Human papillomavirus (HPV) type 81 has recently become one of the most common low-risk HPV types; however, literature focusing on it is limited. This study aimed to analyze the reasons for the increased detection rate of HPV81 and investigate its evolving pathogenicity. We analyzed the detection rates and trends of HPV81 in 229 061 exfoliated cervical cell samples collected from 2014 to 2023; collected samples of HPV81 single infections from two different time periods; and analyzed the allele frequencies, positive selection, viral load, persistent infection capacity, and pathogenicity of E6 and E7 genotypes. We found that the detection rate of HPV81 ranked first among the low-risk types in exfoliated cervical cells and exhibited a significantly increasing trend (p < 0.001). The frequency of the E6 prototype allele of HPV81 (n = 317) was significantly increased (p = 0.018) and demonstrated the strongest adaptive capacity. The viral load and persistent infection capacity of the E6 prototype were significantly higher than those of the mutants, thus serving as key drivers for increasing the detection rate of HPV81 and enhancing its pathogenicity. The viral load was positively correlated with persistent infection capacity and pathogenicity. Persistent infection was a crucial factor in the pathogenicity of HPV81. Successful adaptive evolution of HPV81 is accompanied by enhanced pathogenicity.

Flavobacterium psychrophilum, the causative agent of bacterial cold-water disease, is a devastating, worldwide distributed, fish pathogen causing significant economic loss in inland fish farms. Previous epidemiological studies showed that prevalent clonal complexes (CC) differ in fish species affected with disease such as rainbow trout, coho salmon and ayu, indicating significant associations between particular F. psychrophilum genotypes and host species. Yet, whether the population structure is driven by the trade of fish and eggs or by host-specific pathogenicity is uncertain. Notably, all F. psychrophilum isolates retrieved from ayu belong to Type-3 O antigen (O-Ag) whereas only very few strains retrieved from other fish species possess this O-Ag, suggesting a role in outbreaks affecting ayu. Thus, we investigated the links between genotype and pathogenicity by conducting comparative bath infection challenges in two fish hosts, ayu and rainbow trout, for a collection of isolates representing different MLST genotypes and O-Ag. Highly virulent strains in one host species exhibited low to no virulence in the other. F. psychrophilum strains associated with ayu and possessing Type-3 O-Ag demonstrated significant variability in pathogenicity in ayu, ranging from avirulent to highly virulent. Strikingly, F. psychrophilum strains retrieved from rainbow trout and possessing the Type-3 O-Ag were virulent for rainbow trout but not for ayu, indicating that Type-3 O-Ag alone is not sufficient for pathogenicity in ayu, nor does it prevent pathogenicity in rainbow trout. This study revealed that the association between a particular CC and host species partly depends on the pathogen\'s adaptation to specific host species.

BACKGROUND: The ABO blood group has long been recognized as a significant factor influencing susceptibility to infectious diseases. Numerous studies have explored the links between ABO blood types and both the likelihood of contracting COVID-19 and the severity of the infection, yielding conflicting results.
OBJECTIVE: This study intends to determine the influence of age, gender, the ABO blood group, and Rh factor on the potential development of COVID-19 infection.
METHODS: A cross-sectional, observational study collected data including age, gender, the ABO blood group, and Rh factor from 80 healthcare professionals at R. R. Dental College and Hospital in Udaipur with a positive history of COVID-19 infection via Google Forms (Google LLC, Mountain View, California, United States). Chi-square statistics assessed the distribution of blood types and antibodies within the samples. Odds ratio (OR) assays were used to assess the probability of a certain blood type or Rh factor with version 21.0 of the IBM Statistical Package for Social Sciences (SPSS) for Windows (IBM Corp, Armonk, NY).
RESULTS: In this study, the blood group type O was 45.2% (n = 33), type A was 21.9% (n = 16), type B was 24.7% (n = 18), and type AB was 8.2% (n = 6). Rh-positive samples were 87.7% (n = 64) and Rh-negative samples were 12.3% (n = 9). There was a statistically significant correlation between Type A (p = 0.001) and Type O (p = 0.049). Thirty-one participants (42.5%) were aged 20-30 years, 26 (35.6%) were aged 31-40 years, and 16 (21.9%) were aged 41-50 years. The statistical analysis revealed no statistically significant distinction among the age groups (p > 0.05).
CONCLUSIONS: The patients\' gender, age, and concurrent disorders are crucial risk variables that determine the severity of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection. There is growing data indicating that the ABO blood group has a significant role in disease biology at physiological and biochemical levels. Hence, this study adds valuable information to strengthen and establish the potential role of factors, such as age and gender, in the possible pathogenicity of COVID-19 infection.

