A novel hepatitis B virus subgenotype D10 circulating in Ethiopia.

Hepatitis B virus (HBV) is genetically highly divergent and classified in ten genotypes and forty subgenotypes in distinct ethno-geographic populations worldwide. Ethiopia is a country with high HBV prevalence; however, little is known about the genetic variability of HBV strains that circulate. Here, we characterize the complete genome of 29 HBV strains originating from five Ethiopian regions, by 454 deep sequencing and Sanger sequencing. Phylogenetically, ten strains were classified as genotype A1 and nineteen as genotype D. Fifteen genotype D strains, provisionally named subgenotype D10, showed a novel distinct cluster supported by high bootstrap value and >4% nucleotide divergence from other known subgenotypes. In addition, the novel D10 strains harboured nine unique amino acid signatures in the surface, polymerase and X genes. Seventy-two per cent of the genotype D strains had the precore premature stop codon G1896A. In addition, 63% genotype A and 33% genotype D strains had the basal core promoter mutations, A1762T/G1764A. Furthermore, four pre-S deletion variants and two recombinants were identified in this study. In conclusion, we identified a novel HBV subgenotype D10 circulating in Ethiopia, underlining the high genetic variability of HBV strains in Africa.

Antiviral Activity of Favipiravir (T-705) against a Broad Range of Paramyxoviruses In Vitro and against Human Metapneumovirus in Hamsters.

The clinical impact of infections with respiratory viruses belonging to the family Paramyxoviridae argues for the development of antiviral therapies with broad-spectrum activity. Favipiravir (T-705) has demonstrated potent antiviral activity against multiple RNA virus families and is presently in clinical evaluation for the treatment of influenza. Here we demonstrate in vitro activity of T-705 against the paramyxoviruses human metapneumovirus (HMPV), respiratory syncytial virus, human parainfluenza virus, measles virus, Newcastle disease virus, and avian metapneumovirus. In addition, we demonstrate activity against HMPV in hamsters. T-705 treatment inhibited replication of all paramyxoviruses tested in vitro, with 90% effective concentration (EC90) values of 8 to 40 µM. Treatment of HMPV-challenged hamsters with T-705 at 200 mg/kg of body weight/day resulted in 100% protection from infection of the lungs. In all treated and challenged animals, viral RNA remained detectable in the respiratory tract. The observation that T-705 treatment had a significant effect on infectious viral titers, with a limited effect on viral genome titers, is in agreement with its proposed mode of action of viral mutagenesis. However, next-generation sequencing of viral genomes isolated from treated and challenged hamsters did not reveal (hyper)mutation. Polymerase activity assays revealed a specific effect of T-705 on the activity of the HMPV polymerase. With the reported antiviral activity of T-705 against a broad range of RNA virus families, this small molecule is a promising broad-range antiviral drug candidate for limiting the viral burden of paramyxoviruses and for evaluation for treatment of infections with (re)emerging viruses, such as the henipaviruses.

The sample of choice for detecting Middle East respiratory syndrome coronavirus in asymptomatic dromedary camels using real-time reversetranscription polymerase chain reaction.

The newly identified Middle East respiratory syndrome coronavirus (MERS-CoV), which causes severe respiratory disease, particularly in people with comorbidities, requires further investigation. Studies in Qatar and elsewhere have provided evidence that dromedary camels are a reservoir for the virus, but the exact modes of transmission of MERS-CoV to humans remain unclear. In February 2014, an assessment was made of the suitability and sensitivity of different types of sample for the detection of MERSCoV by real-time reverse-transcription polymerase chain reaction (RT-PCR) for three gene targets: UpE (upstream of the E gene), the N (nucleocapsid) gene and open reading frame (ORF) 1a. Fifty-three animals presented for slaughter were sampled. A high percentage of the sampled camels (79% [95% confidence interval 66.9-91.5%, standard error 0.0625]; 42 out of 53) were shown to be shedding MERS-CoV at the time of slaughter, yet all the animals were apparently healthy. Among the virus-positive animals, nasal swabs were most often positive (97.6%). Oral swabs were the second most frequently positive (35.7%), followed by rectal swabs (28.5%). In addition, the highest viral load, expressed as a cycle threshold (Ct) value of 11.27, was obtained from a nasal swab. These findings lead to the conclusion that nasal swabs are the candidate sample of choice for detecting MERS-CoV using RT-PCR technology in apparently healthy camels.

