopathological analysis classified 58.33% of cases as fibropapillomas and 39.58% as squamous papillomas. Molecular analysis, based on L1 gene amplification and sequencing, identified the presence of previously reported BPV types (BPV2, 4, 5, 12, 13, and 15), along with a novel BPV14 subtype and three putative new types (PNT). Statistical analysis revealed that BPV2 was significantly associated with fibropapillomas (p = 0.023), whereas BPV13 was linked to cauliflower-like morphological lesions (p = 0.008). These findings enhance the understanding of BPV diversity circulating in cattle from the Amazon region and provide valuable insights into the clinicopathological aspects of bovine cutaneous papillomatosis, which may aid in future epidemiological surveillance and disease control strategies. Full article

(This article belongs to the Special Issue Advances in Endemic and Emerging Viral Diseases in Livestock)

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10 pages, 1308 KiB

Open AccessArticle

Assessing Urban Yellow Fever Transmission Risk: Aedes aegypti Vector Competence in Argentina

by Estefanía R. Boaglio, Evangelina Muttis, Mariel Feroci, Cintia Fabbri, Graciela Minardi, Juliana Sánchez, María V. Micieli and Silvina Goenaga

Viruses 2025, 17(5), 718; https://doi.org/10.3390/v17050718 - 16 May 2025

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Abstract

Yellow fever is a viral disease with historical importance since epidemics caused thousands of deaths at the end of the 19th century in Argentina. That event was associated with the presence of Aedes aegypti. After the mosquito eradication in South America in [...] Read more.

Yellow fever is a viral disease with historical importance since epidemics caused thousands of deaths at the end of the 19th century in Argentina. That event was associated with the presence of Aedes aegypti. After the mosquito eradication in South America in the 1960–1970 decade, no epidemic was detected related to this species but epizootics have occurred due to sylvatic vectors belonging to Haemagogus and Sabethes genera. Due to the recolonization of Ae. aegypti and its expanded distribution, the risk of the urbanization of yellow fever has increased over time. However, the reasons why the urban cycle of the yellow fever virus (YFV) has not occurred in South America so far are unknown. We explore the vector competence of Ae. aegypti for YFV transmission. The mosquitos evaluated belonged to colonies from center and northwest cities from Argentina, taking into account the particular genetic features of this mosquito species detected in this country from 2016. We used a viral strain originally isolated in 2009 from Sabethes albiprivus in the country. Viral infection in mosquito body, legs, and saliva was evaluated to estimate the rates of infection, dissemination, and transmission. Our results indicate that both mosquito colonies are competent vectors in the transmission of the YFV but with differences between them. Regarding the infection timeline, we observed a very early infection in the La Plata colony at 3 DPI in contrast to previous studies. This research improves our understanding of the risks of urban YFV transmission in Argentina, highlighting the need for surveillance and specialized vector control strategies in urban settings to prevent yellow fever outbreaks. Full article

(This article belongs to the Special Issue Recent Advances on Arboviruses Pathogenesis and Evolution)

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11 pages, 2256 KiB

Open AccessArticle

Novel Orthohantavirus Associated with Hantavirus Pulmonary Syndrome in Northern Argentina

by Carla M. Bellomo, Sebastian Kehl, Daniel Oscar Alonso, Walter López, Flavia Cassinelli, Rocío María Coelho, Gabriela Bravo, Sara Aguirre, Marcela Dib, Natalia Periolo, Concepción Toscano, José Gil, Francisco García Campos, Ignacio Ferro and Valeria Paula Martinez

Viruses 2025, 17(5), 717; https://doi.org/10.3390/v17050717 - 16 May 2025

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Abstract

In this work, we performed the genetic characterization of a new variant of orthohantavirus associated with a fatal case of hantavirus pulmonary syndrome, outside the known endemic region, in northwestern Argentina. We first confirmed an orthohantavirus infection by ELISA, testing for the detection [...] Read more.

In this work, we performed the genetic characterization of a new variant of orthohantavirus associated with a fatal case of hantavirus pulmonary syndrome, outside the known endemic region, in northwestern Argentina. We first confirmed an orthohantavirus infection by ELISA, testing for the detection of IgM and IgG antibodies. Then, we extracted RNA from 100 microliters of serum, the only sample available, followed by RT-PCR. The amplicons were sequenced using Sanger and next-generation sequencing technology. We obtained partial sequences of 1253 bp, 799 bp and 1675 bp from the S-, M- and L-segments, respectively, showing low sequence identities with all the previously characterized hantaviruses (10.9%, 13.5% and 15.1% of the divergence, respectively). The phylogenetic analysis showed that this virus belongs to the Orthohantavirus andesense species (ANDV), and among the ANDV-like variants, it is more closely related to the Lechiguanas clade. Similar percentages of divergence were considered sufficient to distinguish AND-like variants in previous works. As the patient had no travel history before the onset of disease was reported, we conducted rodent surveys to confirm the presence of reservoirs. The rodent assemblage was compatible with the transitional zone among different ecoregions (Yungas, Chaco and Monte). Moreover, one of the species captured, Oligoryzomys flavescens, was previously described as a reservoir of hantavirus. This species may either host several variants across its range or encompass a species complex, as proposed by some authors. Full article

