High Pathogenicity Research Articles

Single-Nucleus and Spatial Transcriptomics Revealing Host Response Differences Triggered by Mutated Virus in Severe Dengue

Dengue virus (DENV) infection causes various disease manifestations ranging from an asymptomatic state to severe, life-threatening dengue. Despite intensive research, the molecular mechanisms underlying the abnormal host responses and severe disease symptoms caused by evolved DENV strains is not fully understood. First, the spatial structure of mutant DENV was compared via in silico molecular modeling analysis. Second, employing single-nucleus and spatial RNA sequencing, we analyzed and verified transcriptome samples in uninfected, mild (NGC group), and severe (N10 group) liver tissues from murine models. In this study, we obtained a cumulatively mutated DENV-2 N10 with enhanced capability of replication and pathogenicity post 10 serial passages in Ifnra−/− mice. This variant caused severe damage in the liver, as compared with other organs. Furthermore, mutated DENV infection elicited stronger responses in hepatocytes. The critical host factor Nrg4 was identified. It dominated mainly via the activation of the NRG/ErbB pathway in mice with severe symptoms. We report on evolved N10 viruses with changes observed in different organisms and tissue. This evolutionary variant results in high replicability, severe pathogenicity, and strong responses in murine. Moreover, the host responses may play a role by activating the NRG/ErbB signaling pathway. Our findings provide a realistic framework for defining disturbed host responses at the animal model level that might be one of the main causes of severe dengue and the potential application value.

Epidemiological data of an influenza A/H5N1 outbreak in elephant seals in Argentina indicates mammal-to-mammal transmission.

H5N1 high pathogenicity avian influenza virus has killed thousands of marine mammals in South America since 2022. Here we report epidemiological data and full genome characterization of clade 2.3.4.4b H5N1 HPAI viruses associated with a massive outbreak in southern elephant seals (Mirounga leonina) at Península Valdés, Argentina, in October 2023. We also report on H5N1 viruses in concurrently dead terns. Our genomic analysis shows that viruses from pinnipeds and terns in Argentina form a distinct clade with marine mammal viruses from Peru, Chile, Brazil and Uruguay. Additionally, these marine mammal clade viruses share an identical set of mammalian adaptation mutations which were also present in tern viruses. Our combined ecological and phylogenetic data support mammal-to-mammal transmission and occasional mammal-to-bird spillover and suggest multinational transmission of H5N1 viruses in mammals. We reflect that H5N1 viruses becoming more evolutionary flexible and adapting to mammals in new ways could have global consequences for wildlife, humans, and/or livestock.

Reassortants of the Highly Pathogenic Influenza Virus A/H5N1 Causing Mass Swan Mortality in Kazakhstan from 2023 to 2024

In the winter of 2023/2024, the mass death of swans was observed on Lake Karakol on the eastern coast of the Caspian Sea. From 21 December 2023 to 25 January 2024, 1132 swan corpses (Cygnus olor, Cygnus cygnus) were collected and disposed of on the coast by veterinary services and ecologists. Biological samples were collected from 18 birds for analysis at different dates of the epizootic. It was found that the influenza outbreak was associated with a high concentration of migrating birds at Lake Karakol as a result of a sharp cold snap in the northern regions. At different dates of the epizootic, three avian influenza A/H5N1 viruses of clade 2.3.4.4.b were isolated from dead birds and identified as highly pathogenic viruses (HPAIs) based on the amino acid sequence of the hemagglutinin multi-base proteolytic cleavage site (PLREKRRRKR/G). A phylogenetic analysis showed that the viruses isolated from the swans had reassortations in the PB2, PB1, and NP genes between highly pathogenic (HP) and low-pathogenic (LP) avian influenza viruses. Avian influenza viruses A/Cygnus cygnus/Karakol lake/01/2024(H5N1) and A/Mute swan/Karakol lake/02/2024(H5N1) isolated on 10 January 2024 received PB2, PB1, and NP from LPAIV, while A/Mute swan/Mangystau/9809/2023(H5N1) isolated on 26 December 2023 received PB1 and NP from LPAIV, indicating that the H5N1 viruses in this study are new reassortants. All viruses showed amino acid substitutions in the PB2, PB1, NP, and NS1 segments, which are critical for enhanced virulence or adaptation in mammals. An analysis of the genomes of the isolated viruses showed that bird deaths during different periods of the epizootic were caused by different reassortant viruses. Kazakhstan is located at the crossroads of several migratory routes of migratory birds, and the possible participation of wild birds in the introduction of various pathogens into the regions of Kazakhstan requires further study.

