A Chikungunya (CHIK) outbreak hit La Réunion Island in 2005-2006. The implicated vector was Aedes albopictus. Here, we present the first study on the susceptibility of Ae. albopictus populations to ...sympatric CHIKV isolates from La Réunion Island and compare it to other virus/vector combinations.
We orally infected 8 Ae. albopictus collections from La Réunion and 3 from Mayotte collected in March 2006 with two Chikungunya virus (CHIKV) from La Réunion: (i) strain 05.115 collected in June 2005 with an Alanine at the position 226 of the glycoprotein E1 and (ii) strain 06.21 collected in November 2005 with a substitution A226V. Two other CHIKV isolates and four additional mosquito strains/species were also tested. The viral titer of the infectious blood-meal was 10(7) plaque forming units (pfu)/mL. Dissemination rates were assessed by immunofluorescent staining on head squashes of surviving females 14 days after infection. Rates were at least two times higher with CHIKV 06.21 compared to CHIKV 05.115. In addition, 10 individuals were analyzed every day by quantitative RT-PCR. Viral RNA was quantified on (i) whole females and (ii) midguts and salivary glands of infected females. When comparing profiles, CHIKV 06.21 produced nearly 2 log more viral RNA copies than CHIKV 05.115. Furthermore, females infected with CHIKV 05.115 could be divided in two categories: weakly susceptible or strongly susceptible, comparable to those infected by CHIKV 06.21. Histological analysis detected the presence of CHIKV in salivary glands two days after infection. In addition, Ae. albopictus from La Réunion was as efficient vector as Ae. aegypti and Ae. albopictus from Vietnam when infected with the CHIKV 06.21.
Our findings support the hypothesis that the CHIK outbreak in La Réunion Island was due to a highly competent vector Ae. albopictus which allowed an efficient replication and dissemination of CHIKV 06.21.
A resequencing microarray called PathogenID v2.0 has been developed and used to explore various strategies of sequence selection for its design. The part dedicated to influenza viruses was based on ...consensus sequences specific for one gene generated from global alignments of a large number of influenza virus sequences available in databanks.
For each HA (H1, H2, H3, H5, H7 and H9) and NA (N1, N2 and N7) molecular type chosen to be tested, 1 to 3 consensus sequences were computed and tiled on the microarray. A total of 12 influenza virus samples from different host origins (humans, pigs, horses and birds) and isolated over a period of about 50 years were used in this study. Influenza viruses were correctly identified, and in most cases with the accurate information of the time of their emergence.
PathogenID v2.0 microarray demonstrated its ability to type and subtype influenza viruses, often to the level of viral variants, with a minimum number of tiled sequences. This validated the strategy of using consensus sequences, which do not exist in nature, for our microarray design. The versatility, rapidity and high discriminatory power of the PathogenID v2.0 microarray could prove critical to detect and identify viral genome reassortment events resulting in a novel virus with epidemic or pandemic potential and therefore assist health authorities to make efficient decisions about patient treatment and outbreak management.
High-throughput sequencing furnishes a large number of short sequence reads from uncloned DNA and hasrapidly become a major tool for identifying viruses in biological samples, and in particular when ...the targetsequence is undefined. In this study, we assessed the analytical sensitivity of a pipeline for detection of virusesin biological samples based on either the Roche-454 genome sequencer or Illumina genome analyzer platforms.We sequenced biological samples artificially spiked with a wide range of viruses with genomes composed ofsingle or double-stranded DNA or RNA, including linear or circular single-stranded DNA. Viruses were addedat a very low concentration most often corresponding to 3 or 0.8 times the validated level of detection ofquantitative reverse transcriptase PCRs (RT-PCRs). For the viruses represented, or resembling those represented,in public nucleotide sequence databases, we show that the higher output of Illumina is associated witha much greater sensitivity, approaching that of optimized quantitative (RT-)PCRs. In this blind study,identification of viruses was achieved without incorrect identification. Nevertheless, at these low concentrations,the number of reads generated by the Illumina platform was too small to facilitate assembly of contigswithout the use of a reference sequence, thus precluding detection of unknown viruses. When the virus load wassufficiently high, de novo assembly permitted the generation of long contigs corresponding to nearly full-lengthgenomes and thus should facilitate the identification of novel viruses.
La situation épidémiologique du cheptel porcin français est appréhendée au travers d’études sérologiques ainsi que de recherches virales. À la fin des années 1970, le profil sérologique des élevages ...est dominé par la présence d’anticorps A/H3N2 correspondant à des épidémies de grippe humaine. Par la suite, des vagues épizootiques ont déferlé. La maladie se présente désormais sous une forme enzootique et épizootique. Depuis le début des années 2000, la grippe du porc en France concerne avant tout les élevages de Bretagne, où la densité porcine est la plus élevée. Elle a un impact économique considérable dans les élevages de cette région. L’activité grippale est le fait de virus A/H1 d’origine aviaire (A/H1N1) ou de réassortants (A/H1N2). L’instabilité des virus grippaux suppose d’adapter régulièrement les outils de détection afin de permettre une épidémiosurveillance efficace.
