The COVID-19 pandemic caused by SARS-CoV-2 has had a significant impact on global social and economic activities. The continuous emergence of new SARS-CoV-2 variants has made the global pandemic of COVID-19 difficult to...The COVID-19 pandemic caused by SARS-CoV-2 has had a significant impact on global social and economic activities. The continuous emergence of new SARS-CoV-2 variants has made the global pandemic of COVID-19 difficult to predict. Therefore, it is of great significance to closely monitor the SARS-CoV-2 epidemic and understand the evolution and transmission characteristics of SARS-CoV-2. In this study, we examined 36 cases of SARS-CoV-2 infection in Wuhan in June 2023. Genomic surveillance revealed that this outbreak was caused by Omicron XBB variants, among which FY.3 and its descendants FY.3.1 and FY.3.2 dominated, and this trend was consistent with the prevalence of SARS-CoV-2 nationwide in June and July. Analysis of sequence variations within hosts and between populations suggested that the S and ORF8 genes had undergone positive selection, possibly due to their important role in host adaptation, suggesting that some of these variations might be harmful mutations that reduce vaccine effectiveness. These findings may provide insights that will aid in predicting the evolutionary direction of SARS-CoV-2 in terms of variant competition, informing the design of next-generation multivalent vaccines and therapeutic strategies targeting conserved or rapidly evolving regions such as the S and ORF8 genes and supporting the evaluation and adjustment of surveillance, prevention, and control strategies in the Wuhan region.
Mycoviruses have been classified into 35 virus families so far. In addition to numerous mycoviruses with proven fungal or oomycetes hosts, many newly discovered viruses from environmental water and soil samples and vario...Mycoviruses have been classified into 35 virus families so far. In addition to numerous mycoviruses with proven fungal or oomycetes hosts, many newly discovered viruses from environmental water and soil samples and various animal or plant specimens exhibit significant similarity to classified mycoviruses, thereby expanding the known sequence space of fungal and related viruses. In this study, we searched for mycoviruses in two environmental water samples that had been collected from the Teltow Canal and the Havel River in Berlin, Germany. Viral sequences with similarity to members of 16 virus families were identified. The most common viruses in our samples were botourmia-like viruses with moderate similarity to members of the genus Ourmiavirus. Notably, 58 of the ourmia-like sequences from the Teltow Canal and Havel River and 10 ourmia-like sequences from other sources exhibited a dicistronic genome layout. The second open reading frame (ORF) of these viruses encoded a putative capsid protein with an S domain that showed little similarity to the structural proteins of the classified ourmiaviruses. The second-largest virus group (59 sequences) was assigned to the order Ghabrivirales, and 13 of these sequences exhibited similarity to members of the suborder Alphatotivirineae (families Orthototiviridae, Pseudototiviridae, Botybirnaviridae, and Chrysoviridae). Thirty-three sequences clustered with members of the suborder Betatotivirineae - three of them with members of the family Artiviridae. Fifteen highly divergent toti-like sequences suggest the need to establish a new higher-order taxon within the order Ghabrivirales. Other virus sequences were assigned to the families Mitoviridae (three unuamitoviruses and 10 highly divergent mitovirus-like sequences), Narnaviridae (five "alphanarnavirus"-like sequences), Amalgaviridae (two zybavirus-like sequences), Hypoviridae (one partial RdRP sequence), and Mymonaviridae (one partial RdRP sequence), and one was not classified (Sclerophthora macrospora B-like virus). Notable results include a clade of highly divergent mitovirus-like sequences with a standard translation code, three narnavirus-like sequences with a reverse-frame ORF, and a clade of four Ghabrivirales-like replicase sequences that were found to have numerous termination codons regardless of which translation table was used.
Here, we report the isolation of a novel mycovirus from Phomopsis asparagi strain XJ5. The viral genome consists of a positive-sense, single-stranded RNA (+ ssRNA) molecule that is 2,657 nucleotides (nt) in length and ha...Here, we report the isolation of a novel mycovirus from Phomopsis asparagi strain XJ5. The viral genome consists of a positive-sense, single-stranded RNA (+ ssRNA) molecule that is 2,657 nucleotides (nt) in length and has a GC content of 42%. It contains a single open reading frame (ORF) encoding a putative protein of 731 amino acids, with a predicted molecular mass of 83.0 kDa. A BLASTp search showed that the putative protein shared the highest sequence similarity with Fusarium pseudograminearum mitovirus 5 (FpgMV5), exhibiting 55.84% sequence identity. Phylogenetic analysis revealed that this mycovirus clusters with members of the genus Unuamitovirus, belonging to the family Mitoviridae. Based on these findings, we propose to designate this virus as "Phomopsis asparagi mitovirus 1" (PhaMV1).