Lecanicillium attenuatum infection and effects on the reproduction of Frankliniella occidentalis

ABSTRACT Frankliniella occidentalis, western flower thrips, is an invasive pest that seriously damages economic crops such as vegetables, flowers, and fruit trees because of its high fecundity, short generation cycle, and strong adaptability. Lecanicillium is an important entomopathogenic fungus, characterised by its wide host range, high pathogenicity, and environmental safety. It plays an important role in the environmentally friendly management of F. occidentalis. This study clarifies whether L. attenuatum infects F. occidentalis and affects its reproduction. The results of scanning electron microscope showed that conidia of L. attenuatum were attached to many parts of thrips adult after 1 h of treatment with 10^8 conidia/mL, and most F. occidentalis were covered by hyphae after 72–120 h. The cumulative mortality rate of the second instar larvae of the F1, F2, and F3 generations exceeded 60% on the seventh day post-infection and that of female adults was higher than 90% when treated by L. attenuatum with 10^8 conidia/mL. Simultaneously, L. attenuatum had strong sublethal effects on the surviving thrips. Indeed, the number of eggs deposited and the lifespan of female adults decreased considerably after the second instar larvae of F. occidentalis were treated with L. attenuatum, and had the impaction on the thrips offspring too. Altogether, our data suggested that L. attenuatum not only exhibited a high degree of pathogenicity towards F. occidentalis second instar larvae and adults but also affected the longevity and reproduction of surviving thrips.

Isolation and characterization of a novel S-gene mutation porcine deltacoronavirus with high pathogenicity from diarrhea piglet in Zhejiang Province, China, 2022

Porcine deltacoronavirus (PDCoV) is a coronavirus that causes diarrhea in suckling piglets and has the potential for cross-species transmission. Monitoring PDCoV evolution and identifying potential vaccine candidates are crucial due to its high mutation rates in pig populations. In this study, a Chinese PDCoV strain named ZD2022 was successfully isolated from diarrhea piglets in Zhejiang province, followed by genetic evolutionary analysis, assessment of S proteins’ biological functions, in vitro cellular adaptation analysis and pathogenicity evaluation. Phylogenetic analyses placed the PDCoV ZD2022 strain within the Southeast Asia Lineage. Sequence analysis revealed 23 mutations in the S protein of ZD2022 compared to most of other Chinese PDCoV strains, including 8 unique mutations (T529I, L579F, Q614H, V709G, S959L, P1010S, V1016F, A1068V). In addition, bioinformatic predictions indicated these mutations impact the hydrophilicity/hydrophobicity, antigenic epitopes and N-glycosylation sites of the ZD2022 S protein. The virus growth curve of ZD2022 showed good cellular adaptation, with peak viral titers of 8.92 ± 0.31 Log10 TCID50/mL in ST cells. Furthermore, ZD2022 exhibited high virulence in suckling piglets, causing severe diarrhea in piglets at 60 h post-inoculation (hpi) and a mortality rate of 40 % (2/5) within 96 hpi. In summary, our findings indicate that the Chinese PDCoV strains continue to mutate, and the novel S gene mutation in strain ZD2022 offers strong cellular adaptation and high pathogenicity, making it a potential candidate strain for vaccine development.