(This article belongs to the Special Issue Hantavirus 2024)

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16 pages, 1604 KiB

Open AccessArticle

Comparison of Three Commercial ELISA Kits for Detection of Antibodies Against SARS-CoV-2 in Serum Samples from Different Animal Species

by Leira Fernández-Bastit, Sílvia Marfil, Edwards Pradenas, Julià Blanco, Júlia Vergara-Alert and Joaquim Segalés

Viruses 2025, 17(5), 716; https://doi.org/10.3390/v17050716 - 16 May 2025

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Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the coronavirus disease 19 (COVID-19) pandemic, significantly impacting global health, economies, and social stability. In February 2020, the first cases of SARS-CoV-2 infections in animals were documented, highlighting the potential risks posed by regular [...] Read more.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the coronavirus disease 19 (COVID-19) pandemic, significantly impacting global health, economies, and social stability. In February 2020, the first cases of SARS-CoV-2 infections in animals were documented, highlighting the potential risks posed by regular human–animal interactions in facilitating viral transmission. In consequence, it is essential to validate surveillance methods for SARS-CoV-2 in animals. In the present study, 101 sera from different animal species (36 cats, 41 dogs, 4 ferrets, 10 wild boar, 6 domestic goats, and 4 lions) were tested using three different ELISA kits to evaluate humoral responses against SARS-CoV-2. ELISA results were compared and correlated with a pseudovirus neutralization test (pVNT), considered as the reference assay. ELISA-1, targeting the receptor binding domain (RBD) neutralizing antibodies (nAbs) of SARS-CoV-2, exhibited the highest diagnostic performance, and proved to be a reliable tool for initial screenings in high-throughput animal studies. In contrast, ELISA-2 (also targeting RBD nAbs) and ELISA-3 (targeting nucleoprotein antibodies) demonstrated lower sensitivity for detecting seropositive animals. Full article

(This article belongs to the Section Animal Viruses)

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17 pages, 2540 KiB

Open AccessReview

Adaptor Protein Complexes in HIV-1 Pathogenesis: Mechanisms and Therapeutic Potential

by Maria Elena Barone, Alexis Lim, Madison Woody, Parisa Taklifi, Fatema Yeasmin, Kequan Wang, Mary K. Lewinski, Rajendra Singh, Charlotte A. Stoneham, Xiaofei Jia and John Guatelli

Viruses 2025, 17(5), 715; https://doi.org/10.3390/v17050715 - 16 May 2025

Viewed by 174

Abstract

Adaptor protein (AP) complexes are critical components of the cellular membrane transport machinery. They mediate cargo selection during endocytosis and intracellular vesicular trafficking. Five AP complexes have been characterized (AP1-5), and together their roles extend to diverse cellular processes including the homeostasis of [...] Read more.

Adaptor protein (AP) complexes are critical components of the cellular membrane transport machinery. They mediate cargo selection during endocytosis and intracellular vesicular trafficking. Five AP complexes have been characterized (AP1-5), and together their roles extend to diverse cellular processes including the homeostasis of membranous organelles, membrane protein turnover, and immune responses. Human Immunodeficiency Virus type 1 (HIV-1) and other lentiviruses co-opt these complexes to support immune evasion and the assembly of maximally infectious particles. HIV-1 Nef interacts with AP1 and AP2 to manipulate intracellular trafficking and downregulate immune-related proteins such as CD4 and MHC-I. Vpu also co-opts AP1 and AP2, modulating the innate defense protein BST2 (Tetherin) and facilitating the release of virions from infected cells. The envelope glycoprotein (Env) hijacks AP complexes to reduce its expression at the cell surface and potentially support incorporation into virus particles. Some data suggest that Gag co-opts AP3 to drive assembly at intracellular compartments. In principle, targeting the molecular interfaces between HIV-1 proteins and AP complexes is a promising therapeutic approach. Blocking these interactions should impair HIV-1’s ability to produce infectious particles and evade immune defenses, leading to novel antivirals and facilitating a cure. Full article

(This article belongs to the Section Human Virology and Viral Diseases)

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18 pages, 1457 KiB

Open AccessArticle

HIV–HPV Co-Infection and Identification of Novel High-Risk HPV Among Women at Two Hospital Centers in Cotonou, Republic of Benin

by Clémence D. Gouton, Ifeoluwa O. Bejide, Oludayo O. Ope-ewe, Marius Adjagba, Simon Azonbakin, Gaonyadiwe Muzanywa, Florence T. Akinyi, Arnaud Agbanlinsou, Yanique Goussanou, Onikepe Folarin, Anatole Laleye, Christian T. Happi and Chinedu A. Ugwu

Viruses 2025, 17(5), 714; https://doi.org/10.3390/v17050714 - 16 May 2025

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Abstract

Persistent high-risk human papillomaviruses (HR-HPVs) infection is the leading cause of cervical cancer. With over 200 circulating genotypes, HPV detection, management, and prevention remain challenging. In Benin, HPV prevalence and genotype distribution are largely unknown, and no national HPV vaccination program exists. This [...] Read more.

