First evidence of enterovirus A71 and echovirus 30 in Uruguay and genetic relationship with strains circulating in the South American region

Human enteroviruses (EVs) comprise more than 100 types of coxsackievirus, echovirus, poliovirus and numbered enteroviruses, which are mainly transmitted by the faecal-oral route leading to diverse diseases such as aseptic meningitis, encephalitis, and acute flaccid paralysis, among others. Since enteroviruses are excreted in faeces, wastewater-based epidemiology approaches are useful to describe EV diversity in a community. In Uruguay, knowledge about enteroviruses is extremely limited. This study assessed the diversity of enteroviruses through Illumina next-generation sequencing of VP1-amplicons obtained by RT-PCR directly applied to viral concentrates of 84 wastewater samples collected in Uruguay during 2011–2012 and 2017–2018. Fifty out of the 84 samples were positive for enteroviruses. There were detected 27 different types belonging to Enterovirus A species (CVA2-A6, A10, A16, EV-A71, A90), Enterovirus B species (CVA9, B1-B5, E1, E6, E11, E14, E21, E30) and Enterovirus C species (CVA1, A13, A19, A22, A24, EV-C99). Enterovirus A71 (EV-A71) and echovirus 30 (E30) strains were studied more in depth through phylogenetic analysis, together with some strains previously detected by us in Argentina. Results unveiled that EV-A71 sub-genogroup C2 circulates in both countries at least since 2011–2012, and that the C1-like emerging variant recently entered in Argentina. We also confirmed the circulation of echovirus 30 genotypes E and F in Argentina, and reported the detection of genotype E in Uruguay. To the best of our knowledge this is the first report of the EV-A71 C1-like emerging variant in South-America, and the first report of EV-A71 and E30 in Uruguay.

Diversity analysis of genes encoding Mfa1 fimbrial components in Porphyromonas gingivalis strains

Porphyromonas gingivalis, a gram-negative anaerobic bacterium, is associated with the development of periodontal disease. The genetic diversity in virulence factors, such as adhesive fimbriae, among its strains affects the bacterial pathogenicity. P. gingivalis generally expresses two distinct types of fimbriae, FimA and Mfa1. Although the genetic diversity of fimA, encoding the major FimA fimbrilin protein, has been characterized, the genes encoding the Mfa1 fimbrial components, including the Mfa1 to Mfa5 proteins, have not been fully studied. We, therefore, analyzed their genotypes in 12 uncharacterized and 62 known strains of P. gingivalis (74 strains in total). The mfa1 genotype was primarily classified into two genotypes, 53 and 70. Additionally, we found that genotype 70 could be further divided into two subtypes (70A and 70B). The diversity of mfa2 to mfa4 was consistent with the mfa1 genotype, although no subtype in genotype 70 was observed. Protein structure modeling showed high homology between the genotypes in Mfa1 to Mfa4. The mfa5 gene was classified into five genotypes (A to E) independent of other genotypes. Moreover, genotype A was further divided into two subtypes (A1 and A2). Surprisingly, some strains had two mfa5 genes, and the 2nd mfa5 exclusively occurred in genotype E. The Mfa5 protein in all genotypes showed a homologous C-terminal half, including the conserved C-terminal domain recognized by the type IX secretion system. Furthermore, the von Willebrand factor domain at the N-terminal was detected only in genotypes A to C. The mfa1 genotypes partially correlated with the ragA and ragB genotypes (located immediately downstream of the mfa gene cluster) but not with the fimA genotypes.