Leishmania RNA virus 2 (LRV2) has emerged as a potential molecular co-determinant of clinical outcomes in Leishmania major infections, particularly within the Old-World cutaneous leishmaniasis (CL) belt. Recent molecular...Leishmania RNA virus 2 (LRV2) has emerged as a potential molecular co-determinant of clinical outcomes in Leishmania major infections, particularly within the Old-World cutaneous leishmaniasis (CL) belt. Recent molecular investigations from Iran and adjacent endemic regions (2024-2025) have revealed extensive LRV2 diversity and phylogeographic structure. However, the lack of standardized assays, incomplete clinical metadata, and inconsistent reporting frameworks have hindered translation of detection findings into actionable public-health insights. This commentary synthesizes these findings and proposes a six-point, standards-based micro-protocol for harmonizing molecular detection, metadata collection, and clinical outcome recording, aimed at enhancing decision-useful surveillance and global comparability.
Following their identification in French cereals in 2022-2023, the complete genome sequences of two isolates of wheat mosaic virus (WMoV, Emaravirus tritici) were determined. The French isolates showed the closest relati...Following their identification in French cereals in 2022-2023, the complete genome sequences of two isolates of wheat mosaic virus (WMoV, Emaravirus tritici) were determined. The French isolates showed the closest relationship to Ohio group isolates, with 92% (P7) to 98% (P1) amino acid sequence identity in their proteins. Notably, the two French isolates were found to differ significantly in their RNA7, and one of them was found to possess two RNA5 and three RNA6 segments, a feature not previously reported for WMoV. This represents the first identification of WMoV in the European Union, and the data reported here significantly extend our knowledge about the genome composition and diversity of this virus.
A novel partitivirus was detected in quinoa (Chenopodium quinoa) plants growing in China. The complete genome sequence of quinoa cryptic virus (QCV) was determined using a combination of next-generation sequencing, RT-PC...A novel partitivirus was detected in quinoa (Chenopodium quinoa) plants growing in China. The complete genome sequence of quinoa cryptic virus (QCV) was determined using a combination of next-generation sequencing, RT-PCR, and RACE. Phylogenetic analysis based on amino acid (aa) sequences of the RdRP revealed that QCV belongs to the genus Deltapartitivirus within the family Partitiviridae. The aa sequence identity values obtained when comparing RdRP and CP of QCV with those of the most closely related virus, pistacia cryptic virus, were significantly below the threshold for species demarcation within the genus (≤ 90% aa sequence identity for RdRP and ≤ 80% for CP), suggesting that QCV represents a new species.
Alphabaculoviruses rel, in combination with natural putrefaction, on the auxiliary genes v-cath and chiA for host liquefaction, a process that is critical for virus release and horizontal transmission. Here, we describe...Alphabaculoviruses rel, in combination with natural putrefaction, on the auxiliary genes v-cath and chiA for host liquefaction, a process that is critical for virus release and horizontal transmission. Here, we describe DijuNPV-DF/23, a natural isolate infecting the passion fruit caterpillar Dione juno that fails to induce liquefaction. PCR amplification of the v-cath/chiA locus revealed a shorter amplicon compared to a previously reported virus, DijuNPV-Araguarina, suggesting gene disruption. Genome sequencing confirmed a 122,265-bp genome with 152 ORFs and a major structural alteration: v-cath was fragmented into two truncated ORFs due to a 76-nt deletion, while chiA remained intact. This provides a direct molecular explanation for the observed non-liquefying phenotype.