Persistent high-risk human papillomaviruses (HR-HPVs) infection is the leading cause of cervical cancer. With over 200 circulating genotypes, HPV detection, management, and prevention remain challenging. In Benin, HPV prevalence and genotype distribution are largely unknown, and no national HPV vaccination program exists. This study investigates the prevalence, genotypic diversity, and risk factors of HIV–HPV co-infection among women in Cotonou, Benin. Cervical swabs were collected from 100 women living with HIV (WLWHIV) and 51 women without HIV (WWHIV) at two hospitals. DNA extraction and nested polymerase chain reaction (PCR) were used to detect HPV, followed by Sanger sequencing for genotyping. Chi-squared analysis was used to assess risk factors. HPV was detected in 85% (85/100) of WLWHIV and 60.8% (31/51) of WWHIV (p = 0.002), confirming HIV as an independent risk factor. Fifteen HR-HPV genotypes were identified, with HPV 45 most prevalent in WLWHIV and HPV 16 in WWHIV. Notably, HR-HPV 67, 70, and 82 were detected for the first time in Benin. Unmarried status and detectable HIV load were significant risk factors for co-infection. The high HPV prevalence, particularly among WLWHIV, underscores the urgent need for HPV surveillance and vaccination in Benin. Identifying novel HR-HPV genotypes highlights the necessity for ongoing monitoring and targeted prevention strategies. Full article

(This article belongs to the Special Issue Molecular Mechanisms and Clinical Manifestations of Persistent Viral Infections)

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15 pages, 10579 KiB

Open AccessArticle

Infectious Spleen and Kidney Necrosis Virus Triggers Ferroptosis in CPB Cells to Enhance Virus Replication

by Qiushuang Zhang, Ouqin Chang, Qiang Lin, Hongru Liang, Yinjie Niu, Xia Luo, Baofu Ma, Ningqiu Li and Xiaozhe Fu

Viruses 2025, 17(5), 713; https://doi.org/10.3390/v17050713 - 16 May 2025

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Abstract

The role of ferroptosis—a novel iron-dependent programmed cell death pathway—in infectious spleen and kidney necrosis virus (ISKNV) infection remains poorly understood. Here, we demonstrate that ISKNV infection induces ferroptosis in CPB cells. Following ISKNV challenge, CPB cells exhibited hallmark morphological alterations including mitochondrial [...] Read more.

The role of ferroptosis—a novel iron-dependent programmed cell death pathway—in infectious spleen and kidney necrosis virus (ISKNV) infection remains poorly understood. Here, we demonstrate that ISKNV infection induces ferroptosis in CPB cells. Following ISKNV challenge, CPB cells exhibited hallmark morphological alterations including mitochondrial shrinkage, increased membrane density, and cristae reduction. Biochemical assays confirmed significant time-dependent elevations in ferroptosis markers: malondialdehyde (MDA, 1.7-fold), reactive oxygen species (ROS, 3.14-fold), and ferrous iron (Fe²⁺, 1.42-fold) compared to controls (p < 0.05). Mechanistic studies revealed that ISKNV downregulated glutathione peroxidase 4 (GPx4) while upregulating acyl-CoA synthetase long-chain family member 4 (ACSL4), as validated by quantitative real-time PCR (qRT-PCR) and immunoblotting. Ferroptosis induction with erastin enhanced ISKNV replication, whereas inhibition with liproxstatin-1 suppressed viral yield. These findings establish that ISKNV exploits ferroptosis to facilitate its replication, and pharmacological blockade of this pathway significantly suppresses viral propagation, providing a new strategy and intervention approach for controlling ISKNV infection. Full article

(This article belongs to the Special Issue Aquatic Animal Viruses and Antiviral Immunity)

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21 pages, 312 KiB

Open AccessReview

Update: Immunotherapeutic Strategies in HPV-Associated Head and Neck Squamous Cell Carcinoma

by Fangdi Sun and A. Dimitrios Colevas

Viruses 2025, 17(5), 712; https://doi.org/10.3390/v17050712 - 16 May 2025

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Abstract

The incidence of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) has increased substantially over the past three decades, and since 2017, it has been recognized in the AJCC staging system as distinct from its HPV-negative counterpart. The underlying mechanisms of HPV-associated carcinogenesis, [...] Read more.