Update of the global distribution of human gammaherpesvirus 8 genotypes

Human gammaherpesvirus 8 (HHV-8) consists of six major clades (A–F) based on the genetic sequence of the open reading frame (ORF)-K1. There are a few conflicting reports regarding the global distribution of the different HHV-8 genotypes. This study aimed to determine the global distribution of the different HHV-8 genotypes based on phylogenetic analysis of the ORF-K1 coding region using sequences published in the GenBank during 1997–2020 and construct a phylogenetic tree using the maximum likelihood algorithm with the GTR + I + G nucleotide substitution model. A total of 550 sequences from 38 countries/origins were analysed in this study. Genotypes A and C had similar global distributions and were prevalent in Africa and Europe. Genotype B was prevalent in Africa. Of the rare genotypes, genotype D was reported in East Asia and Oceania and genotype E in South America, while genotype F was prevalent in Africa. The highest genotypic diversity was reported in the American continent, with Brazil housing five HHV-8 genotypes (A, B, C, E, and F). In this study, we present update of the global distribution of HHV-8 genotypes, providing a basis for future epidemiological and evolutionary studies of HHV-8.

Profiles of mutations in hepatitis B virus surface and polymerase genes isolated from treatment-naïve Nigerians infected with genotype E

Introduction. Hepatitis B virus (HBV) infection is the leading cause of hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). HBV genotype E (HBV/E) is the predominant genotype in West Africa and has been linked epidemiologically with chronic and occult HBV infections as well as development of HCC. Mutations in the surface and polymerase genes of HBV have been associated with occult infection, drug resistance, vaccine escape, as well as HCC. Hypothesis/Gap Statement. There is limited data on the occurrence and patterns of mutations associated with occult infection, drug resistance, vaccine escape and HCC for HBV/E. Aim. This study characterized amino acid (aa) substitutions in the major hydrophilic (MHR) and reverse transcriptase (RT) regions of the surface and polymerase genes respectively of HBV sequences from a group of Nigerians with genotype E infection. The CpG islands of the PreC/C and PreS/S regions of these sequences were also described. Methodology. HBV surface and polymerase genes were detected using PCR techniques. Occurrence of new and previously described mutations in these genes were analysed using phylogenetic techniques. Results. Overall 13 HBV isolates were each sequenced for polymerase and surface genes mutations. Thirteen and nine PreS/S and PreC/C HBV genes respectively were analysed for CpG islands. Mutations in the MHR and a-determinants region of the S protein were discovered in eleven and nine of the 13 tested isolates respectively. These mutations were concomitant with aa changes in the RT functional domains of the isolates. Mutations associated with vaccine escape, occult infection and poor HCC prognosis were identified in HBV/E isolated in this study. Furthermore, all the isolates had at least one putative nucleotide analogue resistance mutations. Drug resistance mutations had the highest association with CpG islands. Conclusion. The results of this study contribute to further understanding of HBV variability in Nigeria and the West African region. This will aid the planning of adequate HBV immunization and treatment programmes for the countries in the region.

Epichloë Fungal Endophyte Symbiosis May Improve Tall Fescue Responses to Flooding and Oxygen-Limited Conditions

Background and aims There is little information about the effect of grass-fungal endophyte symbiota on plant performance under oxygen-limited conditions. This study aimed to investigate the effect of Epichloë endophyte symbiosis and tall fescue genotype on plant responses to oxygen stress in a greenhouse pot experiment.Methods A greenhouse pot experiment was conducted with seven air-filled porosity levels in a sandy loam soil using two genotypes (75C and 75B) of tall fescue (Festuca arundinacea = Schedonorus arundinaceus Schreb.) infected with and without endophytic fungus Epichlöe coenophiala (E+ and E–, respectively). Some selected growth and physiological parameters were determined after nine-month application of the treatments.Results The results showed that E+ plants benefited from endophytic symbiosis and showed slightly higher root and shoot development, more leaf chlorophyll, and lower catalase and ascorbate peroxidase activity than E– plants under poor aeration. The E– plants also coped with poor aeration conditions by forming adventitious roots at the soil surface, aerenchyma formation within the root tissue, and increased alcohol dehydrogenase (ADH) activity.Conclusions The presence of endophyte improved the performance of the genotype E+ 75B under anaerobic conditions, while endophyte had an adverse effect on the performance of the genotype E+ 75C. In general, Epichloë endophyte presence decreased the flooding induced oxidative stress and prevented the formation and over-accumulation of reactive oxygen species in plant cells.