This comprehensive review delves into the pathogenicity and detection of Shiga Toxin-Producing Escherichia coli (STEC), shedding light on its various genetic and clinical manifestations. STEC originating from E. coli acquires pathogenicity through mobility and genetic elements. The pathogenicity of STEC is explored in terms of clinical progression, complications, and key toxins such as Shiga toxin (Stx). Stx1 and Stx2 are two distinct Stx types exhibiting different toxicities, with Stx2 often associated with severe diseases. This review also delves into Subtilase cytotoxin, an additional cytotoxin produced by some STEC strains. Pathogenic mechanisms of STEC, such as attaching and effacing intestinal lesions, are discussed, with a focus on roles of genetic factors. Plasmids in STEC can confer unique pathogenicity. Hybridization with other pathogenic E. coli can create more lethal pathogens. This review covers a range of detection methods, ranging from DNA amplification to antigen detection techniques, emphasizing the need for innovative approaches to improve the sensitivity and speed of STEC diagnosis. In conclusion, understanding diverse aspects of STEC pathogenicity and exploring enhanced diagnostic methods are critical to addressing this foodborne pathogen effectively. Pathology of Shiga toxin toxicity. STEC-derived Shiga toxin consists of one A subunit and five B subunits. Pathological symptoms of the disease can progress to HUS within two weeks after the onset of diarrhea. Shiga toxin intoxication is also associated with many complications, such as neurological and cardiac complications. This figure was reconstructed based on data from Bruyand et al.

Pectobacterium spp. are important bacterial pathogens that cause soft rot symptoms in various crops. However, their mechanism of pathogenicity requires clarity to help control their infections. Here, genome-wide association studies (GWAS) were conducted by integrating genomic data and measurements of two phenotypes (virulence and cellulase activity) for 120 various Pectobacterium strains in order to identify the genetic basis of their pathogenicity. An artificial intelligence-based software program was developed to automatically measure lesion areas on Chinese cabbage, thereby facilitating accurate and rapid data collection for virulence phenotypes for use in GWAS analysis. The analysis discovered 428 and 158 loci significantly associated with Pectobacterium virulence (lesion area) and cellulase activity, respectively. In addition, 1,229 and 586 epistasis loci pairs were identified for the virulence and cellulase activity phenotypes, respectively. Among them, the AraC transcriptional regulator exerted epistasis effects with another three nutrient transport-related genes in pairs contributing to the virulence phenotype, and their epistatic effects were experimentally confirmed for one pair with knockout mutants of each single gene and double gene. This study consequently provides valuable insights into the genetic mechanism underlying Pectobacterium spp. pathogenicity. IMPORTANCE Plant diseases and pests are responsible for the loss of up to 40% of food crops, and annual economic losses caused by plant diseases reach more than $220 billion. Fighting against plant diseases requires an understanding of the pathogenic mechanisms of pathogens. This study adopted an advanced approach using population genomics integrated with virulence-related phenotype data to investigate the genetic basis of Pectobacterium spp., which causes serious crop losses worldwide. An automated software program based on artificial intelligence was developed to measure the virulence phenotype (lesion area), which greatly facilitated this research. The analysis predicted key genomic loci that were highly associated with virulence phenotypes, exhibited epistasis effects, and were further confirmed as critical for virulence with mutant gene deletion experiments. The present study provides new insights into the genetic determinants associated with Pectobacterium pathogenicity and provides a valuable new software resource that can be adapted to improve plant infection measurements.