The incidence of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) has increased substantially over the past three decades, and since 2017, it has been recognized in the AJCC staging system as distinct from its HPV-negative counterpart. The underlying mechanisms of HPV-associated carcinogenesis, tumor microenvironment, and host immune response represent opportunities for therapeutic development. While anti-PD-1 immunotherapy is now part of standard treatment for recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) in general, there are no established immunotherapeutic strategies specifically for HPV-related HNSCC. In this context, multiple emerging approaches are being actively studied—among these are therapeutic vaccines with or without anti-PD-(L)1 adjuvants, peptide–HLA-based immunotherapeutic platforms, and adoptive cell therapies including tumor-infiltrating lymphocytes (TILs), T-cell receptor (TCR) therapy, and chimeric antigen receptor (CAR) T-cell therapy. Beyond further maturation of these novel immunotherapeutic strategies, additional work is needed to delineate the optimal disease state of application (localized versus recurrent/metastatic), as well as in the development of small molecule inhibitors targeting HPV-specific mechanisms of viral oncogenesis. Full article

(This article belongs to the Special Issue Advancements in Immunotherapy for Human Papillomavirus)

14 pages, 1502 KiB

Open AccessArticle

Genetic Diversity in the Capsid Protein-Coding Region of HIV-1 Circulating in Benguela, Angola: Implications for Primary Resistance to the Novel Capsid Inhibitor Lenacapavir

by Gonçalo Queirós, Lesya Yefimenko, Filomena M. Pereira and João Piedade

Viruses 2025, 17(5), 711; https://doi.org/10.3390/v17050711 - 16 May 2025

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Abstract

In 2023, the HIV-1 pandemic claimed around 630,000 lives worldwide due to AIDS-related complications. Its burden is significantly heavier in Sub-Saharan Africa, where an increased HIV-1 genetic diversity is common, which increases the risk of resistance to antiretroviral (ARV) drugs. This study aims [...] Read more.

In 2023, the HIV-1 pandemic claimed around 630,000 lives worldwide due to AIDS-related complications. Its burden is significantly heavier in Sub-Saharan Africa, where an increased HIV-1 genetic diversity is common, which increases the risk of resistance to antiretroviral (ARV) drugs. This study aims to update the molecular epidemiology of HIV-1 in Angola, focusing specifically on the gag gene, which is often overlooked, and to assess the potential viability of lenacapavir (LEN)-based ARV therapy in the region. A total of 243 blood samples were collected from ARV-naïve, HIV-infected patients at the General Hospital of Benguela, city of Benguela, Angola. The capsid-encoding region of HIV-1 proviral DNA was amplified by PCR and sequenced. Phylogenetic analysis was performed using the maximum likelihood method, and genome recombinant forms were characterised through bootscanning analysis. Primary resistance mutations to LEN were identified using Stanford University’s HIVdb algorithm. Among the 80 successfully sequenced samples, 13 different genetic forms/subtypes were identified, with unique recombinant forms (URFs) (37.5%, 30/80) and subtype C (31.25%, 25/80) being the most prevalent. Regarding resistance mutations, none were detected, apart from four polymorphic mutations. These findings reinforce Angola’s position as a transitional HIV-1 hotspot between the genetically highly diverse Central Africa and the subtype C-dominated Southern Africa, while also supporting the potential effectiveness of LEN-based regimens for treatment and prevention of HIV-1 infections in the future. Full article

(This article belongs to the Section Human Virology and Viral Diseases)

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12 pages, 4621 KiB

Open AccessArticle

Detection of a New Recombinant Rabbit Hemorrhagic Disease Virus 2 in China and Development of Virus-like Particle-Based Vaccine

by Bo Hu, Wenyu Dong, Yanhua Song, Zhiyu Fan, Patrizia Cavadini and Fang Wang

Viruses 2025, 17(5), 710; https://doi.org/10.3390/v17050710 - 16 May 2025

Viewed by 42

Abstract

Rabbit hemorrhagic disease virus (RHDV) is a very virulent virus of the genus Lagovirus causing severe and fatal hepatitis in the European rabbit (Oryctolagus cuniculus). RHDV has two distinct genotypes: GI.1 (RHDV) and GI.2 (RHDV2). The first RHDV2/GI.2 strain was identified [...] Read more.

Rabbit hemorrhagic disease virus (RHDV) is a very virulent virus of the genus Lagovirus causing severe and fatal hepatitis in the European rabbit (Oryctolagus cuniculus). RHDV has two distinct genotypes: GI.1 (RHDV) and GI.2 (RHDV2). The first RHDV2/GI.2 strain was identified as a recombinant virus between a non-pathogenic (GI.3P) and a pathogenic (GI.2) lagovirus, and the recombination is thought to have been a key mechanism in the emergence and evolution of RHDV2. Here, a new variant of RHDV2 was identified affecting domestic rabbits on Chinese farms, with a mortality rate of 70–80%. Phylogenetic analysis indicated that the nonstructural portion of this newly identified strain’s genome clustered with the GI.1a variants. In contrast, the capsid gene shared the highest nucleotide identity of 97.9% with the North American GI.2 strains, suggesting a possible introduction in China of North American strains and recombination with the GI.1a strains circulating in China. We have produced a recombinant vaccine using the first Chinese GI.2 strain, SC2020/0401, by cloning the vp60 gene into a baculovirus expression vector. Virus-like particles (VLPs) were then produced in Sf9 insect cells, and a challenge study was performed. Rabbits immunized with the VLP vaccine survived 7 d after being challenged with the new virus. The results indicate that commercial vaccines are urgently required in China to control the circulation of RHDV2 variants. Full article

