Characterization of the dengue outbreak in Nuevo Leon state, Mexico, 2010.

We studied serotypes circulating dengue virus (DENV) cases, entomological Breteau index, rain-fall index and epidemiology of groups affected during the 2010 outbreak in Nuevo Leon, Mexico. From 2,271 positive cases, 94% were dengue classic and 6% dengue hemorrhagic fever; DENV1 was mainly isolated (99%) (Central-American lineage of American-African-genotype). We found correlation between two environmental phenomena (Increment of rainfall and vector-indexes) (p ≤ 0.05) with epidemiological, clinical and risk of DENV-1 ongoing transmission.

A phylogenetic analysis using full-length viral genomes of South American dengue serotype 3 in consecutive Venezuelan outbreaks reveals a novel NS5 mutation.

Dengue virus currently causes 50-100 million infections annually. Comprehensive knowledge about the evolution of Dengue in response to selection pressure is currently unavailable, but would greatly enhance vaccine design efforts. In the current study, we sequenced 187 new dengue virus serotype 3 (DENV-3) genotype III whole genomes isolated from Asia and the Americas. We analyzed them together with previously-sequenced isolates to gain a more detailed understanding of the evolutionary adaptations existing in this prevalent American serotype. In order to analyze the phylogenetic dynamics of DENV-3 during outbreak periods; we incorporated datasets of 48 and 11 sequences spanning two major outbreaks in Venezuela during 2001 and 2007-2008, respectively. Our phylogenetic analysis of newly sequenced viruses shows that subsets of genomes cluster primarily by geographic location, and secondarily by time of virus isolation. DENV-3 genotype III sequences from Asia are significantly divergent from those from the Americas due to their geographical separation and subsequent speciation. We measured amino acid variation for the E protein by calculating the Shannon entropy at each position between Asian and American genomes. We found a cluster of seven amino acid substitutions having high variability within E protein domain III, which has previously been implicated in serotype-specific neutralization escape mutants. No novel mutations were found in the E protein of sequences isolated during either Venezuelan outbreak. Shannon entropy analysis of the NS5 polymerase mature protein revealed that a G374E mutation, in a region that contributes to interferon resistance in other flaviviruses by interfering with JAK-STAT signaling was present in both the Asian and American sequences from the 2007-2008 Venezuelan outbreak, but was absent in the sequences from the 2001 Venezuelan outbreak. In addition to E, several NS5 amino acid changes were unique to the 2007-2008 epidemic in Venezuela and may give additional insight into the adaptive response of DENV-3 at the population level.

Bacterial communities reflect the spatial variation in pollutant levels in Brazilian mangrove sediment.

The majority of oil from oceanic oil spills converges on coastal ecosystems such as mangrove forests. A major challenge to mangrove bioremediation is defining the mangrove's pollution levels and measuring its recuperation from pollution. Bioindicators can provide a welcome tool for defining such recovery. To determine if the microbial profiles reflected variation in the pollutants, samples from different locations within a single mangrove with a history of exposure to oil were chemically characterised, and the microbial populations were evaluated by a comprehensive range of conventional and molecular methods. Multivariate ordination of denaturing gradient gel electrophoresis (DGGE) microbial community fingerprints revealed a pronounced separation between the sediment and rhizosphere samples for all analysed bacterial communities (Bacteria, Betaproteobacteria, Alphaproteobacteria, Actinobacteria and Pseudomonas). A Mantel test revealed significant relationships between the sediment chemical fertility and oil-derived pollutants, most of the bacterial community fingerprints from sediment samples, and the counts by different cultivation strategies. The level of total petroleum hydrocarbons was significantly associated with the Bacteria and Betaproteobacteria fingerprints, whereas anthracene and the total level of polycyclic aromatic hydrocarbons were associated with the Actinobacteria. These results show that microbial communities from the studied mangrove reflect the spatial variation of the chemicals in the sediment, demonstrating the specific influences of oil-derived pollutants.