Genetic and pathogenic potential of highly pathogenic avian influenza H5N8 viruses from live bird markets in Egypt in avian and mammalian models

Since its first isolation from migratory birds in Egypt in 2016, highly pathogenic avian influenza (HPAI) H5N8 has caused several outbreaks among domestic poultry in various areas of the country affecting poultry health and production systems. However, the genetic and biological properties of the H5N8 HPAI viruses have not been fully elucidated yet. In this study, we aimed to monitor the evolution of circulating H5N8 viruses and identify the pathogenicity and mammalian adaptation in vitro and in vivo. Three H5N8 HPAI viruses were used in this study and were isolated in 2021–2022 from poultry and wild birds during our routine surveillance. RNA extracts were subjected to full genome sequencing. Genetic, phylogenetic, and antigenic analyses were performed to assess viral characteristics and similarities to previously isolated viruses. Phylogenetic analysis showed that the hemagglutinin genes of the three isolates belonged to clade 2.3.4.4b and grouped with the 2019 viruses from G3 with high similarity to Russian and European lineages. Multiple basic amino acids were observed at cleavage sites in the hemagglutinin proteins of the H5N8 isolates, indicating high pathogenicity. In addition, several mutations associated with increased virulence and polymerase activity in mammals were observed. Growth kinetics assays showed that the H5N8 isolate is capable of replicating efficiently in mammalian cells lines. In vivo studies were conducted in SPF chickens (White Leghorn), mice, and hamsters to compare the virological characteristics of the 2022 H5N8 isolates with previous H5N8 viruses isolated in 2016 from the first introduction. The H5N8 viruses caused lethal infection in all tested chickens and transmitted by direct contact. However, we showed that the 2016 H5N8 virus causes a higher mortality in chickens compared to 2022 H5N8 virus. Moreover, the 2022 virus can replicate efficiently in hamsters and mice without preadaptation causing systemic infection. These findings underscore the need for continued surveillance of H5 viruses to identify circulating strains, determine the commercial vaccine’s effectiveness, and identify zoonotic potential.

Discovery of peptidomimetic spiropyrrolidine derivatives as novel 3CLpro inhibitors against SARS-CoV -2

Given the high pathogenicity and rapid mutation rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it is imperative to sustain efforts in drug research and development. Herein, we present the design, synthesis, and evaluation of peptidomimetic spiropyrrolidine derivatives as potent 3CLpro inhibitors against SARS-CoV-2. Among the synthesized derivatives, several compounds exhibited high potency in inhibiting 3CLpro, with IC50 values ranging from 21 nM to 53 nM. Notably, compounds 9b and 9h displayed improved enzymatic inhibition (IC50 = 25 nM and 21 nM, respectively) compared to nirmatrelvir (47 nM). Compound 9b showed enhanced stability in human and mouse liver microsomes compared to nirmatrelvir, whereas 9h exhibited similar stability to nirmatrelvir in both species. Furthermore, compound 9h displayed exceptional potency in cellular assays targeting the SARS-CoV-2 replicon within Huh7 cells, with a single-digit nanomolar activity that is 5.6 times better than that of nirmatrelvir. In a pharmacokinetic study in mice (PO, 20 mg/kg), compound 9h exhibited a prolonged plasma half-life (T1/2 = 2.58 h) compared to nirmatrelvir (T1/2 = 0.51 h) and demonstrated an AUC(0-t) value (1106 h∗ng/mL) equivalent to that of nirmatrelvir (1023 h∗ng/mL). These findings indicate that compound 9h is a promising lead for developing a novel 3CLpro inhibitor against SARS-CoV-2.

Genetic diversity of Bartonella species in small mammals in the Qinghai Menyuan section of Qilian Mountain National Park, China