(This article belongs to the Section Animal Viruses)

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19 pages, 2727 KiB

Open AccessArticle

Single Amino Acid Residue W33 of tva Receptor Is Critical for Viral Entry and High-Affinity Binding of Avian Leukosis Virus Subgroup K

by Eliška Gáliková, David Přikryl, Salomé Prost, Dana Kučerová, Kateřina Trejbalová and Jiří Hejnar

Viruses 2025, 17(5), 709; https://doi.org/10.3390/v17050709 - 15 May 2025

Viewed by 76

Abstract

Avian leukosis virus (ALV), the prototypical alpharetrovirus, causes tumorigenesis, immunosuppression, and wasting disease in poultry. The ALV genus is classified into ten subgroups, which differ in their host range, cell tropism, and receptor usage. The subgroups A, B, K, and J cause significant [...] Read more.

Avian leukosis virus (ALV), the prototypical alpharetrovirus, causes tumorigenesis, immunosuppression, and wasting disease in poultry. The ALV genus is classified into ten subgroups, which differ in their host range, cell tropism, and receptor usage. The subgroups A, B, K, and J cause significant economic losses worldwide. The most recently discovered subgroup, ALV-K, which is now widespread in China, has been shown to use the tva cell receptor and share it with ALV-A. However, the specific amino acid residues crucial for ALV-K host cell entry remain unknown. Using precise tva expression and chimeric tva receptors, we further elucidated the significance of the cysteine-rich domain in mediating interactions with both ALV-A and ALV-K. Through a comprehensive analysis of mutated tva receptor variants, we pinpointed tryptophan at position 33 (W33) as a pivotal amino acid residue essential for ALV-K virus binding and entry. Of note is the finding that the substitution of W33 induced resistance to ALV-K while preserving sensitivity to ALV-A. This study not only represents an advance in the understanding of the specificity of the tva receptor for ALV-K, but also offers a biotechnological strategy for the prevention of ALV-K infections in poultry. Full article

(This article belongs to the Section Animal Viruses)

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25 pages, 3117 KiB

Open AccessArticle

Postnatal Epigenetic Alterations in Calves Persistently Infected with Bovine Viral Diarrhea Virus

by Jessica N. Kincade, Dilyara A. Murtazina, Hanah M. Georges, Carolina L. Gonzalez-Berrios, Jeanette V. Bishop, Terry E. Engle, Marcela Henao-Tamayo, Jordan M. Eder, Erin M. McDonald, Darcy M. Deines, Brie M. Wright, Hana Van Campen and Thomas R. Hansen

Viruses 2025, 17(5), 708; https://doi.org/10.3390/v17050708 - 15 May 2025

Viewed by 153

Abstract

Bovine viral diarrhea virus (BVDV) is a globally prevalent pathogen causing severe detriment to the cattle industry. Vertical infection occurring before the development of the fetal adaptive immune response, before 125 days of gestation, results in an immunotolerant, persistently infected (PI) calf. It [...] Read more.

Bovine viral diarrhea virus (BVDV) is a globally prevalent pathogen causing severe detriment to the cattle industry. Vertical infection occurring before the development of the fetal adaptive immune response, before 125 days of gestation, results in an immunotolerant, persistently infected (PI) calf. It was hypothesized that epigenetic alterations observed in the splenic tissue of PI fetuses at gestational day 245 would persist into the postnatal period. White blood cell DNA from five PI and five control heifers at 4 months of age was subjected to reduced representation bisulfite sequencing and interpreted within the context of complete blood count and flow cytometry data herein. Analysis revealed 8367 differentially methylated sites contained within genes associated with the immune and cardiac system, as well as hematopoiesis. Differences observed in the complete blood counts of PI heifers include increased monocytes, microcytic anemia, and elevated platelets with decreased mean platelet volume. Flow cytometry revealed increased classical monocytes, B cells, and CD4⁺/CD8B⁺ and CD25⁺/CD127⁻ T cells, as well as decreased γδ⁺, CD4⁺, and CD4⁻/CD8B⁻ T cells. Investigation of the PI methylome provides a new perspective on the mechanisms of pathologies and provides potential biomarkers for the rapid identification of PI cattle. Full article

(This article belongs to the Special Issue Bovine Viral Diarrhea Viruses and Other Pestiviruses)

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18 pages, 5844 KiB

Open AccessArticle

Construction of Minigenome Replicon of Nipah Virus and Investigation of Biological Activity

by Fan Wang, Ruyi Chen, Jiayi Zhong, Anqi Zhou, Ran Peng, Bao Xue, Yuan Zhou, Jielin Tang, Xinwen Chen and Qi Yang

Viruses 2025, 17(5), 707; https://doi.org/10.3390/v17050707 - 15 May 2025

Viewed by 219

Abstract

Nipah virus (NiV), a highly lethal zoonotic pathogen causing encephalitis and respiratory diseases with mortality rates up to 40–70%, faces research limitations due to its strict biosafety level 4 (BSL-4) containment requirements, hindering antiviral development. To address this, we generated two NiV minigenome [...] Read more.

