The influence of risk perception in epidemics: a cellular agent model

Our work stems from the consideration that the spreading of a disease is modulated by the individual's perception of the infected neighborhood and his/her strategy to avoid being infected as well. We introduced a general ``cellular agent'' model that accounts for a hetereogeneous and variable network of connections. The probability of infection is assumed to depend on the perception that an individual has about the spreading of the disease in her local neighborhood and on broadcasting media. In the one-dimensional homogeneous case the model reduces to the DK one, while for long-range coupling the dynamics exhibits large fluctuations that may lead to the complete extinction of the disease

Aspects of the molecular evolution of baculoviruses and flaviviruses

Available from British Library Document Supply Centre-DSC:D192137 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Identification, sequence analysis and phylogeny of the lef-2 gene of Helicoverpa armigera single-nucleocapsid baculovirus

The baculovirus late expression factor 2 (LEF-2) is involved in DNA replication, and most likely function as a primase processivity factor. Lef-2 genes have been found in multinucleocapsid nucleopolyhedroviruses (MNPVs) and in granuloviruses (GVs), but not yet in single-nucleocapsid NPV (SNPV). Here, a lef-2 gene homolog was identified from SNPV of Helicoverpa armigera (HearNPV). the open reading frame of the HearNPV lef-2 gene is 696 nucleotides long, encoding a putative protein of 232 amino acids with an M-r of about 26 kDa. the 5'-noncoding region contains two early (CAGT) consensus motifs for transcription initiation and three TATA boxes. Lef-2 transcripts started at a C, 29 nucleotides upstream of a putative translational start. A putative polyA signal, AATAAA, was found 76 nucleotides downstream of the translation stop codon. the HearNPV lef-2 gene has a low but significant degree of amino acid sequence identity (30%) to the lef-2 genes of 15 other baculoviruses of which nine were newly determined. the N-terminal half of the LEF-2 proteins: contains one (I) and the C-terminal half two (II and III) conserved domains. Sixteen amino acids are absolutely conserved in those LEF-2 investigated and are probably critical for LEF-2 function. A phylogenetic tree of 16 baculovirus LEF-2 proteins was constructed by using maximum parsimony analysis and appeared to be comparable: to a tree for ecdysteroid UDP-glucosyl transferases (Chen et al., 1997a). the genomic location of the lef-2 genes relative to polyhedrin/granulin and the clade structure of the gene trees suggest that genome organization and gene phylogeny are useful parameters to study the evolutionary history of baculoviruses. These two independent approaches also give a more complete picture of the ancestral relationship among baculovirus. (C) 1999 Elsevier Science B.V. All rights reserved.Agr Univ Wageningen, Dept Virol, NL-6709 PD Wageningen, NetherlandsChinese Acad Sci, Wuhan Inst Virol, Joint Lab Invertebrate Virol, Wuhan, Peoples R ChinaUniv Guelph, Dept Microbiol, Guelph, ON N1G 2W1, CanadaUniversidade Federal de São Paulo, Lab Retrovirol & Mol Biol, São Paulo, BrazilKyoto Inst Technol, Dept Appl Biol, Kyoto 606, JapanHebrew Univ Jerusalem, Fac Agr, Dept Entomol, IL-76100 Rehovot, IsraelUniv Calif Davis, Dept Entomol, Davis, CA 95616 USANatl Taiwan Univ, Dept Entomol, Taipei 10764, TaiwanMadurai Kamaraj Univ, Sch Biol Sci, Dept Genet, Madurai 625021, Tamil Nadu, IndiaUniversidade Federal de São Paulo, Lab Retrovirol & Mol Biol, São Paulo, BrazilWeb of Scienc

Molecular evolution of respiratory syncytial virus subgroup A genotype NA1 and ON1 attachment glycoprotein (G) gene in central Vietnam

We performed molecular evolutionary analyses of the G gene C-terminal 3rd hypervariable region of RSV-A genotypes NA1 and ON1 strains from the paediatric acute respiratory infection patients in central Vietnam during the 2010?2012 study period. Time-scaled phylogenetic analyses were performed using Bayesian Markov Chain Monte Carlo (MCMC) method, and pairwise distances (p-distances) were calculated. Bayesian Skyline Plot (BSP) was constructed to analyze the time-trend relative genetic diversity of central Vietnam RSV-A strains. We also estimated the N-glycosylation sites within G gene hypervariable region. Amino acid substitutions under positive and negative selection pressure were examined using Conservative Single Likelihood Ancestor Counting (SLAC), Fixed Effects Likelihood (FEL), Internal Fixed Effects Likelihood (IFEL) and Mixed Effects Model for Episodic Diversifying Selection (MEME) models. The majority of central Vietnam ON1 strains detected in 2012 were classified into lineage 1 with few positively selected substitutions. As for the Vietnamese NA1 strains, four lineages were circulating during the study period with a few positive selection sites. Shifting patterns of the predominantly circulating NA1 lineage were observed in each year during the investigation period. Median p-distance of central Vietnam NA1 strains was wider (p-distance = 0.028) than that of ON1 (p-distance = 0.012). The molecular evolutionary rate of central Vietnam ON1 strains was estimated to be 2.55 × 10? 2 (substitutions/site/year) and was faster than NA1 (7.12 × 10? 3 (substitutions/site/year)). Interestingly, the evolutionary rates of both genotypes ON1 and NA1 strains from central Vietnam were faster than the global strains respectively. Furthermore, the shifts of N-glycosylation pattern within the G gene 3rd hypervariable region of Vietnamese NA1 strains were observed in each year. BSP analysis indicated the rapid growth of RSV-A effective population size in early 2012. These results suggested that the molecular evolution of RSV-A G gene detected in central Vietnam was fast with unique evolutionary dynamics