Bartonella are vector-borne gram-negative facultative intracellular bacteria that can infect a wide spectrum of mammals, and are recognized as emerging human pathogens. This study aimed to investigate the prevalence and molecular characteristics of Bartonella infections in small mammals within the Qinghai Menyuan section of Qilian Mountain National Park, China. Small mammals were captured, and the liver, spleen and kidney were collected for Bartonella detection and identification using a combination of real-time PCR targeting the transfer-mRNA (ssrA) gene and followed by sequencing of the citrate synthase (gltA) gene. A total of 52 rodents were captured, and 36 rodents were positive for Bartonella, with a positivity rate of 69.23% (36/52). Bartonella was detected in Cricetulus longicaudatus, Microtus oeconomus, Mus musculus, and Ochotona cansus. The positivity rate was significantly different in the different habitats. Two Bartonella species were observed, including Bartonella grahamii and Bartonella heixiaziensis, and B. grahamii was the dominant epidemic strain in this area. Phylogenetic analysis showed that B. grahamii mainly clustered into two clusters, which were closely related to the Apodemus isolates from China and Japan and the local plateau pika isolates, respectively. In addition, genetic polymorphism analysis showed that B. grahamii had high genetic diversity, and its haplotype had certain regional differences and host specificity. Overall, high prevalence of Bartonella in small mammals in the Qinghai Menyuan section of Qilian Mountain National Park. B. grahamii is the dominant strain with high genetic diversity and potential pathogenicity to humans, and corresponding control measures should be considered.

Emergence of highly virulent and multidrug-resistant Escherichia coli in breeding sheep with pneumonia, Hainan Province, China.

Sheep are a rarely raised livestock in Hainan Island, China, because of the unfavorable tropical marine climate. Here, this article reports a severe pneumonia in the sheep breeding and domestication facility caused acute mortality during the winter 2021-2022. Six sheep were clinically dissected and histopathologically observed. The bacteria were isolated and cultured by traditional methods and identified by 16S rRNA sequencing. The genotypes, serotypes, virulence genes and antimicrobial resistance genes were analyzed by PCR and whole genome sequencing. The pubMLST website was used for phylogenetic analysis of related strains. Kirby-Bauer disk diffusion method was used for antimicrobial susceptibility test. The antimicrobial susceptibility test standard was referred to the Clinical and Laboratory Standards Institute (CLSI). The virulence of bacteria was detected by mouse infection model. Etiology and histopathology examination of the pneumonia reveled pulmonary abscess and alveolar neutrophilia and pulmonary fibrinous exudates. Escherichia coli was the only bacterial species isolated, primarily from the lungs and blood of the six dead or moribund sheep, a total of 29 E. coli strains were isolated. Antimicrobial resistance profiling shows that all the isolates were resistant to six agents (penicillin, ampicillin, cephalothin, neomycin, erythromycin, and vancomycin) belonging to five classes of antibiotics, classifying them as multi drug resistant (MDR). Furthermore, genotyping analysis revealed all strains were common with 11-17 virulence factors indicating high pathogenicity. The lab mice infection model shows that all strains severely affect the health status particularly weight loss, lethargy, pneumonia and shortly lead to death. The molecular epidemiological analysis indicated most strains share the same genotype as previously reported strains in humans and other farmed animals this suggests a high possibility of cross-species transmission (CST) of virulent and MDR isolates. This CST could be from sheep to humans and other farmed animals or from humans and other farmed animals to sheep. Therefore, this study indicates that E. coli is an emerging threat that causes sheep pneumonia in Hainan, and the quarantine of contacts is important to control the spread of virulent E. coli and the transmission of acquired resistance genes between humans and farmed animals such as sheep.

Emergence and etiological characteristics of novel genotype Ⅱ pseudorabies virus variant with high pathogenicity in Tianjin, China