Senecavirus A (SVA) infection causes vesicular disease in pigs, resulting in significant economic losses for swine producers and trade restrictions on pork exports. Due to its clinical similarity to other vesicular disea...Senecavirus A (SVA) infection causes vesicular disease in pigs, resulting in significant economic losses for swine producers and trade restrictions on pork exports. Due to its clinical similarity to other vesicular diseases, implementing control measures, such as vaccination, is essential to mitigate the impact of the disease. In this study, we assessed the immunogenicity of an inactivated SVA vaccine derived from a representative strain circulating in Brazil and the duration of vaccine-induced immunity in swine. Vaccinated 6- to 8-week-old pigs exhibited a robust humoral response, evidenced by significant increases in SVA-specific IgG and virus-neutralizing antibody titers. These humoral responses were detectable as early as seven days after primary vaccination and persisted for at least 11 weeks. Regarding cellular immunity, vaccinated pigs exhibited significantly higher proliferation of B lymphocyte subpopulations (CD19CD79α) and T lymphocyte subpopulations (CD3eCD4, CD3eCD8α, CD3eCD8αCD25, CD3eCD4CD8α), compared to controls (p ≤ 0.05) in splenocytes collected in the fifth-week post-vaccination. A significant increase in T lymphocyte proliferation (CD3eCD4, CD3eCD8α, CD3eCD8αCD25, CD8αCD27) was also observed in splenocytes collected in the eleventh-week post-vaccination. These findings demonstrate that the inactivated SVA vaccine induces a robust and long-lasting humoral and cellular immune response, extending through the market age of slaughter (~ 130 days) and potentially contributing to the effective control of SVA infections in swine herds.
Here, we report the identification of a positive-sense single-stranded RNA virus from Ceratobasidium AG-Bo strain LC-JK-2, designated as "Rhizoctonia cerealis alphaendornavirus 2" (RcAEV-2). The complete genome sequence...Here, we report the identification of a positive-sense single-stranded RNA virus from Ceratobasidium AG-Bo strain LC-JK-2, designated as "Rhizoctonia cerealis alphaendornavirus 2" (RcAEV-2). The complete genome sequence of this virus was determined and found to be 15,244 nt in length with a GC content of 39%. The genome contains a single open reading frame (ORF) encoding an RNA-dependent RNA polymerase (RdRp) of 4974 amino acids (aa) with a predicted molecular weight of 547.14 kDa. BLASTp results showed that the RdRp of RcAEV-2 had the highest amino acid sequence similarity to that of Ceratobasidium endornavirus A (YP_009310113.1). Phylogenetic analysis revealed that RcAEV-2 exhibited the closest evolutionary relationship to Ceratobasidium endornavirus A within the genus Alphaendornavirus, forming a distinct clade separate from other virus families. Thus, RcAEV-2 has been identified as a new member of the genus Alphaendornavirus within the family Endornaviridae.
Aeromonas veronii is a mesophilic bacterium that is widely distributed in terrestrial and aquatic environments and is able to cause disease in various species of fish and other animals. In humans, pathogenic A. veronii c...Aeromonas veronii is a mesophilic bacterium that is widely distributed in terrestrial and aquatic environments and is able to cause disease in various species of fish and other animals. In humans, pathogenic A. veronii causes mainly foodborne infections due to increased consumption of chilled seafood. In this study, the novel lytic Aeromonas veronii phage AerV_348 was isolated and characterized. The phage and its bacterial host, A. veronii CEMTC 9558, were isolated from Lake Pestroe, North Kazakhstan. AerV_348 is a dsDNA virus with a genome size of 43,779 bp. The phage is lytic and has a very narrow host range, reproducing only in its host strain. The latent time was determined to be 50 minutes, and the burst size was 55 plaque-forming units per cell. The AerV_348 genome content corresponds to a lytic phage with myovirus morphology that does not contain genetic signs of being a temperate phage. Comparative analysis revealed that AerV_348 belongs to a large group of unclassified tailed phages that infect aquatic bacteria such as Vibrio, Shewanella, and Oceanospirillum. All of these phages have similar genome sizes and structures and share a conserved cluster of genes that encode structural proteins. However, these phages demonstrate high variability in a cluster of genes responsible for DNA metabolism and translation. Currently, the classification of this phage group is not clear, and new phage genomic data may help to separate this group as a new taxonomic unit within the class Caudoviricetes.