Circulating HBV Genotypes among Animal and Non-Animal Handlers in Osun State, Nigeria

Aim: Hepatitis B virus (HBV) is not uncommon among animal and non-animal handlers. The brutality of HBV infection and the outcome of treatment is linked with exact HBV genotypes. No study on the circulation of HBV genotypes has been reported among animal and non-animal handlers in Nigeria. This study was intended to evaluate the genotypic distribution among animal and non-animal handlers in Osun State, Nigeria. Study Design: Cross-sectional study. Place and Duration of Study: Ladoke Akintola University of Technology (LAUTECH), Nigeria, between June 2015 and July 2019. Methods: Blood samples were obtained from HBsAg positive individuals and screened for HBV-DNA from cohorts of animal and non-animal handlers. HBV-DNA was extracted, amplified and genotyped using a multiplex PCR technique with primers specific for six genotypes of HBV (Genotype A, B, C, D, E and F). Results: Results showed that a total of 11 (6.1%) of the 180 animal and non-animal handlers evaluated were positive to HBsAg and 4.4% were positive for HBV-DNA by a semi-nested PCR using HBV specific primer pairs. The molecular analysis of the sera of 11 HBsAg positive animal and non-animal handlers showed that 72.7% of them had a true HBV infection. Results further show that genotype E (75.0%) was predominant over genotype A (12.5%) and mix genotypes (D and E) with 12.5% prevalence. Other genotypes were not detected. Of the 8 positive HBV-DNA samples, 7 (87.5%) were males and one (12.5%) was a female. All animal and non-animal handlers with true HBV infection were found to harbour HBV genotype E predominantly. Conclusion: The molecular analysis of HBV-DNA and genotypes circulating among animal and non-animal handlers shows that the majority of the subjects with true HBV infection were found to predominantly harbour HBV genotype E in Osun state, Nigeria. The study further highlights the predominance HBV genotype E in Nigeria.

Genetic Diversity Analysis of Coxsackievirus A8 Circulating in China and Worldwide Reveals a Highly Divergent Genotype

Coxsackievirus A8 (CV-A8) is one of the pathogens associated with hand, foot and mouth disease (HFMD) and herpangina (HA), occasionally leading to severe neurological disorders such as acute flaccid paralysis (AFP). Only one study aimed at CV-A8 has been published to date, and only 12 whole-genome sequences are publicly available. In this study, complete genome sequences from 11 CV-A8 strains isolated from HFMD patients in extensive regions from China between 2013 and 2018 were determined, and all sequences from GenBank were retrieved. A phylogenetic analysis based on a total of 34 complete VP1 sequences of CV-A8 revealed five genotypes: A, B, C, D and E. The newly emerging genotype E presented a highly phylogenetic divergence compared with the other genotypes and was composed of the majority of the strains sequenced in this study. Markov chain Monte Carlo (MCMC) analysis revealed that genotype E has been evolving for nearly a century and somehow arose in approximately 2010. The Bayesian skyline plot showed that the population size of CV-A8 has experienced three dynamic fluctuations since 2001. Amino acid residues of VP1100N, 103Y, 240T and 241V, which were embedded in the potential capsid loops of genotype E, might enhance genotype E adaption to the human hosts. The CV-A8 whole genomes displayed significant intra-genotypic genetic diversity in the non-capsid region, and a total of six recombinant lineages were detected. The Chinese viruses from genotype E might have emerged recently from recombining with European CV-A6 strains. CV-A8 is a less important HFMD pathogen, and the capsid gene diversity and non-capsid recombination variety observed in CV-A8 strains indicated that the constant generation of deleterious genomes and a constant selection pressure against these deleterious mutations is still ongoing within CV-A8 quasispecies. It is possible that CV-A8 could become an important pathogen in the HFMD spectrum in the future. Further surveillance of CV-A8 is greatly needed.