Serological and virus identification studies have been carried out in France to assess the epidemiological situation of the swine population. At the end of the 70’s, the serological profile in pig farms was dominated by the presence of A/H3N2 antibodies, associated with epidemics of human influenza. Since then, epizootic outbreaks have succeeded one another in the pig. The disease is now both enzootic and epizootic. Since the early 2000s, swine influenza in France occurs mainly in Brittany, where pig density is the highest. Its economic impact is considerable in pig farms of that area. The disease is caused by the influenza A/H1 virus of avian origin (A/H1N1) or by reassortants (A/H1N2). As influenza viruses are unstable, detection tools need permanent updating to guarantee an effective epidemiological surveillance.
Evaluation of high-throughput sequencing for identifying knwon and unknown viruses in biological samples Cheval , Justine (Institut Pasteur, Paris(France). Genotyping of pathogens and public health platform); Sauvage , Virginie (Institut Pasteur, Paris(France). Laboratory for Urgent responses to biological threats); Frangeul , Lionel (Institut Pasteur, Paris(France). Plateforme intégration et analyse génomique) ...
2011
Publication
Brettanomyces bruxellensis is considered as a spoilage yeast encountered mainly in red wine. It is able to reduce vinylphenols from phenolic acids to ethylphenols. These volatiles are responsible for ...the phenolic “Brett character” described as animal, farm, horse sweat and animal leather odors. Other molecules are responsible for organoleptic deviations described as “mousiness taint”. SO2 is the product most often used by winemakers to prevent B. bruxellensis growth. Usually, the recommended molecular dose of SO2 (active SO2, mSO2) is highly variable, from 0.3 to 0.8mg/L. But these doses do not take into account differences of strain resistance to sulfites or population levels. Moreover, SO2 is known as a chemical stressor inducing a viable but nonculturable (VBNC) state of B. bruxellensis. These cells, which are non-detectable by plate counting, can lead to new contamination when the amount of sulfite decreases over time. Consequently, we first assessed the effect of SO2 levels in red wine on two strains with phenotypically different sulfite resistances. Then, we studied the relationship between amounts of SO2 (0, 0.5, 0.9 and 1.1mg/L active SO2) and population levels (103, 104 and 105cells/mL) in red wine. Yeasts were enumerated by both plate counting and flow cytometry over time using viability dye. Our results showed different SO2 resistances according to the strain used. A relationship between yeast population level and SO2 resistance was demonstrated: the higher the yeast concentration, the lower the efficiency of SO2. Under certain conditions, the VBNC state of B. bruxellensis was highlighted in red wine. Yeasts in this VBNC state did not produce 4-EP. Moreover, cells became culturable again over time. All these results provide new information enabling better management of sulfite addition during wine aging.
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•mSO2 efficiency depends on the population level of B. bruxellensis.•Sulfite impacts on cell wall permeability in B. bruxellensis.•We confirm the VBNC state of B. bruxellensis due to SO2.•Growth recovery could be observed in VBNC cells in red wine.•4-EP is not produced when yeasts are in VBNC state.
The capacity for five Brettanomyces bruxellensis strains to form biofilm on stainless steel was confirmed, and the sanitation of these biofilms was tested using a solution of lactic acid and a ...reference method (a solution of foaming caustic soda and peroxide at 5 %). Different responses were observed depending on the strain: lactic acid solution induced a slight reduction in cell population, while the reference method resulted in the elimination of the adhered cells for three strains, but generated VBNC states for two others. The effects of sanitation on the biofilm formed is strain-dependent.
The capacity for five Brettanomyces bruxellensis strains to form biofilm on stainless steel was confirmed, and the sanitation of these biofilms was tested using a solution of lactic acid and a ...reference method (a solution of foaming caustic soda and peroxide at 5 %). Different responses were observed depending on the strain: lactic acid solution induced a slight reduction in cell population, while the reference method resulted in the elimination of the adhered cells for three strains, but generated VBNC states for two others. The effects of sanitation on the biofilm formed is strain-dependent.
In Western societies, self-rated health (SRH) inequalities have increased over the past decades. Longitudinal studies suggest that the SRH trajectories of disadvantaged populations are declining at a ...faster rate than those of advantaged populations, resulting in an accumulation of (dis)advantages over the life course, as postulated by the Cumulative Advantage/Disadvantage (CAD) model. The objectives of this study are to conduct a systematic review of the factors influencing SRH trajectories in the adult population and to assess to what extent the findings support the CAD model. Based on the inclusion criteria, 36 articles, using 15 nationally representative databases, were reviewed. The results show that young age, high socioeconomic position and marital transitions (entering a partnership) are advantageous factors of change in SRH trajectories. However, evidence for cumulative influences supporting the CAD model remains limited: gender, ethnicity, education and employment status are only moderately associated with growing influences over time, and the cumulative influences of income, occupation, age and marital status are weak. In conclusion, this systematic review provides consolidated evidence on the factors influencing SRH trajectories, though the inclusion of only 15 nationally representative databases may limit the generalization of the results.
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