In this study, the presence of a betacoronavirus (species Betacoronavirus erinacei, genus Betacoronavirus, family Coronaviridae) was investigated in faecal samples collected from northern white-breasted hedgehogs (Erinac...In this study, the presence of a betacoronavirus (species Betacoronavirus erinacei, genus Betacoronavirus, family Coronaviridae) was investigated in faecal samples collected from northern white-breasted hedgehogs (Erinaceus roumanicus) in different sampling areas in Hungary using reverse transcription PCR (RT-PCR) and sequencing methods. A total of 23 (27.4%) of the 84 specimens were positive for betacoronaviruses (PX460030-PX460052), and the region of the viral genome encoding the complete spike protein was sequenced for eight of the positive samples. The complete spike genes from these eight specimens showed 91–94% nucleotide (nt) and 92–94% amino acid (aa) sequence identity to each other and 86–91% nt and 87–92% aa sequence identity to the other European hedgehog coronavirus strains. Hedgehog betacoronavirus is a common and widespread infectious agent in the three hedgehog species (E. europaeus, E. amurensis, and, based on this study, E. roumanicus) studied in Europe and Asia so far, with geographical and probably host-species-specific genetic lineages.
Single-cycle viruses, which lack essential genes for virus replication, demonstrate high protective efficacy and safety, making them promising candidates for commercial vaccines. However, their lack of replication capaci...Single-cycle viruses, which lack essential genes for virus replication, demonstrate high protective efficacy and safety, making them promising candidates for commercial vaccines. However, their lack of replication capacity presents a difficulty for large-scale vaccine production. In this study, we aimed to enhance viral replication by utilizing drugs targeting microtubule dynamics, which play a crucial role in maintaining cell structure, transporting materials, and facilitating the movement of viral particles within the host cell during virus infection. To identify optimal drug concentrations and assess viral replication capacity, we constructed the single-cycle viral hemorrhagic septicemia virus rVHSV-A-MetLuc-GΔTM, which contains a luciferase reporter gene. Using this construct, both drugs enhanced the production of single-cycle viruses in fish cells at a concentration of 100 nM without causing cytotoxicity. Furthermore, we identified the mechanism by which viral replication is increased, which involves upregulation of the c-Fos and c-Jun genes. This indicates that the transcription factor AP-1 plays a key role in this process. This study shows that appropriate treatment with colchicine and paclitaxel, which influence microtubule dynamics, can enhance the replication capacity of single-cycle viruses. This presents opportunities to increase the cost-effectiveness of single-cycle and attenuated virus-based vaccines for industrial use.
We analyzed the dsRNA profiles of Trichoderma spp. and identified a novel mycovirus from Trichoderma harzianum strain NFCF419. Phylogenetic and genomic analysis suggested that this virus is a novel member of the family A...We analyzed the dsRNA profiles of Trichoderma spp. and identified a novel mycovirus from Trichoderma harzianum strain NFCF419. Phylogenetic and genomic analysis suggested that this virus is a novel member of the family Alternaviridae. Next-generation sequencing (NGS) analysis revealed that this virus consisted of four genome segments. The complete genome sequences of the segments were determined by NGS, and the NGS results were confirmed by manual sequencing of RT-PCR amplicons using specific primer pairs. 5’- and 3’-RACE was performed to determine the terminal sequences of each segment. The genome segments were found to be 3,572 bp (dsRNA1), 2,552 bp (dsRNA2), 2,593 bp (dsRNA3), and 1,484 bp (dsRNA4) in size. The largest segment (dsRNA1) contains a single open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRP). dsRNA2, 3, and 4 each contain a single ORF encoding a putative methyltransferase, a coat protein, and a hypothetical protein with unknown function, respectively. Evaluation of the genome organization, analysis of the deduced amino acid sequence of the RdRP, and phylogenetic analysis indicated that this virus is a new member of the genus Alternavirus in the family Alternaviridae. Accordingly, we designated this novel mycovirus "Trichoderma harzianum alternavirus 1" (ThAV1). This is the first report of a mycovirus of the family Alternaviridae that infects a member of the genus Trichoderma.