Vibrio parahaemolyticus causes seafood-borne gastroenteritis infection in human which can even lead to death. The pathogenic strain of V. parahaemolyticus secretes different types of virulence factors that are directly injected into the host cell by a different type of secretion system which helps bacteria to establish its own ecological niche within the organism. Therefore, the aim of this study was to isolate the extracellular secreted proteins from the trh positive strain of V. parahaemolyticus and identify them using two-dimensional gel electrophoresis and MALDI-TOFMS/MS. Seventeen different cellular proteins viz, Carbamoyl-phosphate synthase, 5-methyltetrahydropteroyltriglutamate, tRNA-dihydrouridine synthase, Glycerol-3-phosphate dehydrogenase, Orotidine 5\'-phosphate decarboxylase, Molybdenum import ATP-binding protein, DnaJ, DNA polymerase IV, Ribosomal RNA small subunit methyltransferase G, ATP synthase subunit delta and gamma, Ribosome-recycling factor, 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase, tRNA pseudouridine synthase B, Ditrans, polycis-undecaprenyl-diphosphate synthase, Oxygen-dependent coproporphyrinogen-III oxidase, and Peptide deformylase 2 were identified which are mainly involved in different metabolic and biosynthetic pathways. Furthermore, the molecular function of the identified proteins were associated with catalytic activity, ligase activity, transporter, metal binding, and ATP synthase when they are intercellular. However, to understand the importance of these secreted proteins in the infection and survival of bacteria inside the host cell, pathogen-host protein-protein interactions (PPIs) were carried out which identified the association of eight secreted proteins with 41 human proteins involved in different cellular pathways, including ubiquitination degradation, adhesion, inflammation, immunity, and programmed cell death. The present study provides unreported strategies on host-cell environment\'s survival and adaptation mechanisms for the successful establishment of infections and intracellular propagation.

In the winter of 2010-2011, Japan experienced a large outbreak of infections caused by clade 2.3.2.1 H5N1 high pathogenicity avian influenza viruses (HPAIVs) in wild birds. Interestingly, many tufted ducks (Aythya fuligula), which are migratory diving ducks, succumbed to the infection, whereas only one infection case was reported in migratory dabbling duck species, the major natural hosts of the influenza A virus, during the outbreak. To assess whether the susceptibility of each duck species to HPAIVs was correlated with the number of cases, tufted duck and dabbling duck species (Eurasian wigeon, Mareca penelope; mallard, Anas platyrhynchos; Northern pintail, Anas acuta) were intranasally inoculated with A/Mandarin duck/Miyazaki/22M807-1/2011 (H5N1), an index clade 2.3.2.1 virus previously used for experimental infection studies in various bird species. All ducks observed for 10 days post-inoculation (dpi) mostly shed the virus via the oral route and survived. The tufted ducks shed a higher titer of the virus than the other dabbling duck species, and one of them showed apparent neurological symptoms after 7 dpi, which were accompanied by eye lesions. No clinical symptoms were observed in the dabbling ducks, although systemic infection and viremia were observed in some of them sacrificed at 3 dpi. These results suggest that the susceptibility of clade 2.3.2.1 HPAIVs might differ by duck species.