Nipah virus (NiV), a highly lethal zoonotic pathogen causing encephalitis and respiratory diseases with mortality rates up to 40–70%, faces research limitations due to its strict biosafety level 4 (BSL-4) containment requirements, hindering antiviral development. To address this, we generated two NiV minigenome replicons (Fluc- and EGFP-based) expressed via helper plasmids encoding viral N, P, and L proteins, enabling replication studies under BSL-2 conditions. The minigenome replicon recapitulated the cytoplasmic inclusion body (IB) formation observed in live NiV infections. We further demonstrated that IB assembly is driven by liquid–liquid phase separation (LLPS), with biochemical analyses identifying the C-terminal N core domain of the N protein, as well as N₀ and XD domains and the intrinsically disordered region (IDR) of the P protein, as essential structural determinants for LLPS-mediated IB biogenesis. The targeted siRNA silencing of the 5′ and 3′ untranslated regions (UTRs) significantly reduced replicon-derived mRNA levels, validating the regulatory roles of these regions. Importantly, the minigenome replicon demonstrated sensitivity to type I/II/III interferons and antivirals (remdesivir, azvudine, molnupiravir), establishing its utility for drug screening. This study provides a safe and efficient platform for investigating NiV replication mechanisms and accelerating therapeutic development, circumventing the constraints of BSL-4 facilities while preserving key virological features. Full article

(This article belongs to the Section Animal Viruses)

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15 pages, 4318 KiB

Open AccessBrief Report

Guinea Pigs Are Not a Suitable Model to Study Neurological Impacts of Ancestral SARS-CoV-2 Intranasal Infection

by Jonathan D. Joyce, Greyson A. Moore, Christopher K. Thompson and Andrea S. Bertke

Viruses 2025, 17(5), 706; https://doi.org/10.3390/v17050706 - 15 May 2025

Viewed by 143

Abstract

Neurological symptoms involving the central nervous system (CNS) and peripheral nervous system (PNS) are common complications of acute COVID-19 as well as post-COVID conditions. Most research into these neurological sequalae focuses on the CNS, disregarding the PNS. Guinea pigs were previously shown to [...] Read more.

Neurological symptoms involving the central nervous system (CNS) and peripheral nervous system (PNS) are common complications of acute COVID-19 as well as post-COVID conditions. Most research into these neurological sequalae focuses on the CNS, disregarding the PNS. Guinea pigs were previously shown to be useful models of disease during the SARS-CoV-1 epidemic. However, their suitability for studying SARS-CoV-2 has not been experimentally demonstrated. To assess the suitability of guinea pigs as models for SARS-CoV-2 infection and the impact of SARS-CoV-2 infection on the PNS, and to determine routes of CNS invasion through the PNS, we intranasally infected wild-type Dunkin-Hartley guinea pigs with ancestral SARS-CoV-2 USA-WA1/2020. We assessed PNS sensory neurons (trigeminal ganglia, dorsal root ganglia), autonomic neurons (superior cervical ganglia), brain regions (olfactory bulb, brainstem, cerebellum, cortex, hippocampus), lungs, and blood for viral RNA (RT-qPCR), protein (immunostaining), and infectious virus (plaque assay) at three- and six-days post infection. We show that guinea pigs, which have previously been used as a model of SARS-CoV-1 pulmonary disease, are not susceptible to intranasal infection with ancestral SARS-CoV-2, and are not useful models in assessing neurological impacts of infection with SARS-CoV-2 isolates from the early pandemic. Full article

(This article belongs to the Section Coronaviruses)

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14 pages, 686 KiB

Open AccessReview

Emerging Prognostic and Predictive Biomarkers for Human Cytomegalovirus Infection During Pregnancy: Unmet Needs and Future Perspectives

by Salvatore Rotundo, Maria Teresa Tassone, Rosaria Lionello, Paolo Fusco, Francesca Serapide and Alessandro Russo

Viruses 2025, 17(5), 705; https://doi.org/10.3390/v17050705 - 14 May 2025

Viewed by 177

Abstract

Human cytomegalovirus (HCMV) infection during pregnancy is a leading cause of congenital infections worldwide, posing significant risks to fetal health. Despite advances in prenatal care, managing HCMV infection remains challenging. Early detection, accurate risk assessment, and timely intervention are critical to mitigating the [...] Read more.