Pseudorabies (PR) is a highly infectious disease caused by pseudorabies virus (PRV). This study aimed to detect and identify recent outbreaks of genotype Ⅱ PRV, and further analysis it's etiological characteristics and pathogenicity. The brain tissues with suspected PRV infection were isolated and the main virulence-related genes of the isolated PRV strain were amplified and sequenced for phylogenetic analysis. In addition, the pathogenicity of the isolated PRV strain to 6-week-old mice and 9-days-old suckling piglets were evaluated. The results showed that a PRV strain was successfully isolated and named PRV TJbd2023 strain, which could proliferate in PK-15 cells and TCID50 of the 6th generation virus reached 107.57/0.1 ml. Phylogenetic trees and amino acids analysis were constructed based on full-length gE sequences, which showed that PRV TJbd2023 strain was clustered into genetype Ⅱ PRV variant with a characteristic 21-nucleotide insertion (encoding 63AASTPAA69) in gC gene, and some amino acid point mutations were also found in other virulence-related genes, including gB protein R223H and E836K, gD protein R320S, and gE protein T242A. Animal experiments showed that TJbd2023 could cause acute neurological symptoms with 103.41/mL LD50 on KM mice, and intranasal inoculation of suckling piglets with 2 ml of TJbd2023 strain(106.57/0.1 ml) led to a mortality rate of 66.70 %. Emerging genotype Ⅱ PRV variant such as isolated in our research named TJbd2023 with high pathogenicity might be responsible for recent outbreaks of PRV and immunization failure of Bartha-K61 vaccine in Tianjin, China.

Comparative and experimental pathology of passaged Newcastle disease virus isolates in ducks.

Although waterfowl are less susceptible to Newcastle disease (ND) virus (NDV) infection compared with chickens and turkeys, lethal ND in waterfowl has been sporadically reported. Factors underlying the high pathogenicity of certain NDV strains in waterfowl remain unclear. In ducks, the NDV 9a5b isolate shows low pathogenicity while the d5a20b isolate shows high pathogenicity. This study aimed to identify the definitive lesions that led to the lethal virulence of d5a20b by comparing the histopathology of 9a5b- or d5a20b-inoculated ducks in order to elucidate lesions related to the enhanced pathogenicity of certain NDV strains in ducks. Herein, 7-day-old ducks were intranasally inoculated with either 9a5b or d5a20b NDV strains. The neurological signs were more severe in the d5a20b-inoculated group than in the 9a5b-inoculated group. Ducks in the d5a20b-inoculated group exhibited more severe lymphoid depletion in immune organs than those in the 9a5b-inoculated group, which may have caused an immunosuppressive state in the d5a20b-inoculated ducks. Ducks in the d5a20b-inoculated group had more severe nonsuppurative encephalitis with increased NDV nucleoprotein than those in the 9a5b-inoculated group. Additionally, pancreatic necrosis, with intralesional NDV nucleoprotein, was more severe in the d5a20b-inoculated group than in the 9a5b-inoculated group. Our results showed that the immune organs, brain, and pancreas were significant targets of the NDV d5a20b infection in ducks.

High pathogenicity avian influenza virus emergence: Blame it on chickens or on humans raising chickens?

High pathogenicity avian influenza virus emergence: Blame it on chickens or on humans raising chickens?

A Comparative Analysis of Models for AAV-Mediated Gene Therapy for Inherited Retinal Diseases.

Inherited retinal diseases (IRDs) represent a diverse group of genetic disorders leading to progressive degeneration of the retina due to mutations in over 280 genes. This review focuses on the various methodologies for the preclinical characterization and evaluation of adeno-associated virus (AAV)-mediated gene therapy as a potential treatment option for IRDs, particularly focusing on gene therapies targeting mutations, such as those in the RPE65 and FAM161A genes. AAV vectors, such as AAV2 and AAV5, have been utilized to deliver therapeutic genes, showing promise in preserving vision and enhancing photoreceptor function in animal models. Despite their advantages-including high production efficiency, low pathogenicity, and minimal immunogenicity-AAV-mediated therapies face limitations such as immune responses beyond the retina, vector size constraints, and challenges in large-scale manufacturing. This review systematically compares different experimental models used to investigate AAV-mediated therapies, such as mouse models, human retinal explants (HREs), and induced pluripotent stem cell (iPSC)-derived retinal organoids. Mouse models are advantageous for genetic manipulation and detailed investigations of disease mechanisms; however, anatomical differences between mice and humans may limit the translational applicability of results. HREs offer valuable insights into human retinal pathophysiology but face challenges such as tissue degradation and lack of systemic physiological effects. Retinal organoids, on the other hand, provide a robust platform that closely mimics human retinal development, thereby enabling more comprehensive studies on disease mechanisms and therapeutic strategies, including AAV-based interventions. Specific outcomes targeted in these studies include vision preservation and functional improvements of retinas damaged by genetic mutations. This review highlights the strengths and weaknesses of each experimental model and advocates for their combined use in developing targeted gene therapies for IRDs. As research advances, optimizing AAV vector design and delivery methods will be critical for enhancing therapeutic efficacy and improving clinical outcomes for patients with IRDs.