Despite the widespread implementation of pneumococcal vaccines, hypervirulent Streptococcus pneumoniae serotype 19A is endemic worldwide. It is still unclear whether specific genetic elements contribute to complex pathogenicity of serotype 19A isolates. We performed a large-scale pan-genome-wide association study (pan-GWAS) of 1,292 serotype 19A isolates sampled from patients with invasive disease and asymptomatic carriers. To address the underlying disease-associated genotypes, a comprehensive analysis using three methods (Scoary, a linear mixed model, and random forest) was performed to compare disease and carriage isolates to identify genes consistently associated with disease phenotype. By using three pan-GWAS methods, we found consensus on statistically significant associations between genotypes and disease phenotypes (disease or carriage), with a subset of 30 consistently significant disease-associated genes. The results of functional annotation revealed that these disease-associated genes had diverse predicted functions, including those that participated in mobile genetic elements, antibiotic resistance, virulence, and cellular metabolism. Our findings suggest the multifactorial pathogenicity nature of this hypervirulent serotype and provide important evidence for the design of novel protein-based vaccines to prevent and control pneumococcal disease. IMPORTANCE It is important to understand the genetic and pathogenic characteristics of S. pneumoniae serotype 19A, which may provide important information for the prevention and treatment of pneumococcal disease. This global large-sample pan-GWAS study has identified a subset of 30 consistently significant disease-associated genes that are involved in mobile genetic elements, antibiotic resistance, virulence, and cellular metabolism. These findings suggest the multifactorial pathogenicity nature of hypervirulent S. pneumoniae serotype 19A isolates and provide implications for the design of novel protein-based vaccines.

Chicken infectious anemia (CIA) is caused by chicken anemia virus (CAV). Recently, severe anemia has emerged in layer chickens (8 to 10-week-old) on poultry farms in China. However, the etiological characteristics and pathogenic potential of CAV in chickens at 6 weeks or older are not well understood. In this study, we isolated a CAV strain, termed SD15, from two-month-old chicken with severe anemia and analyzed the genetic evolution relationship. We found that strain SD15 had the highest homology (98.9%) with CAV18 strain. Comparison with 33 reference strains revealed 16 amino acid mutations in strain SD15, two of which were previously unknown (F210S in VP1 and L25S in Vp3). Compared with low pathogenic strains (Cux-1 and C14), highly pathogenic strains (SDLY08 and SD15) had three base mutations in their noncoding region. To further understand its pathogenicity, 10-week-old specific-pathogen-free (SPF) chickens were challenged with the novel strain and SDLY08. No obvious clinical symptoms were observed in the SDLY08 group. However, SD15-infected chickens showed significant growth retardation and immunosuppression. The main manifestations of immunosuppression were the significantly reduced thymus and bursa indices and AIV-H9 vaccine-induced antibody levels (P < 0.05). The lowest number of red blood cells in the SD15 group was just 60% of that in the control group. Taken together, the novel strain SD15 not only showed higher pathogenicity but also exhibited the potential ability to break the age resistance of older chickens to CAV. Our study enhanced the understanding of the epidemiological characteristics of chickens infected with severe anemia and can facilitate the development of improved control strategies of CIA in China.

Shiga toxin-producing Escherichia coli (STEC) infection can cause clinical manifestations ranging from diarrhea to potentially fatal hemolytic uremic syndrome (HUS). This study is aimed at identifying STEC genetic factors associated with the development of HUS in Sweden. A total of 238 STEC genomes from STEC-infected patients with and without HUS between 1994 and 2018 in Sweden were included in this study. Serotypes, Shiga toxin gene (stx) subtypes, and virulence genes were characterized in correlation to clinical symptoms (HUS and non-HUS), and pan-genome wide association study was performed. Sixty-five strains belonged to O157:H7, and 173 belonged to non-O157 serotypes. Our study revealed that strains of O157:H7 serotype especially clade 8 were most commonly found in patients with HUS in Sweden. stx2a and stx2a + stx2c subtypes were significantly associated with HUS. Other virulence factors associated with HUS mainly included intimin (eae) and its receptor (tir), adhesion factors, toxins, and secretion system proteins. Pangenome wide-association study identified numbers of accessory genes significantly overrepresented in HUS-STEC strains, including genes encoding outer membrane proteins, transcriptional regulators, phage-related proteins, and numerous genes related to hypothetical proteins. Whole-genome phylogeny and multiple correspondence analysis of pangenomes could not differentiate HUS-STEC from non-HUS-STEC strains. In O157:H7 cluster, strains from HUS patients clustered closely; however, no significant difference in virulence genes was found in O157 strains from patients with and without HUS. These results suggest that STEC strains from different phylogenetic backgrounds may independently acquire genes determining their pathogenicity and confirm that other non-bacterial factors and/or bacteria-host interaction may affect STEC pathogenesis.