Human cytomegalovirus (HCMV) infection during pregnancy is a leading cause of congenital infections worldwide, posing significant risks to fetal health. Despite advances in prenatal care, managing HCMV infection remains challenging. Early detection, accurate risk assessment, and timely intervention are critical to mitigating the adverse outcomes associated with congenital HCMV (cHCMV), such as neurodevelopmental delays and hearing loss. However, the current landscape of biomarkers for HCMV infection in pregnancy is marked by several unmet needs. These gaps in biomarker development and application limit our ability to predict fetal transmission, assess the risk of fetal damage, and prognosticate long-term outcomes. Addressing these challenges through the identification and validation of novel biomarkers could revolutionize the management of HCMV in pregnancy, leading to improved outcomes for both mothers and their children. This review examines the critical unmet needs regarding HCMV biomarkers during pregnancy, emphasizing the priority areas for further research and innovation. Full article

(This article belongs to the Special Issue Molecular Biomarkers for Viral Infection)

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20 pages, 762 KiB

Open AccessArticle

Perinatal Mother-to-Child Chikungunya Virus Infection: Screening of Cognitive and Learning Difficulties in a Follow-Up Study of the Chimere Cohort on Reunion Island

by Raphaëlle Sarton, Magali Carbonnier, Stéphanie Robin, Duksha Ramful, Sylvain Sampériz, Pascale Gauthier, Marc Bintner, Brahim Boumahni and Patrick Gérardin

Viruses 2025, 17(5), 704; https://doi.org/10.3390/v17050704 - 14 May 2025

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Abstract

In this cohort study, we evaluated the cognitive and learning difficulties of school-age children perinatally infected with Chikungunya virus (CHIKV) on Reunion Island using the Evaluation of Cognitive Functions and Learning in Children (EDA) battery screening test compared to the healthy children cohort [...] Read more.

In this cohort study, we evaluated the cognitive and learning difficulties of school-age children perinatally infected with Chikungunya virus (CHIKV) on Reunion Island using the Evaluation of Cognitive Functions and Learning in Children (EDA) battery screening test compared to the healthy children cohort used for EDA development. Of the 19 infected children, 11 (57.9%) exhibited subnormal or abnormal scores, of whom 3 were classified as high risk, and 8 were classified as at risk for cognitive and learning difficulties. Children who had encephalopathy were at higher risk for displaying at least one difficulty than non-encephalopathic children (relative risk 2.13; 95% CI 1.05–4.33). The difficulties observed affected verbal functions, non-verbal functions, and learning abilities, such as phonology, lexical evocation and comprehension, graphism, selective visual attention, planning, visual–spatial reasoning, dictation and mathematics, as well as core executive functions, such as inhibitory control, shifting, and working memory. Neurocognitive dysfunctions could be linked to severe brain damage, as evidenced by severe white matter reduction mainly in the frontal lobes and corpus callosum and potentially in all functional networks involved in difficulties. These results should motivate further investigation of intellectual and adaptive functioning to diagnose intellectual deficiency and severe maladaptive behaviour in children perinatally infected with Chikungunya virus. Full article

(This article belongs to the Special Issue Long-Term Developmental Outcomes of Congenital Virus Infections)

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18 pages, 2835 KiB

Open AccessArticle

Respiratory Syncytial Virus Elicits Glycolytic Metabolism in Pediatric Upper and Lower Airways

by Armando S. Flores-Torres, Svetlana Rezinciuc, Lavanya Bezavada, Barry L. Shulkin, Stephania A. Cormier and Heather S. Smallwood

Viruses 2025, 17(5), 703; https://doi.org/10.3390/v17050703 - 14 May 2025

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Abstract

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract viral infection in infants and causes around 60,000 in-hospital deaths annually. Emerging evidence suggests that RSV induces metabolic changes in host cells to support viral replication, presenting a potential target for [...] Read more.

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract viral infection in infants and causes around 60,000 in-hospital deaths annually. Emerging evidence suggests that RSV induces metabolic changes in host cells to support viral replication, presenting a potential target for therapeutic intervention. To investigate RSV-driven metabolic changes in situ, we combined positron emission tomography (PET), live-cell bioenergetics, and metabolomic profiling in the upper and lower airways of children. PET imaging revealed persistent, hyper-glycolytic regions in the lungs of RSV-infected children. Bioenergetic analysis of freshly collected nasopharyngeal aspirates from infants showed live upper respiratory cells (URCs) infected with RSV in situ exhibited significantly higher levels of glycolysis, glycolytic capacity, glycolytic reserves, and mitochondrial respiration than uninfected controls. Metabolomic analysis of nasopharyngeal fluids from these patients revealed distinct metabolic signatures, including increased citrate and malate, and decreases in taurine. In vitro infection of pediatric nasopharynx tissue-derived multicellular epithelial cultures (TEpiCs) and bronchial epithelial cells further confirmed RSV-induced increases in glycolysis. Together, these findings demonstrate that RSV infection induces hypermetabolism in both upper and lower primary airways in situ, supporting the potential of host-targeted metabolic interventions as a therapeutic strategy—particularly in vulnerable populations such as infants for whom vaccines are not currently available. Full article

(This article belongs to the Section General Virology)

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14 pages, 596 KiB

Open AccessReview

Thermal Inactivation of Hepatitis E Virus: A Narrative Review

by Tatsuo Kanda and Hiroaki Okamoto

Viruses 2025, 17(5), 702; https://doi.org/10.3390/v17050702 - 14 May 2025

Viewed by 194

Abstract

Hepatitis E virus (HEV) infection is an emerging infectious disease. HEV-1 and HEV-2 infect humans through contaminated water and foods, mainly in developing countries. HEV-3 and HEV-4 also infect humans through contaminated food and are thought to be zoonotic infections occurring in both [...] Read more.