Des travaux de recherche approfondis sont encore nécessaires concernant le coronavirus responsable du syndrome respiratoire du Moyen-Orient (MERSCoV), un virus identifié récemment et qui provoque des troubles respiratoires sévères en particulier chez les individus atteints de pathologies multiples. Les études effectuées au Qatar et ailleurs ont démontré que les dromadaires font office de réservoirs du virus ; toutefois, les modalités précises de la transmission du MERS-CoV à l'être humain demeurent obscures. En février 2014, une équipe de chercheurs a évalué l'adéquation et la sensibilité de plusieurs types d'échantillons pour détecter le MERS-CoV en utilisant l'amplification en chaîne par polymérase couplée à une transcription inverse en temps réel (RT-PCR) spécifique pour trois cibles génétiques, à savoir la séquence UpE (en amont du gène E), le gène N (nucléocapside) et le cadre de lecture ORF1a. Pour ce faire, divers prélèvements ont été effectués sur 53 dromadaires destinés à l'abattage. Un fort pourcentage de ces dromadaires (79 % [intervalle de confiance à 95 % compris entre 66,9 et 91,5 %, erreur standard : 0,0625], soit 42 sur 53) excrétaient le MERSCoV au moment de l'abattage, mais aucun ne présentait le moindre signe clinique. Les échantillons dans lesquels le plus de cas positifs ont été détectés étaient les écouvillons nasaux (97,6 %). Venaient ensuite les écouvillons oraux, qui ont détecté 35,7 % de cas positifs, puis les écouvillons rectaux (28,5 % de cas positifs détectés). Par ailleurs, ce sont les écouvillons nasaux qui ont permis d'obtenir l'intensité la plus élevée de la réponse de la RT-PCR, exprimée en une valeur du seuil de cycles de 11,27. Ces résultats permettent de conclure que les écouvillons nasaux sont les échantillons à privilégier pour la détection du MERS-CoV par RTPCR chez les dromadaires asymptomatiques.

Es preciso investigar más a fondo el coronavirus del síndrome respiratorio de Oriente Medio (MERS-CoV), recién identificado, que provoca una grave enfermedad respiratoria, sobre todo en personas con afecciones concomitantes. Estudios realizados en Qatar y otros lugares han deparado pruebas de que los dromedarios son un reservorio del virus, pero aún no están del todo claros los modelos exactos de transmisión del MERS-CoV al ser humano. Los autores describen un análisis realizado en febrero de 2014 de la idoneidad y sensibilidad de distintos tipos de muestra para detectar el MERS-CoV mediante una reacción en cadena de la polimerasa acoplada a transcripción inversa en tiempo real (RTPCR) dirigida contra tres genes: el gen UpE (upstream of the E gene: en dirección 5' desde el gen E); el gen N (nucleocápside) y el marco de lectura abierto (ORF) 1a. Para ello se tomaron muestras de 53 animales enviados al sacrificio. Se comprobó que un elevado porcentaje de los dromedarios analizados (un 79% [intervalo de confianza al 95%: 66,9­91,5%; error estándar: 0,0625], esto es, 42 de 53) excretaban virus en el momento del sacrificio, pese a que todos los animales parecían estar sanos. Entre los ejemplares positivos para el MERS-CoV, las muestras que con más frecuencia arrojaban resultado positivo eran los frotis nasales (97,6%). Las segundas, por orden de frecuencia, eran los frotis bucales (35,7%), seguidos de los frotis rectales (28,5%). Además, la carga viral más alta, expresada por un valor de ciclo umbral (Ct) (o punto de cruce) de 11,27, se obtuvo a partir de un frotis nasal. Estos resultados llevan a la conclusión de que los frotis nasales son el tipo de muestra más adaptado para detectar el MERS-CoV en dromedarios aparentemente sanos mediante la técnica de RT-PCR.

Detection of novel divergent arenaviruses in boid snakes with inclusion body disease in The Netherlands.

Arenaviruses are bi-segmented negative-stranded RNA viruses, which were until recently only detected in rodents and humans. Now highly divergent arenaviruses have been identified in boid snakes with inclusion body disease (IBD). Here, we describe the identification of a new species and variants of the highly divergent arenaviruses, which were detected in tissues of captive boid snakes with IBD in The Netherlands by next-generation sequencing. Phylogenetic analysis of the complete sequence of the open reading frames of the four predicted proteins of one of the detected viruses revealed that this virus was most closely related to the recently identified Golden Gate virus, while considerable sequence differences were observed between the highly divergent arenaviruses detected in this study. These findings add to the recent identification of the highly divergent arenaviruses in boid snakes with IBD in the United States and indicate that these viruses also circulate among boid snakes in Europe.

Human bocavirus infection as a cause of severe acute respiratory tract infection in children.

