Porcine circovirus 3 (PCV3) has emerged as a significant pathogen associated with various clinical manifestations affecting global swine populations. To investigate the prevalence and molecular characteristics of PCV3 strains, we collected 11,194 tissue samples from pigs across 650 farms of varying breeding scales in 18 cities of Henan province from March 2022 to December 2024. Detection of PCV3 was performed using a validated real-time quantitative PCR assay. The results showed that the total positive rate of PCV3 was 9.25% (1035/11,194), and PCV3 was detected on pig farms in 18 cities of Henan Province. The complete genome sequences of six PCV3 strains and the ORF2 gene sequences of four PCV3 strains were determined and analyzed. These 10 PCV3 strains shared 98% to 99.7% nucleotide sequence identity in ORF2 with PCV3 reference strains. The complete ORF2 gene sequences of these 10 PCV3 strains shared 98.4% to 99.8% nucleotide sequence identity with each other, and the encoded proteins shared 98.1% to 100% amino sequence acid identity. Phylogenetic analysis based on the ORF2 gene indicated that all 10 sequenced PCV3 strains belonged to genotype PCV3b. Notably, two amino acid mutations were identified in predicted B cell epitopes within the Cap protein of the these strains, which may affect the immunogenicity of PCV3. These data contribute to our understanding of the molecular epidemiology and evolution of PCV3 and provide a foundation for the prevention and control of PCV3 and other PCVs.

Here, we report a novel fungal virus, tentatively named "Rhizoctonia solani endornavirus 15" (RsEV15), isolated from Rhizoctonia solani AG-1 IA strain MY-JK-1. The RsEV15 genome consists of 18,934 nucleotides with a GC content of 44.5% and contains two open reading frames (ORFs). ORF1 encodes a large polypeptide of 5070 amino acids with conserved RNA-dependent RNA polymerase (RdRp), helicase (Hel), and glycosyltransferase domains. ORF2 encodes a protein of unknown function composed of 1063 amino acids. BLASTp results showed a relationship between RsEV15 and RsEV8, although their genomes share only 49.56% nucleotide sequence identity. Phylogenetic analysis based on RdRp sequences indicated that RsEV15 is a new member of the genus Alphaendornavirus (family Endornaviridae).

Oyster hatcheries suffer significant mortality caused by members of the bacterial genus Vibrio, which infect Crassostrea gigas larvae. Bacteriophages present a potential alternative to antibiotics, with N4-like phages showing promise against vibriosis. We investigated the adsorption properties and determined the complete genome sequence of phage pVco-7 and performed phylogenetic and comparative analysis with other N4-like Vibrio phages to gain insights into phage resistance mechanisms and infection strategies. The phage has a linear dsDNA genome with 126 genes and a typical N4-like organization. Tail fiber variations were identified that could potentially influence host recognition, providing insights into how phages of the genus Vicoquintavirus interact with their host as well as their evolutionary relationships. These findings will contribute to the development effective biocontrol strategies against vibriosis in commercially important bivalve aquaculture.

In this study, we isolated two novel mitoviruses co-infecting the fungus Gnomoniopsis sanguisorbae, which were designated as "Gnomoniopsis sanguisorbae mitovirus L" (GsMV-L) and "Gnomoniopsis sanguisorbae mitovirus M" (GsMV-M). The complete genome lengths of GsMV-L and GsMV-M were determined to be 2,785 and 2,529 nucleotides, respectively, with a GC content of 44% and 35%, respectively. Both viruses possess a single open reading frame (ORF) that encodes an RNA-dependent RNA polymerase (RdRp) containing conserved catalytic motifs. BLASTp analysis revealed that the RdRps of GsMV-L and GsMV-M exhibited the highest amino acid sequence similarity to those of sunflower phomopsis-associated mitovirus 1 and Phomopsis viticola mitovirus 962_1, with 50.97% and 41.97% identity, respectively. Phylogenetic analysis based on RdRp sequences indicated that GsMV-L clustered with members of the genus Triamitovirus, while GsMV-M clustered with members of the genus Unuamitovirus, both of which are taxonomically classified within the family Mitoviridae.

Antimicrobial resistance is escalating among Staphylococcus species, which are major pathogens affecting both humans and animals. As therapeutic options continue to narrow, phage therapy is re-emerging as a promising strategy to combat resistant strains. In this study, we isolated from pig farm effluents a bacteriophage named CSF, infecting a Staphylococcus xylosus strain. The CSF phage demonstrated a broad host range, lysing mecA-positive, multidrug-resistant strains across nine species of the genera Staphylococcus and Mammaliicoccus. Notably, it also inhibited biofilm formation in strains that it could not infect directly, and this activity persisted at low virus concentrations and in combination with antibiotics. The phage maintained its lytic activity under extreme conditions of temperature, pH, and UV exposure, underscoring its resilience for practical use. Sequencing of the viral genome revealed that it is 140 kb in length and has a genetic composition consistent with a lytic lifestyle. Phylogenetic analysis showed that phage CSF is related to members of the family Herelleviridae that are found globally, suggesting a widespread distribution of related viral lineages. Importantly, the phage genome was found to lack bacterial virulence or antimicrobial resistance genes, suggesting its safety for biotechnological applications. Intergenomic comparisons indicated that CSF should be classified as a member of a new genus, expanding the known diversity of bacteriophages. These findings demonstrate potential of CSF for phage therapy and other biotechnological applications.