Genetic Diversity and Pathogenicity of Phytophthora infestans Isolates on Four Solanum tuberosum (Potato) Cultivars in Nariño, Colombia

Phytophthora infestans remains a major threat to global potato production. This study focused on characterizing and assessing the pathogenicity of P. infestans isolates on detached potato leaves and in greenhouse trials across four cultivars. Seven isolates were obtained from high potato-producing regions in the department of Nariño, Colombia. The isolates were analyzed using 12 microsatellite markers to determine genetic distances. Two genetically distinct isolates showed markedly different pathogenicity on detached leaves: isolate P00921 caused complete infection by day five, whereas P00321 showed no symptoms. These two isolates (P00921 and P00321) selected for having the greatest genetic distance and highest pathogenicity among the seven analyzed were further tested in a greenhouse setup on four potato cultivars using a randomized block design. Disease progression was monitored over nine days. The results indicated significant variations in pathogenicity linked to genetic diversity among isolates. Notably, Capiro and Margarita cultivars were more prone to severe disease than Suprema and Única. These findings highlight the complex nature of host–pathogen interactions and suggest the need for tailored approaches in disease management and cultivar selection.

Pathogenomic profiling: Decoding the pathogenic potential of virulent Bacillus cereus associated with mortality of farmed Labeo rohita (Hamilton, 1822), in India

Bacillus cereus is widely used as probiotics in aquaculture. However, present research work identified B. cereus from diseased fish (Labeo rohita) associated with mass mortality in Hooghly, West Bengal, India. The bacterium was identified based on morphological, biochemical characterization and molecular identification, which comprise 16S rRNA gene and housekeeping gene sequencing analysis. Furthermore, the pathogenic potential of the isolates was confirmed by the presence of different toxin-encoding genes viz. hemolytic enterotoxin (hblA, hblC, hblD), non-hemolytic enterotoxin (nheA, nheB, nheC), cytotoxin K (cytK) and enterotoxin FM (entFM), Diarrheal enterotoxin (bceT) and Cereolysin AB. All these toxin-encoding genes were regulated by a master virulence regulating transcription factor plcr, which is also present in this isolate. Additionally, this bacterium also secretes caseinase and lecithinase, which helps the bacteria to invade the host tissue. The intraperitoneal injection of B. cereus at a dose of 3.6× 106 CFU ml−1 resulted in 100 % mortality of L. rohita. The histopathological changes revealed that the bacterium induces severe damage and necrosis in the liver and kidney of the infected fish. To understand the innate immune response once bacteria invade the host, a quantitative gene expression study was carried out using different immune-related genes and stress-related genes viz. Complement factor 3a (C3a), Toll-like receptor (TLR), Myeloid differentiation primary response 88 (Mydd88), Interleukin 6 (IL6), Nucleotide oligomerization domain (NOD)-like receptor, Catalase (CAT), Glutathione peroxidase (GPx) and Superoxide dismutase (SOD) in the hepatic and renal tissue. The over-expression of TLR, NOD and Mydd88 shared a common downstream inflammatory signaling pathway and the upregulation of antioxidant enzymes SOD, CAT and GPx was evident for combating strategies as well as safeguarding the host's cells from oxidative damage. Overall, this study showed that an isolated strain of B. cereus exhibits high pathogenicity, which may be attributed to climate change, urbanization or horizontal gene transfer. This presents a potential threat to the aquaculture industry and raises concerns about the possibility of cross-contamination within the human population.