Hepatitis E virus (HEV) infection is an emerging infectious disease. HEV-1 and HEV-2 infect humans through contaminated water and foods, mainly in developing countries. HEV-3 and HEV-4 also infect humans through contaminated food and are thought to be zoonotic infections occurring in both developing and developed countries. A vaccine for hepatitis E is licensed in only limited countries. The inactivation of infectious HEV is very important to ensure the safety of drinking water and foods. HEV-3 and HEV-4 RNA have been detected in some pig liver products, and it is possible that these foods may represent an infectious source of HEV. In this article, previous publications on the heat inactivation and heat stability of HEV are collected, and we discuss the present assessment of the heat inactivation of HEV. The thermal stability of HEV infection in cell culture systems and pig bioassays has been demonstrated, while the efficacy of the method of thermal inactivation using plasma products has not yet been established. Here, we propose that the treatment of HEV-contaminated foods at 95 °C for 10 min is one of the safest options for the inactivation of HEV. Full article

(This article belongs to the Section Animal Viruses)

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23 pages, 3118 KiB

Open AccessArticle

Treatment of E. coli Infections with T4-Related Bacteriophages Belonging to Class Caudoviricetes: Selecting Phage on the Basis of Their Generalized Transduction Capability

by Alexandra N. Nikulina, Nikita A. Nikulin, Natalia E. Suzina and Andrei A. Zimin

Viruses 2025, 17(5), 701; https://doi.org/10.3390/v17050701 - 14 May 2025

Viewed by 218

Abstract

The problem of the multidrug resistance of pathogenic bacteria is a serious concern, one which only becomes more pressing with every year that passes, motivating scientists to look for new therapeutic agents. In this situation, phage therapy, i.e., the use of phages to [...] Read more.

The problem of the multidrug resistance of pathogenic bacteria is a serious concern, one which only becomes more pressing with every year that passes, motivating scientists to look for new therapeutic agents. In this situation, phage therapy, i.e., the use of phages to combat bacterial infections, is back in the spotlight of research interest. Bacterial viruses are highly strain-specific towards their hosts, which makes them particularly valuable for targeting pathogenic variants amidst non-pathogenic microflora, represented by such commensals of animals and humans as E. coli, S. aureus, etc. However, selecting phages for the treatment of bacterial infections is a complex task. The prospective candidates should meet a number of criteria; in particular, the selected phage must not contain potentially dangerous genes (e.g., antibiotic resistance genes, genes of toxins and virulence factors etc.)—or be capable of transferring them from their hosts. This work introduces a new approach to selecting T4-related coliphages; it allows one to identify strains which may be safer in terms of involvement in the horizontal gene transfer. The approach is based on the search for genes that reduce the frequency of genetic transduction. Full article

(This article belongs to the Section Bacterial Viruses)

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23 pages, 2899 KiB

Open AccessReview

A Systematic Study of Bovine Viral Diarrhoea Virus Co-Infection with Other Pathogens

by Zhiwei Hou, Jiahui Wang, Bin Tan and Shuqin Zhang

Viruses 2025, 17(5), 700; https://doi.org/10.3390/v17050700 - 14 May 2025

Viewed by 241

Abstract

Bovine viral diarrhoea virus (BVDV) is the causative agent of bovine viral diarrhoea/mucocutaneous disease (BVD-MD). Its associated co-infections pose a threat to the cattle industry, which is becoming a key breakthrough in the global system of prevention in the cattle industry. In recent [...] Read more.

Bovine viral diarrhoea virus (BVDV) is the causative agent of bovine viral diarrhoea/mucocutaneous disease (BVD-MD). Its associated co-infections pose a threat to the cattle industry, which is becoming a key breakthrough in the global system of prevention in the cattle industry. In recent years, cases of co-infection have occurred and been reported from time to time, and this situation not only poses certain difficulties in controlling the outbreak and in treatment in the farming industry, but also poses considerable challenges in detection and diagnosis. In this review, by systematically integrating studies on BVDV co-infection, we firstly compared and analysed the characteristics of BVDV co-infection with viruses, bacteria and other pathogens in in vivo/in vitro models in terms of synergism, host immune response and epidemiological transmission. Then we systematically constructed a BVDV Co-infection Impact Map, which demonstrates a paradigm of pathogen–host–immune interactions in the transmission of BVDV and provides a theoretical framework for breaking through the current precision diagnostic strategies and showcasing the effectiveness of integrated prevention and control. Full article

(This article belongs to the Special Issue Bovine Viral Diarrhea Viruses and Other Pestiviruses)

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