Dahlia mosaic virus (DMV) and dahlia common mosaic virus (DCMV), members of the genus Caulimovirus, are associated with dahlia mosaic disease and are prevalent in dahlia plants in the USA and in several other parts of th...Dahlia mosaic virus (DMV) and dahlia common mosaic virus (DCMV), members of the genus Caulimovirus, are associated with dahlia mosaic disease and are prevalent in dahlia plants in the USA and in several other parts of the world. To resolve a discrepancy in the publicly available genomic sequence of DMV and its taxonomic status with respect to DCMV, the complete genome sequences of several DMV and DCMV isolates from different regions of the USA were determined. Based on this sequence analysis, we resolved a discrepancy in the previously reported DMV sequence, confirmed that DMV possesses a genome structure and organization that is typical of a caulimovirus, and found that it shares 81% identity in the polyprotein coding sequence and 85% in the RT and RNase H domains of the polyprotein with DCMV. Greater sequence divergence was observed in the remainder of their genomes. As per the guidelines for demarcation of caulimoviruses at the species level by the International Committee on Taxonomy of Viruses, we propose that DMV and DCMV should be considered variants of the same virus.
Highly pathogenic avian influenza (HPAI) H5N8 virus, first identified in late 2016 in Egypt, continues to circulate and has replaced the previously dominant HPAI H5N1 virus of clade 2.2.1. In this study, HPAI H5N8 was de...Highly pathogenic avian influenza (HPAI) H5N8 virus, first identified in late 2016 in Egypt, continues to circulate and has replaced the previously dominant HPAI H5N1 virus of clade 2.2.1. In this study, HPAI H5N8 was detected on 23 commercial poultry farms in Egypt. Complete genome sequences of three isolates collected in 2021 were obtained using next-generation sequencing (NGS) and subjected to genetic characterization. Phylogenetic analysis showed these isolates to belong to clade 2.3.4.4b, comprising two genotypes: EA-2021-Q and EA-2020-A. Molecular analysis of the haemagglutinin (HA) protein revealed the presence of T156A and V538A substitutions in the duck isolate and an N183S substitution in the chicken isolate. Several additional nonsynonymous mutations were identified, including 147I and 504V in the PB2 protein, 127V, 672L, and 550L in the PA protein, 64F and 69P in the M2 protein, and 42S in the NS1 protein. Comparative analysis of HA antigenic sites between these isolates and the human vaccine against H5N8 revealed four nonsynonymous mutations: S141P, A154N, D45N, and V174I. Notably, the HA sequences of the studied isolates shared 98.7-99.4% amino acid sequence identity, and the NA sequences shared 96.1-97.1% identity to those of the 2.3.4.4b candidate human H5N8 vaccine strain (CVV) A/Astrakhan/3212/2020-like. These findings underscore the importance of continuous monitoring of the genetic evolution of avian influenza viruses to guide updates of candidate vaccine strains. Furthermore, the high similarity between the detected isolates and a zoonotic Russian H5N8 wild-type strain highlights the potential risk of cross-species transmission and possible human infection.
Patients with chronic hepatitis B (CHB) are at risk of developing hepatocellular carcinoma (HCC) during treatment with nucleos(t)ide analogs (NAs). Several factors, including abnormal ALT levels during NA treatment, are...Patients with chronic hepatitis B (CHB) are at risk of developing hepatocellular carcinoma (HCC) during treatment with nucleos(t)ide analogs (NAs). Several factors, including abnormal ALT levels during NA treatment, are associated with HCC risk; however, the mechanisms of ALT abnormalities remain unknown. Here, deletions in the preS1/2 region of the hepatitis B virus (HBV) genome were evaluated in the context of persistent ALT abnormalities after NA treatment. Out of the 198 patients with CHB who had been treated with NAs, 40 who had been treated with entecavir, tenofovir disoproxil fumarate, or tenofovir alafenamide fumarate as the first-line therapy and from whom serum samples had been collected before NA treatment were selected for analysis of the infecting virus. Total DNA was extracted from the samples and subjected to nested PCR to detect deletions in the preS1/2 region of the HBV genome. Patients for whom deletions were found in ≥ 40% of the amplicons were classified as the "high-del" group, and the others were the "low-del" group. The preS1/2 region was amplified from 39 (97.5%) of the 40 samples, and a deletion was found in 19 of these patients (48.7%). The cumulative incidence of HCC was found to be significantly higher in the high-del group than in the low-del group (25% vs. 7% at 2 years, P = 0.021). The high-del group also had significantly higher ALT levels than the low-del group after 1 year of NA treatment (35 vs. 26 U/L, P = 0.020). In summary, patients with CHB with frequent preS1/2 deletions showed higher ALT levels after NA treatment and a higher risk of developing HCC.