Effect of X-ray radiation on Multi-drug Resistant (MDR) Enterobacteriaceae & P.aeruginosa isolated from burn unit patient. The phenotypic and molecular study, Biofilm formation

Background: Multi-drug-resistant (MDR) bacteria are a significant global health concern due to their elevated rates of morbidity and mortality in burn patients. In This study investigated the presence of multidrug-resistant pathogenic bacteria in individuals with burn injuries, the formation of biofilms, and the impact of X-ray radiation. Method: For this study Clinical swabs about120 burn patients were obtained between December 2023 and June 2024 from burn units at Ramadi and Falluja Teaching Hospitals. Both conventional and Vitek2(bioMérieux) methods were used to identify the bacterial isolates. The isolates were then divided into three multi-drug resistance groups. The Colorimetric method (MTP) detected biofilms. To detect blaOXA-23,blaOXA-48, Omp, and blaTEM resistance genes, multiplex PCR was used. This research used two lumbosacral spine X-ray levels. Two levels of radiation were used 40 (80KV) mAs and 51.2 (85KV). Result: Results of burn isolation revealed 30(27%) P.aeruginosa, 18(16%) k.pneumoniae, 7(6%) E.coli, 7(6%) P.mirabilis. Of the all isolates, 100% produced biofilm. The Multiplex-PCR analysis revealed that the blaTEM genes were the predominant ones, constituting 30% of the samples. Subsequently, blaOXA-23 constituted 24.5% of the cases, whereas Omp accounted for 22.7% and blaOXA-48 for 13.6%. The radiation impact of X-rays produced by two dosages, 40(80KV)mAs for 125msec and 51,2(85KV) mAs for 160msec, demonstrates that there is no effect or alteration in the resistance capacity of all the bacterial isolates tested. Conclusion: This study showed that burn unit isolates produce ESBLs, which is a major concern in the intensive care unit due to its high morbidity and potential mortality. These data match antibiotic phenotypic test results showing substantial cefepime resistance. All isolates forming biofilms, this may association with high pathogenicity. This demands quick intervention to manage nosocomial outbreaks. No X-ray effect was seen on susceptibility a burn unit bacterial isolate.

Molecular Characterization of a Clade 2.3.4.4b H5N1 High Pathogenicity Avian Influenza Virus from a 2022 Outbreak in Layer Chickens in the Philippines.

H5 subtype high-pathogenicity avian influenza (HPAI) viruses continue to devastate the poultry industry and threaten food security and public health. The first outbreak of H5 HPAI in the Philippines was reported in 2017. Since then, H5 HPAI outbreaks have been reported in 2020, 2022, and 2023. Here, we report the first publicly available complete whole-genome sequence of an H5N1 high-pathogenicity avian influenza virus from a case in Central Luzon. Samples were collected from a flock of layer chickens exhibiting signs of lethargy, droopy wings, and ecchymotic hemorrhages in trachea with excessive mucus exudates. A high mortality rate of 96-100% was observed within the week. Days prior to the high mortality event, migratory birds were observed around the chicken farm. Lungs, spleen, cloacal swabs, and oropharyngeal-tracheal swabs were taken from two chickens from this flock. These samples were positive in quantitative RT-PCR assays for influenza matrix and H5 hemagglutinin (HA) genes. To further characterize the virus, the same samples were subjected to whole-virus-genome amplification and sequencing using the Oxford Nanopore method with mean coverages of 19,190 and 2984, respectively. A phylogenetic analysis of the HA genes revealed that the H5N1 HPAI virus from Central Luzon belongs to the Goose/Guangdong lineage clade 2.3.4.4b viruses. Other segments also have high sequence identity and the same genetic lineages as other clade 2.3.4.4b viruses from Asia. Collectively, these data indicate that wild migratory birds are the likely source of H5N1 viruses from the 2022 outbreaks in the Philippines. Thus, biosecurity practices and surveillance for HPAI viruses in both domestic and wild birds should be increased to prevent and mitigate HPAI outbreaks.