In 2005 human bocavirus (HBoV) was discovered in respiratory tract samples of children. The role of HBoV as the single causative agent for respiratory tract infections remains unclear. Detection of HBoV in children with respiratory disease is frequently in combination with other viruses or bacteria. We set up an algorithm to study whether HBoV alone can cause severe acute respiratory tract infection (SARI) in children. The algorithm was developed to exclude cases with no other likely cause than HBoV for the need for admission to the paediatric intensive care unit (PICU) with SARI. We searched for other viruses by next-generation sequencing (NGS) in these cases and studied their HBoV viral loads. To benchmark our algorithm, the same was applied to respiratory syncytial virus (RSV)-positive patients. From our total group of 990 patients who tested positive for a respiratory virus by means of RT-PCR, HBoV and RSV were detected in 178 and 366 children admitted to our hospital. Forty-nine HBoV-positive patients and 72 RSV-positive patients were admitted to the PICU. We found seven single HBoV-infected cases with SARI admitted to PICU (7/49, 14%). They had no other detectable virus by NGS. They had much higher HBoV loads than other patients positive for HBoV. We identified 14 RSV-infected SARI patients with a single RSV infection (14/72, 19%). We conclude that our study provides strong support that HBoV can cause SARI in children in the absence of viral and bacterial co-infections.

Identification and characterization of a novel adenovirus in the cloacal bursa of gulls.

Several viruses of the family of Adenoviridae are associated with disease in birds. Here we report the detection of a novel adenovirus in the cloacal bursa of herring gulls (Larus argentatus) and lesser black-backed gulls (Larus fuscus) that were found dead in the Netherlands in 2001. Histopathological analysis of the cloacal bursa revealed cytomegaly and karyomegaly with basophilic intranuclear inclusions typical for adenovirus infection. The presence of an adenovirus was confirmed by electron microscopy. By random PCR in combination with deep sequencing, sequences were detected that had the best hit with known adenoviruses. Phylogenetic analysis of complete coding sequences of the hexon, penton and polymerase genes indicates that this novel virus, tentatively named Gull adenovirus, belongs to the genus Aviadenovirus. The present study demonstrates that birds of the Laridae family are infected by family-specific adenoviruses that differ from known adenoviruses in other bird species.

Discontinuous and non-discontinuous subgenomic RNA transcription in a nidovirus.

Arteri-, corona-, toro- and roniviruses are evolutionarily related positive-strand RNA viruses, united in the order Nidovirales. The best studied nidoviruses, the corona- and arteriviruses, employ a unique transcription mechanism, which involves discontinuous RNA synthesis, a process resembling similarity-assisted copy-choice RNA recombination. During infection, multiple subgenomic (sg) mRNAs are transcribed from a mirror set of sg negative-strand RNA templates. The sg mRNAs all possess a short 5' common leader sequence, derived from the 5' end of the genomic RNA. The joining of the non-contiguous 'leader' and 'body' sequences presumably occurs during minus-strand synthesis. To study whether toroviruses use a similar transcription mechanism, we characterized the 5' termini of the genome and the four sg mRNAs of Berne virus (BEV). We show that BEV mRNAs 3-5 lack a leader sequence. Surprisingly, however, RNA 2 does contain a leader, identical to the 5'-terminal 18 residues of the genome. Apparently, BEV combines discontinuous and non-discontinuous RNA synthesis to produce its sg mRNAs. Our findings have important implications for the understanding of the mechanism and evolution of nidovirus transcription.

Phylogenetic and evolutionary relationships among torovirus field variants: evidence for multiple intertypic recombination events.

Toroviruses (family Coronaviridae, order Nidovirales) are enveloped, positive-stranded RNA viruses that have been implicated in enteric disease in cattle and possibly in humans. Despite their potential veterinary and clinical relevance, little is known about torovirus epidemiology and molecular genetics. Here, we present the first study into the diversity among toroviruses currently present in European swine and cattle herds. Comparative sequence analysis was performed focusing on the genes for the structural proteins S, M, HE, and N, with fecal specimens serving as sources of viral RNA. Sequence data published for animal and human torovirus variants were included. Four genotypes, displaying 30 to 40% divergence, were readily distinguished, exemplified by bovine torovirus (BToV) Breda, porcine torovirus (PToV) Markelo, equine torovirus Berne, and the putative human torovirus. The ungulate toroviruses apparently display host species preference. In phylogenetic analyses, all PToV variants clustered, while the recent European BToVs mostly resembled the New World BToV variant Breda, identified 19 years ago. However, we found ample evidence for recurring intertypic recombination. All newly characterized BToV variants seem to have arisen from a genetic exchange, during which the 3' end of the HE gene, the N gene, and the 3' nontranslated region of a Breda virus-like parent had been swapped for those of PToV. Moreover, some PToV and BToV variants carried chimeric HE genes, which apparently resulted from recombination events involving hitherto unknown toroviruses. From these observations, the existence of two additional torovirus genotypes can be inferred. Toroviruses may be even more promiscuous than their closest relatives, the coronaviruses and arteriviruses.