Few studies have examined adenoviruses (AdVs) in bats from the U.S.; therefore, we targeted a fragment of the adenoviral DNA polymerase gene from 94 fecal samples from nine bat species in Texas. Three samples from Antroz...Few studies have examined adenoviruses (AdVs) in bats from the U.S.; therefore, we targeted a fragment of the adenoviral DNA polymerase gene from 94 fecal samples from nine bat species in Texas. Three samples from Antrozous pallidus had identical sequences, but these differed from those found in one Myotis yumanensis and one Tadarida brasiliensis sample. Phylogenetic analysis showed that these DNA sequences were most similar to those of a previously described AdV found in Myotis velifer in Oklahoma. Each of these sequences differed by more than > 12% from those of any currently classified AdVs and by more than 10% from that of a currently unclassified AdV isolate from Myotis myotis.
Human papillomavirus (HPV) 16 variants can differ in their oncogenic potential. Here, we investigated the effect of the amino acid substitutions H78Y and L83V in the E6 oncoprotein of HPV16 on early immune escape and p53...Human papillomavirus (HPV) 16 variants can differ in their oncogenic potential. Here, we investigated the effect of the amino acid substitutions H78Y and L83V in the E6 oncoprotein of HPV16 on early immune escape and p53 degradation in vitro. Although E6 inhibits the RIG-I-IRF-3-IFN-β pathway, this inhibition was not affected by the H78Y substitution. We found that the L83V mutation did not significantly affect p53 and p21 expression, cell migration and proliferation, or resistance to apoptosis. We therefore conclude that the H78Y and L83V substitutions in E6 had no phenotypic effect on early immune escape and p53 degradation, respectively, in our model.
The diversity of viral communities in inland hypersaline environments remains largely unexplored. Here, we characterized viral assemblages of the thalassohaline inland hypersaline Tuz Lake (Turkey). To identify viral gro...The diversity of viral communities in inland hypersaline environments remains largely unexplored. Here, we characterized viral assemblages of the thalassohaline inland hypersaline Tuz Lake (Turkey). To identify viral groups and viral sequences present in multiple samples, brine and precipitated salt samples were analysed using microscopy and metagenomics. Viral assemblages showed an abundance and morphology similar to what is commonly found in hypersaline systems. Despite these similarities, the vast majority of sequences remained unknown with regard to taxonomy and function and could not be characterized, highlighting their novelty. A remarkably high fraction of the viral sequences identified were present in both brine and salt samples, indicating viral stability during salt precipitation and dissolution in the lake, suggesting that Tuz Lake might be of considerable astrobiological interest. Alongside this high level of similarity, read recruitments revealed the presence of some sample-specific viral sequences in the salt sample. Tuz Lake viral assemblages displayed a distinct composition when compared to previously described viral metagenomes and haloviral genomes from hypersaline environments, with the highest similarity to the viral assemblages of the crystallizer ponds in the Bras del Port saltern (Spain).
Vibrio alginolyticus is a zoonotic pathogenic bacterium that causes various diseases in marine animals, including Penaeus vannamei. Phage therapy, as a natural antibiotic, offers a novel approach to the prevention and co...Vibrio alginolyticus is a zoonotic pathogenic bacterium that causes various diseases in marine animals, including Penaeus vannamei. Phage therapy, as a natural antibiotic, offers a novel approach to the prevention and control of vibriosis. In this study, we isolated, identified, and characterized a novel bacteriophage targeting V. alginolyticus, designated as PV48. PV48, a short-tailed bacteriophage isolated from the Ningbo aquaculture farm, possesses the ability to lyse V. alginolyticus strains that affect shrimp. It displays stability over a range of temperatures (30–50°C) and pH values (4–10). The latent period and burst size for phage PV48 were determined to be 20 minutes and 15.6 PFU/cell, respectively. Whole-genome sequencing revealed that PV48 has a dsDNA genome with a length of 43,398 bp and a G + C content of 49.54%. The phage genome contains 44 open reading frames (ORFs). Comparative genomic analysis suggested that PV48 might represent a new species within the genus Maculvirus. Phylogenetic analysis indicated a close evolutionary link between PV48 and other Vibrio-targeting phages, suggesting a shared viral lineage. This study lays the groundwork for the application of V. alginolyticus bacteriophage in aquaculture.