Epidemiological investigation and analysis of the infection of porcine circovirus in Xinjiang

Porcine circoviruses, particularly porcine circovirus type 2 (PCV2) and porcine circovirus type 3 (PCV3), significantly impact the global pig industry due to their high prevalence and pathogenicity. Conversely, porcine circovirus type 1 (PCV1) and porcine circovirus type 4 (PCV4) currently have low positivity rates. This study aimed to characterize the distribution and epidemiology of porcine circoviruses in Xinjiang, while also analyzing the genetic diversity and evolution of PCV2 and PCV3, which pose the greatest threats to the industry. In this study, we collected blood and tissue samples from 453 deceased pigs across eight regions in Xinjiang Province from 2022 to 2024. We utilized real-time PCR to detect the presence of PCV1, PCV2, PCV3, and PCV4. The positive rates were 15%, 71%, 25%, and 17%, respectively. Genetic analysis showed 9 PCV2 sequences and 12 PCV3 sequences. The capsid protein of PCV2 showed significant variability. In contrast, the amino acid sequences of capsid in PCV3 were relatively stable. Moreover, we predicted antigenic epitopes for PCV3 capsid using IEDB and ElliPro. The findings from this study provide valuable epidemiological data on PCV coinfection in the Xinjiang region and enhance the understanding of virus diversity nationwide. This research may serve as an important reference for the development of strategies to prevent and control porcine circovirus infections.

The global H5N1 influenza panzootic in mammals.

Influenza A viruses (IAV) have caused more documented global pandemics in human history than any other pathogen1,2. High pathogenicity avian influenza (HPAI) viruses belonging to the H5N1 subtype are a leading pandemic risk. Two decades after H5N1 "bird flu" became established in poultry in Southeast Asia, its descendants have resurged3, setting off an H5N1 panzootic in wild birds that is fueled by (a) rapid intercontinental spread, reaching South America and Antarctica for the first time4,5; (b) fast evolution via genomic reassortment6; and (c) frequent spillover into terrestrial7,8 and marine mammals9. The virus has sustained mammal-to-mammal transmission in multiple settings, including European fur farms10,11, South American marine mammals12-15, and US dairy cattle16-19, raising questions about whether humans are next. Historically, swine are considered optimal intermediary hosts that help avian influenza viruses (AIV) adapt to mammals before jumping to humans20. However, the altered ecology of H5N1 has opened the door to new evolutionary pathways. Could dairy cattle, farmed mink, or South American sea lions serve as new mammalian gateways to humans? Here we explore the molecular and ecological factors driving H5N1's sudden expansion in host range and assess the likelihood of different zoonotic pathways leading to an H5N1 pandemic.

Hemagglutinin and neuraminidase of a non-pathogenic H7N7 avian influenza virus coevolved during the acquisition of intranasal pathogenicity in chickens.

Polybasic amino acid residues at the hemagglutinin (HA) cleavage site are insufficient to induce the highly pathogenic phenotype of avian influenza viruses in chickens. In our previous study, an H7N7 avian influenza virus named "Vac2sub-P0", which is nonpathogenic despite carrying polybasic amino acids at the HA cleavage site, was passaged in chick air sacs, and a virus with high intravenous pathogenicity, Vac2sub-P3, was obtained. Intranasal infection with Vac2sub-P3 resulted in limited lethality in chickens; therefore, in this study, this virus was further passaged in chicken lungs, and the resultant virus, Vac2sub-P3L4, acquired high intranasal pathogenicity. Experimental infection of chickens with recombinant viruses demonstrated that mutations in HA and neuraminidase (NA) found in consecutive passages were responsible for the increased pathogenicity. The HA and NA functions of Vac2sub-P3L4 were compared with those of the parental virus in vitro; the virus growth at 40 °C was faster, the binding affinity to a sialic acid receptor was lower, and the rate of release by NA from the cell surface was lower, suggesting that these changes enabled the virus to replicate efficiently in chickens with high intranasal pathogenicity. This study demonstrates that viruses that are highly pathogenic when administered intranasally require additional adaptations for increased pathogenicity to be highly lethal to intranasally infected chickens.