Many studies have shown that, during mpox outbreaks, concomitant infections with monkeypox virus and varicella-zoster virus (VZV) are not uncommon. Infection with either monkeypox virus or VZV may increase the host's susceptibility to contracting a subsequent infection. Here, we summarize the clinical presentation, diagnosis, and management of cases of reported monkeypox virus and VZV coinfection. We conducted a thorough search of four databases: PubMed, Scopus, Medline, and Web of Science, covering the period up to 10 March 2025, and identified studies reporting coinfections with monkeypox virus and VZV. Data were extracted using a standardized sheet, and case reports and the quality of case series were assessed using the JBI critical appraisal tool. Cross-sectional and cohort quality was assessed using the NIH tool. Our systematic review included 18 studies with 448 cases of coinfection with monkeypox virus and VZV. The majority of cases were reported in African countries, particularly Nigeria and the DRC. Most of the patients were children or young adults, and 41.51% were male. Common predisposing factors included contact with animals, confirmed exposure to infected individuals, and immunocompromised status. Treatment approaches included antivirals (primarily acyclovir or tecovirimat) and supportive care. While most cases were managed successfully, four deaths (0.89%) were reported. This review highlights the complex interplay between monkeypox virus and VZV in coinfections, emphasizing the need for heightened awareness, standardized diagnostic protocols, and tailored management strategies. It is important to consider coinfections when making diagnoses, especially in places where mpox is common or in cases in which the patient is at high risk.

A previously uncharacterized mitovirus, designated as "Diaporthe mitovirus 3" (DMV3), was identified and isolated from the fungal pathogen Diaporthe sp. (isolate B-16) in this study. The DMV3 genome is a positive-sense, single-stranded RNA (+ ssRNA) molecule of 2,319 nucleotides (nt) with a GC content of 40%. It contains a single open reading frame (ORF) encoding an RNA-dependent RNA polymerase (RdRp) consisting of 679 amino acids (aa) with a molecular mass of 76.4 kDa. Comparative analysis using BLASTp revealed that the RdRp of DMV3 exhibits the highest sequence similarity (64.56% identity) to Pestalotiopsis mitovirus 2 (PMV2). Phylogenetic analysis based on RdRp sequences demonstrated that DMV3 clusters together with PMV2 within a distinct clade, supporting its classification as a member of the genus Unuamitovirus within the family Mitoviridae.

The Retroviridae are a family of viruses that reverse transcribe their RNA genome and integrate the resulting double-stranded DNA copy into the genome of the host cell. Retroviruses are well-documented pathogens that have been associated with a variety of diseases. The International Committee on Taxonomy of Viruses (ICTV) currently lists 65 species of retroviruses. As required by the ICTV, we have converted the species nomenclature to a binomial format comprised of the genus and a freeform epithet. Assigning binomial species names to classify new retroviruses will be facilitated when following the epithet rules described herein.

Porcine circovirus 2 (PCV2) and porcine circovirus 3 (PCV3) are considered a threat to the pig industry due to their association with growth retardation and reproductive disorders. In this study, we developed a multiplex real-time PCR (qPCR) assay for simultaneous detection of PCV2 and PCV3 and used it to investigate the epidemiology of PCV2 and PCV3 at different stages of pig production. The sensitivity of the multiplex qPCR was 4.32 × 101copies/µL for PCV2 and 1.01 × 101copies/µL for PCV3, and the coefficient of variation was less than 1%. The correlation coefficients (R2) of the standard curves were all greater than 0.990. Out of 1241 samples tested, nine (0.73%) were positive for PCV2, 209 (16.84%) for PCV3, and three (0.24%) for both. PCV2 was detected in saliva from asymptomatic gilts on one farm, and PCV3 was detected in all sample types except semen at all production stages on all of the farms where samples were collected. The main sample types that tested positive were saliva (23.19%, 77/322), blood (17.80%, 102/573), saliva/blood mixture (18.75%, 9/48), and pigpen swabs (32.14%, 9/28). Viral loads ranged from 103.9 to 108.2 copies/mL. Gilts (37.85%, 81/214) and grow-finish pigs (42.25%, 30/71) were the main asymptomatic PCV3 carriers. Piglets (16.67%, 3/18) and nursery pigs (22.73%, 5/22) were the main symptomatic PCV3 carriers. The assay described here is a practical and sensitive diagnostic technique for identification and monitoring of PCV2 and PCV3 infections and can provide new information on the epidemiology of PCV2 and PCV3 that can be applied for developing effective prevention and control strategies.